National Park Service 

U.S. Department of the Interior 

Natural Resource Program Center 

Assessment of natural resource conditions 

in and adjacent to Acadia National Park, Maine 

Natural Resource Report NPS/NRPC/WRD/NRR—2008/069

 
ON THE COVER 

Clockwise, from top left: Maple Spring Bridge, view from Sargent Mountain, ferns near Sieur de Monts Spring, water striders on 

Hadlock Brook, Cañon Brook near Murray Young trail, sunrise from Schoodic Point in winter, Jesup Path in autumn, Cañon 

Brook in winter. Center: trail signpost near Cadillac Mountain. 

All photos: Sarah Nelson or Ken Johnson. 
Assessment of natural resource conditions 

in and adjacent to Acadia National Park 

Natural Resource Report NPS/NRPC/WRD/NRR—2008/069

Peter D. Vaux (1)

Sarah J. Nelson (1)

Nishi Rajakaruna (2)

Glen Mittelhauser (3)

Kathleen Bell (4)

Blaine Kopp (5)

John Peckenham (1)

Gordon Longsworth (2)

(1) Senator George J. Mitchell Center for Environmental and Watershed Research 

 University of Maine, Orono, Maine 04469 

(2) College of the Atlantic, Bar Harbor, Maine 04609 

(3) Maine Natural History Observatory, Gouldsboro, Maine 04607 

(4) Dept. of Resource Economics and Policy, University of Maine, Orono, Maine 04469 

(5) 48 Winthrop St., Hallowell, ME 04347 

This report was prepared under Task Order J4506060620 of the North Atlantic Coast Cooperative 

Ecosystem Studies Unit (Cooperative Agreement between the National Park Service and University of 

Maine, 1443CA4520-99-007, amendment #2) 

November 2008 

U.S. Department of the Interior 

National Park Service 

Natural Resource Program Center 

Fort Collins, Colorado 
ii 

The Natural Resource Publication series addresses natural resource topics that are of interest and 

applicability to a broad readership in the National Park Service and to others in the management 

of natural resources, including the scientific community, the public, and the NPS conservation 

and environmental constituencies. Manuscripts are peer-reviewed to ensure that the information 

is scientifically credible, technically accurate, appropriately written for the intended audience, 

and is designed and published in a professional manner. 

Natural Resource Reports are the designated medium for disseminating high priority, current 

natural resource management information with managerial application. The series targets a 

general, diverse audience, and may contain NPS policy considerations or address sensitive issues

of management applicability. Examples of the diverse array of reports published in this series

include vital signs monitoring plans; monitoring protocols; "how to" resource management

papers; proceedings of resource management workshops or conferences; annual reports of

resource programs or divisions of the Natural Resource Program Center; resource action plans;

fact sheets; and regularly-published newsletters. 

Views, statements, findings, conclusions, recommendations and data in this report are solely 

those of the author(s) and do not necessarily reflect views and policies of the U.S. Department of 

the Interior, NPS. Mention of trade names or commercial products does not constitute 

endorsement or recommendation for use by the National Park Service. 

Printed copies of reports in these series may be produced in a limited quantity and they are only 

available as long as the supply lasts. This report is also available from the Water Resources 

Division of the National Park Service website (http://www.nature.nps.gov/water/wrdpub.cfm) or 

http://www.nature.nps.gov/publications/NRPM/ on the internet, or by sending a request to the 

address on the back cover. 

Please cite this publication as: 

Vaux, P. D., S. J. Nelson, N. Rajakaruna, G. Mittelhauser, K. Bell, B. Kopp, J. Peckenham, and G. 

Longsworth. 2008. Assessment of natural resource conditions in and adjacent to Acadia National 

Park, Maine. Natural Resource Report NPS/NRPC/WRD/NRR—2008/069. National Park 

Service, Fort Collins, Colorado. 

NPS D-344, November 2008
iii 

Contents 

Figures.......................................................................................................................................... viii

Tables ............................................................................................................................................ xii

Acronyms and Abbreviations ........................................................................................................ xiii

Executive Summary...................................................................................................................... xv

Acknowledgements.....................................................................................................................xviii

Introduction ..................................................................................................................................... 1

Park Description.............................................................................................................................. 3

Size and Location of Park Lands and Conservation Easements ..................................................... 3

Location and Extent of the Upland, Freshwater, Wetland and Marine/Coastal Systems ............... 6

Legislative Background and Management Objectives ................................................................... 9

Human Utilization of Park Resources ............................................................................................. 9

Terrestrial, Freshwater and Coastal/Marine Resources ................................................................ 17

Terrestrial Systems........................................................................................................................ 17

Physico-Chemical Environment of Terrestrial Systems ................................................... 17

Biological Resources of Terrestrial Systems .................................................................... 19

Freshwater Systems (Lakes, Streams, Riparian Systems, Wetlands and Groundwater) .............. 33

Physico-Chemical Environment of Freshwater Systems .................................................. 33

Biological Resources of Freshwater Systems ................................................................... 47

Marine / Coastal Systems .............................................................................................................. 56

Physico-Chemical Environment of Marine / Coastal Systems ......................................... 56

Biological Resources of Marine / Coastal Systems .......................................................... 59

Assessment of Threats .................................................................................................................. 64
iv 

Introduction ................................................................................................................................... 64

Ultraviolet Radiation ..................................................................................................................... 65

Visibility Impairments .................................................................................................................. 67

Ozone ............................................................................................................................................ 67

Atmospheric Ozone Levels ............................................................................................... 67

Ozone Impacts on Terrestrial Vegetation ......................................................................... 70

Atmospheric Deposition (Acidity and Related Chemistry) .......................................................... 71

Atmosphere: Deposition Chemistry .................................................................................. 72

Impacts of Atmospheric Acidity on Terrestrial Systems .................................................. 76

Impacts of Atmospheric Nitrogen on Terrestrial Vegetation ........................................... 76

Impacts of Atmospheric Deposition on Freshwater Systems ........................................... 79

Atmospheric Nitrogen Deposition to Coastal and Marine Systems ................................. 83

Mercury ......................................................................................................................................... 84

Atmospheric Sources ........................................................................................................ 84

Mercury in Terrestrial Systems ......................................................................................... 86

Mercury in Freshwater Systems (Abiotic Components) ................................................... 87

Mercury in Terrestrial and Freshwater Biota .................................................................... 89

Mercury in Marine Systems .............................................................................................. 92

Nutrient Enrichment ...................................................................................................................... 95

Nutrient Enrichment: Terrestrial Systems ........................................................................ 95

Nutrient Enrichment: Lakes and Streams ......................................................................... 95

Nutrient Enrichment: Wetlands and Estuaries .................................................................. 98

Nutrient Enrichment: Other Coastal and Marine Areas .................................................. 103

Microbial Contamination ............................................................................................................ 105

Bacterial contamination of beaches ................................................................................ 105
v 

Shellfish closures ............................................................................................................ 106

Other Contaminants .................................................................................................................... 108

Air Pathway .................................................................................................................... 108

Freshwater Pathway ........................................................................................................ 108

Saltwater Pathway ........................................................................................................... 109

Groundwater Pathway ..................................................................................................... 110

Additional Contaminant Data ......................................................................................... 110

Fire .............................................................................................................................................. 112

Impacts of Fire on Terrestrial Systems ........................................................................... 112

Altered Hydrology ...................................................................................................................... 114

Lake Water Levels .......................................................................................................... 114

Stream Discharge ............................................................................................................ 114

Wetland Hydrology ......................................................................................................... 116

Groundwater Levels ........................................................................................................ 116

Impacts of Hydrologic Changes on Rare Plant Species.................................................. 117

Habitat Loss and Impairment ...................................................................................................... 117

Stream Barriers ............................................................................................................... 117

Beaver Impacts on Wetlands .......................................................................................... 118

Terrestrial Habitat Loss and Fragmentation ................................................................... 119

Impacts from Shellfish Harvesting and Boat Moorings on Eelgrass Beds ..................... 119

Visitor Use and Habitat Disturbance .......................................................................................... 120

Visitor Impacts on Terrestrial Habitat ............................................................................ 120

Visitor Impacts on Birds ................................................................................................. 121

Visitor Impacts on Freshwater Systems .......................................................................... 121

Visitor Impacts on Intertidal Areas ................................................................................. 122
vi 

Herbivory and Predation ............................................................................................................. 123

Herbivore Impacts on Vegetation ................................................................................... 123

Predation Effects on Mammal Populations ..................................................................... 124

Harvest / Hunting / Take ............................................................................................................. 124

Exotic Species ............................................................................................................................. 125

Terrestrial Exotic Plants .................................................................................................. 125

Freshwater Exotic Plants................................................................................................. 128

Exotic Birds .................................................................................................................... 129

Exotic Fish ...................................................................................................................... 129

Exotic Terrestrial Invertebrates ....................................................................................... 130

Invasive Marine Species ................................................................................................. 131

Pests and Pathogens .................................................................................................................... 132

Pests and Pathogens of Terrestrial Vegetation ................................................................ 132

Pests and Pathogens of Wetland Fauna .......................................................................... 133

Pests and Pathogens of Birds .......................................................................................... 134

Giardia and Beaver Populations ...................................................................................... 134

Climate Change ........................................................................................................................... 134

Light Pollution ............................................................................................................................ 136

Multiple Stressors ....................................................................................................................... 137

Threat Asssessments: A Summary.............................................................................................. 137

Assessment of Condition ............................................................................................................ 141

Introduction ................................................................................................................................. 141

Condition summaries by resource group .................................................................................... 142

Air Quality ...................................................................................................................... 144

Terrestrial Resources ...................................................................................................... 146
vii 

Streams ............................................................................................................................ 150

Lakes and Ponds ............................................................................................................. 153

Wetlands (Freshwater and Saltwater) ............................................................................. 156

Groundwater ................................................................................................................... 158

Marine Intertidal ............................................................................................................. 159

Climate - Related ............................................................................................................ 161

Conclusions and Information Needs ........................................................................................... 162

Biological resource inventories ................................................................................................... 162

Threat and Condition Assessments: Information Needs ............................................................. 164

Literature Cited ........................................................................................................................... 168

Appendices .................................................................................................................................. 190
viii 

Figures 

Figure 1. Locator map of Acadia National Park. ............................................................................ 3

Figure 2. Acadia National Park lands, acquisition parcels, conservation easements, and other 

conservation lands in the vicinity of the Park. ................................................................................ 4

Figure 3. Named features in ACAD and surrounding areas. .......................................................... 5

Figure 4. Aggregations of watersheds on MDI. .............................................................................. 8

Figure 5. Landcover/use statistics by watershed cluster. ............................................................. 12

Figure 6. Anthropogenic land-use in watersheds of MDI. ............................................................ 13

Figure 7. Visitation at ACAD. ...................................................................................................... 13

Figure 8. Hiking trail use, number of hikers per day. ................................................................... 14

Figure 9. Water supply watersheds, dams, and wells on MDI. .................................................... 16

Figure 10. Annual precipitation measured at the McFarland Hill NADP site, 1982-2006. ......... 18

Figure 11. Distribution of hydric and erodible soils in the ACAD region. .................................. 18

Figure 12. Soil pH at ACAD and vicinity. .................................................................................... 19

Figure 13. Vegetation and land-use in the ACAD region (from Lubinski et al. 2003). ............... 22

Figure 14. Fire history, prescribed burns and fire risk at ACAD. ................................................ 23

Figure 15. Minimum known percent of streams (n = 37) occupied by northern dusky salamanders 

in ACAD, 1938–2003. .................................................................................................................. 33

Figure 16. Watersheds and hydrography of ACAD and vicinity .................................................. 34

Figure 17. Lakes and ponds in the ACAD region: area-depth relationships. ............................... 35

Figure 18. Air and surface water monitoring sites. ....................................................................... 36

Figure 19. Water quality of ACAD lakes compared to the population of all surveyed lakes in 

Maine ............................................................................................................................................ 38

Figure 20. Mean pH in ACAD lakes and ponds. .......................................................................... 39

Figure 21. Trends in water transparency at Jordan Pond, 1980-2006, by month. ........................ 41

Figure 22. Distribution of specific conductance, pH, dissolved oxygen, and nitrogen species in 

streams on MDI............................................................................................................................. 43
ix 

Figure 23. Acid-neutralizing capacity (ANC) in MDI streams .................................................... 44

Figure 24. Bedrock well depths and yields. .................................................................................. 47

Figure 25. Relationship between number of aquatic macrophyte species (per lake) and (A) lake 

area, (B) alkalinity in ACAD and other Maine lakes.................................................................... 48

Figure 26. Loon populations on Maine and ACAD lakes. ........................................................... 50

Figure 27. Location and status of beaver dams on MDI. .............................................................. 51

Figure 28. Fish species richness of ACAD area lakes and ponds ................................................. 54

Figure 29. Fish species richness in ACAD area lakes compared to all surveyed lakes in southern 

Maine ............................................................................................................................................ 54

Figure 30. Sediment characterization in Penobscot to Frenchman Bay region of Maine ............. 58

Figure 31. Circulation patterns in the Gulf of Maine .................................................................... 58

Figure 32. (A) Occurrence of eelgrass in the Acadia region. (B) Changes in eelgrass distribution 

in the Sears Island area between 1992 and 2004 .......................................................................... 60

Figure 33. Historical spawning areas of cod and haddock in Maine territorial waters. ............... 62

Figure 34. Density of Atlantic herring and American lobster in fall benthic trawl surveys. ........ 62

Figure 35. Mean dose of UV-B radiation at six national parks .................................................... 66

Figure 36. Visibility at ACAD. ..................................................................................................... 68

Figure 37. Precipitation chemistry at the McFarland Hill NADP site, 1981-2006. ..................... 72

Figure 38. 2006 sulfate concentrations in wet deposition............................................................. 73

Figure 39. Modeled total atmospheric deposition of S and N to MDI for the year 2000. ............ 74

Figure 40. Sulfate (shaded bars) and nitrate (open bars) concentrations of acidic cloud/fog events 

in Bar Harbor compared with other sites. ..................................................................................... 75

Figure 41. Forested areas of Maine that are sensitive to the negative effects of combined 

atmospheric sulfur and nitrogen deposition .................................................................................. 78

Figure 42. Spring and fall stream sulfate concentrations measured in the 1980s and 2000s ....... 80

Figure 43. Nutrient export rates for MDI watersheds inside and partially or completely outside 

ACAD. .......................................................................................................................................... 82
x 

Figure 44. Winter (a) and growing season (b) mercury (Hg) deposition measured in throughfall 

in ACAD ....................................................................................................................................... 85

Figure 45. Wet-only and total mercury deposition in eastern North America .............................. 86

Figure 46. Hg deposition stratified by site aspect for the period May-November 2000, at Cadillac 

and Hadlock watersheds study sites. ............................................................................................. 87

Figure 47. Summary of Hg concentrations in environmental media from established research 

sites in upland, forested sites at Acadia National Park and Bear Brook ....................................... 88

Figure 48. Mercury in streams and wetlands extent in watersheds .............................................. 90

Figure 49. Average concentrations of total mercury (ng/g wet wt.) in two-lined salamanders 

(Eurycea bislineata bislineata) larvae, June-July 2001-2002 ....................................................... 91

Figure 50. Mean (SE) concentrations of total-Hg in tree swallow carcasses at three ACAD lakes 

compared to another Maine site and Massachusetts superfund sites, 1997-1999 ......................... 91

Figure 51. Mercury (A) and arsenic (B) concentrations in coastal sediments of Maine .............. 92

Figure 52. Relationship between total phosphorus and chlorophyll concentrations in Maine and 

ACAD lakes .................................................................................................................................. 96

Figure 53. Dissolved oxygen concentrations at depth in four MDI lakes: 1942, 1992-2006.. ..... 97

Figure 54. Nutrient loading and algal biomass in Bass Harbor Marsh. ........................................ 99

Figure 55. Groundwater use and nitrate concentrations in selected sub-watersheds of the 

Northeast Creek system .............................................................................................................. 101

Figure 56. Aquaculture sites in the MDI area. ............................................................................ 104

Figure 57. Cell densities of the toxic dinoflagellate Alexandrium fundyense in surface waters of 

the Gulf of Maine in June 2000. ................................................................................................. 105

Figure 58. Bacteria concentrations at four ACAD beach sites: Echo Lake, Lake Wood, Sand 

Beach and Sand Beach lagoon. ................................................................................................... 106

Figure 59. Worm and shellfish habitat and shellfish closures in the ACAD region ................... 107

Figure 60. Total trace metal concentrations in streams and springs on MDI, June 2003 ........... 111

Figure 61. Fire model output for MDI region based on vegetation map data. ........................... 113

Figure 62. Lake levels and water withdrawals. ........................................................................... 115

Figure 63. Maximum incision in low- and high-use trail classes on IAH .................................. 121
xi 

Figure 64. Selected management activities at ACAD. ............................................................... 127

Figure 65. Distribution of invasive plants on MDI. .................................................................... 128

Figure 66. Distribution of European fire ant (Mymica rubra) on MDI. ..................................... 130

Figure 67. Ranavirus-associated amphibian die-off events on MDI. ......................................... 133

Figure 68. Impact of sea level rise on MDI ................................................................................ 135

Figure 69. Map of MDI showing illumination in the night sky .................................................. 136

Figure 70. Summary of “extent of problem” for threats / stressors at ACAD, by resource ....... 139

Figure 71. Summary of information richness for threats / stressors at ACAD, by resource ...... 140
xii 

Tables 

Table 1. Geography of Acadia National Park – key statistics ........................................................ 7

Table 2. Summary land-cover / land-use statistics for ACAD and the ACAD region ................. 10

Table 3. Land cover change in the ACAD region, 1976-2002. .................................................... 10

Table 4. Compilation of visitor use statistics. ............................................................................... 15

Table 5. Documented taxonomic richness for selected plant and animal groups in ACAD and 

vicinity .......................................................................................................................................... 20

Table 6. Exemplary natural communities in the ACAD region. ................................................... 25

Table 7A. Rare plant species at ACAD, conservation status, and potential stressors .................. 26

Table 7B. Other ACAD plant taxa listed by Maine Natural Areas Program as threatened or 

endangered in Maine. .................................................................................................................... 27

Table 8. Resident birds of ACAD: Summary of species richness, conservation status, population 

trends and information quality ...................................................................................................... 31

Table 9. Selected morphological and productivity-related parameters for lakes and ponds in the 

Acadia region. ............................................................................................................................... 37

Table 10. Comparison of trend results for regional and ACAD lakes for 1990-2000 .................. 41

Table 11. Hydrogeomorphic classes of wetlands on MDI ............................................................ 46

Table 12. Freshwater fishes currently found in 24 lakes/ponds and 32 streams ........................... 52

Table 13. Fish stocking history for lakes in the ACAD region .................................................... 55

Table 14. Stream water quality attainment based on macroinvertebrate biomonitoring data. ..... 57

Table 15. Groups of fishes recorded from Bass Harbor marsh. .................................................... 61

Table 16. Monitoring of physical and chemical parameters at ACAD. ........................................ 66

Table 17. Annual number of 8-hour ozone exceedances at six park units ................................... 69

Table 18. Forest plot-level data for four condition metrics .......................................................... 77

Table 19. Mercury concentrations in biota: a summary of data .................................................. 93

Table 20. Mercury in terrestrial and freshwater biota: selected observations ............................. 94

Table 21. Resource stressor matrix showing extent of problem and knowledge base. .............. 138 
xiii

Acronyms and Abbreviations 

ACAD – Acadia National Park 

ANC – acid neutralizing capacity 

AOP – aquatic organism passage 

C:N – carbon to nitrogen ration 

Ca:Al – calcium to aluminum ratio 

CACO – Cape Cod National Seashore. 

CASTNET – Clean Air Status and Trends Network 

CBC – Christmas Bird Counts 

CERCLA – Comprehensive Environmental Response, Compensation and Liability Act 

CM – Cadillac Mountain 

CWD – coarse woody debris 

DDE – dichlorodiphenyldichloroethylene, a metabolite of DDT 

DMR – Maine Division of Marine Resources 

DO – dissolved oxygen 

DOC – dissolved organic carbon 

EP – Existing problem 

EVI – Marine Environmental Vulnerability Index 

GIS – Geographic Information System 

GMP – General Management Plan 

GNOME – General NOAA Ocean Modeling Environment 

GRSM–LR – Great Smoky Mountains NP - Loon Rock 

H2SO4 – sulfuric acid 

Hg – mercury 

HGM – hydrogeomorphic classification system 

HP – Historic problem 

IAH – Isle au Haut 

IMPROVE – Interagency Monitoring of Protected Visual Environments 

ISL – small offshore islands 

MANE–VU – Mid-Atlantic/Northeast Visibility Union 

MDEP – Maine Department of Environmental Protection 

MDI – Mount Desert Island 

MDIFW – Maine Department of Inland Fisheries and Wildlife 

ME–DOT – Maine Department of Transportation 

MeHg – methymercury 

MH – McFarland Hill 

MNAP – Maine Natural Areas Program 

MOSIS – Marine Oil Spill Information System 

N – nitrogen 

NADP – National Atmospheric Deposition Program 

NEC – Northeast Creek 

NEEA – National Estuarine Eutrophication Assessment 

NETN – Northeastern Temperate Network 

NEWS – New England Wadeable Streams Project 

NH4 – ammonium 
xiv 

NLERT – GIS-based decision support system developed by USGS 

NO3 – nitrate 

NOAA – National Oceanic and Atmospheric Administration 

NPS – National Park Service 

NRCS – Natural Resources Conservation Service 

NST – National Status and Trends 

OK – Problem unlikely 

P – phosphorus 

PAH – polynuclear aromatic hydrocarbons 

PCBs – polychlorinated biphenyls 

PEARL – Maine source for environmental information; www.pearl.maine.edu 

PP – Potential problem 

PRIMENet – Park Research and Intensive Monitoring of Ecosystems 

RCRA – Resource Conservation and Recovery Act 

ROMO – Rocky Mountain NP 

S – sulfur 

SCH – Schoodic Peninsula 

SHEN – Shenandoah NP 

SO2 – sulfur dioxide 

SO4 – sulfate 

S–Rank – State rank 

TN – total nitrogen 

TP – total phosphorus 

TRI – Toxics Release Inventory 

Unk – Unknown 

URI – University of Rhode Island 

USEPA – U.S. Environmental Protection Agency 

USGS – U.S. Geological Survey 

UV – Ultraviolet radiation 

VOCs – volatile organic compounds 

WHAM – Wildland Hazard Assessment Methodology 

YOSE–TD – Yosemite NP - Turtleback Dome 
xv 

Executive Summary 

This report is an assessment of condition of the natural resources of Acadia National Park 

(ACAD) and an evaluation of the threats and stressors that act on these resources. A variety of 

threats to habitat and biological integrity are management concerns at ACAD. Consequently, 

improved understanding of the state of knowledge regarding the condition of the Park’s natural 

resources and the threats acting on these resources is needed to guide data collection and broader 

natural resource assessment efforts. As development continues to expand adjacent to the park 

boundaries and as visitor use increases, park managers are continually challenged to address a 

spectrum of issues such as water quality degradation, introduction of exotic species, air pollution, 

habitat fragmentation, recreational use, and others. These may all have dramatic impacts on 

aquatic and terrestrial ecosystem function and integrity, and habitat quantity and quality. 

This Assessment focuses on three broad resource groups: Uplands, Freshwaters (lakes, streams, 

wetlands, groundwater), and Marine/Coastal areas. It is based entirely on compilations, syntheses 

and new analyses of pre-existing data, and an in-depth review of the scientific literature 

associated with ACAD. No new field data were collected for the study. The Assessment is 

intended to assist Park managers and external researchers by (i) providing a synthesis of 

information about natural resources at ACAD, (ii) describing the suite of threats known or 

thought to be affecting these resources, (iii) analyzing information from a series of metrics and 

other descriptors of resource condition, and (iv) evaluating information richness and identifying 

key information gaps. 

This report is structured into five primary sections: (i) Park Description; (ii) Resource 

Characterization (a synthesis of information describing the physical, chemical and biological 

resources of ACAD); (iii) Assessment of Threats (an in-depth review of the suite of 

environmental threats and stressors present in the Acadia region and their impacts on Park 

ecosystems); (iv) Assessment of Resource Condition (quantitative and qualitative analyses of 

data from metrics and other descriptors of resource condition); (v) Conclusions and 

Information Needs (a review of the extent of knowledge about natural resources at ACAD and 

key data gaps). 

The Park includes a mix of islands and ocean unequaled along the Atlantic coast of the United 

States. Most of the Park lands are on Mount Desert Island (MDI); other holdings are on the 

Schoodic Peninsula, Isle au Haut and several smaller islands. ACAD is located in a broad 

transition zone between southern deciduous and northern coniferous forests. Local habitats range 

from coastal to sub-alpine, and include old-growth spruce-fir and jack pine forests, meadows, 

freshwater wetlands and salt marsh, over 20 lakes (with some of the best water quality in the 

state), and a stream network occupying 12 major watersheds. Forests and human-affected areas 

comprise 75% and 10%, respectively, of the total area of ACAD and vicinity. Urban land and 

areas of herbaceous vegetation increased by 118% and 68%, respectively, between 1976 and 

2002, with most of the increase in urban land cover occurring in a buffer area around the Park. 

ACAD harbors 54% of the plant species listed for Maine. Nearly 20% of ACAD plants are 

locally-rare or State-listed, while about a quarter are exotic. The Acadia area has over 200 

resident bird species, as well as over 40 migrants. Twenty eight freshwater fish species, and 19 
xvi 

amphibians and reptiles are known to be present in the Park. ACAD receives over 2 million 

visitors per year, with most visits occurring during the summer and fall months. 

Some of the major threats to natural resources at ACAD include: 

• Ozone - causes leaf damage and reduces growth rate in some plant species. 

• Atmospheric deposition of nitrogen, sulfur, acidity, mercury and other contaminants – 

producing multiple effects on both abiotic and biotic components of terrestrial and 

aquatic systems, including high mercury levels in fish and other animals, and chronically 

elevated nitrogen concentrations in streams. 

• Nutrient enrichment – of particular concern for the two major estuarine/wetland 

complexes on MDI as development increases in their watersheds. Although 

eutrophication remains a threat for the Park’s lakes and ponds, current water quality in 

these waters is good. 

• Contaminants – although there are a number of potential contaminant sources in the 

Acadia region, levels in environmental media are generally low (except for mercury). 

• Changes in fire regimes – a major fire on MDI 61 years ago has had a major and lasting 

influence on terrestrial and aquatic systems, re-setting biogeochemical responses. Other 

areas have not burned in centuries, possibly longer than the natural fire return interval. 

• Altered hydrology – dams, culverts, ditching and other factors have likely resulted in 

multiple impacts to lakes, stream and wetland habitats. 

• Habitat impairment and loss – including fragmentation of terrestrial habitat, and barriers 

to passage of fish and other aquatic organisms. Over 80% of stream crossings on MDI are 

thought to completely or partially block passage. 

• Visitor use – including trampling of vegetation and disturbance of some birds. 

• Exotic species, including invasive species – although ACAD has fewer exotic species 

than other park units in the Northeast, approximately one quarter of its plant species are 

non-natives. Park management includes control of invasive species such as purple 

loosestrife. Currently no aquatic invasive plant species occur in the Park. Approximately 

one half of the freshwater fish species in the Park are not native to MDI and “bait bucket” 

introductions may increase this number. Several marine invasive animal species are 

known to occur in or near ACAD. 

• Pests and pathogens – including beech bark disease and hemlock woody adelgid, as well 

as several pathogens in amphibian populations. 

• Climate change – although this will have (and is likely already having) multiple impacts 

at ACAD, these have so far not been well-studied. 

A suite of metrics and other attributes was used to characterize resource condition by assigning 

to each metric in each resource group a three-class ranking system: “Good”, “Caution”, or 

“Significant Concern”. This process was based on a very heterogeneous information base – one 

that made it impossible to conduct a fully quantitative and consistent condition assessment. 

Because of this, it is potentially misleading to compare condition across the different resource 
xvii 

groups by simply summarizing the numbers of metrics assigned to each condition rank value. 

Nonetheless, a summary of metric rankings is as follows: 

 Air: Good (0); Caution (4); Significant Concern (5); Insufficient data (0). 

 Terrestrial: Good (9); Caution (10); Significant Concern (1); Insufficient data (5). 

 Streams: Good (7); Caution (3); Significant Concern (3); Insufficient data (1). 

 Lakes: Good (12); Caution (4); Significant Concern (1); Insufficient data (0). 

 Wetlands/Estuaries: Good (3); Caution (2); Significant Concern (2); Insufficient data (7). 

 Groundwater: Good (4); other ranks (0). 

 Marine: Good (2); Caution (2); Significant Concern (3); Insufficient data (3). 

The information on which threat and condition assessments at ACAD are based is best developed 

for terrestrial systems, lakes/ponds and streams. It is least developed for wetlands and intertidal / 

coastal areas. While much is known about some stressors (for example atmospheric deposition 

and other aspects of air quality), the impacts of these stressors on the plants and animals of the 

Park are generally much less well understood. Synergistic effects from multiple stressors are 

virtually unstudied at ACAD. There is an urgent need for more information to document 

temporal trends and variability in population structure and community composition of floral and 

faunal groups. In addition, inventories are needed for many biological groups. 
xviii 

Acknowledgements

We acknowledge the assistance of staff at Acadia National Park, in particular D. Manski, B. 

Gawley, K. Anderson and B. Connery. J. McKenna also provided input to the early stages of this 

study. C. Roman and M. Flora (NPS) were sources of many helpful suggestions, both during 

implementation of the study and through their thoughtful reviews of report drafts. B. Mitchell 

(NPS) also reviewed report drafts, and supplied unpublished data and supporting materials for 

our use. K. Keteles (NPS) provided valuable project coordination and oversight. At the 

University of Rhode Island, R. Duhaime and M. Christiano helped with analyses of land-use data 

and produced many maps used in this report. At College of the Atlantic, J. Perez Orozco and B. 

Wheeler helped with retrieving bibliographic information and generating mapping products. H. 

Neckles, C. Culbertson and M. Nielsen (USGS) provided insights and access to unpublished 

information. Several other individuals shared unpublished data with us – they are all 

acknowledged in the text of this report. 
1 

Introduction 

The U.S. Congress, in its FY 2003 Appropriations Act, instructed and funded the National Park 

Service (NPS) to assess environmental conditions in watersheds where National Park units are 

located. A variety of threats to habitat and biological integrity are management concerns for 

many Parks. Consequently, NPS needs to better understand and evaluate the state of knowledge 

regarding the condition of its natural resources and the threats that affect these resources, and 

then use this information to further guide data collection and broader natural resource assessment 

efforts. 

This report is an assessment of condition of the natural resources of Acadia National Park 

(ACAD) and an evaluation of the threats and stressors that act on these resources. The study 

(hereinafter referred to as the “Assessment”) focuses on three broad resource groups: Uplands, 

Freshwaters (lakes, streams, wetlands, groundwater), and Marine/Coastal areas. The landscape at 

ACAD is diverse, including mountains, valleys and flatter terrain, forest and open lands, lakes 

and ponds, freshwater wetlands and salt marshes, estuaries and extensive rocky shores. As 

development continues to expand adjacent to the park boundaries and visitor use increases, park 

managers are continually challenged to address a spectrum of issues such as water quality 

degradation, introduction of exotic species, air pollution, habitat fragmentation, recreational use, 

and others. These may all have dramatic effects on aquatic and terrestrial ecosystem function 

and integrity, and habitat quantity and quality. 

Ecologically, many of the natural resources at ACAD are integrally linked to surrounding 

watershed and coastal areas that lie outside of the Park boundary. Thus, although the primary 

focus of the Assessment is on Park lands and waters, we also include information from outside of 

the Park, particularly on Mount Desert Island. 

The Assessment is based entirely on compilations and syntheses of pre-existing data, and an indepth review of the scientific literature associated with ACAD. No new field data were collected 

for the Assessment. There is an impressive body of scientific research at ACAD, undertaken over 

many decades. A substantial segment of this material was addressed during our study. The 

Assessment is intended to assist Park managers and external researchers by (i) providing a 

synthesis of information about natural resources at ACAD, (ii) describing the suite of threats 

known or thought to be impacting these resources, (iii) analyzing information from a series of 

metrics and other descriptors considered useful to assess condition in the Park, and (iv) 

evaluating information richness and identifying key information gaps. 

This report is structured into five primary sections. 

Park description: This section includes a brief introduction to ACAD, summarizing the extent 

and location of Park-associated lands, and providing an overview of the areal extent and 

composition of the natural resources. 

Resource characterization: In this section we present a synthesis of information characterizing 

the physical, chemical and biological resources of ACAD. Rather than attempting a 

comprehensive characterization of ACAD ecosystems, we focus on (i) key ecosystem descriptors 
2 

and (ii) additional selected attributes that are associated with generally accepted measures of 

resource condition. Further information describing the natural resources of the Acadia region is 

contained in the sections of this report that address threat and condition assessments. 

Assessment of threats: Threat assessments cannot be fully separated from a discussion of 

resource condition. For example, spatial and temporal patterns of mercury levels or non-native 

species relate both to assessment of threats and to characterization of condition. To maintain a 

tighter focus on individual topics in this report, we present most of the assessment information 

within this section. Information that specifically addresses metrics and other attributes of 

condition is then summarized within a subsequent section, “Assessment of Resource Condition”. 

Assessment of resource condition: This Assessment used an information base that is very 

heterogeneous in terms of both quantity and quality. Consequently, a consistent and fully 

quantitative assessment of resource conditions was an unrealistic goal. Rather, using our 

evaluation of threats, approaches adopted by other programs (e.g. Mitchell et al. 2006, Kahl et 

al. 2000), as well as ecological theory, we identified a series of metrics or attributes with which 

to characterize condition. We then assessed condition by describing metric or attribute “values” 

to the extent possible using available data. For some metrics, it was possible to compare 

conditions at ACAD with ‘external’ criteria or regional data sets. For others, it was only possible 

to make general statements about condition. The approach is further described later in this report. 

Conclusions and Information Needs: The Assessment concludes with an overview of 

information richness and data gaps. Discussion of information needs is largely organized around 

the series of threat sub-topics and is intended to highlight areas where new research is needed to 

better understand the action of stressors, document status and trends, and measure ecological 

condition. 
3 

Park Description 

Size and Location of Park Lands and Conservation Easements 

Acadia National Park (ACAD) preserves approximately 20,000 hectares in Hancock and Knox 

Counties, located along the Maine coast in the northeastern United States (Figure 1). It consists 

of land on Mount Desert Island (MDI) plus portions of and entire outlying smaller islands, a 

portion of Isle au Haut (IAH) to the southwest of MDI, and the tip of the Schoodic Peninsula 

(SCH) located on Maine's mainland to the east of MDI (Figure 2, Figure 3). 

Eighty-five percent of ACAD fee-owned lands are on MDI, 6% on SCH and 9% on IAH (Table 

1). Approximately one half of each of MDI and IAH is within the Park. In addition, the Park 

holds over 200 conservation easements in the Penobscot and Frenchman Bay areas. Park lands 

are not contiguous but are rather interspersed with private lands. 

 

Figure 1. Locator map of Acadia National Park. 

The Park was created to protect the natural beauty of the highest rocky headlands along the 

Atlantic shore of the United States. The enabling legislation specifically mentioned the "historic 

significance" of the area and the unique natural resources which were of great "scientific 

interest" (Manski 1998). 

The Park’s mission statement is: "The National Park Service at Acadia National Park protects 

and conserves outstanding scenic, natural, and cultural resources for present and future 

generations. These resources include a glaciated coastal and island landscape, biological 

diversity, clean air and water, and a rich cultural heritage. Acadia National Park also offers 

opportunities for high-quality non-consumptive recreation, education, and scientific research" 

(NPS 1997). 
4 

Figure 2. Acadia National Park lands, acquisition parcels, conservation easements, and other 

conservation lands in the vicinity of the Park. Not shown: several small islands with fee-owned 

or conservation easement status. Data source: Acadia National Park. 
5 

Figure 3. Named features in ACAD and surrounding areas. 
6 

The ACAD General Management Plan (GMP) describes the Park's significance as a mix of 

islands and ocean unequaled along the Atlantic coast of the United States (NPS 1992). Natural 

resources, as described within the GMP, emphasize the Park's unique location as a transition 

zone between temperate deciduous and northern coniferous forests overlaying glacially 

sculptured granite mountains with interspersed glacially scoured lakebeds and bounded by high 

rocky headlands. Noteworthy natural resources within the Park include old-growth forests, subalpine communities, heaths and marshes, an exceptionally diverse flora, over 40 species of 

mammals, and documented sightings of over 300 bird species. Significant cultural resources 

include light stations, 19th century frame buildings, an 80 km carriage road system with 17 stone 

bridges, and the Islesford Historical Museum. 

Location and Extent of the Upland, Freshwater, Wetland and Marine/Coastal 

Systems

For this assessment, we considered not only lands in fee ownership by the NPS, but also other 

lands that contribute to the major watersheds on MDI (Figure 2). Because of the fragmented 

nature of ACAD, many of the park-owned lands are ecologically linked to lands in private 

ownership. The total watershed area considered in this report, therefore, is ~ 32,000 ha, of which 

lands within the ACAD legal boundary comprise approximately 63% (20,179 ha; Table 1). We 

use the term ‘ACAD region’ to refer to the total watershed area treated in this document. 

Elevation at ACAD ranges from 0 m to 466 m above sea level; the Otter Creek and Cañon Brook 

sub-watershed on MDI includes both extremes. The total length of roads in the ACAD region is 

241 km, and the total length of mapped trails is 785 km; within the Park itself, there are 193 km 

(120 miles) of hiking trails and 71 km (44 miles) of carriage roads (Table 1 and Manski, pers. 

comm. September 2008). There are 32 ponds and lakes in the ACAD region (Table 1), with a 

total pond/lake area of 83 ha. Nineteen of these waterbodies are considered “Great Ponds” 

(surface area >10 acres) by the State of Maine. Of these 19 Great Ponds, 14 are entirely or 

partially within ACAD (although not legally considered Park-owned resources). Mapped streams 

total 301 km length in the ACAD region. Including lakes, streams, coastal wetlands and estuaries 

in the broad category of ‘wetlands’, there are 2,478 ha of wetlands in the ACAD region (this 

estimate does not include many vernal pools). Approximately 65 km of coastline are within / 

adjacent to the Park boundary; coastline within the broader ACAD region is substantially longer. 

The ACAD region has been delineated into 300 sub-watersheds, 256 of which are on MDI 

(Perrin 1996). Sixty percent (154) of the MDI watersheds have areas greater than 5 ha. These 

sub-watersheds can be aggregated into larger units at several spatial scales (Figure 4). Core 

attributes of watershed clusters (level C in Figure 4) are provided in Appendix 1. At the subwatershed level, drainages range from 0%-98% within the Park. On average, 51.5% of subwatershed areas on MDI are within the Park (overall, ACAD lands represent just under 45% of 

the total area of MDI). 

Using USGS-NPS Vegetation Mapping Project (Lubinski et al. 2003) data for the ACAD region, 

we determined land-use/cover for lands within Park boundaries and for the whole-watershed 

areas, including small offshore islands (total area of offshore islands in fee ownership = 264 ha). 
7 

Table 1. Geography of Acadia National Park – key statistics 

______________________________________________________________ 

Total area within park boundary 20,179 ha 

 Lands under NPS fee ownership 14,501 ha 

 Conservation easements to NPS 5,067 ha 

 Acquisition parcels 611 ha 

Percent total fee-owned lands on : 

Mt. Desert Island (MDI) 85.2 % 

 Schoodic (SCH) 5.6 % 

 Isle au Haut (IAH) 9.2 % 

MDI – Total area (park and non-park lands) 28,105 ha 

IAH – Total area (park and non-park lands) 2,711 ha 

Resource Management Classes 

 Natural environment zone (1) 12,343 ha 

 Outstanding Natural Zone (2) 1,893 ha 

 Historic and Cultural Zones 197 ha 

 Development Zone (3) 369 ha 

Length of coastline within park boundary approx. 65 km 

Number of major watershed systems (MDI) (4) 12 

Number of “Great Ponds” (> 4 ha/10acres): 

 Completely surrounded by park lands (5) 12 

 Partially surrounded by park lands 5 

 On MDI, not surrounded by park lands 5 

Number of ponds < 4 ha completely surrounded by park lands 10 

Number of named streams: 

 Inside park boundary 13 

 Partly outside park boundary 21 

Maximum elevations: MDI: 466 m IAH: 163 m SCH: 134 m 

Total length of park-maintained paved and unpaved roads: 241 km 

Total length of trails 785 km 

______________________________________________________________ 

(1) Predominantly forested lands; development and use limited to trails network. 

(2) Areas of ‘scenic splendor, natural wonder or scientific importance’. 

(3) Visitor center, park housing, campgrounds and other park infrastructure. 

(4) See Fig. 4 for finer-scale watershed ‘clusters’

(5) Lands within ACAD legal boundary 

Data sources: Park areas, 2005 data supplied by ACAD. Resource management classes – NPS 2004. 

Hydrology and roads: Kahl et al. 2000. Other data derived from GIS coverages supplied by ACAD staff. 
8 

(A) (B) 

(C) (D) 

Figure 4. Aggregations of watersheds on MDI. (A) Small watersheds as delineated by Perrin 

(1996). (B) and (C) are increasing aggregations of small watersheds. (D) Perrin’s three drainage 

districts. For level C drainages, small coastal watersheds were grouped subjectively; interior 

watersheds were largely grouped based on a hydrology-based code in the Perrin database. The 

level C aggregation is used for summarizing land cover/use statistics in Appendix 1. 
9 

We report statistics based on the attribute LUC-II (Land-use/cover), as reported in the ACAD 

vegetation map data. Table 2 presents summary data for the ACAD region, while Figures 5 and 

Appendix 1 provide land-use/cover data summarized by watershed cluster (Level C in Figure 4). 

The extent of anthropogenic land-use in sub-watersheds greater than 5 ha is shown in Figure 6. 

Within the Park (fee-owned lands), forests are the largest landcover type (12,688 ha, or 86.5% of 

the Park’s area), followed by wetlands (1201 ha [8.2%], which includes lakes and riparian areas), 

herbaceous/shrub/brush rangeland (464 ha [3.2%]), human-affected areas (214 ha [1.5%]; 

includes utilities, residential, service areas, roads, quarries, etc.), and finally bare rock (92 ha 

[0.6%]). For the entire area mapped by Lubinski et al. (2003) – i.e. ACAD plus surrounding 

areas – forests and human-affected areas comprise 75% and 10%, respectively, of the total area. 

Wang et al. (2006) reported on change in land-use/cover over the period 1976-2002 (Table 3). 

There were large percentage increases in areas of urban land and herbaceous vegetation – 118% 

and 68%, respectively, between 1976 and 2002. The data in Table 3 cover ACAD itself together 

with a 5-km buffer zone around the Park. Most of the increase in urban land cover occurred in 

this buffer area. 

Legislative Background and Management Objectives

Acadia National Park was established in 1916 as the Sieur de Monts National Monument. It was 

was given its current name in 1929, at which time legislation authorized expansion of the Park. 

In 1986 the permanent boundary was established. Four resource management classes have been 

defined for ACAD (NPS 1992). Descriptions and areas of these are provided in Table 1. For 

more information on legislative background and management objectives for ACAD, see 

Appendix 2. 

Human Utilization of Park Resources 

ACAD receives over 2 million visitors per year, with most visits occurring during the summer 

and fall months (Figure 7). Visitation appears to have peaked in the mid 1990s (note that this 

assumes that the disparity in the two curves in Figure 7A reflects the change in the visitor 

estimation method). Table 4 provides a synthesis of several visitor use data sets. Hiking trail use 

is shown in Figure 8. The eastern half of MDI is more visited than the western half. Most popular 

destinations include Cadillac Mountain, Sand Beach / Thunder Hole and Jordan Pond. Eleven 

percent of individuals surveyed in the late 1990s visited the Schoodic Peninsula, while 2% 

visited IAH. Counts of hikers in August indicate that >5,000 visitors enter trails daily. Typically, 

over 1,400 visitors per day use carriage roads during the peak months of July and August. 

Day use visitation to IAH is between 5,500 and 6,900 persons per year, while overnight camper 

days range from 1,100 to 1,500 per year (Marion 2006). As with MDI, the majority of visitation 

to IAH occurs from late June through early September. Hiker numbers on IAH trails are much 

lower than on MDI – a high-use trail on IAH has about 10 visitors per day. 
10 

Table 2. Summary land-cover / land-use statistics for fee-owned parcels in ACAD (within-park 

area) and in the Park plus surrounding areas (total area)*. Data are based on USGS-NPS 

Vegetation Mapping Project (Lubinski et al. 2003). 

 

USGS Land Use Code (LUC-II) Within-Park Area (ha) Total Area (ha) 

11 – Residential 16.3 1533.4

12 - Commercial and Services 107.6 363.2

14 - Transportation, Communications, and Utilities 65.1 121.9

16 - Mixed Urban or Built-up Land 9.3 963.7

17 - Other Urban or Built-up Land 4.2 98.1

24 - Other Agricultural Land 3.3 124.4

31 - Herbaceous Rangeland 37.4 503.8

32 - Shrub and Brush Rangeland 426.6 733.6

41 – Deciduous Forest Land 1929.7 2382.6

42 - Evergreen Forest Land 5780.1 11699.6

43 - Mixed Forest Land 4977.8 10717.6

52 – Lakes and ponds ** n/a 933.8

54 - Bays and Estuaries 74.3 311.9

61 - Forested Wetland 876.0 1623.7

62 - Nonforested Wetland 250.6 541.2

74 - Bare Exposed Rock 92.2 163

75 - Strip Mines, Quarries, and Gravel Pits 7.7 203.9

Totals: 14668.8 34020.7

* See Lubinski et al. (2003) for description of area covered by the Vegetation Mapping Project. 

** Lubinski et al. (2003) classify many smaller lakes and ponds as wetlands, not as lakes/ponds (LUC=52). Many 

Great Ponds (> 4 ha) are classified as LUC 52. However, Great Ponds are not included within the legal ACAD 

boundary. Hence within-park statistics are not calculated for LUC 52. 

(Statistics produced by the URI Environmental Data Center and University of Maine) 

Table 3. Land cover change in the ACAD region, 1976-2002. The study area includes ACAD 

plus a 5-km buffer zone around the Park. Areas are from Wang et al. 2006 (1). 

Land cover class 1976 

acres 

1986 

acres (% change from 

1976) 

2002 

acres (% change 

from 1976) 

Urban 11,601 16,293 (+40.4) 25,160 (+116.9) 

Deciduous forest 74,970 88,651 (+18.2) 89,851 (+19.8) 

Coniferous forest 264,402 205,444 (-22.3) 229,997 (-13.0) 

Mixed forest 152,861 187,421 (+22.6) 143,627 (-6.0) 

Water 653,248 769,047 (+17.7) 801,590 (+22.7) 

Wetland 25,341 33,167 (+30.9) 30,368 (+19.8) 

Herbaceous vegetation 17,645 20,215 (+14.6) 29,599 (+67.7) 

Bare rockface 27,577 17,168 (-37.7) 25,366 (-8.0) 

(1) Across class areas do not sum to the same total area in each year. The reason for this is unclear. 
11 

In addition to Park visitors, local residents both use and have an impact on Park resources. The 

resident population on MDI is distributed among four towns with a total population in 2000 of 

10,424 (Town of Bar Harbor 2005). The population increased by 11% between 1980 and 2000. 

Between 1992 and 2004, the town of Bar Harbor granted 613 residential building permits and 

1,411 commercial building permits. As will be discussed in the Assessment of Threats section, 

residential development in parts of MDI is threatening some Park-associated resources. 

Aside from hiking and vista experience, human uses of Park resources include recreational 

fishing, boating, swimming / beach use and water supply. Fishing is permitted on all lakes in the 

ACAD region. The Maine Department of Inland Fisheries and Wildlife (MDIFW) has a lead role 

in fisheries management on Great Ponds (lakes > 4 ha surface area). Management goals of this 

agency do not always concur with NPS management goals, for example as they relate to the 

stocking of non-native fish (Kahl et al. 2000). There are boat restrictions on most of the lakes 

and ponds on MDI (MDIFW regulations may be viewed at www.pearl.maine.edu). Internal 

combustion engines are currently prohibited from: Round Pond, Aunt Betty Pond, Witch Hole 

Pond, Bubble Pond and Lake Wood. Engines larger than 10 h.p. are prohibited from Seal Cove 

Pond, Echo Lake, Upper and Lower Hadlock Ponds and Jordan Pond. Personal water craft (jet 

skis, etc.) are prohibited from Hamilton Pond, Long Pond and Somes Pond, as well as the other 

lakes with engine-size restrictions. 

The following lakes are municipal water supply sources: Eagle Lake (Bar Harbor), Jordan Pond 

(Seal Harbor), Lower Hadlock Pond (Northeast Harbor), Long Pond (Southwest Harbor) 

(Figure 9). Swimming is prohibited from these lakes and their feeder lakes (e.g. Bubble Pond 

which flows into Eagle Lake). There is a swimming beach at Echo Lake. 

No authorization of hunting and trapping is included in any federal legislation related to ACAD, 

although these activities are permitted on Great Ponds by Colonial Ordinances. Kahl et al. (2000, 

p. 3-14) provide an extended discussion of hunting and trapping issues at ACAD. 

Marine worm (Nereis virens) and shellfish (including soft-shelled clam, Mya arenaria) 

harvesting, lobstering and fishing occur in the coastal waters surrounding ACAD. Further 

information on worm and shellfish areas is presented in the Assessment of Threats section. 
12 

Figure 5. Landcover/use statistics by watershed cluster. 

Wetlands, lakes, ponds and development data are from Vegetation Mapping Project database (Lubinski et al. 2003). 

Note that this database considers some smaller ponds to be wetlands; thus the combined wetland/lake-ponds 

summary is the most accurate depiction of surface water extent. Buildings data are from building footprint database 

(courtesy of G. Longsworth, College of the Atlantic, Bar Harbor, ME). Roads data are from ME-DOT GIS 

coverage. Note also that class breaks are not uniform within any individual map panel. Maps were developed by B. 

Wheeler (College of the Atlantic).
13 

Figure 6. Anthropogenic land-use in watersheds of MDI. Data are derived from Lubinski et al. 

(2003) and show the number of watersheds with various levels of the “Urban” land-use class. 

Watersheds inside the Park lie completely within the ACAD legal boundary. Watersheds outside 

the Park lie partly or fully outside the boundary. Watersheds are those delineated by Perrin 

(1996) that are > 5 ha (the Sargent Mountain Pond watershed is included, although smaller). The 

two vertical lines refer to two “reference” values: one adopted by the New England Wadeable 

Streams Project (<10% of land use in watershed is anthropogenic) (NEWS; Snook et al. 2007) 

and one by the Northeast Temperate Network Vital Signs Monitoring Program (<40% of land 

use in watershed is anthropogenic) (Mitchell et al. 2006). See further information under 

Assessment of Condition. 

0

1

2

3

4

5

6

50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 00 02 04 06

Year

Number of Visitors (millions)

0

100,000

200,000

300,000

400,000

500,000

600,000

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Month

Number of Visitors

Recreation Non-recreation

(A) (B) 

Figure 7. Visitation at ACAD. (A) Annual number of visitors, 1950-2006. (B) Monthly number 

of visitors, 2006. Note that a new method for estimating visitation was implemented in 1990. 

(Data source: http://www2.nature.nps.gov/stats/)
14 

(Census data from Jacobi 2003d) 

Figure 8. Hiking trail use, number of hikers per day. 
15 

Table 4. Compilation of visitor use statistics. 

A. Visitors to ACAD (see Figure 7) 

B. Visitors, Cadillac summit (1)

# persons (2001) 

# persons (2002) 

# cars (2001) 

# cars (2002) 

5969 

4930 

1971 

1802 

C. Average # hikers / hour on summits: 1999-2001 (# observation days) (2)

Beehive 

Penobscot 

Champlain 

Gorham 

Beech 

Acadia 

Pemetic 

Dorr 

Sargent 

Bernard 

59 (3) 

47 (1) 

43 (4) 

34 (20) 

30 (12) 

27 (10) 

19 (7) 

15 (8) 

10 (3) 

2 (1) 

D. # Hikers entering trails (# observation days): (3) (See also Figure 8) 

Eastern MDI Western MDI 

1999 

2000 

2001 

2002 

2003 

2759 (42) 

3370 (48) 

3513 (48) 

5219 (50) 

3586 (43) 

2090 (16) 

1726 (20) 

2896 (21) 

2717 (21) 

1904 (18) 

E. IAH trail use: average # visitors / trail / day (4): 

0.6 (low-use trails - 10.4 (high-use trails) 

F. Estimated daily carriage road use (± 80% confidence interval) for: (5)

July August 

1997 

1998 

1999 

2000 

2001 

2002 

1663 (208) 

1431 (208) 

1567 (207) 

1379 (208) 

1362 (208) 

1632 (257) 

1984 (216) 

1796 (211) 

1851 (212) 

1755 (210) 

1552 (207) 

1867 (258) 

G. Places visited by visitors (N = 1062 visitor groups) (6)

Cadillac summit – 76% 

Sand Beach/Thunder Hole – 75% 

Jordan Pond House - 61% 

Visitor Center – 59% 

Seawall area – 55% 

Eagle Lake parking area – 32% 

Sieur de Monts area – 32% 

Acadia Mt. parking area – 28% 

Pretty Marsh picnic area – 16% 

Schoodic Peninsula – 11% 

Baker Island – 5% 

Isle au Haut – 2% 

Other park islands – 7% 

H. Visitor use at Anenome Cave (7)

Average # persons entering case per 3-hour period around low tide, May-August, 1998-99 = 47 (± 9) 

Data sources: (1) Jacobi 2001a, 2003a. (2) Jacobi 2001b, 2003c. (3) Jacobi 2003d. (4) Marion 2006. (5) Jacobi 2003b. (6) 

Littlejohn 1999. (7) Jacobi 2000.
16 

Figure 9. Water supply watersheds, dams, and wells on MDI. 

(Data from multiple GIS sources) 
17 

Terrestrial, Freshwater and Coastal/Marine Resources 

This section provides an overview of the physical, chemical and biological features of the natural 

resources in the ACAD region. Further information on the ecosystems of ACAD is presented in 

subsequent sections of this report that address threats and condition. 

 

Terrestrial Systems 

Physico-Chemical Environment of Terrestrial Systems 

Climate: Kahl et al. (2000) provide an overview of weather in the mid-coast region of Maine. 

ACAD’s climate is cool and moist with abundant fog. Daily weather records for MDI exist for 

over a century. Since 1981, there has been a NOAA weather station on McFarland Hill. 

Temperatures typically range from -10 C to 35 C. Annual precipitation has ranged from a low of 

about 60 cm in the drought year of 2001 to almost 220 cm in 2005 (Figure 10). Snowfall depths 

average about 24 cm (Johnson et al. 2007). There appears to be considerable local variation in 

temperature, precipitation and evaporation. 

Geology and Soils: Calhoun et al. (1994) provide a concise description of the geologic history 

of the ACAD region. Most of area is underlain by granite, which gives the Park much of its 

rugged character. The dominant soil class is a shallow, stony Schoodic-rock outcrop-Lyman 

complex derived from granite and schist tills (Kahl et al. 2000). Soils in valleys are mainly sandy 

loams and range from excessively to moderately well-drained. Organic soils, including a range 

of poorly- to well-decomposed peats, are associated with wetlands. An extensive discussion of 

hydric soils in the ACAD region is provided by Calhoun et al. (1994). The distributions of hydric 

and erodible soils are shown in Figure 11, while Figure 12 shows soil pH. The shallow depth and 

reduced buffering capacity of many soils in the Park, coupled with steep slopes, influence the 

chemistry of surface waters (Kahl et al. 2000). Soil composition in the eastern portions of MDI 

has been affected by the 1947 fire (see Threats: Fire). 

Soil chemistry is influenced by atmospheric deposition of acidity, nitrogen, sulfur and other 

elements. The recently established Northeastern Temperate Network (NETN) long-term forest 

monitoring sites are beginning to produce baseline data to evaluate long-term trends in soil and 

vegetation characteristics. Data from this program, as well as from other studies, are discussed 

under Threats: Atmospheric Deposition (Acidity and Related Chemistry). 
18 

Figure 10. Annual precipitation measured at the McFarland Hill NADP site, 1982-2006. State of 

Maine 30-year normal precipitation mean (1971-2000) is 105 cm. McFarland Hill site mean 

precipitation (1981-2005) is 138 cm. 

(Data sources: NADP; means from Seger et al. 2006) 

 (A) (B) 

Figure 11. Distribution of hydric and erodible soils in the ACAD region. 

(Data from NRCS soils GIS coverage, courtesy of ACAD Office of GIS) 
19 

Figure 12. Soil pH at ACAD and vicinity. 

(Figure from Maniero and Breen 2004, with permission) 

Biological Resources of Terrestrial Systems 

Terrestrial Plant Communities: ACAD is located in a broad transition zone between southern 

deciduous and northern coniferous forests. Local habitats within ACAD range from coastal to 

sub-alpine including old-growth spruce-fir forests, wetlands (heaths, marshes), meadows, and 

jack pine forests. ACAD harbors 1,135 of the 2,103 taxa (54%) listed for Maine (Campbell et al.

1995). Nearly 20% (~183 taxa) of vascular plants at ACAD have been designated locally-rare or 

State-listed (calculated from data in Greene et al. 2005). A third of the plants (~283 taxa) are 

exotic (Greene et al. 2005) (see Threats: Exotic Species). 

MDI is the most floristically diverse unit of the Park, supporting more than one half of Maine’s 

known plant species (Table 5). Isle au Haut supports 1/3 of plant taxa listed for Maine. Current 

knowledge of the Schoodic Peninsula flora is limited. Most field surveys at SCH have been 

restricted to the southern 1/3 of the peninsula (Mittelhauser et al. 1996). Greene et al. (2005) 

believe that the current flora for MDI is more-or-less complete but that further surveys are 

needed for IAH and SCH units of ACAD. Many taxa currently listed for MDI are not 

documented for SCH or IAH. For example, of 12 members of Lycopodiaceae (clubmoss family) 

listed for ACAD, only one has been documented for SCH. Similarly, four common tree species, 

Fagus grandifolia (American beech), Picea mariana (black spruce), Populus grandidentata (big- 
20 

Table 5. Documented taxonomic richness for selected plant and animal groups in ACAD and 

vicinity. Note that, for some groups, documented diversity is likely less than actual diversity. 

Data are for MDI, SCH and IAH park units, except where noted. 

Group Number of ACAD Taxa 

 Present in 

Park *

Unconfirmed 

in Park *

Historic 

Records *

Total Taxa State-Listed 

Taxa **

Vascular plants (1) 894 241 1135 18 

Freshwater plants (1) 91 6

Fresh and Salt Wetland 

plants (9)

 220 

Marine macroalgae (8) 146 0 

Lichens (10) 379 taxa 

(103 genera) 

Birds (2) 230 117 17 364 21 

Birds – residents (3) 205 

 

Mammals (2) 43 7 1 51 0 

Snakes (2) 5 - 1 6 1 (historic 

ACAD 

record) 

Turtles (2) 2 3 1 6 2 (both 

unconfirmed 

ACAD 

records) 

Amphibians (2) 12 1 2 15 0 

Fish – freshwater (2) 27 - 5 32 0 

Fish – estuarine/marine (2) 11 3 - 14 0 

Fish – Bass Harbor marsh 

system (4)

 23 0

Freshwater mussels (5) 3 0 

Dragonflies/damselflies (6) 107 

Mayflies (6) 58 

Butterflies/Moths (11) 1479 

Butterflies/Moths (7) 155 

Beetles (11) 1175 

Beetles (7) 315 

Ants (11) 42 

Ants (7) 44 

 

* ‘Present in park’ = taxon records from within park boundaries. ‘Unconfirmed’ = reported in the area but not within 

park boundaries. ‘Historic’ = written record of taxon that has not been observed since ca. 1970. For full metadata, 

see http://www.pearl.maine.edu/DADataUpload/MetaData/ACAD05_09.HTM. 

** State endangered and threatened species include faunal taxa proposed for listing (IFW 2007). Endangered and 

threatened taxa do not include all rare taxa. 

Data sources

(1) Vascular plants: Greene et al. 2005. See Table 7 for listing of rare taxa. Freshwater plants: Greene et al. 1997. 

(2) W. Gawley (ACAD), derived from NPSpecies database and accessed from www.pearl.maine.edu in March 2007. 

 (3) G. Mittelhauser (this report). Resident species include breeders, summer residents and winter residents. 

Excluded are migrant and vagrant species. 

(4) Doering et al. 1995. 

(5) Nedeau et al. 2000, Vaux (2005). Data from MDI only. 
21 

(Table 5, continued) 

(6) Multiple sources, as compiled by Vaux (2005). Data from MDI, only. Key original data sources are: Odonates – 

MDDS (2005) and White (1989) following MDDS (2005). Mayflies – Burian and Gibbs (1991), Burian et al. (1995) 

and Mack (1988). Note that historical data of Procter (1946) for odonates and mayflies are not included here since 

those data are included in the more recent inventories. 

(7) ACAD “bioblitz” data provided by W. Gawley (ACAD) and accessed at www.pearl.maine.edu. Ant data are from 

MDI, only; beetle and butterfly/moth data are from SCH, only. 

(8) Mathieson et al. 1998. 

(9) Calhoun et al. 1994. Note that this total includes taxa from lakes and ponds, and freshwater and salt marshes. The 

total of 220 taxa is likely an under-estimate. 

(10) Sullivan 1996. 

(11) Procter 1946. 

____________________________________________________________________________ 

toothed aspen), and Quercus rubra (red oak) – all common to New England – have not been 

documented for SCH. A similar case can be made for IAH. 

The USGS-NPS Vegetation Mapping Program (Lubinski et al. 2003) recently used remote 

sensing and field data to describe spatial vegetation and land-use patterns in the ACAD region. 

Using the National Vegetation Classification System to classify field-collected data, a total of 53 

vegetation community types (associations) were recognized at ACAD. They include 10 upland 

forest types, 13 upland woodland types, 2 wetland forest types, 3 wetland woodland types, 6 

non-forested upland types, 6 shrub or dwarf shrub wetland types, and 13 herbaceous wetland 

types. Vegetation associations derived from field-based data were cross-walked to map classes 

based on remote-sensing data. These map classes are shown in Figure 13. 

Spruce - Fir Forests are the most extensive vegetation type, covering over 60% of natural 

vegetated classes and over half of all vegetated classes. ACAD is within the southern coastal 

range limit of this association. Among the natural vegetated classes, the rarest are the Dune 

Grassland, Pitch Pine - Heath Barren and Pitch Pine - Corema Woodland, and the Crowberry - 

Bayberry Headlands. 

Several species and communities within these vegetation types are at the edge of their 

geographic ranges making the study and preservation of local populations critical from a species 

conservation standpoint. Certain physical features of the Park, including habitats with thin soils 

and steep slopes, abundant surface waters, and high mountains contribute to ACAD’s sensitivity 

to perturbations (Kahl et al. 2007b). Further, stressors such as fire, grazing, pests/pathogens, 

ozone, airborne pollutants, heavy metals, visitor use, and land-use patterns can influence some or 

all of ACAD’s plant species. For example, fire has played a critical role in shaping ACAD’s 

vegetation. The 1947 fire burned most of the eastern side of MDI (Figure 14), and evidence of 

past burns is also present in trees and soils throughout the park (Patterson et al. 1983). The 

present vegetation on the MDI unit of ACAD includes large areas of 60-year-old forest and 

woodland, as well as areas that have had a longer time since disturbance to develop. Additional 

information on the stressors acting on ACAD terrestrial vegetation is provided under the Threats 

Assessment. 
22

Figure 13. Vegetation and land-use in the ACAD region (from Lubinski et al. 2003).
23 

Figure 14. Fire history, prescribed burns and fire risk at ACAD. The 1947 fire is shown by the 

shaded area. Other fires are shown as point data, by decade. The WHAM points indicate 

structures with medium – very high fire risk as assessed in the wildland/urban interface structure 

assessment program. 

(Data from Patterson 1981 and other sources supplied by ACAD Office of GIS) 
24 

Exemplary Natural Plant Communities: The Maine Natural Areas Program 

(www.mainenaturalareas.org) recognizes a number of exemplary natural plant communities in 

the ACAD region. These are listed in Table 6, along with their S-Rank (State rank) values that 

characterize community rarity. One of the outstanding natural communities at SCH is the jack 

pine woodland. Jack pine (Pinus banksiana) occurs on dry, acidic sites with shallow soil. Jack 

pine woodlands are rare in Maine, with only a few sites known statewide. Little Moose Island at 

SCH contains an extensive and diverse example of a Downeast Maritime Shrubland community. 

Although not part of ACAD, Great Cranberry Island (Figure 3) is notable for the outstanding 

example of a Coastal Plateau Bog Ecosystem, one of the best examples of this type in Maine. 

Rare Plants: ACAD harbors a wide range of plant communities, including species of 

international, national, regional, and state significance (Greene et al. 2002). Six plant species at 

ACAD are listed as globally rare (Brumback et al. 1996). No federally listed plant species occur 

in ACAD. According to Greene et al. (2005), 14 taxa listed as being endangered or threatened in 

Maine have been documented at ACAD (Table 7A). However, more recent data published by 

the Maine Natural Areas Program indicate that the number of threatened and endangered species 

at ACAD is larger (Table 7B). 

State-endangered species are New England northern reed grass (Calamagrostis stricta subsp. 

inexpansa), swarthy sedge (Carex adjusta), and a historic record for beach plum (Prunus 

maritima), last documented in 1920 at IAH. State-threatened species include Nantucket shadbush 

(Amelanchier nantucketensis), screw stem (Bartonia paniculata), pickering’s bluejoint 

(Calamagrostis pickeringii), inkberry (Ilex glabra), Acadian and prototype quillworts (Isoetes 

acadiensis and I. prototypes), one-sided rush (Juncus secundus), Marsh felwort (Lomatogonium 

rotatum), northeastern sea-blight (Suaeda calceoliformis), boreal blueberry (Vaccinium boreale) 

and an historic record for alpine clubmoss (Huperzia selago), last documented in 1920, also at 

IAH. 

Though ranked only as threatened in Maine, on a global scale Isoetes prototypus is the rarest 

plant at ACAD. It is known from 11 locations globally, one on MDI and 10 in New Brunswick 

and Nova Scotia and is considered globally rare (G1). Also considered globally rare (G2) is 

Isoetes acadiensis, which occurs in 1 pond at ACAD and is distributed from Newfoundland to 

New York. Suaeda calceoliformis, although globally secure, is locally extremely rare and has 

been documented from only one site at ACAD (Greene et al. 2005). 

Locational information for Kalmia latifolia, a species uncommon on MDI, suggests that it was 

destroyed by the 1947 fire and has not re-established colonies since. Prunus maritima, now 

thought to be extinct, was observed at IAH in 1920. IAH also harbors Maine’s only population of 

Ilex glabra. Maine and Nova Scotia populations are disjunct, making this population worthy of 

preservation and careful study. Given our limited current floristic understanding of IAH and 

SCH (Greene et al. 2005), it is critical that these areas are surveyed rigorously to document 

additional populations of these rare or thought-to-be-extinct taxa as well as to document any new 

taxa that may have gone unnoticed in previous studies. 
25 

Table 6. Exemplary natural communities in the ACAD region. Locations of communities are 

shown in figure inset. 

Natural Community Name Locations Code S-Rank * 

Coastal Plateau Bog Ecosytem MDI, Great Cranberry 

Island Heath **

CPBE S3 

Raised Level Bog Ecosystem MDI RLBE S4 

Cinquefoil-Blueberry Low Summit 

Bald 

MDI Bald S3 

Maritime Spruce-Fir Forest MDI MSFF S4 

Pitch Pine Woodland MDI PPW S3 

Red Pine Woodland MDI RPW S3 

Spruce-Pine Woodland MDI SPW S4 

Spruce – Northern Hardwood 

Forest 

MDI SNHF S4 

Streamshore Ecosystem MDI Stream S4 

White Cedar Woodland MDI WCW S2 

Jack Pine Woodland MDI, SCH JPW S3 

Downeast Maritime Shrubland SCH DEMS S3 

Open Headland SCH Head S4 

Footnotes: 

* State rank ranges from 1 (rare) to 5 (common). S3 = rare in Maine (on the order of 20-100 occurrences); 

S4 = apparently secure in Maine. 

** Not within ACAD boundary. 

(Information source: Maine Natural Areas Program [www.mainenaturalareas.org, accessed 7/2007]) 
26 

Table 7A. Rare plant species at ACAD, with state and global conservation status and potential 

stressors (Greene et al. 2002). 

Taxon State 

(Global) 

Rank (1)

State 

Status 

(1)

# 

Populations

ACAD (2)

Potential Stressors (2)

Amerlanchier nantucketensis 

(Nantucket shadbush) 

S2 (G3Q) T 6 Loss of habitat 

Bartonia paniculata 

(Screwstem) 

S1 (G5) T ~ 6 Possibly changes in 

hydrology 

Calamagrostis pickeringii 

(Pickering’s reed bent-grass) 

S1 (G4) T ~ 1 Possibly changes in 

hydrology 

Calamagrostis stricta ssp. inexpansa 

(Northern reed-grass) 

S1 

(G5T5) 

E (ACAD has 

largest 

population in 

ME) 

ACAD population threatened 

by carriage road activity; 

spread of invasive Celastrus 

orbiculata (Oriental 

bittersweet) 

Carex adusta 

(Swarthy sedge) 

S2 (G5) E Possibly 

extirpated 

from ACAD 

Lack of disturbance 

Carex recta 

(Salt-marsh sedge) 

S1 (G4) T 1 Trampling by hikers and 

visitor overuse; non-native 

species 

Carex vacillans 

(Brackish sedge) 

S1 (G?) SC 1 Possibly non-native species 

Carex wiegandii 

(Wiegand sedge) 

S3 (G3) SC 9 Changes in hydrology 

Isoetes acadiensis 

(Acadian quillwort) 

S2? 

(G2G3) 

T 1 Changes in hydrology; nonnative plant and animal 

species 

Isoetes prototypus 

(Prototype quillwort) 

S1 (G1?) T 1 Changes in hydrology; nonnative plant and animal 

species 

Lomatogonium rotatum 

(Marsh felwort) 

S1 (G5) T 2 Trampling by hikers; nonnative species 

Mertensia maritima * 

(Oysterleaf) 

 2 Trampling by hikers; winter 

storms; non-native species 

Minuartia glabra 

(Smooth sandwort) 

S3 (G4) SC Regionally 

rare; common 

in ACAD 

Trampling by hikers 

Minuartia groenlandica 

(Mountain sandwort) 

S3 (G5) SC Regionally 

rare; common 

in ACAD 

Trampling by hikers 

Montia fontana 

(Blinks) 

S2 (G5) SC 3 Unknown 

Oryzopsis canadensis 

(Canada mountain-ricegrass) 

S2 (G5) SC 2 Loss of habitat; trampling and 

erosion from excessive trail 

use 
27 

Table 7A (continued) 

Taxon State 

(Global) 

Rank (1)

State 

Status 

(1)

# 

Populations

ACAD (2)

Potential Stressors (2)

Potamogeton confervoides 

(Alga-like pondweed) 

S3 (G4) SC 8 Changes in hydrology; nonnative plant and animal 

species 

Sagina nodosa ssp. borealis * 

(Knotted pearlwort) 

 2 Non-native species 

Selaginella rupestris * 

(Ledge spike-moss) 

 1 Trampling by hikers; invasive 

Rumex acetosella (Sheep 

sorrel) 

Suaeda calceoliformis 

(American sea-blite) 

S1 (G5) T 1 

(only 1 other 

population in 

ME) 

Excessive trail use; trampling 

by visitors 

Vaccinium boreale 

(Alpine blueberry) 

S2 (G4) T 2 Excessive trail use; trampling 

by visitors; erosion of 

minimal soil layer via heavy 

use or damage to adjacent 

vegetation 

Table 7B. Other ACAD plant taxa listed by Maine Natural Areas Program as threatened or 

endangered in Maine, but not included in list of Greene et al. 2002. 

Taxon State 

(Global) 

Rank (1)

State 

Status 

(1)

 

Adlumia fungosa 

(Allegheny vine) 

S1 (G4) T 

Botrychium lunaria 

(Moonwort) 

S1 (G5) E 

Callitriche heterophylla 

(Water-starwort) 

S2 (G5) SC 

Carex bushii 

(Bush’s sedge) 

SX (G4) PE 

Carex silicea 

(Sea-beach sedge) 

S3 (G5) SC 

Clethra alnifolia 

(Sweet pepper-bush) 

S2 (G5) SC 

Cypripedium reginae 

(Showy lady’s-slipper) 

S3 (G4) T 

Dryopteris fragrans 

(Fragrant cliff wood-fern) 

S3 (G5) SC 

Eleocharis aestuum 

(Bay spikerush) 

S2? (G3) SC 

Huperzia selago 

(Alpine clubmoss) 

S1? 

(G4G5) 

T 

Ilex glabra 

(Ink-berry) 

S1 (G5) T 
28 

Table 7B (continued) 

Taxon State 

(Global) 

Rank (1)

State 

Status 

(1)

 

Juncus secundus 

(Secund rush) 

S1 (G5?) SC 

Kalmia latifolia 

(Mountain-laurel) 

S2 (G5) SC 

Listeria auriculata 

(Auricled twayblade) 

S2 (G3) T 

Parietaria pensylvanica 

(Pennsylvania pellitory) 

SX (G5) PE 

Potamogeton bicupulata 

(Snail-seed pondweed) 

S3 (G4?) SC 

Proserpinaca pectinata 

(Comb-leaved mermaid-weed) 

S1 (G5) SC 

Prunus maritima 

(Beach plum) 

S1 (G4) E 

Salicornia maritima 

(Jointed glasswort) 

SH (G5) PE 

Salix humilus var. tristis 

(Dwarf praire willow) 

SU (G5) 

Spiranthes lacera var. gracilis 

(So. Slender ladies’ tresses) 

SH (G5) PE 

Suaeda maritima ssp. richii 

(Rich’s sea-blite) 

S1 

(G5T3) 

SC 

Subularia aquatica 

(Water awlwort) 

S3 (G5) SC 

Zannichellia palustris 

(Horned pondweed) 

S2 (G5) SC 

(1) Designations from Maine Natural Areas Program list of rare, threatened and endangered plant species in Maine 

(www.mainenaturalareas.org; accessed May 5, 2007). 

State ranks: S1 Critically imperiled in Maine because of extreme rarity (five or fewer occurrences or very few remaining 

individuals or acres) or because some aspect of its biology makes it especially vulnerable to extirpation from the State of Maine.

S2 Imperiled in Maine because of rarity (6-20 occurrences or few remaining individuals or acres) or because of other factors 

making it vulnerable to further decline. S3 Rare in Maine (on the order of 20-100 occurrences). 

Global ranks: G1 Critically imperiled globally because of extreme rarity (five or fewer occurrences or very few remaining 

individuals or acres) or because some aspect of its biology makes it especially vulnerable to extirpation from the State of Maine. 

G2 Globally imperiled because of rarity (6-20 occurrences or few remaining individuals or acres) or because of other factors 

making it vulnerable to further decline. G3 Globally rare (on the order of 20-100 occurrences). G4 Apparently secure globally. 

G5 Demonstrably secure globally. 

State legal status: E Endangered; Rare and in danger of being lost from the state in the foreseeable future, or federally listed as 

Endangered. T Threatened; Rare and, with further decline, could become endangered; or federally listed as Threatened. SC

Special Concern; Rare in Maine, based on available information, but not sufficiently rare to be considered Threatened or 

Endangered. PE Potentially endangered. 

(2) Based on information in Greene et al. 2002 

* Taxon not included in MNAP list 
29 

Rare plant conservation is a high priority for ACAD. The report by Greene et al. (2002) 

identified a number of critical questions that have to be addressed in order to develop a long-term 

plan for the conservation of rare species at ACAD. Their effort helped prioritize species for 

monitoring, develop appropriate protocols for monitoring, and provide management responses 

for some selected rare taxa. 

Table 7A identifies potential stressors for 20 rare plants found at ACAD (based on Greene et al.

2002). Potential stressors are species-specific and include factors such as habitat loss, change in 

hydrology, invasive species, visitor over-use, trampling by hikers and walkers, and erosion. 

These are further discussed in the individual Threats sections. Careful study of these rare plants 

will no doubt reveal additional stressors as well as best approaches for their conservation. 

Birds: For this study, we focused on resident ACAD taxa, excluding species that occur in the 

region only as migrants or vagrants. Nevertheless, it is important to note that ACAD is a 

significant stopover location for many migrants. Appendix 3 provides a list of migrant species. 

We include all resident bird species in this terrestrial section, even though some taxa are 

associated with freshwater, wetland or marine environments. 

A recent study of bird assemblages of Northeast Creek and Bass Harbor Marsh documented a 

total of 152 species, of which 41% were determined to be breeding species and 59% nonbreeding species (Wilson et al. undated1

). While some of the non-breeding taxa were known to 

be local breeders on MDI, others were using the wetlands for migration stop-over sites. 

To assess the status of birds in the ACAD region, we conducted new analyses of existing data 

and literature resources. We compiled up-to-date population information on all species using 

multiple data sources, including systematic surveys, scientific publications, agency reports, and 

general observations for each species. To develop a list of resident species (i.e., breeders, 

summer residents, or winter residents) within the Park, we consulted ACAD’s ‘NPSpecies’ 

database, which is designed to track species status in the park through links to references, 

museum vouchers, and observations. We also consulted Sibley (2000) to determine migrants and 

vagrants in the ACAD region and excluded them from our analysis. We divided resident species 

into three categories: land birds, marsh birds, and marine birds. Although some birds can be 

placed in more than one category, each species was assigned to only one category. 

Condition, population trend and stressors were determined on a species-level basis. Population 

trends used Christmas Bird Counts and Breeding Bird Surveys. Data for the CBC have been 

collected every December/January (with few exceptions) on MDI since 1934 and on Schoodic 

Peninsula since 1957; we used these data to assess long-term changes in bird populations in the 

ACAD region. Breeding bird survey data are available for three consecutive years (1995-1997). 

Appendix 4 contains more information on the approaches used to develop the bird analyses. 

 

1

 The final version of the Wilson et al. report was not available when this Assessment was prepared. Hence we do 

not include here a more detailed summary of data from the Wilson et al. study. 
30 

The ACAD region provides habitat for 205 species of resident (i.e., breeding, summer resident, 

and winter resident) birds (Table 8)2

. Although scattered species lists for specific areas within 

ACAD have been generated over the years (Greene et al. 2002), details on distribution of species 

and population size within ACAD are lacking for most species and are not of sufficient 

resolution to document fine-scale patterns of distribution. We separate out specific details for 

MDI, IAH, SCH, and small offshore islands (ISL) where possible. 

Of the 205 total resident bird species, 136 species are landbirds (Appendix 5), 29 species are 

marsh birds (Appendix 6), and 40 species are marine birds (Appendix 7). There has been little to 

no effort to discern population status or distribution throughout ACAD for 93% of land birds, 

79% of marsh birds, and 58% of marine birds. Although less research emphasis has been placed 

on land birds versus water birds, land birds have a significant percentage of species of 

conservation concern: 46% for land birds, 59% for marsh birds, and 68% for marine birds (Table 

8). 

Stressors potentially affecting species of conservation concern in ACAD are detailed for land 

birds (Appendix 8), marsh birds (Appendix 9), and marine birds (Appendix 10). Documentation 

of these potential stressors within ACAD has been limited. Appendix 11 summarizes park 

specific ‘existing problems’ and ‘potential problems’ based on the best information available. 

This information is further discussed under Assessment of Threats. 

Terrestrial Mammals: Forty-three mammal species are known to inhabit ACAD and another 

seven are suspected (based on their presence outside the Park) (Table 5; species list can be found 

at http://www.pearl.maine.edu/linkeddatasets/acad_mammals.htm). No mammal species is statelisted for conservation purposes. Fuller and Harrison (2003) provide an excellent overview of the 

status of mammal populations on MDI. Related spatial data available as GIS layers from the 

ACAD Office of GIS include the Fuller and Harrison survey transects and mammal observation 

locations. 

Although some population trend information is available, long-term monitoring data for most 

mammal species do not exist. Fuller and Harrison (2003) recommend that such monitoring be 

implemented and they provided a thorough evaluation of different survey methodologies. The 

white-tailed deer (Odocoileus virginianus) population on MDI is currently stable or declining 

and is below forage carrying capacity (Long et al. 1997). For more information on the status of 

deer and other mammal species, see section on Threats: Herbivory / Predation. 

Amphibians and Reptiles: Twelve amphibian species are known to inhabit ACAD and another 

one may also be present (Table 5). Two species are known from historical records only. The 

Park is known to hold seven reptile species, with another three species possibly present but 

unconfirmed (Table 5). Two reptile species are known from historical records only. A detailed 

survey of ACAD herpetofauna was conducted in 2001 and documented 18 species (Brotherton et 

al. 2004) including the first IAH record for the northern ring-necked snake (Diadophis 

punctuatus edwardsii). 

 

2

 The Maine Audubon (www.maineaudubon.org) field checklist of Maine birds includes a total of 299 species for 

the state. 
31 

Table 8. Resident birds of ACAD: Summary of species richness, conservation status, population 

trends and information quality. For species-level information on population trends and stressors, 

see Appendices 3-10. Data are from multiple sources – see text for more information. 

 LAND SPP. MARSH SPP. MARINE SPP. 

Total # Species (A)

 136 29 40 

Priority Status of Taxa (B)

Priority # Species

1 2 1 2 

2 39 10 13 

3 36 8 13 

T 1 0 4 

E 2 1 2 

SC 6 1 5 

Taxa of Regional Concern (C)

Concern Level # Species 

Moderate 23 5 8 

High 15 2 6 

Highest 4 2 8 

“Management 

concern” 

-- 2 -- 

Population Trends (D)

Trend # Species 

Increasing 18 (MDI); 12 (SCH) 4 (MDI); 1 (SCH) 8 (MDI); 6 (SCH) 

Decreasing 3 (MDI); 2 (SCH) 0 (MDI); 1 (SCH) 2 (MDI); 6 (SCH) 

No Change 23 (MDI); 23 (SCH) 0 (MDI); 2 (SCH) 13 (MDI); 14 (SCH) 

Insufficient data 93 (MDI); 99 (SCH) 25 (MDI); 25 (SCH) 16 (MDI); 13 (SCH) 

Population Status Data Quality (E)

Quality Category # Species 

1 127 23 23 

2 6 6 11 

3 0 0 3 

4 3 0 2 

 

(A) Species numbers refer to breeding, summer and/or winter residents. 

(B) Maine Priority Status: Maine Fish and Wildlife priority codes(Maine Department of Inland Fisheries and 

Wildlife 2005): 1: high potential for state extirpation without management intervention and/or protection; 2: 

moderate to high potential for state extirpation without management intervention and/or protection; 3 low to 

moderate potential for state extirpation, yet, there are some remaining concerns regarding restricted distribution, 

status, and/or extreme habitat specialization. T: Threatened in Maine; E: Endangered in Maine; SC: ‘Special 

Concern’ in Maine (Maine Department of Inland Fisheries and Wildlife 1996). Note that a species may have a 

numeric priority status as well as a listing status (T, E, SC). 

(C) Regional Concern: Conservation priority categories for birds in BCR 14 (Dettmers 2007). 

(D) Population Trends: Trends are for Christmas Bird Count (CBC) data, only. For more information on analytical 

methods used in this analysis, as well as other trend analyses, see Appendix 3. 

(E) Data Quality: 1) Poorly known: little or no effort to discern population status or distribution throughout ANP; 2) 

Scattered reports: existing information may or may not correctly estimate status or distribution; 3) Generally well 

known: scattered anecdotal reports likely reflects status and distribution, but only poor or incomplete data available; 

4) Reliable data: park-wide survey with good status and distribution information. 
32 

The 23 amphibian and reptile species from the ACAD region may be compared to the total of 36 

species known from Maine’s mainland (Hunter et al. 1999). Maine is one of the most 

depauperate states in terms of herpetofauna (Brotherton et al. 2004). The authors of the 2001 

survey state that: 

“The 18 species of amphibians and reptiles documented at Acadia are mostly species that 

are common to the Northeast .... and are representatives of species that are even more 

widespread. Many are at or close to the northern limit of their distributions. From a 

preservation of species at risk perspective, Acadia does not support any species that are 

exceptionally rare, such that it could be considered a critical site for a rare or declining 

species. The only species present that is listed by the State of Maine is the four-toed 

salamander (Species of Special Concern). The four-toed salamander is a habitat 

specialist (Sphagnum-dominated wetlands and vernal ponds) difficult to detect and its 

true abundance is likely underestimated, both at Acadia and throughout much of its 

range. Thus, Acadia is not currently a significant refuge for locally rare and endangered 

amphibian and reptile species. However, this may change in time as Maine experiences 

coastal development and urban-suburban populations expand” (Brotherton et al. 2004). 

According to these authors, while most of ACAD’s amphibian and reptile species appear to be 

maintaining themselves, some evidence suggests that the herpetofauna of the Park is in decline. 

The populations of 16 species “appear to be relatively unchanged in overall population size, one 

(painted turtle) has increased, one (American toad) has declined, and two (dusky salamander, 

northern leopard frog) appear to be extirpated or nearly so.” The authors suggest that declines 

may be because of the same factors believed to be responsible for amphibian declines 

worldwide. Of particular interest is the emerging role of multiple and synergistic stressors (e.g., 

habitat loss, degradation, and chemical stressors) in potentially weakening amphibian fitness. 

Two such stressors have been identified at Acadia: amphibian disease and mercury. These are 

further discussed in the Threats section. 

Bank et al. (2006) reported that the dusky salamander (Desmognathus fuscus) is currently found 

in <15% of the number of streams from which this species had been reported during the middle 

years of the 20th century (Figure 15). 

Chalmers and Loftin (2006) studied the habitat of four-toed salamander (Hemidactylium 

scutatum). They recorded this salamander in 36 wetlands at ACAD – previously, the species had 

been known from just 32 sites in the entire state (Chalmers 2004). A series of biotic and 

geomorphological factors were associated with nesting presence of this species. Biotic factors 

included the presence of plant species (e.g. Sphagnum, Calamagrostis canadensis, Spiraea alba

and S. tomentosa) and absence of other species such as Kalmia angustifolia or deciduous forest 

canopy. Nesting presence was also associated with wood substrate, water flow and shoreline 

gradient. 
33 

Figure 15. Minimum known percent of streams (n = 37) occupied by northern dusky salamanders 

in ACAD, 1938–2003. 

(Figure from Bank et al. 2006, used with permission) 

Terrestrial Invertebrates: There is a long history of invertebrate collections on MDI, including 

the extensive collections of Procter between 1928 and 1945 (Procter 1946). However, with the 

exception of recent bioblitzes conducted by ACAD and external researchers, there are few 

comprehensive recent collections. Species richness for selected invertebrate groups is presented 

in Table 5. In this report we do not address invertebrate assemblages in further detail.

Freshwater Systems (Lakes, Streams, Riparian Systems, Wetlands and 

Groundwater) 

Physico-Chemical Environment of Freshwater Systems 

Drainage Systems: Twelve major watershed systems drain the interior of MDI (Perrin 1996); 

additional watersheds drain directly to the ocean (Figure 4, Figure 16). The alignment of the 

interior watershed systems roughly parallels the north-south orientation of Acadia ridges and 

valleys resulting from glacial action. These drainages are characterized by bold topographic 

relief of up to 450 m across a distance of only 6-8 km (Kahl et al. 2000). The largest of these 

watershed systems extends to 2,700 ha and comprises up to nine sub-watersheds. 

Lakes and Ponds: Nine Great Ponds (lakes ≥ 4 ha) and 11 smaller lakes (< 4 ha) are completely 

surrounded by ACAD (Table 1, Figure 16). Five lakes are partially within the Park and two are 

completely outside. Surface areas range from 0.5 ha (e.g. Sargent Mountain Pond, located near 

the top of Penobscot Mountain) to 359 ha (Long Pond). Jordan Pond is the deepest lake at 46 m 

(Figure 17). 
34 

Figure 16. Watersheds and hydrography of ACAD and vicinity. Watersheds shown are clusters 

of sub-watersheds aggregated into drainage systems. 
35 

Figure 17. Lakes and ponds in the ACAD region: area-depth relationships. 

Lake codes: (1) Bear Brook P. (2) The Bowl. (3) Sargent Mountain P. (4) Seawall P. (5) Fawn 

P. (6) Duck P. (7) The Tarn. (8) Little Long P. (9) Aunt Betty’s P. (10) Lake Wood. (11) Upper 

Breakneck P. (12) Little Round P. (13) Round P. (14) Half Moon P. (15) Lower Breakneck P. 

(16) Hodgdon P. (17) Somes P. (18) Witch Hole P. (19) Upper Hadlock P. (20) Bubble P. (21) 

Lower Hadlock P. (22) Seal Cove P. (23) Long Pond (IAH). (24) Echo L. (25) Eagle L. 

(26) Long P. (27) Jordan P. 
36 

 

Figure 18. Air and surface water monitoring sites. 

Lake water quality data for ACAD lakes extend back to the 1940s (Fuller and Cooper 1946), 

although the first survey using present-day analytical techniques was done in the 1980s (Kahl et 

al. 2000). Currently, ACAD scientists monitor water quality on 19 lakes (Figure 18); eight are 

sampled once per year, two are sampled twice per year and nine are visited on a 3-year rotation. 

Table 9 provides an overview of productivity-related water quality data for ACAD lakes. Figure 

19 compares selected water quality parameters for ACAD and all surveyed Maine lakes. 
37 

Table 9. Selected morphological and productivity-related parameters for lakes and ponds in the 

Acadia region. Lake area-depth relationships are depicted in Figure 18. 

Lake/Pond 

Area 

(ha) 

Total 

Drainage 

Area 

(km2) 

Flushing 

Rate 

(times per 

year) 

Secchi 

Depth 

(m) 

Alkalinity 

(mg/L) 

Conductivity 

(uS) 

Chl a 

(ppb) 

Trophic 

State 

(1) 

Long P 380.0 18.2 0.3 7.3 3.4 51.5 2.8 O 

Eagle L 188.6 9.7 0.3 10.7 3.0 37.7 2.4 O 

Seal Cove P 103.2 11.5 1.9 6.9 4.4 45.0 2.7 M 

Echo L 95.5 5.9 0.6 8.0 5.5 65.0 2.2 O 

Jordan P 75.3 5.0 0.2 13.3 3.5 37.5 1.0 O 

Somes P 41.7 22.4 12.8 4.3 5.3 6.8 

Long P (IAH) 25.5 1.2 8.1 2.0 88.0 2.0 

Hodgdon P 18.2 3.2 4.0 4.8 4.4 50.0 7.9 

Hamilton L 16.6 7.0 

Upper 

Hadlock P 15.4 3.4 4.1 6.6 2.9 47.0 2.7 M 

Lower Hadlock 

P 15.0 4.7 4.6 7.0 2.6 55.0 1.2 

Round P 14.6 1.0 1.5 4.6 7.3 37.0 4.1 

Little Long P 13.8 8.3 25.9 

Bubble P 13.4 1.9 1.9 9.6 3.8 36.5 1.7 O 

Aunt Betty P 13.0 5.3 37.1 1.6 6.7 54.0 

Witch Hole P 9.7 1.1 1.2 4.1 2.9 31.0 4.1 M 

Lower 

Breakneck P 8.5 1.5 4.2 4.5 42.0 

The Tarn 7.7 0.8 10.1 1.0 5.5 88.0 

Lake Wood 6.9 1.5 7.6 3.5 4.3 28.5 2.7 

Little Round P 4.9 0.8 3.4 

The Bowl 4.0 0.2 1.3 6.0 1.7 47.0 M 

Upper 

Breakneck P 3.6 1.2 51.0 3.3 5.8 45.0 

Bear Brook P 3.0 93 

Seawall P 2.0 0.6 

Halfmoon P 0.4 4.7 3.2 25.5 

Sargent Mt. P 0.4 0.0 3.4 -0.1 31.0 M 

Duck P 0.1 0.5 1.6 0.6 34.0 

 

(1) O = oligotrophic (unproductive), M = mesotrophic (moderately productive) 

Empty cells indicate no data. 

Lakes in boldface are those currently monitored routinely by ACAD staff. 

Data sources: morphology and water quality data from Maine Dept. of Environmental Protection, accessed from PEARL Web 

site (www.pearl.maine.edu) which also provides associated metadata. ME DEP calculates overall lake average values for water 

quality parameters from date-specific data provided by ACAD staff and others. Where data are available from multiple stations, 

these data have been averaged. Period of data record varies among lakes. Trophic state designations taken from Seger et al. 

(2006). 
38 

0

2

4

6

8

10

12

14

16

0 1 10 100 1,000 10,000 100,000

Lake Area (ha)

Secchi Depth (m)

Maine

ACAD

 

0.1

1

10

100

1000

0 1 10 100 1,000 10,000 100,000

Lake Area (ha)

Alkalinity (mg/L)

Maine

ACAD

(A) (B) 

10

100

1000

0 1 10 100 1,000 10,000 100,000

Lake Area (ha)

Conductivity (umho/cm)

Maine

ACAD

 

0.1

1

10

100

1000

0 1 10 100 1,000 10,000 100,000

Lake Area (ha)

Chlorophyll (ug/L)

Maine

ACAD

(C) (D) 

1

10

100

1000

0 1 10 100 1,000 10,000 100,000

Lake Area (ha)

Total Phosphorus (ug/L)

Maine

ACAD

(E) 

Figure 19. Water quality of ACAD lakes compared to the population of all surveyed lakes in 

Maine. (A) Secchi depth, (B) Alkalinity, (C) Conductivity, (D) Chlorophyll, (E) Total 

phosphorus. For some lakes, data are not available for some water quality parameters. Note that 

all lakes in the state have not been surveyed; consequently, the population of “all surveyed lakes” 

is smaller than the population of all Maine lakes. Note the logarithmic scales. 

All data are lake averages as provided by Maine Dept. of Environmental Protection and accessed at 

www.pearl.maine.edu. Where there are >1 sampling stations in a lake, data have been averaged across stations. 

Total phosphorus data are for epilimnetic cores. 
39 

Chemically-resistant granites underlying most of the ACAD region result in surface waters with 

low alkalinity and nutrient concentrations. The alkalinity of nine of 24 ACAD region lakes and 

ponds is in the lowest 10th percentile for all Maine lakes, with only two small ponds (Little Long 

Pond and Bear Brook Pond) having greater alkalinity than the state average (Kahl et al. 2000). 

Alkalinity data (Figure 19B) indicate that most ACAD lakes have low buffering capacity, 

making them susceptible to acidification from atmospheric deposition. Phosphorus 

concentrations in ACAD lakes tend to be on the low end of range for Maine lakes (Figure 19E). 

Since phosphorus is typically the nutrient that limits lake productivity, most ACAD lakes are 

relatively unproductive, with low chlorophyll concentrations and high water transparency (see 

below). Nevertheless, in terms of total ionic strength (as measured by conductivity), ACAD lakes 

are similar to the statewide population (Figure 19C). 

While some ponds are stained with humic compounds (e.g. Round, Duck and Hamilton Ponds), 

many are clear because freely-draining soils dominate their watersheds (Kahl et al. 2000). 

Average water column transparency (Secchi depth) ranges from about 1.0 meter (The Tarn, 

Duck and Aunt Betty Ponds) to >13 m at Jordan Pond. This lake has some of the clearest water 

in the State. Large lakes at ACAD tend to exhibit higher Secchi depths (greater water 

transparency) than other large Maine lakes (Figure 19A). Paralleling trends in water 

transparency, chlorophyll concentrations in larger ACAD lakes tend to be lower that the 

statewide average (Figure 19D). At least five lakes are oligotrophic (low productivity). Other 

ACAD lakes are mesotrophic (moderately productive); none can be considered eutrophic (high 

productivity). Although higher productivity may be a ‘natural’ condition of lakes in some 

regions, oligotrophic lakes are frequently considered to be in ‘good’ condition because of their 

generally high water clarity. 

Most lakes in the ACAD region are circum-neutral, with mean pH values between 6.5 and 7.5 

(Figure 20). Only 2 waterbodies are acidic (pH ≤5.0). Duck Pond is part of a naturally acidic 

wetland system where acidity derives mainly from natural organic matter. Sargent Mountain 

Pond has a small watershed with minimal soil development; its water is acidic largely as a result 

of atmospheric deposition (Kahl et al. 2000). For more information, see Threats: Atmospheric 

Deposition (Acidity and Related Chemistry). 

Some trend data for ACAD lakes are summarized in Table 10. Other trend analyses regarding 

lake water quality parameters, including Secchi depth, are currently being carried out by a 

number of researchers (K. Webster and P. Vaux, University of Maine, unpublished data; J. 

Runde, NPS, pers. comm. 2007). Although published results from this work are not yet available, 

there is evidence of increasing transparency in some ACAD lakes, at least during the period 

1980-2000 (Figure 21). Other lake water quality trend data are discussed under Threats: Acidity 

and Related Chemistry. 

Streams: Most of MDI’s 41 named streams flow through the Park at some point and many 

streams have their headwaters in the Park (Figure 16; Kahl et al. 2000). Streams are typically 

less than 3-5 km long and reported widths for second order streams are 2-6 m (Dubuc et al.

1988). Discharge records exist for several streams, including three USGS continuous-record, 

streamflow gaging-stations: Cadillac Brook (USGS station 01022835) and Hadlock Brook 
40 

 Figure 20. Mean pH in ACAD lakes and ponds. 

(Data provided by B. Gawley, NPS) 
41 

Table 10. Comparison of trend results for regional and ACAD lakes for the period 1990-2000. 

Values are median slopes for set of sites in each region. Trend significance levels: * p < 0.05; ** 

p < 0.01; ns p > 0.05. (Kahl et al. 2004) 

Parameter (1) Acadia Lakes (N=21) New England Lakes 

Aluminum + 0.05 ns + 0.09 ns 

Base cations (Ca + Mg) - 0.43 * - 1.48 ** 

Sulfate - 0.39 * - 1.77 ** 

Nitrate - 0.06 ns + 0.01 ns 

Gran ANC + 0.33 ns + 0.11 ns 

Hydrogen + 0.02 ns - 0.01 ns 

DOC insufficient data + 0.03 * 

 

 (1) Units for sulfate, nitrate, base cations [Ca + Mg], Gran ANC and hydrogen are μeq/L/year. Units for DOC are 

mg/L/year. Units for aluminum are μg/L/year. 

Figure 21. Trends in water transparency (Secchi depth) at Jordan Pond, 1980-2006, by month. 

Monthly means from Maine Dept. of Environmental Protection, accessed at 

www.pearl.maine.edu (March 2007). 
42 

(USGS station 01022860), both of which have eight years of data but were discontinued in 2006; 

and Otter Creek (USGS station 01022840) which was initiated in 2006. All other stream 

discharge measurements were one-time measurements or estimates related to specific projects 

(see list in Kahl et al. 2000). 

Recent (late 1990s on) stream water quality data are available for a number of streams across 

MDI (Figure 18). These include data from the following programs: 

● Hadlock – Cadillac paired watersheds studies, 1998-2000. This work was initiated 

during the PRIMENet (Park Research and Intensive Monitoring of Ecosystems) program 

and continued with funding from the NPS Natural Resources Challenge to assess the 

ecological effects of atmospheric deposition of nitrogen and mercury; included a survey 

of streams across the Park for Hg and full chemistry (Kahl et al. 2003, Kahl et al. 2007a 

and 2007b). 

● USGS study of 14 small watersheds on MDI from 1999 to 2001 (Nielsen et al. 2002c). 

Data include nutrients, major ions, some metals, and basic water-quality parameters 

including dissolved oxygen, temperature. Figure 22 presents a selection of these data. 

● NPS Northeast Temperate Network; stream monitoring on MDI began in 2006. 3 sites 

are monitored every year (Cadillac Brook, Hadlock Brook, Otter Creek); 17 sites are 

monitored every other year (Hunters Brook, Kebo Brook, Sargent Brook, Jordan Stream, 

Breakneck Brook, Aunt Betty’s Pond Inlet, Marshall Brook, Lurvey Spring, Browns 

Brook, Man o’War Brook, Stanley Brook, Eagle Lake Inlet, Duck Pond Brook, Lake 

Wood Outlet, Duck Brook, Lurvey Brook). 

● Monitoring by ACAD scientists at sites representing a range of stream sizes and levels 

of anthropogenic impacts (Breen et al. 2001). This monitoring also includes 

macroinvertebrate sampling (see below). 

● A study of mercury in streams across MDI (Peckenham et al. 2007). 

● A study of the impacts of vehicular traffic on stream water quality (Peckenham et al. 

2006). 

● Nutrient loading studies focusing on Bass Harbor Marsh, Northeast Creek and Somes 

Sound. 

Streamwater survey data exist for the early 1980s (Kahl et al. 1985), and intensive monitoring 

data exist for the late 1980s for upland watersheds around Hadlock Pond (Heath et al. 1992). 

Several other projects have sampled streams for brief periods or in surveys, including Reeb 

(1992), Bank (2005), and many single-site studies; these data are not yet integrated into the 

Park’s streamwater database. 

Most streams are dilute, with acid-neutralizing capacities generally below 100 μeq/L (Figure 23). 

Stream water quality is further discussed under Assessment of Threats (see especially the 

sections on Atmospheric Deposition and Nutrient Enrichment) and Assessment of Condition. 
43 

Figure 22. Distribution of specific conductance, pH, dissolved oxygen, and nitrogen species in 

streams on MDI. 

(Figure from Nielsen et al. 2002c, used with permission)
44 

Figure 23. Acid-neutralizing capacity (ANC) in MDI streams. Vertical lines are tolerance criteria 

for aquatic organisms: 40 μeq/L suggested by Dupont et al. (2005) and 100 μeq/L adopted by 

Mitchell et al. 2006. See further information under Assessment of Condition. 

Wetlands: Wetlands comprise approximately 11% of fee-ownership lands in ACAD and 5% of 

conservation easements (Calhoun et al. 1994). There are two major freshwater / estuarine 

wetland complexes. Northeast Creek, in the northern part of MDI, drains an extensive low-lying 

wetland and Bass Harbor Marsh on the southwest side of the island drains another. 

Calhoun et al. (1994) provide detailed descriptions of the geologic history, morphology, 

hydrology and biology of ACAD wetlands. As these authors note, “[t]he Acadia region has a 

wealth of wetland settings owing to coastal influences and geologic and glacial history.” The 

mountainous eastern region of MDI supports wetlands along valleys and in areas of groundwater 

discharge, while the gentler landscape of the western half of the island supports the majority of 

the area’s estuarine wetlands, peatlands and riverine wetlands. Neighboring islands, including 

IAH, support ombrotrophic peatlands, hillside seep forested wetlands, estuarine and marine 

wetlands. 

ACAD wetlands have been classified using the Cowardin system (Cowardin et al. 1979). 

Aggregating the classes into systems reveals the following representation, expressed as % of 

total wetland area (Calhoun et al. 1994): 

Marine (37.5%) Estuarine (20.0%) Riverine (<1%) 

 Lacustrine (10.7%) Palustrine (31.6%) 
45 

According to recent analyses of the Vegetation Mapping Project (Lubinski et al. 2003), forested 

wetlands comprise 1,463 ha on MDI, non-forested wetlands 514 ha, and bays and estuaries 199 

ha. Appendix 1 provides watershed-level wetland and other landcover statistics for MDI, SCH 

and IAH regions and outlying islands. Figure 5 depicts some of these data. 

Neckles et al. (2008) compared total wetland areas and number of wetland polygons in nine 

parks of the Northeast Temperate Network. As expected from its size relative to other parks, 

ACAD has the largest extent of wetlands. Of the 280 ArcHydro catchments3

 on MDI that 

intersect the Park, 172 contain wetland complexes. Approximately 78% of these complexes 

contain emergent or scrub-shrub vegetation. Basin size, water chemistry and hydrology are all 

factors that influence wetland type (Neckles et al. 2008). 

Nielsen et al. (2006) recently developed a preliminary hydrogeomorphic (HGM) classification of 

wetlands on MDI. This classification is based on three key factors that determine how wetlands 

function: position in the landscape, dominant source of water, and hydrodynamics. Unlike the 

HGM approach, the widely-used Cowardin system for delineating wetlands does not include 

much hydrologic information. For example, the Cowardin system groups most of the nontidal 

freshwater wetlands on MDI into the palustrine hydrologic system, without further definition of 

sources of water (Nielsen et al. 2006). The HGM classification defines 12 wetland classes (Table 

11). Ground-truthing indicated that the classification had an 88% accuracy rate for undisturbed 

wetlands and 82% rate for disturbed wetlands. The authors do not provide statistics on the 

relative abundance of the various classes of wetlands on MDI. 

Wetlands of the ACAD region are further discussed later sections in this report. 

Groundwater: Nielsen (2002a) and Kahl et al. (2000) provide overviews of the geohydrologic 

setting of MDI. Groundwater exists in bedrock and surficial units. With the exception of a small 

glaciofluvial deposit south of Jordan Pond (Figure 9), there are no significant surficial aquifers 

on MDI (Nielsen 2002a). However, some residents obtain water from dug (shallow) wells. In 

many parts of the ACAD region, coarser glacial till is capped by deposits of the Presumpscot 

Formation, a glacio-marine ‘clay’ or silt. These deposits inhibit percolation into the groundwater 

and thus increase surface runoff (Kahl et al. 2000). Wells in the ACAD region are generally 

>150 feet in depth, with many being >400 feet (Figure 24). Most of these wells have a yield of 

<15 gallons per minute. 

The chemistry of groundwaters is less studied than that of surface waters. Hansen (1980, cited by 

Kahl et al. 2000) characterized MDI groundwater as ‘soft’ and of a sufficient quality for 

domestic use. Groundwater chemistry data exist for USGS monitoring wells. Other data are 

reported to the Maine Drinking Water Program, in particular from wells that serve commercial 

operations. According to Kahl et al. (2000), “high concentrations of radon in groundwater from 

MDI pose a potential concern to human health”. 

 

3

 Catchments delineated in GIS using ESRI ArcHydro tool. 
46 

Table 11. Hydrogeomorphic classes of wetlands on MDI (based on Nielsen et al. 2006). 

Class Landscape setting Source of water 

Riverine – Upper 

Perennial 

Within 50 m of perennial stream, at 

roughly same altitude 

Primarily lateral exchange with 

perennial 1st/2nd order stream; 

may also have groundwater 

inflow 

Riverine - Nonperennial Within 50 m of intermitten stream, at 

roughly same altitude 

Primarily lateral exchange with 

intermittent stream; may also 

have groundwater inflow 

Riverine - Tidal Within 50 m of a tidal stream, at roughly 

same altitude 

Primarily lateral exchange and 

flooding with tidal freshwater 

stream; may also have 

groundwater inflow 

Depressional - Closed In topographic depression; no surface 

inflow or outflow 

Inflow from groundwater, 

precipitation or overland flow 

Depressional - 

Semiclosed 

In topographic depression, some surfacewater outflow Inflow from groundwater, 

precipitation or overland flow 

Depressional - Open In topographic depression; surface inflow 

and outflow 

Inflow from groundwater, 

precipitation, overland flow or 

stream flow 

Depressional – No 

Groundwater Input 

In topographic depression, but underlain 

by Presumpscot Formation; may have 

surface-water inflows or outflows 

Precipitation, overland flow or 

stream inflow 

Mineral Soil Flat Wide, flat area, low topographic relief in 

surrounding area, mineral soils 

Precipitation 

Organic Soil Flat Wide, flat area, low topographic relief in 

surrounding area, organic soils 

Precipitation 

Tidal Fringe Adjacent to tidal saltwater body, within 50 

m of limit of saltwater influence 

Overbank flow (lateral exchange) 

from estuary or other saltwater 

body 

Lacustrine Fringe Adjacent to large open-water lake or pond 

(within 100 m and same altitude; lake or 

pond must be large enough to control 

water level in wetland 

Overbank flow (lateral exchange) 

from lake; may also have 

groundwater inflow 

Slope On a sloping surface or hillside Return flow (discharge) from 

groundwater 
47 

 

Figure 24. Bedrock well depths and yields. 

Biological Resources of Freshwater Systems 

Freshwater Plants: The most comprehensive survey of freshwater plants in the ACAD region 

is that of Greene et al. (1997). Thirty-nine lakes and ponds were surveyed across all three park 

units. A total of 92 taxa were collected from the ACAD region (80 fully aquatic species and 12 

semi-aquatic shoreline species), including eleven taxa that had not been previously reported from 

the island4

. The highest species richness was recorded from Somes Pond (46 taxa) while the 

lowest number of species was observed in a pond at SCH (2 taxa). Figure 25 compares plant 

diversity in ACAD ponds and other Maine waters as a function of lake area and alkalinity (an 

indicator of potential productivity). Although different sampling designs make it difficult to 

compare data across different studies, plant diversity in ACAD lakes and ponds appears to mirror 

that of other Maine waterbodies of similar size and alkalinity (Vaux 2005). 

The rarest plant at ACAD is a freshwater species, the Prototype quillwort (Isoetes prototypus). It 

is known from 11 locations globally, one on MDI and 10 in New Brunswick and Nova Scotia. 

Also considered globally rare is the Acadian quillwort (Isoetes acadiensis) which occurs in one 

pond at ACAD and is distributed from Newfoundland to New York. The list of aquatic species 

 

4

 In comparison, 130 obligate aquatic plant species and 438 wetland species are known to occur in Maine (Vaux 

2005). 
48 

(A) 

0

10

20

30

40

50

60

70

1 10 100 1,000 10,000

Lake Area (acres)

# Taxa

# 35

# 63

# 8

# 194

(B) 

0

10

20

30

40

50

0.1 1.0 10.0 100.0

Alkalinity (mg/l)

# Taxa

# 35

# 63

# 8

# 194

Figure 25. Relationship between number of aquatic macrophyte species (per lake) and (A) lake 

area, (B) alkalinity in ACAD and other Maine lakes. ACAD lakes are shown in as yellow 

diamonds. (Figure from Vaux 2005) 

Data are from four different studies and are shown separately because sampling type and effort was not consistent 

among studies. Studies are: #35 = Greene et al. (1997); #63 = Dieffenbacher-Krall (1998); #8 = Cameron (2000); 

#194 = MNAP rapid bioassessment surveys (unpublished data, courtesy of D. Cameron). 
49 

reported by Greene et al. (1997) included seven species that were state-listed or proposed for 

state listing. About 30 other species appeared to be locally rare in the Park. Of these, 21 occurred 

at a single sampling site. Eight aquatic or semi-aquatic species at ACAD are known only from 

historic records; they were not re-located during the Greene et al. survey or in the previous 20 

years of sampling on MDI. 

Calhoun et al. (1994) provide an excellent review of freshwater wetland and salt marsh plant 

communities in the ACAD region. They list a total of 220 taxa in five major community types 

(aquatic bed/freshwater marsh, salt marsh, emergent peatland, shrub peatland, and forested 

wetlands). This taxon total is an under-estimate of total species richness since several species 

included in the list of Greene et al. (1997) are not included in the Calhoun et al. list. 

Little (2005) and Neckles et al. (2008) contain information on ACAD wetland plant communites. 

Human-impacted wetlands tend to be sedge meadow or cattail marsh, whereas non-degraded 

wetlands tended to have fen communities. 

The Vegetation Mapping Project (Lubinski et al. 2003) recognizes a total of 53 vegetation types 

in the ACAD region. Approximately one half (24/53) of vegetation types are wetland types. Of 

the 24 wetland types, 13 fall within the broad group of herbaceous wetland vegetation types, 

while six are shrub / dwarf shrub vegetation types. 

Birds: Lakes, ponds and wetlands are important habitat for a number of bird species. Of the 205 

resident bird species in the ACAD region, 29 are considered to be ‘marsh’ taxa (Table 8, 

Appendix 6). For most (25) of these species, data are insufficient to document temporal trends in 

population size. Four species on MDI appear to have expanding populations (Table 8). 

The annual Maine Audubon loon count has documented common loon (Gavia immer) adults, 

chicks and nests on MDI since 1983. According to Evers et al. 2003 (cited by Bank et al. 2007), 

loon recruitment on MDI is below the level needed to maintain populations. Furthermore, 

according to Kahl et al. (2000), MDI lakes appear to have fewer loons compared to other lakes in 

Hancock County. However, analysis of Maine Audubon data suggest that the average numbers 

of loon adults on MDI lakes over the period 1983-2004 appear to be similar to those observed on 

other Maine lakes (Figure 26, upper panel). Other data indicate that the productivity of loons on 

MDI is very similar to loons elsewhere in Maine (approximately 0.5 fledged chicks per nesting 

pair; D. Lamon, Somes-Meynell Wildlife Sanctuary, unpublished data). The Audubon data 

demonstrate that there is significant inter-annual variation in loon densities on MDI (Figure 26, 

lower panel). 

Mammals: Wetlands in the ACAD region are used by a diverse group of mammals, including 

beaver (Castor canadensis), river otter (Lutra canadensis), mink (Mustela vision) and other taxa 

that would be considered primarily terrestrial. Beaver have played a dominant role in the creation 

or modification of many wetlands on MDI (Calhoun et al. 1994). Although extirpated from MDI 

in the early 1900s, beaver were re-introduced in the early 1920s. Numbers remained low until the 

1947 fire after which regenerating aspen stands created ideal habitat and thence a rapidly 

expanding population. The number of ponded wetlands at ACAD increased by 89% between 

1947 and 1997 (Cunningham et al. 2006). More recently, the beaver population has decreased by 
50 

Figure 26. Loon populations on Maine and ACAD lakes. Upper panel shows average number of 

adults counted during July loon census as a function of lake area (data are for the period 1983-

2004; the number of years with data varies among lakes). Lower panel shows temporal patterns 

in adult numbers on four ACAD lakes. Data source: Maine Audubon data accessed at 

www.pearl.maine.edu. 

_______________________________________ 

approximately two thirds (Calhoun et al. 1994), with the result that many beaver dams are 

currently not maintained (Figure 27). 

Beaver-created wetlands are used by other species. The river otter, in particular, is closely 

associated with these wetlands, occupying abandoned beaver lodges and dams as den sites 

(Dubuc et al. 1988, 1990). Surveys in the 1980s demonstrated that otter were present in over half 

of MDI’s watersheds. Otter provide a link between fresh and marine wetlands since they move 

between these two environments and feed on marine fishes in winter (Dubuc et al. 1991). 

Beaver-created wetlands also provide breeding habitat for amphibians (Cunningham et al. 2006). 

0

10

20

30

40

1 10 100 1,000 10,000 100,000

Lake Area (ha)

# Adults

ME lakes ACAD lakes

0

2

4

6

8

1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005

Year

# Adults

Long P Eagle L Seal Cove P Jordan P
51 

Figure 27. Location and status of beaver dams on MDI. 

(Data source: ACAD Office of GIS, based on work of G. Mittelhauser and others)

Freshwater Fish: Lake and stream fish assemblages of ACAD were recently surveyed by Stone 

et al. (2007; see also Bowes et al. 1999). Using literature reviews and field sampling during 

1998-1999, these authors concluded that 31 species of freshwater fishes have been recorded from 

ACAD and waters bordering the Park. Twenty-eight of these species are currently present (Table 

12). One species (bridle shiner, Notropis bifrenatus) is known from just one collection in the 

1990s and likely represents a bait introduction. One additional species, largemouth bass 

(Micropterus salmoides), is present in Hamilton Pond, which is outside the Park, and thus not 

included in the total of 28 species. Two species are generally considered estuarine taxa but were 

included in the list because they were collected in coastal streams. 
52 

Table 12. Freshwater fishes currently found in 24 lakes/ponds and 32 streams. Data are from 

Stone et al. (2007) and were compiled from past records and surveys conducted in 1998 and 

1999. 

Common Name Scientific Name W/S* Native? # Ponds # 

Streams 

American eel Anguilla rostrata W yes 17 17 

Alewife Alosa pseudoharengus W,S yes 5 0 

Common shiner Luxilus cornutus W no 5 2 

Golden shiner Notemigonus crysoleucas W yes 20 4 

Bridle shiner Notropis bifrenatus W no 0 1 

Blacknose shiner Notropis heterolepis W no 1 0 

Northern redbelly dace Phoxinus eos W yes 12 1 

Creek chub Semotilus atromaculatus W no 3 2 

Fallfish Semotilus corporalis W no 4 0 

White sucker Catostomus commersoni W yes 11 4 

Brown bullhead Ameiurus nebulosus W no 5 1 

Chain pickerel Esox niger W no 4 2 

Rainbow smelt Osmerus mordax W yes 12 0 

Landlocked salmon Salmo salar W,S no 7 0 

Brown trout Salmo trutta S no 4 0 

Brook trout (landlocked) Salvelinus fontinalis W,S yes 17 18 

Brook trout (sea-run) Salvelinus fontinalis W yes 1b

 1b

Lake trout Salvelinus namaycush W,S no 2 0 

Banded killifish Fundulus diaphanus W yes 18 3 

Mummichog a Fundulus heteroclitus W yes 0 2 

Atlantic silverside a Menidia menidia W yes 0 1 

Fourspine stickleback Apeltes quadracus W yes 1 3 

Threespine stickleback Gasterosteus aculeatus W,S yes 6 3 

Ninespine stickleback Pungitius pungitius W yes 10 5 

White perch Morone americana W yes 4 0 

Redbreast sunfish Lepomis auritus W ? 3 0 

Pumpkinseed Lepomis gibbosus W yes 15 5 

Smallmouth bass Micropterus dolomieu W,S no 5 0 

Yellow perch Perca flavescens W no 3 1 

 * W/S = wild / stocked populations 

a Found in lower, freshwater stations of some coastal streams

b Confirmed in at least 1 pond and 1 stream, but reported in several other coastal streams 

Note that one additional species, largemouth bass (Micropterus salmoides) is present in Hamilton Pond, which is 

outside of the Park.

____________________________________ 

The golden shiner (Notemigonus crysoleucas) is the most common species in lakes and ponds, 

while brook trout (Salvelinus fontinalis) is most common in streams (Table 12). Seven species 

were recorded from half or more (≥12) of the surveyed lakes, while two species were present in 

half or more (≥17) of the streams. Two species were present in just one lake, while five species 

were present in just one stream. Ten species found in lakes were not found in streams. 
53 

The number of fish species in each lake is shown in Figure 28. Only one pond is fishless 

(Sargent Mountain Pond). From its high-elevation location we can infer that it is naturally 

fishless. Its acidic waters likely are one reason why it remains fishless today even though there 

are anecdotal accounts of unauthorized fish introductions. According to Stone et al. (2007), 15 of 

the 28 fish species currently present in ACAD are native to MDI waters. Only the depauperate 

Duck Pond appears to have never supported any fish species that is a non-MDI native (Figure 

28). 

As expected, larger ACAD lakes tend to contain more fish species than smaller lakes (Figure 

29). Compared to other lakes in southern Maine, fish species richness in ACAD lakes larger than 

about 50 ha is similar to the regional lake population. However, smaller ACAD lakes appear to 

be somewhat more species-rich than other lakes in the southern region of the State. As will be 

discussed in the Assessment of Threats section, higher species richness is not necessarily a 

desirable condition since it may reflect introductions of non-native species. 

Fisheries management in the ACAD region lakes falls under the jurisdiction of the Maine 

Department of Inland Fisheries and Wildlife (MDIFW), although management is implemented 

collaboratively with NPS. Since 2000, 14 out of 27 lakes in the region have been stocked by 

MDIFW with one or more species (Table 13). Seven lakes have not been stocked since 1989, 

although three of these were stocked in previous years. The most commonly stocked species is 

brook trout; other species include landlocked salmon (Salmo salar) and lake trout (Salvelinus 

namaycush). All three species are native to Maine, although lake trout and salmon are likely not 

native to MDI. Brown trout (Salmo trutta) has been stocked in two lakes frequently over the past 

two decades; this species is not native to North America. Stone et al. (2007) note that, of the 31 

total historical species, 10 have been stocked at some time; these include three species that are no 

longer present on the island. The issue of fish introductions is further discussed under Threats: 

Exotic Species. 

Although several diadromous species exist in the ACAD region, it is likely that runs are much 

smaller today than historically (D. Lamon, Somes-Meynell Wildlife Sanctuary, pers. comm. 

August 2007). Four species are present as anadromous as well as landlocked populations: alewife 

(Alosa pseudoharengus), rainbow smelt (Osmerus mordax), white perch (Morone americana) 

and brook trout (Stone et al. 2007). Letcher et al. (2006) are currently studying movement of 

brook trout between marine and fresh water at Stanley Brook, one of three or four systems on the 

island that are known to contain “salters” (sea-run brook trout). Final results from this research 

are not yet available. The catadromous species, American eel (Anguilla rostrata) is known from 

17 streams in the ACAD region (Table 12). 

Recent research studying the genetic structure of brook trout at ACAD (T. King, USGS-BRD, 

pers. comm. December 2004) has identified levels of relatedness among populations of minor 

drainages and has been able to detect the influence of past stocking events. Out of six brook trout 

populations studied on MDI, four have similar genetic structure (Marshall Brook, Jordan Stream, 

Stanley Brook and Hunters Brook), while two others appear relatively distinct (Lurvey and 

Hadlock Brooks). The final report from this study is not yet available. 
54 

0 5 10 15 20

Long P

Eagle L

Seal Cove P

Echo L

Jordan P

Somes P

Long P (IAH)

Hamilton P

Lower Hadlock P

Little Long P

Round P

Upper Hadlock P

Hodgdon P

Aunt Betty P

Bubble P

Witch Hole P

Breakneck Ponds

LakeWood

The Tarn

Duck P

The Bowl

Halfmoon P

Sargent Mountain P

Number of Species

Historically present Probable natives

Figure 28. Fish species richness of ACAD area lakes and ponds. “Historically present” indicates 

all species known to have been present. “Probable natives” are species thought to be natives to 

the specific waterbody. Data from Bowes et al. 1999. 

(Note that species totals do not always agree with those in the MDIFW database, from which data in Fig. 29 are 

derived. One reason is that some of the species recorded by Bowes et al. [1999] as being “historically present” are 

thought to be no longer present.) 

Figure 29. Fish species richness in ACAD area lakes compared to all surveyed lakes in southern 

Maine (red area in the inset map). 

Note: Sebago lake [12,327 ha, 27 fish species] is excluded from this figure. 

(Figure from Vaux [2005], based on data from ME Dept. of Inland Fisheries and Wildlife) 

0

5

10

15

20

25

30

0 1 10 100 1,000 10,000

Lake Area (ha)

# Species

Southern Maine ACAD Lakes
55 

Table 13. Fish stocking history for lakes in the ACAD region. Data are number of years that 

species has been stocked during the period 1989-2006 and the most recent stocking year (through 

2006). An asterisk (*) indicates that stocking occurred at some time during the period 1937-

1988, but not since then. 

Lake Brook trout LL Salmon Lake trout Brown trout Splake 

# 

years 

Most 

recent 

# 

years 

Most 

recent 

# 

years 

Most 

recent 

# 

years 

Most 

recent 

# 

years 

Most 

recent 

Long 15 2005 17 2005 

Eagle 17 2005 16 2006 3 1994 

Seal Cove * 10 2003 

Echo 17 2005 14 2005 1 1994 

Jordan * 16 2004 3 1991 

Somes 

Long P 

(IAH) 

 

Hodgdon 

Hamilton 

Upper 

Hadlock 

13 2005 * 1 2001 

Lower 

Hadlock 

17 2006 15 2005 

Round 17 2005 

Little Long * * 

Bubble 14 2006 

Aunt Betty 5 1993 

Witch Hole 17 2005 

Lower 

Breakneck 

17 2005 

Lake Wood 8 2005 

Little Round * 

Upper 

Breakneck 

17 2005 

Duck * 

Halfmoon 17 2005 

The Tarn 11 1999 

 

Data are from ME Dept. of Inland Fisheries & Wildlife, as accessed on PEARL Website (www.pearl.maine.edu). 

2006 data are from MDIFW Website. 
56 

Amphibians and Reptiles: Streams, wetlands and the littoral zone of some lakes are important 

habitat for many of ACAD’s amphibians and reptiles. These taxa have been discussed as a group 

under the section on Biological Resources of Terrestrial Systems. 

Freshwater Macroinvertebrates: Three of Maine’s 11 freshwater mussel species are known 

from MDI: triangle floater (Alasmidonta undulate), eastern elliptio (Elliptio complanata) and 

eastern floater (Pyganodon cataracta). None of these three species is listed as threatened or 

endangered by the State of Maine. 

Odonates (dragonflies and damselflies), mayflies and rotifers are perhaps the most welldocumented groups of freshwater-associated invertebrates in the ACAD region. Over 100 of 

Maine’s ca. 160 dragonfly and damselfly species have been recorded from MDI (data source: 

Maine Damselfly and Dragonfly Survey data as compiled in the Maine Aquatic Biodiversity 

Project database [Vaux 2005], including data of White [1989]). Just over one third (~58/~151) of 

Maine’s known mayfly species are known to occur on MDI (Burian and Gibbs 1991; Mack 

1998). The freshwater rotifers of MDI were thoroughly inventoried during a decade of field work 

by F. Myers during the 1920s and 1930s (see Kahl et al. 2000 for reference list). 

Macroinvertebrate assemblages in nine streams on MDI have been surveyed by ACAD and 

MDEP staff to evaluate the extent to which these streams attain their designated water quality 

class. The streams are: Duck Brook, Lurvey Spring Brook, Richardson Brook, Marshall Brook, 

Otter Creek, Hunters Brook, Stanley Brook, Heath Brook, and Lake Wood outlet stream. All 

streams are designated class AA, the highest quality class for streams in the State of Maine. Only 

two streams (Stanley Brook and Richardson Brook) attained the AA designation in all samples 

(Table 14). Heath Brook and Otter Creek had the poorest attainment rates. Biodiversity data 

(taxon lists and guild representation) for selected samples are available from MDEP’s 

biomonitoring Web site 

(http://www.maine.gov/dep/blwq/docmonitoring/biomonitoring/data.htm). 

There are baseline data on the benthic macroinvertebrates of the two major estuarine / marsh 

areas on MDI: Bass Harbor Marsh (Doering et al. 1995) and Northeast Creek (Keats and Osher 

2007). In both systems there is, as expected, a spatial gradient from freshwater to marine 

communities. In the case of Northeast Creek, the spatial arrangement of this gradient varies 

seasonally since the system is dominated by freshwater inflow in the spring, but by marine 

waters later in the year. Estuarine macroinvertebrate data are further discussed under the 

assessments of threats and conditions. 

Marine / Coastal Systems 

Physico-Chemical Environment of Marine / Coastal Systems 

The Acadia region has 4,818 ha of marine wetlands and 2,575 ha of estuarine wetlands (Calhoun 

et al. 1994). Using the Cowardin system of classification, marine and estuarine wetlands 

comprise 37.5% and 20%, respectively, of the total wetland area in the Acadia region (Calhoun 

et al. 1994). Park lands include 81 ha of intertidal areas and 38 ha of coastal salt marsh 
57 

Table 14. Stream water quality attainment based on macroinvertebrate biomonitoring data*

. 

Site Number of samples for which site attains 

designated class** of AA (total # of samples) 

Duck Brook Site S-854: 0 (1) Site S-322: 8 (11) 

Richardson Brook 2 (2) 

Lurvey Spring Brook 4 (9) 

Marshall Brook 5 (7) 

Hunter’s Brook 5 (8) 

Stanley Brook 11 (11) 

Heath Brook 1 (6) 

Otter Creek 1 (6) 

Lake Wood outlet 0 (1) 

 

*

 Most samples were collected during the period 1997 – 2004; number of samples varies per site. Data are from 

Maine Department of Environmental Protection’s biomonitoring Web site, accessed July 2008: 

http://www.maine.gov/dep/blwq/docmonitoring/biomonitoring/data.htm

Class descriptions may be found in MDEP (2004). 

** Stream Class is a legal designation adopted by MDEP. All ACAD streams are designated class AA, which is the 

highest quality designation possible. Macroinvertebrate samples are collected to measure the extent to which actual 

stream quality attains designated quality. 

______________________________________ 

(Mitchell et al. 2006). Fee ownership lands include extended sections of coastline in six areas of 

the Acadia region: (i) the southeastern section of MDI, from Schooner Head to Hunters Brook; 

(ii) east and west mid-sections of Somes Sound; (iii) the southern tip of western MDI; (iv) the 

Schoodic peninsula; (v) approximately one third of Isle au Haut; and (vi) several smaller islands, 

including Baker, Schoodic and Long Porcupine (Figure 2). 

With a total perimeter of about 208 km, MDI is the third largest island on the east coast of the 

United States and the largest in Maine. As described by Mathieson et al. (1998), MDI’s “diverse 

and irregular coastline ranges from exposed and semi-exposed open coastal sites, to hectares of 

protected waters, extensive mudflats, and salt marshes. .... Protected open coastal habitats are 

interspersed among the exposed ones, particularly within the embayed waters behind the 

Cranberry Isles, Somes Sound, Seal Harbor, Northeast Harbor, Southwest Harbor and Manset 

Harbor”. Mean tidal ranges are between 2.83 m on Isle au Haut and 3.23 m at Bar Harbor 

(Calhoun et al. 1994). Spring tidal ranges are approximately 0.5 m greater. 

While Somes Sound is often viewed as the only fjord on the east coast of the United States, it 

resembles other Maine estuaries in terms of hydrology and stratification (Pettigrew et al. 1997). 

Calhoun et al. (1994) provide a detailed overview of the geography, structure and hydrology of 

marine and estuarine wetlands in the Acadia region. There are two major freshwater / estuarine 

wetland complexes on MDI: Northeast Creek and Bass Harbor Marsh. More information on both 

these systems is provided under the Assessment of Threats. 

 

Although marine waters beyond low tide are outside National Park Service jurisdiction, they are 

an integral part of the park's setting (Kahl et al. 2000). Frenchman Bay is a relatively enclosed 
58 

body of water to the northeast of MDI. Blue Hill Bay, to the west, is a “sheltered and often 

muddy location fed by several large brooks and the Union River” (Mathieson et al. 1998). 

Waters to the south of MDI are more exposed. Marine sediments to the south of MDI are 

typically gravel, while those to the east of MDI (and, presumably, in Blue Hill Bay) are generally 

finer (Figure 30). 

Ocean currents along the mid-Maine coast typically run east to west (Figure 31), although finer 

level patterns can be more complex (e.g. Xue et al. 2000). Circulation patterns in the Blue Hill 

Bay region are of particular interest from the perspective of evaluating impacts from existing and 

future aquaculture operations (see Threats: Nutrient Enrichment). 

Figure 30. Sediment characterization in the Penobscot Bay to Frenchman Bay region of Maine. 

(Map generated from usSEABED database [Reid et al. 2005]) 

Figure 31. Circulation patterns in the Gulf of Maine. Data show mean 2005 surface current 

velocity vectors and are from the Gulf of Maine Princeton Ocean Model. Mount Desert Island is 

just west of center. 
59 

Biological Resources of Marine / Coastal Systems 

Marine Plant Communities: Calhoun et al. (1994) provide an overview of algal and vascular 

plant communities in the marine and estuarine wetlands of the ACAD region. Plant communities 

include: 

Marine system: 

- Aquatic beds – developed on an outstanding variety of substrates in the intertidal region. 

Estuarine system: 

- Intertidal flats (unconsolidated bottom) – expansive because of the high tidal 

range. 

- Estuarine aquatic beds – dominated by eelgrass (Zostera marina) and widgeon 

grass (Ruppia maritima). 

- Estuarine emergent wetlands (salt marshes) – three common communities in 

the region are (i) tidal stream salt marshes (e.g. Bass Harbor Marsh), (ii) 

fringe salt marshes (associated with steeply sloping coves and embayments), 

and (iii) transitional marshes. An example of the latter is where freshwater 

wetlands are inundated by rising sea level. With a sea level rise of 3 mm/year, 

this type of salt marsh may be occurring at a number of locations in the 

ACAD region. 

These authors note that zonation patterns in the salt marshes of the Acadia region more closely 

resemble marshes in the Bay of Fundy than those farther south. They also note that “study of salt 

marsh community development, plant community composition and distribution, hydrology, and 

wildlife value has been very limited in the region” (Calhoun et al. 1994). Most of the available 

information on salt marshes of the Acadia region comes from studies on Bass Harbor Marsh, 

research that was done in part because of the marsh’s proximity to the Worcester Landfill. 

Doering et al. (1995) and Kinney and Roman (1998) summarize this research, which is further 

discussed in the section Threats: Nutrient Enrichment.

Research by Mathieson et al. (1998) provided the most detailed information available on the 

marine aquatic beds at ACAD. These authors studied the composition and zonation patterns of 

macroalgal communities at a series of high and low wave energy sites around MDI. A total of 

113 taxa were collected by these researchers in the 1990s; this total was compared to 121 taxa 

that had been recorded during previous studies. Combining data from all studies, a total of 146 

taxa have been recorded from the ACAD region (Table 5). Approximately one third of these 

species were represented by each of the major groups of seaweeds: green, brown and red algae. 

Highest species richness occurred in exposed areas (Otter Cliffs and Seawall), while sheltered 

sites exhibited the lowest diversity. 

Benchmarked collections made in 1928 from Otter Cliffs (Johnson and Skutch 1928a, b, c) 

allowed Mathieson et al. (1998) to compare zonation patterns for different species over a ca. 60-

year time period. There has been a marked reduction in the upper distributional limit for 13 

species. In contrast, no species showed an upward expansion. The reasons for this change in 

distribution are unknown, although the authors speculate that the general warming trend in the 

Gulf of Maine may be a factor. 
60 

Ongoing research (Olson 2007) is documenting the flora (and fauna) of rocky intertidal habitats 

on the Schoodic Peninsula, perhaps one of the most pristine examples of this habitat in the State 

of Maine. The data will serve as a baseline from which to evaluate the impacts of visitor 

trampling. In addition, researchers at Northeastern University (J. Long and G, Trussell) are 

developing a rocky intertidal monitoring program for ACAD (development in 2008 and 2009, 

implementation in 2010); this program will also look at trampling impacts (B. Mitchell, NETN, 

pers. comm. January 2008). Muhlin et al. (2008) studied reproduction and genetic variation in 

focus around two peninsulas in Maine, one of which was the Schoodic peninsula. Coleman and 

Brawley (2005) also researched algal genetics and dispersal at SCH. 

Figure 32A shows the distribution of eelgrass (Zostera marina) in the Acadia region during the 

1990s. Eelgrass beds were most expansive in the upper part of Frenchman Bay and to the east of 

the Schoodic Peninsula. There were relatively few eelgrass beds around MDI, possibly as a result 

of coastline morphology. Quantitative time series data on eelgrass distribution are available only 

for around Sears Island, to the west of the main ACAD region. In that area, eelgrass cover 

decreased between 1992 and 2004 (Figure 32B). Similar kinds of time-series evaluations of 

eelgrass distribution are needed for waters in the vicinity of MDI5

. 

(A) (B) 

Figure 32. (A) Occurrence of eelgrass in the Acadia region. (B) Changes in eelgrass distribution 

in the Sears Island area between 1992 and 2004 (top left corner in [A]). 

Data in panel (A) are a section of a statewide coverage developed from work done between 1992 and 1997. In this 

region, mapping was conducted using photography from: 1992 - Most of Penobscot Bay except for the Fox Islands (North Haven & Vinalhaven) 1993 - Pen Bay around the Fox Islands 1997 - East of Schoodic Point

1996 - Everything else (MDI, Isle au Haut, Blue Hill Bay, Frenchmans Bay, Deer Isle, Swans Island etc.) 

Data sources: (A) Maine Office of GIS (http://megisims.state.me.us/metadata/megrass.htm). (B) S. Barker, Maine 

DMR, unpublished data.

 

5

 Two eelgrass GIS coverages are available at ME Office of GIS (http://megis.maine.gov/catalog), dated 1997 and 

2005. Comparison of these coverages reveals that eelgrass areas around MDI are identical. Metadata suggest that the 

MDI area was not re-surveyed during the 2004 survey – the Penobscot Bay was, however, re-surveyed. 
61 

Marine Birds: Approximately 20% of the resident bird species of the ACAD region, as well as 

a number of migrant species, are associated with marine habitats (Table 8). Birds are discussed 

above, under Terrestrial Systems. 

Marine Mammals: The list of ACAD mammals includes two marine species: gray seal 

(Halichoerus grypus) and harbor seal (Phoca vitulina). The full species list, developed from the 

NPSpecies database, may be found at www.pearl.maine.edu. According to Richardson (1973), an 

area of 500 square nautical miles in the ACAD region supported an estimated resident population 

of 1,600 harbor seals and an estimated seasonal population of 40 gray seals. At the time of that 

study, an absence of historical quantitative data prevented any conclusions being made about 

trends in population densities. 

Because most other marine mammals generally do not utilize Park lands, they are outside the 

scope of this report. 

Marine Fish: In their study of the Bass Harbor Marsh system, Doering et al. (1995) reported 

that 30% of the 23 fish species recorded from this estuary were marine taxa (Table 15). Jordaan 

(2006) conducted an extensive study of fish community structure on the coasts of MDI, SCH and 

neighboring areas. A total of 12 species were collected from tidepools, 50% of which were 

considered to be residents and 50% transients. Twenty species were collected from estuarine 

habitats, including Bass Harbor, Somes Sound and Northeast Creek sites. 

Although we do not focus on off-shore marine species in this report, it should be noted that there 

is quite extensive information on marine fish populations in the MDI area and elsewhere along 

the Maine coast. Coastal waters in the ACAD region provide spawning habitat for a number of 

species, for example cod and haddock (Ames 1997, 2004; Figure 33). Sherman et al. (2005) 

summarize data from a comprehensive bottom trawl survey of groundfish and other species for 

Maine and New Hampshire’s inshore waters. Sampling included many trawl sites around MDI. 

Trawl data are available for >70 fish species as well as some invertebrates. Figure 34 shows a 

selection of their data. Neal et al. (2003) reported on spawning habitat and temporal trends in 

spawning by Atlantic herring (Clupea harrengus) in the Gulf of Maine. One of their sampling 

sites was off Islesford. Herring is one of the keystone species in the Gulf of Maine and 

populations appear to have decreased over the past two decades. 

Table 15. Groups of fishes recorded from Bass Harbor marsh (Doering et al. 1995). 

Life History Group Number of 

Species 

Examples 

Freshwater 4 Minnows and brook trout 

Diadromous 1 American eel 

Nursery 4 Clupeids, atherinid, mullet 

Resident 7 Mummichog, sticklebacks 

Marine 7 Hake, haddock, pollock, flounder, mackerel 

 
62 

Figure 33. Historical spawning areas of cod and haddock in Maine territorial waters. 

Map based on data in Ames (1997). 

Figure 34. Density of Atlantic herring and American lobster in fall benthic trawl surveys. 

(Figure from Sherman et al. 2005). 
63 

Marine Reptiles: Three marine turtles occur along the Maine coast as vagrants: leatherback 

(Dermochelys coriacea), loggerhead (Caretta caretta) and Atlantic ridley (Lepidochelys kempii). 

Although all three are federally listed as threatened or endangered species (Hunter et al. 1999), 

none are known to use habitat within or bordering ACAD. 

Marine Macroinvertebrates: There are limited inventories of marine macroinvertebrates in the 

intertidal and sub-tidal regions of ACAD, and few time series monitoring data. Procter (1933) 

conducted an inventory of marine invertebrates at subtidal and intertidal sites in Frenchman and 

Blue Hill Bays from 1926 to 1932. His work documented a total of 668 species and represents 

the most complete survey of invertebrates in marine waters surrounding ACAD (Procter 1933, 

Mittelhauser and Kelly 2007). In 1929, Procter collected the eelgrass limpet (Lottia alveus) off 

Mount Desert Island. This species is now believed to be extinct (Carlton et al. 1991). 

Fefer and Schettig (1980) provide a detailed review of the invertebrate populations of coastal 

Maine mudflats and their ecological role. Cammen and Larsen (1992) sampled intertidal 

macrofauna at high-energy rocky shore sites and on low-energy mudflats at Thompson Island, 

Compass Harbor, Thunder Hole and Otter Cove. Their data include taxonomic composition and 

an analysis of seasonal and inter-annual variability. They recommended repeat monitoring of 

their sites every 10 years using identical protocols. Doering et al. (1995) sampled benthic 

invertebrates in Bass Harbor Marsh and concluded that the communities were typical of the 

region and paralleled mudflat data reported by Cammen and Larsen (1992). Doering and Roman 

(1994) noted that baseline data are lacking on the benthic invertebrates of Somes Sound. 

Rocky intertidal areas in the Schoodic Peninsula unit of ACAD may represent some of the most 

pristine shoreline habitat in the State of Maine (S. Brawley, University of Maine, pers. comm.). 

This is because much of the area was off-limits to the public during occupation by the U.S. 

Navy. It has been identified as a Maine Critical Area for its high macroinvertebrate diversity 

(Doggett et al. 1978). Although detailed baseline data do not currently exist for this intertidal 

area, the ongoing research of Olson (2007), as well as the intertidal monitoring protocol 

mentioned previously, include detailed floral and faunal inventories and should help to fill this 

information gap. 

A further source of information on marine macroinvertebrates in the Acadia region includes the 

Massachusetts Institute of Technology Marine Invader Tracking Information System 

(http://chartis.mit.edu/mitis/), which in turn contributes to the International Nonindigenous 

Species Database Network (http://www.nisbase.org/nisbase). While reporting is targeted toward 

invasives, some of these monitoring efforts provide a limited amount of time-series data on 

endemic marine species in the ACAD region as well. 
64 

Assessment of Threats 

Introduction 

This section discusses the threats and stressors6 that are affecting, or thought to be affecting, 

natural resources at ACAD. An individual stressor can have multiple interacting causal factors. 

For example, changes in surface water and groundwater hydrology can result from increased 

residential use and/or residential development, changes in the proportion of runoff to infiltration, 

reduced precipitation, and other factors. 

We focus on threats/stressors that have anthropogenic associations. In some cases, the action of 

an essentially natural factor has been influenced by human-associated events. An example is the 

disturbance regime caused by beaver colonization. Although a natural process, it has been 

influenced on MDI by re-introduction of this species and the major fire of 1947. 

To organize our examination of threats, we developed a resource-stressor matrix to indicate 

which stressors are associated with each ecological system. Matrix content was based on 

conversations with ACAD scientists and other researchers, as well as a study of the 

comprehensive bibliographic database maintained at ACAD. Each cell in the matrix contains 

information on the extent or scale of a stressor and its impact on biotic or abiotic components of 

a resource. An example cell is: 

Resource: Terrestrial systems 

Stressor: Invasive species 

Extent: Spatial / temporal distribution 

Impact(s): Documented or inferred affects on other taxa. 

For each cell in the resource-stressor matrix, the extent of the problem was categorized as 

follows: 

• Existing problem (EP): convincing recent (since 1980) evidence, or earlier evidence 

plus reason to be fairly confident that the problem still occurs. 

• Potential problem (PP): either i) evidence external to the Park suggests there may be a 

problem at ACAD, (ii) there is earlier evidence for the problem but we are not certain 

that it still occurs, or (iii) what we know about the Park suggests the problem could be 

occurring but is currently undocumented. 

• Historic problem (HP): documented to have occurred >30 years ago, and there are no 

new data suggesting continuation. 

• Problem unlikely (OK): the issue has been investigated and it does not seem to 

represent a problem based on available data, which may be limited. 

• Unknown (Unk): not enough data to determine if problem exists at ACAD. 

 

6

 We use the terms ‘threat’ and ‘stressor’ almost interchangeably in this report. Threat is sometimes viewed as a 

potentially problematic environmental trend while stressor is the process whereby the threat impacts the target 

system. 
65 

We assigned a confidence value to each problem evaluation by characterizing the extent of the 

information base: Good, Fair, Poor, Inferential. The latter category was used when we based 

conclusions about a problem at ACAD entirely on information derived from outside the ACAD 

region. 

For each threat, we first describe the sources and magnitude of the threat. We then review how 

that threat is affecting the terrestrial, freshwater and marine resources at ACAD. Where possible, 

we compare and contrast ACAD data with regional or national data. Discussion of each threat is 

preceded by a summary matrix that lists (i) the key issues to be discussed, (ii) the scale of the 

problem, and (iii) the extent of supporting information about the issue. The threat assessment 

section concludes with a presentation of the complete resource-stressor matrix that summarizes 

the extent to which the full suite of stressors is acting on all ecosystems in the Acadia region. 

Some stressors incorporate multiple sub-topics each of which may be characterized differently 

with respect to the scale of the problem and information richness. While the matrices simply 

record the multiple characterizations (e.g. EP / PP), the main text addresses each sub-topic, and 

the associated scale of problem and extent of information. 

Ultraviolet Radiation 

 Key Issues Extent of Problem Information Base

UV dose to and flux in wetlands PP Good 

UV impacts on amphibians PP Inferential 

Reduced stratospheric ozone levels have resulted in increasing amounts of UV-B radiation 

reaching the earth’s surface. Higher levels of UV-B radiation can be detrimental to human health 

and biological resources, including amphibians, and marine and freshwater plant and animal 

populations. The EPA UV-Net program has operated a network of spectrophotometers across the 

U.S. to measure full-sky solar radiation in the UV-B and UV-A bands 

(http://www.epa.gov/uvnet/). Fourteen of the monitoring sites were located in National Parks as 

part of the PRIMENet program. The ACAD site was active from 1998 to 2004 (Table 16). 

As part of a larger study to measure UV-B radiation in wetlands of six national parks, Diamond 

et al. (2005) collected dosimetry data at ACAD between 1999 and 2001 (Figure 18). The 

research was designed to assess the role of UV-B as a stressor affecting amphibian health. The 

UV dose is the amount of radiation arriving at the wetland surface. The flux of UV radiation is 

the amount of radiation transmitted through the water column; it is influenced by the surrounding 

landscape and attenuation by the water. Mean UV-B dose at ACAD was lower than at the other 

five parks (Figure 35). Lowest values of UV-B flux were also observed at ACAD, in part 

because of relatively high dissolved organic carbon in ACAD wetlands (Diamond et al. 2005). 
66 

Table 16. Monitoring of physical and chemical parameters at ACAD. 

CM = Cadillac Mountain, MH = McFarland Hill. 

Parameter Location Start Year End Year 

Meteorology(1) CM, MH 1995 (CM), 1981 (MH) present 

Wet deposition(2) MH 1981 present 

Dry deposition(3) MH 1998 present 

Mercury deposition(4) MH 1995 present 

Ozone CM 1995 present 

MH 1982 present 

Schoodic 2003 present 

Sulfur dioxide CM 1988 1990 

Nitrogen oxides CM 1991, 1993, 1995- present 

VOCs(5) CM 1991, 1993, 1995- present 

Carbon monoxide CM 2002 present 

UV MH 1998 2004 

Particulate matter MH 1988 present 

Teleradiometer(6) MH 1980 1986 

Transmissometer(6) MH 1987 1994 

Nephelometer(6) MH 1993 present 

Web camera(7) CM 1999 present 

Surface water chemistry(8) 19 park lakes 1997(9) present 

 (1) Includes wind speed, wind direction, temperature and relative humidity 

(2) National Atmospheric Deposition Program / National Trends Network 

(3) Clean Air Status and Trends Program 

(4) Mercury Deposition Network 

(5) Volatile organic compounds 

(6) Used to monitor visibility impairment 

(7) Used to interpret current visibility conditions 

(8) Acidification and eutrophication parameters 

(9) Some data exist prior to this date. 

(Data from Maniero and Breen 2004) 

Figure 35. Mean dose of UV-B radiation at six national parks. Figure uses data from Table 2 of 

Diamond et al. 2005. 
67 

Current research on some ACAD lakes is investigating the association between UV-B radiation 

and zooplankton populations (E. Whitmore, University of Maine, pers. comm. June 2007). 

 

Visibility Impairments 

Key Issues Extent of Problem Information Base

Visibility at ACAD, primarily an issue for 

visitors/residents. 

EP Good 

Visibility and haze monitoring has been carried out at ACAD since the 1980s as part of the 

IMPROVE program (Table 16). Selected visibility-related data are presented in Figure 36. The 

standard visual range in the ACAD region is greater than in most of the eastern part of the 

country, but is lower than in the western U.S. Visibility at ACAD depends on air trajectories – 

days with highest visibility are those when air masses derive from the north, while lowest 

visibility occurs when trajectories are from the south and southwest. 

Ozone 

Key Issues Extent of Problem Information Base

Ozone concentrations EP Good 

Impacts on terrestrial plants EP Good 

Atmospheric Ozone Levels

Tropospheric (ground level) ozone has been monitored on MDI since 1982 and at SCH since 

2003 (Table 16). Information on park ozone monitoring is available on the Web site of the NPS 

Air Resources Division (http://www2.nature.nps.gov/air/monitoring/network.cfm). 

Urban-derived plumes of ozone (and other pollutants) have been tracked from the Boston and 

New York areas to coastal Maine. Ozone levels in coastal areas are higher than those at inland 

Maine sites (Jagels et al. 1989). The annual number of 8-hour ozone exceedances at ACAD since 

1983 has ranged from 1 to 17 (Table 17). Ozone concentrations are consistent with values 

documented from other non-urban sites in New England (Maniero and Breen 2004). Like many 

other NPS sites, ozone concentrations (both 1-hour and 8-hour) at ACAD showed an increasing 

trend between 1992 and 2002 (Maniero and Breen 2004). However, the most recent NPS Air 

Quality Division report on air quality trends in national parks concluded that there was no 

significant trend in tropospheric ozone concentrations (measured as the average 3-year, 4th

highest, 8-hour ozone concentration) during the period 1996-2005 (NPS 2006). Ozone condition 

at ACAD was considered “moderate” and stable. In 2004, EPA designated ACAD as a nonattainment area for the 8-hour National Ambient Air Quality Standard of 0.85 ppm. 

 
68 

(A) 

 (B) (C) 

Figure 36. Visibility at ACAD. 

(A) Standard visual range (km) for the U.S. Data are average values for the period 1996-1998 

(figure from the IMPROVE program, http://vista.cira.colostate.edu/improve/). 

(B) Air trajectories on days with the 20% best visibility at ACAD, 1997-1999. 

(C) Air trajectories on days with the 20% worst visibility at ACAD, 1997-1999. 

Air trajectory figures provided by D. Manski, ACAD, and originated from MANE-VU (MidAtlantic/Northeast Visbility Union, www.mane-vu.org). 
69 

Table 17. Annual number of 8-hour ozone exceedances at six park units. Data for individual 

years are shown for ACAD, only. 

 ACAD: 

MH 

ACAD: 

CM 

CACO GRSMLR ROMO SHEN YOSETD 

Mean 5.2 4.6 9.1 11.7 2.7 6.6 9.7 

Max. 17 9 25 37 7 24 31 

Min. 1 1 2 2 1 1 2 

# years 

with data 

19 10 19 21 7 20 15 

 

Legend

ACAD: MH – Acadia – McFarland Hill. 

ACAD: CM – Acadia – Cadillac Mountain. 

CACO – Cape Cod National Seashore. 

GRSM-LR – Great Smoky Mountains NP – 

Loon Rock. 

ROMO – Rocky Mountain NP. 

SHEN – Shenandoah NP. 

YOSE-TD – Yosemite NP – Turtleback Dome. 

Year 

1983 11 -- 

1984 7 -- 

1985 3 -- 

1986 3 -- 

1987 6 -- 

1988 17 -- 

1989 2 -- 

1990 4 -- 

1991 7 -- 

1992 1 -- 

1993 3 -- 

1994 -- -- 

1995 5 2 

1996 2 1 

1997 1 5 

1998 4 8 

1999 5 4 

2000 -- 3 

2001 9 9 

2002 6 8 

2003 2 3 

2004 -- -- 

2005 -- 3 

 
70 

Ozone Impacts on Terrestrial Vegetation 

Extensive research has evaluated ozone effects on terrestrial vegetation at ACAD. Maniero and 

Breen (2004) provide an excellent synopsis of much of this research. Some of the more recent 

studies are summarized below. 

Kohut et al. (2000) examined 32 plant species exposed to ozone under experimental conditions 

to identify potential bioindicator taxa at ACAD. Species injured at ambient ozone levels were 

black cherry (Prunus serotina), quaking aspen (Populus tremuloides), white ash (Fraxinus 

americana), jack pine (Pinus banksiana), big-leaf aster (Aster macrophyllus), and spreading 

dogbane (Apocynum androsaemifolium). Red maple (Acer rubrum), pin cherry (Prunus 

pensylvanica), mountain ash (Sorbus americana), mountain holly (Nemopanthus mucronatus), 

and flat-topped aster (Doellingeria umbellata) were also injured at ambient levels. Species that 

showed foliar injury at >150% of current ambient levels were gray birch (Betula populifolia), 

small sundrops (Oenothera perennis), and bunchberry (Cornus canadensis), suggesting their 

ability to tolerate somewhat higher than ambient ozone levels. Some species were not injured 

even at twice the ambient levels of ozone, including paper birch (Betula papyrifera), eastern 

white pine (Pinus strobus), pitch pine (Pinus rigida), red spruce (Picea rubens), northern white 

cedar (Thuja occidentalis), northern red oak (Quercus rubra), Canada bluejoint grass 

(Calamagrostis canadensis), wild radish (Raphanus raphanistrum), and Canada mayflower 

(Mianthemum canadensis). Due to characteristic injury patterns big-leaf aster (Aster 

macrophyllus), spreading dogbane (Apocynum androsaemifolium), quaking aspen (Populus 

tremuloides), white ash (Fraxinus americana), flat-topped aster (Doellingeria umbellata), and 

black cherry (Prunus serotina) were recommended by Kohut et al. (2000) as reliable ozoneindicator species. They further suggested that these species should be the core of any biomonitoring program designed to assess the incidence and extent of ozone injury at ACAD. 

Plants are seldom exposed to only one stressor and the interaction of multiple stressors can have 

significant effects on plants. Much of the vegetation at ACAD is frequently exposed to fog, some 

of which may be acidic (see further discussion under Threats: Acidity and Related Chemisty). 

The combined effects of ozone and acidic deposition should be explored in further detail (Jagels 

et al. 2002). 

Kohut (cited by Maniero and Breen 2004) used multiple ozone exposure metrics to identify 

ozone-sensitive species and determine the likelihood of injury. These 16 species include the 

reliable ozone-indicator species listed above. 

Another study (Eckert et al. 1997) examined the effects of ozone at ACAD by quantitatively 

sampling natural populations of big-leaf aster and spreading dogbane for visually detectable 

symptoms of ozone injury. The authors concluded that ozone injury in big-leaf aster in 1996 

occurred at more sites than in 1993-1994 and one fewer site than in 1995. Ozone injury for 

spreading dogbane occurred in 25% of populations examined, contrasting with the virtual 

absence of injury noted in previous surveys (1993-1995) by these authors. This difference may 

be associated with increased precipitation in 1996 relative to other years. Wetter conditions may 

have promoted enhanced stomatal opening, thus permitting greater uptake of ozone (Eckert et al.

1997). 
71 

Bartholomay et al. (1997) showed that white pine radial growth at ACAD is inversely related to 

ozone level and duration of exposure. Seven of eight stands observed in their dendroclimatic 

survey documented negative associations between tree-ring indices and ozone levels. This 

association was stronger than any modeled association between tree-ring indices and climate 

factors. Short-term, high-level ozone events were shown to have the greatest negative association 

with tree-ring widths. The study showed stand (habitat) level variation suggesting that microecological characteristics could affect tree response to ozone pollution. The authors note that 

trees growing on better sites could be more susceptible to ozone damage because they have 

higher rates of photosynthesis. 

Wenner and Merrill (1998) concluded that ozone tissue damage on white pines is rare, contrary 

to what was believed in earlier years. According to these authors, observed foliar damage in this 

species is more likely the result of needle blight associated with a fungal infection, rather than 

elevated ozone levels. 

Chappelka and Samuelson (1988) reviewed ambient ozone effects on forest trees of the eastern 

United States. Appendix 12 presents their data for eight species found at ACAD. Ozone had no 

effect on growth for five of these species, although there were effects on some physiological 

measures. For the other three species, ozone levels reduced growth rates and/or height or tissue 

biomass. 

Theisen et al. (1994) used fluorescence to study the physiological response of white pine to 

short-term ozone exposure at ACAD. They concluded that photosynthetic processes partially 

recover within 48 hours following ozone exposure. 

Atmospheric Deposition (Acidity and Related Chemistry) 

ACAD “is uniquely located downwind of major pollution sources and, as a result the watersheds 

receive some of the highest levels of air pollutants ... in the northeastern United States” (Haines 

and Webber 1999). Atmospheric deposition contributes acidity (hydrogen ions), nitrogen, sulfur 

and other constituents to terrestrial and aquatic systems. It has been the subject of extensive 

research at ACAD. In this section, we first provide an overview of deposition chemistry at 

ACAD. We then discuss this chemistry from the perspective of the Park’s terrestrial and aquatic 

systems. A subsequent section of this report (Threats: Nutrient Enrichment) focuses on the issue 

of nutrient enrichment in aquatic systems. This separation is somewhat artificial – nitrogen, 

while contributing to acidity, is also a nutrient, and atmospheric deposition is a significant source 

of this element. 

Key Issues Extent of Problem Information Base

Precipitation chemistry EP Good 

Fog chemistry EP Fair 

Impacts of acidity on terrestrial 

vegetation 

EP Good 

Impacts of N on terrestrial vegetation EP Fair + inferential 

Impacts on freshwater chemistry EP Good 

Impacts on freshwater biota PP Poor 

Impacts on marine/coastal systems PP Fair 
72 

(A) (B) 

 (C) (D) 

Figure 37. Precipitation chemistry at the McFarland Hill NADP site, 1981-2006. 

(A) pH, (B) sulfate, (C) nitrate, (D) ammonium. 

Atmosphere: Deposition Chemistry 

During the period 1981-2006, the annual average pH of precipitation at ACAD ranged from 4.4 

to 4.9 (Figure 37A). These pH levels are considered to be three- to four-times more acidic than 

pre-industrial precipitation chemistry in eastern North America (see references in Kahl et al. 

2000). Annual average values of precipitation pH suggest a possible increasing trend in recent 

years (Figure 37A). Previous analyses of data from the period 1981-1993 suggested a slight pH 

decrease (increase in acidity) (Kahl et al. 2000). 

Sulfur (S) and nitrogen (N) compounds both contribute to acidity, although the former have been 

the major acidifying substances in acid rain in Maine (Kahl et al. 1991). Primary anthropogenic 

sources of atmospheric S and N include power plants, other industrial sites and vehicle 

emissions. Natural sources of atmospheric S are volcanoes (SO2) and emissions from organisms 

and decaying matter (dimethyl sulfide), which are subsequently oxidized in the atmosphere to 

sulfuric acid (H2SO4) (Turco 2002). Deposition of atmospheric S and N occurs through 

precipitation (wet deposition), dry deposition and ground-level cloud/fog. Because of its 

proximity to the ocean and the marine origin of some sulfate (SO4), ACAD received 20% to 40% 

more SO4 in wet deposition annually than inland sites in Maine during 1997-2001 (NADP 2007). 
73 

Because S has a short residence time (days) in the atmosphere and is readily scavenged by wet 

deposition (Turco 2002), emissions reductions following implementation of the 1990 Clean Air 

Act Amendments had immediate effects on S deposition (Kahl et al. 2004). Across the 

Northeast, a region strongly affected by acidic deposition, SO4 in wet atmospheric deposition 

declined ~39% between 1993 and 2003 (Kahl et al. 2004). At ACAD, annual average SO4

concentrations in wet-only deposition measured at the NADP site suggest a similar decline 

(Figure 37B). In contrast, N deposition through the early 2000s did not decline to the same 

extent. Recent data, however, suggest that nitrate (NO3) concentrations may be trending lower 

than levels observed during the most of the 1980s and 1990s while ammonium (NH4) deposition 

appears to remain more constant (Figure 37C, D). Kahl et al. (2004) observed that continued N 

deposition may contribute to the lack of recovery in acid neutralizing capacity (ANC) of surface 

waters. 

Using NADP SO4 data from 2006 as an example, ACAD wet deposition values were comparable 

to those recorded from other NADP sites in Maine (Figure 38). They were lower than values 

reported from sites in the Midwest and Mid-Atlantic, and higher than values for Western sites. 

Wet-only deposition underestimates total deposition for some ions, such as S. The chemistry of 

throughfall provides a reasonable estimate of total deposition to a watershed for more 

conservative ions (Grigal 2002, Rea et al. 2000, Lovett 1994, Rustad et al. 1994, Lindberg and 

Lovett 1992). 

Figure 38. 2006 sulfate concentrations in wet deposition (from http://nadp.sws.uiuc.edu/). 
74 

Two recent projects have quantified throughfall deposition of S at ACAD: an MDI-wide study 

that used resin beads to collect S data (Simkin et al. 2004, Weathers et al. 2006), and a paired 

watershed study that quantified S mass balances (Nelson 2002, Kahl et al. 2007b). Both studies 

found that S deposition as throughfall was dependent on landscape factors, with elevation and 

vegetation type driving differences in enhancement of S across the heterogeneous landscapes. 

Weathers et al. (2006) reported modeled S deposition hotspots up to 25 kg/ha/yr (Figure 39), 

while Kahl et al. (2007b) found maxima of only 13 kg/ha/yr, based on data collected from 

smaller watersheds. However, both models suggest relative hotspots of S deposition in coniferforested and in high-elevation areas. Regardless of the differences in magnitude, both studies 

clearly demonstrate that wet-only deposition represents less than half of total S inputs at sites 

that have forest canopy cover. 

In contrast to S, N tends to be under-represented by throughfall measurements because the forest 

canopy takes up N as it is deposited, reducing the amount of N that appears below the forest 

canopy. Weathers et al. (2000, 2006) used relationships developed for S to scale up N wet 

deposition to model total deposition of N. Using such relationships, these authors report a range 

for total N deposition at Acadia from 3.0-13.5 kg/ha/yr (Figure 39). These model-based estimates 

of total N deposition are an average of 70% greater than those derived from summing wet 

Figure 39. Modeled total atmospheric deposition of S and N to MDI for the year 2000. 

(Image from Weathers et al. 2006, used with permission) 
75 

(NADP) and dry (CASTNET) deposition data. Because much of ACAD is under coniferous and 

mixed forest canopy (the forest types that are associated with the highest total depositional inputs 

of N), continued N deposition is a threat to the park’s freshwater and marine resources. 

Although fog is a common phenomenon in coastal areas of Maine, few research projects have 

examined fog acidity and chemistry at ACAD. Weathers et al. (1986) conducted one of the first 

acidic fog research projects and documented fog pH, nitrate, and sulfate across the eastern U.S., 

including Bar Harbor (Figure 40). The Bar Harbor site had the greatest SO4 concentration of all 

sites sampled during the August 1984 cloud/fog event. For all sites, fog pH was extremely low, 

ranging from 2.8-3.09, considerably lower than the average pH of rain in the region. The lowest 

pH value was measured in Bar Harbor. 

Jagels et al. (1989) and Kimball et al. (1988) provide additional data on fog and cloud chemistry. 

Figure 40. Sulfate (shaded bars) and nitrate (open bars) concentrations of acidic cloud/fog events 

in Bar Harbor compared with other sites. 

Site ME is Bar Harbor; MK is New York; HB- Hubbard Brook, NH; VA is Virginia. Mean 

precipitation data are from Whiteface Mountain, NY; Ithaca, NY; Hubbard Brook, NH; and 

Charlottesville, VA. 

* Bar Harbor sample collected on 7-8 August 1984; ** Bar Harbor sample collected on 8-9 

August 1984. 

(Figure from Weathers et al. 1986, used with permission) 
76 

Impacts of Atmospheric Acidity on Terrestrial Systems 

An extensive literature review on potential impacts of acid precipitation by Anderson (1984) 

examined the susceptibility of vegetation and other biota to acidic deposition, sulfur dioxide7

(SO2), and other contaminants. Plant species are listed based on relative sensitivity to SO2 (see 

Tables III and IV in Anderson 1984). 

Jagels et al. (2002) studied differential sensitivities of red spruce (Picea rubens) and white pine 

(Pinus strobus), two common species at ACAD, to acid fog. The major symptom observed on 

coastal red spruce was upper surface chlorosis of needles older than the current year (Jagels et al. 

1989). White pine is a frequent cohort of red spruce stands at ACAD, yet pine show sensitivity to 

ozone but not to acid fog (Kohut et al. 1990, but see Wenner and Merrill 1998). Symptoms of 

red spruce decline in Maine were observed at sites which received both acid fog and acid rain, 

but not at locations which received only acid rain (Jiang and Jagels 1999). The greatest symptom 

development was in mid-coast Maine where ACAD is located (Jagels et al. 1989). Differential 

sensitivities of red spruce and white pine to acid fog and ozone could be explained by differences 

in physiological responses with respect to photosynthetic gas exchange patterns (stomatal 

conductance). Research on red spruce at Isle au Haut and other sites in Maine indicated that acid 

fog enhanced epicuticular wax production and calcium leaching from needles (Percy et al. 1993, 

Jiang and Jagels 1999). 

The recently established Northeastern Temperate Network (NETN) long-term forest monitoring 

sites are beginning to produce baseline data to evaluate long-term trends in soil and vegetation 

characteristics at ACAD. This program uses the ratio of calcium to aluminum (Ca:Al) in soil or 

soil solution as an indicator of acidification stress to forest vegetation. Initial Ca:Al ratio data 

from NETN soil plots indicate that 46% of plots show ratios that may be considered to be of 

“significant concern”, while 37% were rated “good” (Table 18). 

Impacts of Atmospheric Nitrogen on Terrestrial Vegetation 

Nitrogen deposition in forests of the northeastern U.S. has led to changes in forest species 

composition and increased N leaching into surface waters (Aber et al. 2003). High levels of 

forest floor N can lead to foliar nutrient imbalances in many species, as well as reduced cold 

tolerance and increased freeze injury to foliage. Such stresses can in turn reduce sugar reserves 

and increase the potential for secondary stressors that cause tree mortality (McNulty et al. 1991). 

Drought, aluminum toxicity, and nutrient leaching from the forest floor could act synergistically 

with N saturation to increase the potential for tree mortality. These factors could also lead to a 

shift in species composition to stands of birch (Betula spp.) and sugar maple (Acer saccharum) 

and a faster N-cycling ecosystem (McNulty et al. 1991). 

Tree species common to ACAD have very different patterns of N cycling (Finzi et al. 1998) and 

may respond differently to increased N deposition. There are significant relationships among N 

deposition, soil C:N ratio, and nitrification, but the strength and significance of these 

 

7

 The form of S that is typically emitted and dominatesin the atmosphere; dissolved in water it becomes sulfuric acid 

and is typically measured as sulfate in precipitation. 
77 

Table 18. Forest plot-level data for four condition metrics. Data are number of sites at each rating 

value, by park region*. 

Metric / Rating Region 

 IAH MDI-West MDI_East SCH 

 

CWD**: Sig. concern 5 17 19 4 

 Caution 2 9 7 1 

 Good 1 4 10 0 

 

Tree condition: Sig. concern 1 1 2 0 

 Caution 1 13 11 2 

 Good 6 16 24 3 

 

Ca:Al ratio: Sig. concern 3 16 16 2 

 Caution 3 5 9 1 

 Good 3 9 12 2 

 

C:N ratio: Sig. concern 1 1 0 0 

 Caution 1 4 8 0 

 Good 6 25 29 5 

*Data provided by B. Mitchell, May 2008 

** CWD = coarse woody debris 

______________________________________ 

relationships differ among forest types and soil horizons (Aber et al. 2003). Lovett et al. (2004) 

showed that five species, Fagus grandifolia, Betula alleghaniensis, Acer saccharum, Tsuga 

canadensis, Quercus rubra, all occurring at ACAD, varied markedly in their N cycling 

characteristics. Their work suggested that tree species can exert a strong influence on N cycling 

in forest ecosystems and that this influence is generally mediated by the quality of the organic 

matter they produce. Hence, N cycling in forest ecosystems could be patchy and dependent on 

the dominant trees in the patch. As a result, species-specific processes and stressors such as 

selective harvesting, pests/pathogens, global warming, and pollutants could substantially alter N 

cycling. For example, beech bark disease, targeting American beech (Fagus grandifolia), could 

potentially result in an increase in sugar maple (Acer saccharum), currently uncommon at ACAD 

(Greene et al. 2005), as both beech and sugar maple coexist in similar habitats. Dominance of 

sugar maple could then result in an increase in N enrichment in forest soils. Lovett and Mitchell 

(2004) listed sugar maple as a unique and critical species with regard to N cycling and retention 

in northeastern forests because sugar maple-dominated stands generally have higher rates of 

nitrification and nitrate leaching into surface waters. In some areas, sugar maple may be 

increasing due to the population decline of its primary competitor, American beech. Alternately, 

any threats to sugar maple (e.g. pests, acidic deposition, etc.) could drastically alter nutrient 

cycling. Hence, population dynamics of this species could have major impacts on forest 

composition and processes, and should be carefully monitored at ACAD. 

Parker et al. (2001) conducted a study at ACAD looking at effects of N enrichment, wildfire, and 

harvesting on soil C and N pools at the paired-watersheds (Cadillac [burned] and Hadlock 
78 

[unburned]) and other watersheds outside the Park that were characterized by different 

disturbance regimes (harvesting, N enrichment). Although no soil data for either C or N prior to 

disturbance were available, it was clear that all three disturbances can have long-term impacts on 

soil C and N, particularly on C pools in forest floor. They concluded that the shifts in species 

composition that might result from such forest disturbances (harvesting, N enrichment, and fire) 

could be at least as important in determining soil C and N content as the level of removal or 

additions of C and N from the disturbance itself. 

Using a variety of biogeochemical, landuse and nutrient uptake data, Miller (2006) evaluated the 

sensitivity of forests across the Northeast to N and S deposition. Figure 41 shows the areas of 

Maine where deposition rates were greater than critical loads estimated from other data. 

According to this model, ACAD forests were not designated as sensitive. 

Monitoring recently initiated by the NETN is using carbon to nitrogen (C:N) ratios in soil as a 

primary indicator of forest nitrogen status and the impacts of atmospheric deposition. Initial 

results from soil plots suggest that although most have favorable C:N ratios, some plots have 

C:N ratios that potentially indicate some ecological concern (Table 18). 

Figure 41. Forested areas of Maine that are sensitive to the negative effects of combined 

atmospheric sulfur and nitrogen deposition. Red areas indicate current sulfur and nitrogen 

atmospheric deposition rates greater than the critical load. The critical load is influenced by land 

use. Land use information was obtained from Maine Office of GIS in 2003 and may not 

accurately represent present or future land use. 

(Figure and legend from Miller 2006)
79 

Forest stand composition and age, along with soil structure, are key factors at ACAD influencing 

both atmospheric deposition of N, S and other elements, and the movement of these substances 

into surface and groundwaters. The legacy of major fires on MDI continues to influence 

vegetation structure, soil characteristics and, in turn, stream water chemistry (Campbell et al. 

2004, Kahl et al. 2007a, Johnson et al. 2007, Nelson et al. 2008). Surface water chemistry is 

discussed below. 

Acadia is one of the few remaining areas in the Northeastern U.S. with a diverse assemblage of 

macro-lichens (N. Cleavitt, Cornell University, pers. comm. March 2008). Several studies have 

investigated air pollution impacts on lichen assemblages. Wetmore (1984) and Sullivan (1996) 

both concluded that lichens at ACAD were not being adversely influenced by air pollution. In 

contrast, Stubbs et al. (1988, 1990 [cited in Maniero and Breen 2004]) suggested that air 

pollution (and red spruce health) has reduced lichen diversity in both coastal and inland sites in 

Maine – including Isle au Haut. Recent research provides evidence that the vertical dimension is 

a critical factor influencing the extent of air pollution impacts on lichens. Tree canopies at high 

elevations receive higher volumes of more acidic cloud water than trees at lower elevations. 

Pollution effect gradients are vertical and at the scale of individual trees, with the result that 

impacts tend not to be detectable using site-based assessment protocols (N. Cleavitt, Cornell 

University, pers. comm. March 2008). The impacts of air pollution on lichen assemblages 

depend on tree species, elevation, and forest assemblage type. 

Impacts of Atmospheric Deposition on Freshwater Systems 

Lakes: Kahl et al. (2000) and Seger et al. (2006) summarize surface water quality at 

ACAD, including pH status. Most surface waters are poorly buffered, low in nutrients 

and potentially vulnerable to acidification. As previously discussed, only two ponds at 

ACAD are acidic (Figure 20). One (Duck Pond) is part of a naturally acidic wetland 

complex, while the other (Sargent Mountain Pond) is acidic because of atmospheric 

deposition and the characteristics of its watershed. 

A few studies have addressed temporal patterns in acidity-related (and other) water 

quality parameters for surface waters on MDI. Kahl et al. (1993, cited in Kahl et al. 

2000) compared sulfate and acid-neutralizing capacity (ANC) of 22 lakes and ponds on 

MDI for the period 1982-1985. Most of the lakes exhibited a trend toward increased 

ANC and decreased sulfate (although none of these changes were statistically significant 

because of the small number of samples involved). However, for the period 1990-2000, 

Kahl et al. (2004) documented significant decreases in sulfate and base cations in ACAD 

lakes (Table 10), presumably in response to decreased atmospheric S deposition that 

occurred following S emissions reductions legislated in the Clean Air Act Amendments 

(Figure 37). Sulfate in ACAD surface waters declined 10% during this period. In the 

broader population of sensitive Maine lakes, sulfate declined by 10 to 25%. Kahl et al. 

(2004) suggested that input of sulfate from marine aerosols could explain the modest 

response in ACAD lakes as compared to lakes in the broader northeast region. There was 

a trend (insignificant) toward higher acidity (hydrogen ion concentration) in ACAD lakes 

during this period, apparently slowing or reversing the trend toward decreasing acidity 

observed during the 1980s in Maine. 
80 

There appear to be no studies that have investigated the impact of N loading on lake 

productivity or other aspects of ecosystem functioning. 

Streams: Streams at ACAD tend to be dilute (Figure 23), suggesting they could be 

susceptible to the effects of acid deposition. Heath et al. (1993) compared ANC and 

sulfate concentrations in ACAD streams over the period 1982-1990 and were unable to 

document any significant changes (Heath et al. 1993). In contrast, recent analyses of 

composite stream water quality data suggest decreased sulfate concentrations between the 

1980s and the present (S. Nelson, University of Maine, unpublished; Figure 42). 

Although statistical trend analyses from these data are not yet available, the decline 

appears to be particularly marked for fall samples. 

Streams at ACAD exhibit episodic acidification (defined as an ANC decline of ≥50 

μeq/L, or 50%) following precipitation events, with pH values as low as 4.7 (Kahl et al. 

1992, Heath et al. 1993). Episodic acidification results from a number of factors, 

Figure 42. Spring and fall stream sulfate concentrations measured in the 1980s and 2000s. Data 

are from Heath et al. (1993) and Kahl et al. 2007b). 
81 

including sulfuric and nitric acids from precipitation and natural sources, organic acids 

from soils and wetlands, and hydrochloric acid derived from salt-effect reactions within 

watershed soils. 

The role of sea salt exchange in episodic acidification has been documented for the Hadlock 

Pond watershed (Heath et al. 1993). At ACAD, salt inputs from atmospheric deposition were 

greatest during winter (Nelson 2007, NADP 2007). Road salt used for de-icing can contribute 

sodium (and calcium) chloride to streams, making early spring/snowmelt season the most 

vulnerable to this type of acidification. Whitaker (1999) found significantly higher road salt at 

sites below roads as compared to those above roads in six catchments at ACAD. Nelson (2006) 

reported similar findings; however, the salt signal was attenuated just a few hundred meters 

downstream of roads in the Downeast region of Maine. At ACAD, chloride concentrations in 

streams across the park do not show clear linkage with road density, which is generally low 

throughout the Park area. Other landscape factors (e.g. elevation) may play a role mediating sea 

salt inputs to terrestrial systems. There is also evidence that salt concentrations measured during 

high-discharge episodes during 1999-2003 were greater than those during 1988-1989 (S. Nelson, 

unpublished data). 

As discussed above, ACAD receives moderate to low amounts of NO3 and NH4 in wet-only 

atmospheric deposition. However, the forested landscape results in enhanced dry deposition 

(e.g., Weathers et al. 2000, 2006). The undisturbed status of many spruce-fir forests at Acadia 

leads to increased leaching of N from the terrestrial system to surface waters, where it may cause 

eutrophication and acidification. Nitrate concentrations in some streams in the Park are 

chronically elevated (Nelson et al. 2008), a condition that suggests N saturation of older growth 

forested watersheds. Nitrogen saturation may occur across the Northeast as well as at ACAD 

(Aber et al. 1998, Aber et al. 1989, McNulty et al. 1990, Nelson et al. 2007). 

Several controls on N in streamwater have been proposed, including the initial N status of a site, 

history of disturbance by harvesting and fire, vegetation composition, and hydrology (Aber et al. 

1998, Campbell et al. 2004). Studies of the paired Cadillac and Hadlock Brook watersheds at 

ACAD have shown that the export of inorganic N from a burned watershed (Cadillac) was about 

one tenth of the export from an unburned watershed (Hadlock) (11.5 eq/ha/year vs. 92.5 

eq/ha/year; Kahl et al. 2007a, Nelson et al. 2007). Furthermore, N retention at Cadillac was 

among the highest in a regional assessment of N input-output budgets (Campbell et al. 2004). 

An MDI-wide study conducted during 1999-2000 found that other landscape-level factors can 

mask the effect of fire (Nielsen and Kahl 2007). The study found no significant difference 

between streams located in watersheds that had burned as compared to those that were 

undisturbed by fire. However, the authors reported that watersheds entirely inside the Park 

boundary exported significantly less total N than watersheds partly or entirely outside the Park 

boundary (Figure 43). These findings suggest that different factors could control N retention 

inside as compared to outside the Park. 
82 

Figure 43. Nutrient export rates for MDI watersheds inside and partially or completely outside 

ACAD. 

(Figure from Nielsen and Kahl 2007, used with permission) 

In summary, threats to the Park’s streamwater N status include natural disturbances such as fire, 

non-point source pollution (continued elevated levels of N deposition), and a potentially 

anthropogenic stressor related to a watershed’s location with respect to Park boundaries. It is 

unclear whether this stressor may be related to roads (automobile emissions of N), management 

of riparian buffer areas, issues with septic systems and other discharges, or other as yet 

unidentified factors. 

Modeling of the Northeast Creek system has been used to predict the effects of total N loading 

(i.e. from all sources) on the ecology of this system; for extended discussion of this topic, see 

Threats: Nutrient Enrichment.

Acidic precipitation can mobilize toxic aluminum in surface waters (Munson and Gherini 

1991a, 1991b), cause leaching of base cations from soils (Fernandez et al. 2003), and it 

may directly damage vegetation through contact with leaf surfaces or inhibition of 
83 

transpiration (Turco 2002). Aluminum dynamics are influenced by complexation with 

fluoride and organic carbon – which may both increase aluminum in solution and also 

decreasing toxicity to aquatic organisms. No information exists regarding whether biota 

are affected by aluminum at ACAD. 

 

Organic materials (dissolved organic carbon, DOC) also contribute acidity to freshwater systems. 

There is little published research regarding the status of organic acidity in ACAD lakes and 

streams. As discussed above, the acidity in Duck Pond (one of two naturally acidic lakes on 

MDI; Figure 20) is mostly from natural organic matter (Kahl et al. 1989). There are two potential 

threats or stressors related to DOC levels in surface waters at the Park. First, Nelson et al. (2007) 

concluded that DOC is correlated with mercury, and thus freshwaters with high levels of DOC 

may be potentially at risk for mercury contamination (see Threats: Mercury section). Second, 

Kahl et al. (2004) and Stoddard et al. (2003) found statistically significant increases in DOC in 

lakes across the northeastern US in an EPA assessment of 20 years of water chemistry data. The 

source of this increased DOC and implications of rising DOC levels are currently an active area 

of research. At ACAD, further research is necessary to determine both the temporal change in 

DOC at the Park (if any) and the potential interaction with Hg in freshwaters and biota.

Atmospheric Nitrogen Deposition to Coastal and Marine Systems 

Nitrogen fluxes from watersheds in the Northeast United States have increased 3-8 fold since the 

early 1900s (Jaworski et al. 1997; note that all watersheds discussed by these authors are to the 

south of Maine). Evidence strongly suggests a linkage between increases in cultural 

eutrophication (higher productivity) and the increase in N emissions from fossil fuel combustion. 

Nielsen et al. (2002b) developed a water budget and estimated nitrogen loads to 

Northeast Creek. Direct deposition to the creek surface represented a small proportion of 

total N loading to this system from all sources. Total atmospheric N deposition (wet and 

dry, inorganic and organic) across the entire watershed was estimated to be 510 

kg/km2

/year. This estimate of atmospheric deposition can be compared to total-N yields

to Northeast Creek from its various sub-watersheds of 130-270 kg/km2

/year (Nielsen et 

al. 2002b). These data suggest that N processing and uptake by biota are major sinks for 

N in this system. 

In their study of Bass Harbor Marsh, Doering et al. (1995) did not explicitly model 

atmospheric input, but rather assumed that it was accounted for in overall loads from 

freshwater sources. 

Studies of estuaries on the east coast of the U.S. (the closest to ACAD is Casco Bay in 

southern Maine) have shown that total atmospheric N deposition (direct deposition plus 

surface runoff) accounts for 15-42% of the total N loading to these systems (Castro and 

Driscoll 2002). The value for Casco Bay was in the middle of this range: 24%. In some 

estuaries, direct deposition to the water surface represented a significant proportion (35-

50% of the total atmospheric input). Roman et al. (2000) concluded that atmospheric 

deposition represented an average of approximately 70% of total nitrogen loading to four 

Maine esturaries (Penobscot Bay, Sheepscot Bay, Casco Bay and Saco River). In more 
84 

urbanized watersheds, atmospheric loading represented generally <50% of total nitrogen 

loading because more was derived from agricultural runoff and/or wastewater treatment 

facilities. 

The impacts of nitrogen loading on the ecology of the Northeast Creek system are 

discussed below, under Threats: Nutrient Enrichment. 

Mercury 

Key Issues Extent of Problem Information Base

Atmospheric sources EP Good 

Hg in terrestrial systems EP Good 

Hg in freshwater – abiotic components EP Good 

Hg in biota EP Fair 

Hg in coastal sediments OK ? Good 

Atmospheric Sources 

Mercury (Hg) is atmospherically deposited in regions remote to its origin (Haines and Webber 

1999). Atmospheric Hg is delivered to ecosystems by rain, snow, dry, and occult (cloud and fog) 

deposition. Where total deposition of Hg has been measured, dry deposition (particles and gases) 

equals or exceeds wet deposition (Hg in rain and snow) and is likely the largest vector of Hg 

input from the atmosphere to terrestrial ecosystems (Lindberg et al. 2007, Miller et al. 2005, 

Grigal 2002). 

At ACAD, dry deposition of Hg equals or exceeds wet-only deposition, during both the growing 

season and in winter (Figure 44). Recent research regarding snow Hg deposition indicates that 

total deposition was much greater than previously thought during winter (Nelson 2007); 

however, much of the Hg that is deposited in snow is volatilized and emitted back to the 

atmosphere as snowpack matures. Snow research at ACAD suggests future work to determine 

the processes leading to snowpack Hg burdens and the fate of re-emitted Hg. A regional model 

for dry deposition of Hg that incorporates enhancement of Hg deposition by vegetation type 

suggests that total Hg deposition in the ACAD region is at least twice the reported value for wetonly deposition (Miller et al. 2005) (Figure 45). 

Evidence from the Canadian Maritimes suggests that fog could be enriched in Hg as well as in S 

and N. Ritchie et al. (2006) observed Hg concentrations in fog ranging from 2 – 435 ng/L along 

a geospatial gradient from an ocean island (Grand Manan, high concentration) to an inland site 

(Fredericton NB, low concentration). At these sites in Canada, Hg concentrations were greatest 

on days with stationary fog banks. Because of its coastal location and frequent fog immersion, 

these data suggest that future research regarding fog contributions to both Hg and acid loading to 

the Park’s ecosystems is warranted. 
85 

Figure 44. Winter (a) and growing season (b) mercury (Hg) deposition measured in throughfall 

in ACAD. Bars show the contribution of Mercury Deposition Network wet-only deposition, plus 

the amount of dry deposition inferred from throughfall measurements. Winter throughfall was 

measured December 15, 2004-March 16, 2005, and growing season throughfall was measured 

from May 28, 2004-November 17, 2004. The graph shows estimates from these measurements 

annualized to per year rates, for comparison. 

(Source: Nelson 2007) 
86 

 (A) (B) 

Figure 45. Wet-only and total mercury deposition in eastern North America. (A) 2006 wet 

deposition, (B) estimated total mercury deposition (wet + dry) to rural areas. 

Image sources: (A) Mercury Deposition Network (http://nadp.sws.uiuc.edu/mdn/ accessed September 2007). (B) 

Miller et al. 2005. Note that “deposition was not estimated for areas with urban or residential land cover. Mercury 

deposition is likely to be much greater than depicted here in the immediate vicinity of urban areas and emissions 

sources.”

Mercury in Terrestrial Systems 

Forest cover enhances Hg deposition because forests act as filters that scavenge dry particles and 

gases from air masses (Rea et al. 2000, Lindberg et al. 1994). Forest canopies also take up Hg 

and can re-emit Hg previously deposited on the canopy (Graydon et al. 2007). Wet deposition 

and the net remaining Hg deposited on forest canopies via dry deposition subsequently are 

washed by precipitation as throughfall to the forest floor or deposited later as litterfall (Rea et al.

2000, Lindberg et al. 1994). 

Mercury in throughfall at ACAD is dependent on vegetation type and watershed aspect. In a 

network of 52 study sites distributed throughout Hadlock and Cadillac watersheds, throughfall 

deposition was, on average, 1.6 (deciduous), 2.3 (coniferous), and 2.6 (mixed) times higher at 

forested than open sites during 1999-2000 (Johnson 2002). Site aspect also influenced Hg 

concentrations in throughfall. Southwest and west aspects had significantly higher Hg deposition 

than other aspects studied (Figure 46). Higher deposition at west-facing sites has been attributed 

to the dominant wind direction, which typically tracks through the Midwest before reaching the 

Northeast (Johnson 2002). 

Sheehan et al. (2006) estimated Hg fluxes through the Cadillac and Hadlock watersheds, and 

compared them to precipitation and throughfall inputs. Litterfall contributed as much Hg as total 

deposition to the study watersheds (Sheehan et al. 2006), and presumably represented Hg that 

was scavenged from the atmosphere and trapped in or on leaves (Grigal 2002). 
87 

Figure 46. Hg deposition stratified by site aspect for the period May-November 2000, at Cadillac 

and Hadlock watersheds study sites. Matched letters are not significantly different (ANOVA, P > 

0.05). Error bars represent standard error. 

(Figure from Johnson 2007)

Mercury in Freshwater Systems (Abiotic Components) 

The relationship between landscape factors and Hg in fresh waters has been the subject of 

ongoing research in the Park since 1998 (Kahl et al. 2007a). 

Mercury (measured as total dissolved Hg) was collected in streams across MDI during two 

surveys in 1999-2000 and in 2004 (Figure 48; Kahl et al. 2006, Peckenham et al. 2007). The 

greatest Hg concentrations were found in Squid Cove Brook, Oak Hill Stream, Hodgdon Brook, 

and Whalesback Brook. Hodgdon Brook is a tributary to Hodgdon Pond, the waterbody where 

the greatest Hg concentration in a Maine fish was found in 1995 (Burgess 1997). Streams 

draining unburned watersheds tended to have higher Hg concentrations that those draining 

burned watersheds (this trend was not statistically significant). 

The influence of fire history on mercury dynamics was further explored during the Acadia paired 

watersheds project (see Kahl et al. 2007a for an overview of this project). The research was 

designed to compare ecosystem processes in the Cadillac Brook watershed that burned in 1947 

and the Hadlock Brook watershed that has been largely undisturbed for at least 300 years 

(Schauffler et al. 2007). The project hypothesis was that fluxes of Hg from the unburned 

watershed would be higher because: i) mature coniferous forest in the Hadlock watershed would 

enhance dry deposition, in turn resulting in higher total Hg deposition; ii) elemental Hg pools in 
88 

Figure 47. Summary of Hg concentrations in environmental media from established 

research sites in upland, forested sites at Acadia National Park and Bear Brook 

Watershed in Maine. Values for total Hg are means or ranges, with standard deviations. 

The * denotes that standard errors were reported rather than standard deviation. 

(From Nelson 2007) 

47.7±1.9* ng/g ww
89 

Hadlock watershed soils would be higher compared to the burned soils of the Cadillac watershed 

(Nelson et al. 2007). 

Discharge-weighted Hg in streamwater draining the unburned watershed was twice that in 

streamwater draining the burned watershed (Kahl et al. 2007a, Nelson et al. 2007, Johnson 2002) 

(Figure 47 – see ‘streams’ data). Soils in Cadillac (burned) watershed were more able to bind Hg, 

keeping it from moving through ecosystems and into water (Kahl et al. 2007). Approximately 

13% (burned watershed) and 5% (unburned watershed) of total mercury deposition was exported 

in streamwater (Nelson et al. 2007) – although scientific debate is ongoing whether the Hg in 

streamwater is new (recently deposited) Hg or old (stored in soils) Hg (e.g., Hintelmann et al. 

2002). 

Mercury concentrations measured in MDI streams fall within the range of concentrations 

documented from a study of 58 Maine rivers (Peckenham et al. 2003 - none of those river sites 

were in the ACAD area). The average concentration measured in this statewide survey was 1.80 

ng/L (range = 0.093 – 7.01 ng/L). The highest MDI stream mercury concentrations (Figure 48) 

were approximately 70% of the maximum values observed in the statewide survey. Although 

MDI data therefore fall within the statewide range, Hg levels in MDI streams are unusually high 

from a more regional basis. According to Hg contour maps presented by Peckenham et al. 

(2003), the ACAD region falls within a broader coastal / Downeast zone of minimal Hg 

concentrations, typically <1 ng/L (in contrast, highest values occurred in the northern and 

western parts of the state). The higher values measured on MDI therefore suggest that MDI 

represents a hotspot of elevated Hg concentrations within the regional context of coastal and 

Downeast Maine. 

Norton et al. (1997) reported that accumulation rates of Hg to sediments in Big Heath Bog and 

Sargent Mountain Pond during the 1980s were substantially higher than would be expected from 

measured wet-only atmospheric deposition. This observation reinforces the likely contribution of 

dry deposition. 

Mercury in Terrestrial and Freshwater Biota 

Mercury is converted by micro-organisms to methymercury (MeHg). In this form, Hg is 

biologically active and toxic to animals. Mercury is not actively taken up by most plants. 

Consequently it is unlikely that the elevated Hg levels at ACAD are affecting vegetation. 

A number of studies have documented Hg and MeHg levels in the biota of ACAD. Bank et al. 

(2007a) reviewed available data on Hg levels in biota of ACAD and vicinity. Bank et al. (2005 

and 2007b) reported data on mercury levels in ACAD amphibians, and Longcore et al. 

(2007a, b) provide data on tree swallows. Table 19 presents a synthesis of these data. Figure 49 

shows spatial patterns of mercury levels in two-lined salamanders and Figure 50 compares Hg in 

trees swallows at three ACAD lakes with levels at other Maine and Massachusetts sites. Table 20 

summarizes some key conclusions from these publications. Although ACAD fauna clearly 

display elevated tissue Hg concentrations, the physiological and ecological implications of these 

body burdens are unclear. 
90 

Figure 48. Mercury in streams and wetlands extent in watersheds. Stream surveys were 

conducted in 1999-2000 and 2004 to characterize total mercury (average values are shown). 

Wetlands data are derived from data in Lubinski et al. (2003) and are presented as watershedlevel summaries. 
91 

Figure 49. Average concentrations of total mercury (ng/g wet wt.) in two-lined salamanders 

(Eurycea bislineata bislineata) larvae, June-July 2001-2002. Note that samples were not 

collected in all MDI watersheds. 

(Figure from Bank et al. 2006, used with permission)

Figure 50. Mean (SE) concentrations of total-Hg in tree swallow carcasses at three ACAD lakes 

(Aunt Betty, Hodgdon and Seal Cove) compared to another Maine site (Orono) and 

Massachusetts superfund sites (Grove and Plow Shop), 1997-1999. Different letters indicate 

statistical differences of means. 

(Figure from Longcore et al. 2007b, used with permission) 
92 

Mercury in Marine Systems 

Mercury contamination in the Gulf of Maine is widely recognized as an important regional issue 

(Jones and Wells 2002). However, Hg concentrations in marine sediments around the MDI area 

appear low when compared to the entire Maine coast (Figure 51). 

The mercury content of intertidal and subtidal species has been studied recently by C. Chen and 

B. Mayes (Dartmouth College, NH) at a series of sites on MDI, including Northeast Creek, 

Salisbury Cove, Seal Cove, and Somes Sound. Although published results are not yet available, 

this study documented that, although sediments around MDI are relatively uncontaminated with 

Hg, this contaminant does become biomagnified in marine fauna at higher trophic levels (C. 

Chen, Dartmouth College, pers. comm.). D. Kopec (University of Maine) is currently 

investigating Hg in seals and their prey in offshore areas near the Park, such as near Mount 

Desert Rock. 

Metal: Mercury

2000-2003 Northeast NCA Data State = ME

ERL/ERM threshold limits are in effect

ERL = 0.15 ppm

ERM = 0.71 ppm

State map Symbols designate condition as defined in legend below.

Pie diagram & statistics table indicate percentage of estuarine area in state in 4 condition categories

State pie chart: 

State statistics:

Percentage of Estuarine Area in ME

Good 87.8%

Fair 12.2%

Poor 0.0%

Missing 0.0%

42.5

43.0

43.5

44.0

44.5

45.0

45.5

-71.2 -70.7 -70.2 -69.7 -69.2 -68.7 -68.2 -67.7 -67.2 -66.7

ME Mercury

Good, 

88%

Fair, 12%

Poor, 0%

Missing, 

0%

Good: <0.15 ppm

Fair: 0.15 to 0.71

Poor: >0.71 ppm

Missing

 

Metal: Arsenic

2000-2003 Northeast NCA Data State = ME

ERL/ERM threshold limits are in effect

ERL = 8.2 ppm

ERM = 70 ppm

State map Symbols designate condition as defined in legend below.

Pie diagram & statistics table indicate percentage of estuarine area in state in 4 condition categories

State pie chart: 

State statistics:

Percentage of Estuarine Area in ME

Good 26.4%

Fair 73.6%

Poor 0.0%

Missing 0.0%

42.5

43.0

43.5

44.0

44.5

45.0

45.5

-71.2 -70.7 -70.2 -69.7 -69.2 -68.7 -68.2 -67.7 -67.2 -66.7

ME Arsenic

Good, 

26%

Fair, 74%

Poor, 0%

Missing, 

0%

Good: <8.2 ppm

Fair: 8.2 to 70

Poor: >70 ppm

Missing

(A) (B) 

Figure 51. Mercury (A) and arsenic (B) concentrations in coastal sediments of Maine. (Data and 

plots from EPA National Coastal Assessment database)
93 

Table 19. Mercury concentrations in biota: a summary of data presented by Bank et al. 

(2007a, b). 

Group Site Total Hg: Mean (st. dev.) 

μg/g DRY weight (2)

Original 

Source 

 

Plankton (1) Hodgdon P. 0.53 (0.14) Burgess 1997 

Plankton (1) Seal Cove P. 0.51 (0.22) 

Anisoptera (1) Hodgdon P. 0.45 (0.17) 

Anisoptera (1) Seal Cove P. 0.32 (013) 

Isopoda (1) Hodgdon P. 0.38 (0.10) 

Amphipoda (1) Hodgdon P. 0.21 (0.40) 

Amphipoda (1) Seal Cove P. 0.39 (0.09) 

Total Hg: Mean (range) of lake 

means. 

μg/g WET weight 

Predator fishes - fillets 11 lakes 0.54 (0.15 – 1.72) Burgess 1997 

Predator fishes – whole body 10 lakes 0.27 (0.14 – 0.51) 

Forage fishes (yellow perch) – 

whole body (3)

2 lakes 0.14 (0.12 – 0.18) 

Total Hg: Mean (st. dev.). 

μg/g WET weight (2)

2-lined salamanders, 1-3 yr old 

larvae 

14 streams 0.066 (0.003) Bank et al.

2005 

Green frog tadpoles 9 ponds 0.025 (0.001) Bank et al. 

2007b 

Bullfrog tadpoles 9 ponds 0.019 (0.007) Bank et al.

2007b 

Total Hg: Mean (range) of 

sample values. 

μg/g WET weight 

Bald eagles (6-8 wk old): 

-- feather 

-- blood 

5 small island and 

MDI sites 5.21 (2.8 – 6.5) 

0.10 (0.03 – 0.15) 

Welch 1994 

Total Hg: Range of sample 

values. 

μg/g fresh (fur) and wet (liver) 

weights 

River otter and mink fur Long and Round 

Ponds 

1.14 – 9.90 BioDiversity 

Research 

Institute, 

unpublished 

data 

River otter and mink liver Long and Round 

Ponds 

0.48 – 0.86 

(1) Plankton and macro-invertebrates: composite of spring (May-June) and summer (Aug-Sept) samples. 

(2) Data from plankton, invertebrate and amphibian samples have been converted from ng/g (Bank et al. 2007a, b) to μg/l for 

consistency within this table. 

(3) Yellow perch data include both spring and summer samples and exclude the young-of-young data presented by Bank et al. 

(2007).
94 

Table 20. Mercury in terrestrial and freshwater biota: selected observations. 

METHYLATION AND BIOCONCENTATION 

• All trophic levels at ACAD have elevated levels of Hg and MeHg (1). 

• Bioconcentration factors(8) from pond water to amphibian tadpoles are within the ranges of 2.7-4.0 (total Hg), and 

3.6-5.2 (MeHg). These levels are comparable to those observed in amphipods from other ACAD lakes (3). 

• The ratio of MeHg to total Hg in tadpoles from nine ACAD lakes ranges from about 5% to almost 20%, with four 

of nine study ponds showing a methylation efficiency of >10% (3). 

• Methylation efficiency is enhanced by acidification, higher temperatures, elevated DOC, among other factors (3)

TISSUE CONCENTRATIONS 

• ACAD plankton Hg and MeHg levels tend to be higher than values in Wisconsin meso-oligotrophic lakes (1). 

• ACAD invertebrate Hg concentrations are comparable to values observed elsewhere (1). 

• Higher Hg concentrations in 2-lined salamanders, relative to frogs, likely reflect invertebrate vs. grazer diets, 

respectively (2). 

• Salamanders from undisturbed watersheds (e.g. Hadlock) exhibit higher Hg levels than animals from burned 

watersheds (e.g. Cadillac) (2, 8). (Figure 49) 

• Non-salmonid fish species on MDI generally have similar or lower Hg concentrations than statewide averages for 

these species (1). 

• Chain pickerel on MDI had much lower Hg concentrations than the statewide mean, although this comparison 

may be influenced by size of sampled fish. 

• Smallmouth bass on MDI had higher Hg concentrations than the statewide average (1). 

• Highest Hg concentrations in MDI fish fillet samples were recorded from Hodgdon Pond (smallmouth bass) (1). 

• The State of Maine mercury consumption advisory recommends that the sensitive human population not eat fish 

containing > 0.27 μg/L Hg. All 11 lakes samples for fish Hg levels had at least one fish sample for which the fillet 

concentration exceeded the advisory (6). 

• Tree swallow chicks and eggs from ACAD are at least as contaminated with Hg as birds living at a Hgcontaminated Superfund site in Massachusetts (5). (Figure 50) 

• Loon blood Hg levels are highly correlated to prey fish Hg levels on breeding lakes (1). 

ECOLOGICAL IMPACTS 

• The risk of negative effects from MeHg in fish and amphibians is likely higher than in birds, mammals and 

reptiles which store MeHg in body parts away from vital organs (1). 

• Hg levels in bald eagles reflect upper trophic level biomagnification. However, when compared to levels in 

juvenile eagles elsewhere, MDI marine habitats do not pose a risk to eagles (1). 

• Compared to Hg exposure levels elsewhere in Maine and across North America, Hg exposure on the larger MDI 

lakes represents a low risk to breeding loons. While loon recruitment is below sustainable levels on MDI (Evers et 

al. 2003, cited by Bank et al. 2007), Hg levels are not thought to be a contributing factor (1). 

• Although early growth rate in weight in tree swallows was negatively associated with MeHg levels in feathers, 

long-term growth appeared to be unaffected by MeHg body burdens (4). 

• Limited mammal (mink and otter) data from MDI suggest potential low risk from Hg (1). 

• Research suggests that commonly observed levels of Hg increase vulnerability of golden shiners to predation. 

They do not appear to influence mortality or growth rates (7). 

KEY INFORMATION GAPS 

• No reptiles have been sampled for Hg exposure on MDI. Amphibian data are available for only three species (1). 

• There are many gaps in knowledge of the factors influencing exposure to and toxicological effect from Hg. In 

particular, a better understanding is needed of the interaction between Hg and other anthropogenic stressors (1). 

• More research is necessary at ACAD to determine whether wetlands are hotspots for Hg methylation and 

transport (3). 

(1) Bank et al. 2007a. (2) Bank et al. 2005. (3) Bank et al. 2007b. (4) Longcore et al. 2007a. (5) Longcore et al. 2007b. 

(6) Haines and Weber 1999. (7) Webber and Haines 2003. (8) Bank et al. 2006. (9) Log(biota concentration / water 

concentration), based on composite samples. 
95 

Nutrient Enrichment 

Key Issues Extent of Problem Information Base

Atmospheric N loading to terrestrial 

systems 

EP Good 

Nutrient loading to lakes and streams PP Fair 

Nutrient loading to wetlands and 

estuaries 

EP / PP Good 

Nutrient issues for coastal/marine 

systems, incl.algal blooms, aquaculture, 

sewage 

PP Fair 

Nutrient Enrichment: Terrestrial Systems 

Atmospheric deposition includes elevated concentrations of nitrogen derived from industrial and 

other emissions. The effects of nitrogen enrichment on forest ecosystems at ACAD have been 

discussed above (Threats: Atmospheric Deposition: Acidity and Related chemistry). 

Nutrient Enrichment: Lakes and Streams 

Freshwaters and estuaries in the northeastern U.S. are increasingly at risk of eutrophication as a 

result of elevated nutrient loading rates (e.g. Nielsen and Kahl 2007, Roman et al. 2000, Kinney 

and Roman 1998, Jaworski et al. 1997). Excessive nutrient enrichment may lead to dense algal 

growth, decreased dissolved oxygen concentrations, reduction in submerged vascular plant beds 

and deterioration of habitat for finfish and shellfish (Rohweder et al. 2004). Even though MDI 

watersheds are relatively unaffected compared to many in the Northeast, accelerated nutrient 

enrichment is a concern in the ACAD region. Nutrient loading to aquatic systems has been 

identified as a key resource management issue at ACAD. 

According to Nielsen and Kahl (2007), nutrient export from 13 small watersheds across MDI is 

relatively low. Nevertheless, their data suggest that land-use may be influencing stream nutrient 

levels. Watersheds partially or completely outside the Park boundary exported more total N and 

phosphorus (P) than those entirely within the Park (Figure 43). The three watersheds with the 

highest nitrate exports were Marshall, Stony, and Stanley Brooks. All have relatively high human 

populations. There is a capped landfill in the Marshall Brook watershed and there are nearstream septic systems in the Stanley Brook watershed (Nielsen and Kahl 2007). Even though 

these authors detected a possible land-use signature in nutrient export rates, atmospheric 

deposition was considered to be the greatest single source of nitrate in the studied watersheds. 

Atmospheric deposition has resulted in elevated flux of N in wet and dry precipitation across the 

Northeast (see above). Atmospheric N loading has typically not been thought to result in 

eutrophication of lakes because P is the nutrient that most commonly limits primary production 

in north temperate systems (Bergstrom et al. 2005). However, there is a growing body of 

evidence to suggest that P limitation in relatively unproductive lakes is a derived characteristic 

that has resulted from increased atmospheric N loading over the past several decades (Goldman 

1988, Bergstrom et al. 2005). 
96 

Most lakes and ponds in and around ACAD are nutrient-poor and unproductive (Kahl et al. 

2000; Table 9). There is a positive association between total phosphorus and chlorophyll 

concentrations in Maine lakes as well as in the subset of ACAD lakes (Figure 52). This 

relationship is indicative of the fact that many lakes are P-limited. Nitrogen to phosphorus ratios 

suggest P-limitation in at least some ACAD lakes. For example, using 2007 (June and August) 

water chemistry data collected by the NETN monitoring program (data provided by B. Gawley, 

NPS), we calculated two sets of ratios for 11 lakes - total N:total P and dissolved inorganic 

N:dissolved inorganic P. Ratios were not calculated when either N or P samples were below 

detection. Total N:P ratios were between 19:1 and 53:1. Dissolved N:P ratios were between 38:1 

and 104:1. Typically, N:P ratios of >7:1 on a mass basis suggest P limitation (Redfield 1958). To 

our knowledge, there has been no attempt to use nutrient bioassays to document whether ACAD 

lakes are limited by N or P. These bioassays would provide important background information 

relating to eutrophication risk in ACAD lakes. 

Although cultural eutrophication (human-associated productivity increase) is a concern in many 

Maine lakes (Nieratko 1992), there is little evidence of this process occurring in ACAD lakes. In 

some lakes, water transparencies (Secchi depths) appear to have actually increased over the past 

several years and trophic state index values have decreased. 

Nutrient enrichment, and the resulting elevated rates of primary production, can increase the 

extent and severity of hypolimnetic oxygen depletion in lakes. In addition to reducing the 

amount of habitat available to aquatic organisms, anoxia triggers internal loading of phosphorus 

from lake sediments, in turn further increasing primary production. The hypolimnia of 

0.1

1

10

100

1 10 100

Total Phosphorus (ug/L)

Chlorophyll-a (ug/L)

Maine

ACAD

Figure 52. Relationship between total phosphorus and chlorophyll concentrations in Maine and 

ACAD lakes. Data are overall averages for each lake, calculated by MDEP and accessed at 

www.pearl.maine.edu. Where data were available for >1 basin / lake, data were averaged across 

basins. Original water quality data for ACAD lakes were provided to MDEP by ACAD staff. 
97 

mesotrophic (moderately productive) ACAD lakes (e.g. Seal Cove, Witch Hole and Upper 

Hadlock) exhibit reduced oxygen levels or complete anoxia during summer months (Seger et al. 

2006). This is likely a natural – or at least long-standing – feature of these lakes. Many exhibited 

similar reductions in hypolimnetic dissolved oxygen over 60 years ago (Figure 53; Fuller and 

Cooper 1946). Oligotrophic lakes remain well-oxygenated throughout the growing season. 

Although there is currently no evidence of eutrophication affecting ACAD lakes, the potential 

for this exists, particularly in lakes whose watersheds are not completely within ACAD. The 

excellent water quality of many ACAD lakes with respect to nutrient concentrations highlights 

the need to ensure their future protection. Current monitoring at ACAD includes collection of 

water quality data from a set of lakes potentially at risk of eutrophication (Seger et al. 2006). 

This monitoring is essential for early detection of changing conditions, at a time when it may be 

possible to mitigate the effects of nutrient enrichment. 

Figure 53. Dissolved oxygen concentrations at depth in four MDI lakes: 1942 and 1992-2006. 

Bars show the depths at which there was > 3.0 mg/L dissolved oxygen in August samples. Data 

from 1942 are from Fuller and Cooper (1946); more recent data are from ME Dept. of 

Environmental Protection, as accessed at www. pearl.maine.edu. 
98 

Nutrient Enrichment: Wetlands and Estuaries 

Water quality degradation resulting from eutrophication is a particular concern for the estuaries 

at ACAD. Evidence of eutrophication has been observed at Bass Harbor Marsh (Doering et al. 

1995, Kinney and Roman 1998, Farris and Oviatt 1999). Although water quality problems have 

not yet been documented in Northeast Creek (Culbertson et al. 2007), there is concern that 

increasing residential development in this watershed could adversely affect estuarine water 

quality. Compared to inputs of phosphorus, anthropogenic inputs of dissolved inorganic N likely 

represent a much greater risk to the estuaries of the ACAD region (Culbertson et al. 2007). 

Water quality and nutrient loading have been studied in three coastal ecosystems on MDI: Bass 

Harbor Marsh, Northeast Creek and Somes Sound.

Bass Harbor Marsh: In response to qualitative observations of increasing macroalgal biomass 

and a decreasing recreational (brook trout) fishery in Bass Harbor Marsh, Doering et al. (1995) 

implemented water quality surveys in the early 1990s. They addressed N and P loading from 

freshwater and ocean sources; atmospheric deposition was assumed to be incorporated into the 

freshwater component. Ocean and freshwater sources contributed approximately equal loads of 

inorganic N, whereas most of the inorganic P loading came from the ocean. Of the freshwater 

inputs, Marshall Brook provided the most dissolved inorganic N (Figure 54, upper panel). This 

stream drains the closed Worcester landfill and has been the subject of extensive water quality 

investigations (see review in Haines and Webber 1999).

In general, nutrient concentrations of streams draining into Bass Harbor Marsh were similar to 

those observed in tributaries to Somes Sound. According to Doering et al. (1995), a future 

decrease in nutrient loading from Marshall Brook to levels characteristic of more pristine streams 

would likely lead to an upstream shift in the boundary between N-limited and P-limited primary 

production. 

Kinney and Roman (1998) compared Bass Harbor Marsh to other shallow estuaries in the 

Northeast8

 (Figure 54, lower panel). Watersheds of these other estuaries are much more 

urbanized than the Bass Harbor Marsh watershed. While nitrogen loading rates and macroalgal 

biomass in Bass Harbor Marsh were lower than at the two most highly eutrophic sites (CR and 

MC1), Bass Harbor Marsh displayed productivity patterns similar to other sites in the Northeast, 

all of which are in urbanized watersheds and are considered relatively degraded. Kinney and 

Roman (1998) considered biomass of widgeon grass (Ruppia maritima) in Bass Harbor Marsh to 

be similar to other estuaries except for those with high nutrient loading rates. 

 

Characteristics of the macrofaunal benthic community of Bass Harbor Marsh provide uncertain 

evidence of enrichment – generally this community was considered healthy in the early 1990s 

(Doering et al. 1995). 

 

8

 Three estuaries (CR, QR and SLP) are all parts of the Waquoit Bay on Cape Cod. Three other three sites (GH, NP 

and PJ) are also in Rhode Island. Sites MC1 and MC represent Mumford Cove, CT, before and after sewage 

diversion, respectively. 
99 

0 20 40 60 80

Adams

Buttermilk

China

Lurvey &

Heath

Marshall

Percent Total FW Load

Total-N

NH3

NO2 + NO3

Figure 54. Nutrient loading and algal biomass in Bass Harbor Marsh. 

Upper panel summarizes nitrogen loading from five freshwater inflows. Data show the 

contribution of each sub-watershed to total loads of nitrogen ‘species’ to the Bass Harbor Marsh. 

For each nitrogen form, loads total 100% across all tributaries. 

Lower panel shows the relationship between peak green macroalgal biomass and dissolved 

inorganic nitrogen loading to Bass Harbor marsh (BHM) and eight other shallow estuarine sites 

in the Northeast. See text for more information. 

(Figure from Kinney and Roman 1998, used with permission) 

(Data from Doering et al. 1995) 

Culbertson et al. (2007) used aerial thermal imaging of shallow groundwater discharge and water 

samples from seeps and wells to characterize nutrient enrichment of Bass Harbor Marsh (and 

Northeast Creek – see below) from groundwater sources. Concentrations of dissolved nitrogen in 

shallow groundwater were elevated relative to those of the adjacent estuary and surface water 

tributaries, indicating that the hyporheic zone (the region beneath and lateral to a stream bed) 
100 

represented a nitrogen source to the estuary. Initial loading estimates suggested that shallow 

groundwater could be contributing a substantial percentage to the total N load of this system. 

Although elevated N levels in shallow groundwater indicated that there may be contamination 

from septic systems, household wastewater-related compounds were generally at or below 

detection in bedrock wells. This observation suggested that septic sources were not 

contaminating the local aquifer. 

Northeast Creek: Extensive research on the Northeast Creek (NEC) estuary and associated 

wetlands has investigated how increasing residential development in this watershed may affect 

nutrient loads. Since housing in this region of MDI is served by septic systems, there is concern 

that increasing development may contribute to accelerated eutrophication of the estuary. The 

population of the NEC drainage basin increased by almost 50% between 1981 and 1996 (Nielsen 

2002a). 

Nielsen (2002a) investigated the influence of nitrogen loads from septic system discharge on 

groundwater quality. Nielsen (2002b) developed a water and nutrient budget for the basin. 

Nielsen and Kahl (2007) studied nutrient export from 13 small watersheds on MDI, including 

NEC (see also Nielsen et al. 2002). Caron (2005) investigated groundwater contributions of 

water and nutrients in one sub-watershed of NEC – Aunt Betsey’s Brook. A GIS-based decision 

support system (NLERT) was developed by the USGS for evaluating the effect of land-use 

changes on nutrient loading to NEC, and the responses of estuarine autotrophic communities to 

various levels of enrichment (Rohweder et al. 2004). This study used mesocosms to investigate 

the influence of nitrogen loading on vascular plants, phytoplankton, epiphytes and 

macroinvertebrates (e.g. Keats 2002). Recently, K. Anderson (ACAD Office of GIS, pers. 

comm. September 2007) used the NLERT model to estimate the impact of increasing residential 

development on the ecological condition of the NEC estuary. As noted above, Culbertson et al. 

(2007) included Northeast Creek in their study of nutrient enrichment from discharge of shallow 

groundwater on MDI. Twenty seven groundwater seeps were identified in NEC. 

Key findings from these studies are summarized below. For discussion of water use and 

groundwater recharge issues, see section on Threats: Altered Hydrology. 

Groundwater Nitrogen Concentrations 

(i) Estimated groundwater NO3-N concentrations were sensitive to the rate of recharge. 

In populated NEC sub-watersheds, estimated concentrations ranged from 0.3 mg/L 

(Stony Brook watershed, high recharge rate) to 11 mg/L (Liscomb Brook watershed, low 

recharge rate). Figure 55 shows nitrogen data and dilution factors for the medium 

recharge scenario. (Nielsen 2002a, b) 

(ii) With the exception of the Liscomb Brook estimate, estimated NO3-N groundwater 

concentrations in the NEC basin are below the human health limit of 10 mg/L (USEPA 

2001). (Nielsen 2002b) 
101 

(iii) Dissolved N concentrations in hyporheic zone wells adjacent to NEC were elevated 

relative to NEC tributaries, suggesting that contamination from septic sources may be 

influencing the quality of shallow groundwater. (Culbertson et al. 2007) 

(A) 

0 5 10 15 20

Aunt Betseys Brook

Breakneck Brook

French Hill Brook

Fresh Meadow Wetland

Kitteredge Brook

Liscomb Brook

Old Mill Brook

Stony Brook

% Recharge

(B) 

0 0.5 1 1.5 2 2.5 3 3.5 4

Aunt Betseys Brook

Breakneck Brook

French Hill Brook

Fresh Meadow Wetland

Kitteredge Brook

Liscomb Brook

Old Mill Brook

Stony Brook

NO3-N (mg/L)

(C) 

0 100 200 300 400 500 600 700

Aunt Betseys Brook

Breakneck Brook

French Hill Brook

Fresh Meadow Wetland

Kitteredge Brook

Liscomb Brook

Old Mill Brook

Stony Brook

Dilution Factor

Figure 55. Groundwater use and nitrate concentrations in selected sub-watersheds of the 

Northeast Creek system. (A) Groundwater use as a percentage of recharge. (B) Estimated 

nitrate-nitrogen concentration in the bedrock aquifer. (C) Dilution factor. All data are for 

medium groundwater recharge rate of 9 in/yr. (Data source: Nielsen 2002b) 
102 

Nutrient Loading 

(iv) Overall, nitrogen yields to NEC were lower than yields to eutrophic estuaries 

elsewhere on the East Coast. Most of the other estuaries are, however, in more urbanized 

settings. (Nielsen 2002b) 

(v) The Stony Brook sub-watershed contributed 59% and 46% of the system’s total nonmarine load of nitrate (NO3) and total N, respectively. This watershed has a higher 

population than any of the other NEC sub-watersheds. Slightly less than half of this 

watershed lies within the ACAD boundary. Even though its population has been 

relatively stable over the past 20 years, many of its houses are likely served by older 

septic systems. (Nielsen 2002b) 

(vi) Recent population growth in the NEC basin has been greatest in the Old Mill Brook 

(about one third of the watershed is within ACAD) and French Hill Brook (entirely 

outside ACAD) sub-watersheds. Together, these contributed 23% of total NO3 loading to 

the NEC system. (Nielsen 2002b) 

(vii) Direct atmospheric inputs (i.e. to the creek surface) represented only 1% of the total 

N load and <10% of the inorganic N load. (Nielsen 2002b) 

(viii) Nitrogen flux to Aunt Betsey’s Brook from groundwater was insignificant relative 

to contributions from surface water loads. (Nielsen 2002b) 

(ix) However, initial loading estimates from the work of Culbertson et al. (2007) suggest 

that shallow groundwater seeps could represent a substantial proportion of the total 

dissolved N load to the NEC system. Because groundwater seeps are likely to be less 

influenced by short-term drought that stream flow, the shallow groundwater load may be 

especially important during periods of low stream flow. 

(x) Nitrogen loading from tidal inflow may be significant if the NEC system behaves 

similarly to the Bass Harbor Marsh (Doering et al. 1995). 

(xi) In 13 watersheds across MDI (including the studied watersheds in the NEC basin), 

drainages entirely within ACAD exported significantly less total N and total P than did 

watersheds partially or completely outside the park. (Nielsen and Kahl 2007) 

Ecosystem Response 

(xii) Using results from mesocosm experiments, three classes of estuarine condition were 

defined (Rohweder et al. 2004). Average watershed loadings of dissolved inorganic 

nitrogen associated with each class are: 

 “Healthy”: < 2.2 kg/ha/yr; 

 “Degrading”: 2.2 – 4.4 kg/ha/yr; 

 “Degraded”: > 4.4 kg/ha/yr. 
103 

(xiii) Based on 2001 land-use patterns, the estimated NEC nitrogen loading was 1.86 

kg/ha/yr. This places the system in the “healthy estuary” class. Using 2004 data for 

building footprints and building permit records, the estimated loading would increase to 

2.1 kg/ha/yr., still within the healthy class but approaching the modeled threshold to 

degrading. Land-use projections based on the draft Bar Harbor comprehensive plan 

suggest that the loading would further increase to 2.72 kg/ha/yr (K. Anderson, NPS, pers. 

comm. September 2007). This scenario would place the estuary within the “degrading” 

class. 

Somes Sound: Nutrient loading to Somes Sound was investigated by Doering and Roman 

(1994). Six streams provide 86% of the freshwater inflow to the Sound. The Somesville water 

pollution control facility contributed < 0.1% of the freshwater input, but 37% of total dissolved 

inorganic N loading and 51% of the phosphate loading. Nutrient concentrations entering the 

Sound via freshwater sources were considered low compared to other estuaries – inorganic N and 

P loadings were two orders of magnitude lower than in other systems. Because of the importance 

of marine-derived nutrient loading, a 20% increase in nutrient loading from freshwater sources 

would have negligible impact on nutrient concentrations in Somes Sound. Overall, Somes Sound 

is relatively pristine, with low nutrient and chlorophyll levels. The water column is always 

oxygen saturated (Doering and Roman 1994). 

Nutrient Enrichment: Other Coastal and Marine Areas 

Eutrophication Assessments: The expression of eutrophic conditions within the ACAD region 

can be best evaluated using the NOAA National Estuarine Eutrophication Assessment (NEEA). 

Condition reports have been released three times over the past decade (NOAA 1997, Bricker et 

al. 1999, and Bricker et al. 2007). Methods have evolved with subsequent assessments, but are 

based in principle upon evaluating influencing factors (nutrient load, flushing, susceptibility), 

and the level at which eutrophic conditions and symptoms are expressed. Blue Hill Bay is among 

the 10 NEEA estuaries within the Gulf of Maine, and it has consistently expressed low-level 

eutrophic conditions. Assessments for 1999 and 2004 both predicted small deteriorations in 

condition within Blue Hill Bay due to anticipated changes in nutrient loading. However, the 

trend between these two assessments was actually a slight improvement in chlorophyll-a levels 

(Bricker et al. 2007). 

Aquaculture: There are at least 20 permitted aquaculture lease sites around MDI covering 

169.2 ha, but none within 2 km of ACAD lands (Figure 56). Most of the leased resource (148.3 

ha) is permitted for shellfish aquaculture and presents no particular threat to exacerbating 

nutrient stresses on these waters since no fertilizer or feed is used. Three lease sites have been 

permitted for finfish aquaculture – all in the vicinity of Swans Island. Of these, two sites (13.3 

ha) are currently leased into 2009, and the remaining (7.6 ha) is leased until 2014. Due to the 

necessary application of feed and medication, finfish aquaculture may adversely affect benthic 

habitat and water quality, and promote eutrophication (Jones and Wells 2002). Past interest in 

expanding finfish aquaculture into Blue Hill Bay has been unsuccessful, but prompted 

investigations into computer simulation modeling of dispersal of aquaculture wastes (e.g. Dudley 

et al. 2000). Pesticides used in finfish culture are a potential contaminant source (see below). 
104 

Figure 56. Aquaculture sites in the MDI area. Additional sites are pending permitting. 

(Data from ME Division of Marine Resources)

Algal Blooms: Harmful and nuisance algal blooms are an important issue in the Gulf of Maine 

(Jones and Wells 2002). Blooms occur both near-shore and off-shore, and are often related to 

nutrient levels. 

Blooms of the toxic dinoflagellate, Alexandrium fundyense, are common in the Gulf of Maine 

during summer months (Figure 57; Townsend et al. 2005). Blooms may be associated with 

relative concentrations of inorganic nitrogen and silicate, which are in turn influenced by 

oceanographic processes. The blooms can result in paralytic shellfish poisoning when infected 

shellfish are consumed by humans. Aside from this, however, it appears unlikely that these 

marine phytoplankton blooms have a direct effect on ACAD natural resources. 

Sewage: Discharge of treated and untreated sewage is a recognized concern in the Gulf of 

Maine (Jones and Wells 2002). Along with municipal discharge of treated wastes, numerous 

direct overboard discharges of household sewage are still grandfathered by the state. While once 

common practice, the overboard discharge of untreated raw sewage from boats into the ocean is 
105 

Figure 57. Cell densities of the toxic dinoflagellate Alexandrium fundyense in surface waters of 

the Gulf of Maine in June 2000. MDI is shown in mid-coast area. 

(Figure from Townsend et al. 2005, used with permission) 

no longer permissible within 3 miles of shore. However, vessel operators may still pump out 

sewage that has been treated to reduce bacteria and remove visible floating solids. In addition to 

its contribution to nutrient pollution, bacterial contamination from untreated or inadequately 

treated wastes poses significant health risks and can result in beach and shellfish closures around 

MDI (see below). 

Microbial Contamination 

Key Issues Extent of Problem Information Base

Bacteria contamination of beaches PP Good 

Shellfish closures EP Good 

Microbial contamination is primarily a human health issue and is not known to directly affect 

non-human biota at ACAD. 

Bacterial contamination of beaches 

Bacterial monitoring is carried out at Echo Lake, Lake Wood and Sand Beach by ACAD staff 

because of human health concerns. The Maine Healthy Beaches Program monitors other beach 

sites on MDI but outside the Park. Data from these surveys are shown in Figure 58. While most 

samples are within Maine standards, some bacterial counts exceed these criteria. 
106 

Location - Parameter (EC = E. coli. ENT = Enteroccoci)

Echo Lake - EC LakeWood - EC Sand Beach - ENT SB Lagoon - ENT Other MDI - ENT

# colonies / 100 ml

0

50

100

150

200

250

300

Figure 58. Bacteria concentrations at four ACAD beach sites: Echo Lake, Lake Wood, Sand 

Beach and Sand Beach lagoon. Also included are data from other MDI beach and stream 

(Stanley Brook) sites outside of, or bordering, ACAD. 

ACAD data are from 1993-2006. Number of sampling dates vary with location. Data for other 

MDI sites are from 2004-2006. 

Boxes indicate 25th and 75th percentiles, with median line; whiskers are 10th and 90th percentiles; 

dots are outliers. 

Maine standards are: E. coli = 29 (geometric mean), 194 (single sample); Enteroccoci = 8 

(geometric mean), 54 (single sample). 

(Note that one unusually high value from Sand Beach Lagoon has been omitted from this plot.) 

Shellfish closures 

The Maine Shellfish Growing Area Classification Program follows National Shellfish Sanitation 

Program standards to judge the cleanliness of all the marine waters of the State of Maine (Figure 

59). This is accomplished by monitoring water along marine shores in the vicinity of shellfish 

beds six times per year for bacterial contamination (green points in Figure 59C are current and 

historic shellfish monitoring stations) and by conducting shoreline surveys to determine the 

location and magnitude of potential sewage pollution problems. Updated legal notices for the 

Maine Shellfish Closed Area Inventory are available from Maine Division of Marine Resources 

(http://www.maine.gov/dmr/rm/public_health/closures/closedarea.htm). 
107 

 (A) (B) 

(C) 

Figure 59. Worm and shellfish habitat and shellfish closures in the ACAD region. 

(A) Marine worm and (B) shellfish habitat in the 1970s. 

Maps were produced from GIS data from Maine Office of GIS (http://megisims.state.me.us/metadata/worm.htm) 

and are based on original maps in Fefer and Schettig (1980). 

(C) Areas closed (red) and conditionally closed (yellow) to shellfish harvesting as of July 2003. 

Note that this inventory does not include shellfish areas closed due to the presence of biotoxins 

(red tide). 

The Maine Shellfish Growing Area Classification Program follows National Shellfish Sanitation Program standards 

to judge the cleanliness of all the marine waters of the State of Maine. This is accomplished by monitoring water 

along marine shores six times per year for bacterial contamination (green points) and by conducting shoreline 

surveys to determine the location and magnitude of potential sewage pollution problems. Vector digital data for 

closed areas (Maine Office of GIS CLASS03E dataset) are based upon descriptions from rules promulgated by the 

Maine Department of Marine Resources (DMR) current at the time of data publication. Updated legal notices for the 

Maine Shellfish Closed Area Inventory are available from Maine DMR 

(http://www.maine.gov/dmr/rm/public_health/closures/closedarea.htm). Point locations of water quality sampling 

stations were compiled from paper maps by the Maine DMR (Maine Office of GIS NEWWQ dataset). 
108 

Other Contaminants 

Key Issues Extent of Problem Information Base

PCBs EP Poor 

Sewage PP Poor 

Schoodic naval base legacy PP Fair 

Parking lot runoff PP Inferential 

Boat traffic and oil spills PP Inferential 

Aquaculture pesticides PP Poor 

Landfills EP Fair 

Road salt/sand PP Poor 

Underground storage tanks OK ? Poor 

Metals in stream water PP ? Good 

Arsenic and radon in groundwater PP Poor 

Metals in marine sediments OK Good 

Fire retardants PP? Inferential 

Trace metals and organics in mussels PP (dep. on 

contaminant) 

Good 

Haines and Webber (1999) provide a detailed assessment of contaminant threats at ACAD. Their 

assessment concludes that the majority of the Park’s pollutant load arrives via atmospheric 

transport. In this section we provide a brief overview of key findings from the Haines and 

Webber assessment as they relate to contaminants potentially affecting the ACAD region. For 

more information, and for source references, see Haines and Webber (1999). The overview is 

structured around the four transport mechanisms (pathways) described by the authors: air, 

surface fresh water, surface salt water, and ground water. 

Following a review of the Haines and Webber (1999) assessment, we summarize additional 

information on freshwater, ground water, and marine contaminants. 

Air Pathway 

Four primary contaminants of concern were identified: ozone, acid rain, Hg and organochlorines. 

The first three have been discussed above under Threats: Atmospheric Deposition and Mercury.

Organochlorine compounds are deposited in areas remote to their origin. Within 200 km of the 

Park, there are 130 facilities reporting emissions of air toxics. A 1993-94 survey of contaminants 

in fish throughout Maine did not record “appreciable” quantities of PCBs or pesticides in fish 

collected from ACAD lakes. In contrast, PCBs and DDE have been recorded in nesting bald 

eagles within and near the Park at concentrations high enough to cause damage to raptors. These 

contaminants probably were derived from marine organisms. The entire Park is at risk from 

organochlorines. Sensitive species are those with high percentages of fish in their diets and 

naturally low reproductive rates. Examples include loons and kingfishers. There is inadequate 

information on the extent of, and impacts from, contamination by organochlorine compounds at 

ACAD. 

Freshwater Pathway 

Pollutant sources of highest concern include: (i) RCRA hazardous waste generators (13 listed for 

MDI); (ii) CERCLA sites of gross environmental damage (none on MDI, but 19 in the Maine 

Coastal watershed); (iii) TRI (toxics release inventory) sites (none on MDI, SCH or IAH); (iv) 
109 

pollution control facilities (3 on MDI; Bar Harbor and Mount Desert, each with three discharge 

points, and Southwest Harbor with one discharge point); (v) mining sites (1 listed for MDI, but 

likely inactive); (vi) local pesticide use (no aerial spraying occurs on MDI, SCH or IAH, but 

ground-based spraying occurs along power line routes); (vii) uncontrolled spills (six sites within 

five km of the Park); (viii) parking lots. 

The two highest risk sources were considered to be the Mount Desert sewage outfall at Otter 

Creek and the former Naval Security Group at SCH. The Otter Creek sewage outfall has recently 

been closed – sewage is now pumped to Seal Harbor where it is treated at an upgraded facility. A 

key concern at SCH was contamination caused by capacitors that had been stored there for many 

years and some of which had ruptured. Both sources are probably today of much lower risk 

because of remediation actions that have been implemented over the past several years. 

Parking lot runoff may be a source of non-point source pollution. Primary parking lots in the 

Park are at Echo Lake, Eagle Lake, Sand Beach, the Visitor Center and Jordan Pond. At Jordan 

Pond (one of the clearest lakes in the State of Maine), runoff from the boat ramp at Jordan Pond 

is a concern (D. Manski, NPS, pers. comm.). 

Saltwater Pathway 

Pollutant sources with greatest potential to damage Park resources are (i) oil spills (2 reported 

from MDI in the five years prior to the assessment of Haines and Webber [1999]); (ii) boat 

traffic (tour boats, smaller pleasure craft and fishing boats); (iii) merchant transport; (iv) bulk oil 

and hazardous material storage facilities (four on MDI, all of which are hazardous material 

storage, plus a more recently constructed bulk oil facility); (v) some aquaculture operations 

(Figure 56). 

Fine-scale models of the circulation patterns in the Acadia region are limited to Blue Hill Bay 

(Dudley et al. 2000). Interest in information for this area was driven by concern over the possible 

expansion of finfish aquaculture in this area, as noted above. For the rest of the Acadia region, 

circulation models are based on coarser spatial and temporal domains (e.g. Xue et al. 2000). On 

average, one major oil spill (greater thatn 100,000 gallons) occurs in Maine each decade. 

Circulation models are an important component of the responses to manage oil spills. The State 

of Maine uses the Marine Oil Spill Information System (MOSIS) which is based on output from 

the General NOAA Ocean Modeling Environment (GNOME). Maine has also developed a 

detailed Marine Environmental Vulnerability Index (EVI) for the entire state to give first 

responders a tool for prioritizing and targeting protection strategies. Nonetheless, there is still 

great uncertainty as to how a major oil spill in the Penobscot Bay or neighboring waters might 

affect ACAD resources. The concern for potential future impacts is particularly strong around 

Isle au Haut, an area with regular tanker traffic. An additional concern is possible collisions 

and/or fuel spills from the large number of cruise ships that visit Frenchman Bay each year. 

A study of ocean currents in the immediate ACAD area was carried out by Muhlin (2007) who 

focused on the influence of near-shore circulation patterns around Schoodic Point on gene flow 

in the brown alga Fucus vesiculosus. Using surface drifters, the study highlighted the dynamic 

association between near-shore coastal oceanography and population genetics. 
110 

Groundwater Pathway 

Pollutant sources of highest concern are (i) landfills (see below); (ii) road salt and sand (only the 

Southwest Harbor pile is upstream of Park resources); (iii) underground storage tanks 

(approximately 80 on MDI and 19 at SCH) – all tanks are fitted with leak and corrosion detectors 

and are thus of low concern to the Park; (iv) shallow-well injection sites (16 wells listed for 

MDI; mainly waste pipes to streams, storm drains and soil from businesses such as garages and 

cleaners) – all are considered to be of low contaminant risk to Park resources on account of their 

location downgradient or distant from the Park. 

There are four municipal landfills within five km of the Park. All are closed, but the Winter 

Harbor landfill is of high concern because of the presence of PCBs and hydrocarbons in surface 

and groundwater samples taken around the landfill. The Worcester landfill in Southwest Harbor 

is a private operation that operated from the 1930s to the early 1990s. Leachate from the landfill 

has affected water quality in Marshall Brook. This brook formerly supported large runs of searun brook trout. It is currently a high priority system for stream crossing restoration (see Threats: 

Habitat Loss / Impairment). There has been an extensive series of studies relating to Marshall 

Brook – see full list in Haines and Webber (1999). 

Additional Contaminant Data 

Surface Freshwaters: Peckenham et al. (2006) sampled streams and springs on MDI to 

investigate the impact of vehicular traffic on water quality. Samples were analyzed for volatile 

organic compounds (VOCs), polynuclear aromatic hydrocarbons (PAHs) and trace metals. VOCs 

and PAHs were below detection at all sites. Trace metals were detected in all samples (Figure 

60), with the five most concentrated elements being aluminum, zinc, copper, molybdenum and 

arsenic. 

Concentrations were below acceptable ecological limits but above amounts expected from local 

geology. Arsenic and molybdenum concentrations were statistically associated with traffic 

counts. However, enhanced metal levels also occurred distant from roads. This suggests that 

atmospheric transport of vehicle-derived contaminants is an important factor influencing their 

distribution in ACAD surface waters. Surprisingly, springs had elevated metal concentrations. 

Molybdenum was consistently high in Sieur de Monts Spring, while the higher elevation Birch 

Spring had relatively high total metal concentrations. 

Lead contamination in loons and other freshwater taxa is a concern as a result of ingestion of 

lead sinkers (D. Lamon, Somes-Meynell Wildlife Sanctuary, pers. comm.). Although some loon 

tissues and unhatched eggs have been analyzed for lead and other toxins, data from these studies 

are not currently available. 

Groundwaters: Analyses of water quality in domestic and bedrock monitoring wells in the 

Northeast Creek and Bass Harbor Marsh areas showed that, except for phenol, all household 

wastewater-related compounds were below detection at all sites (Culbertson et al. 2007). Phenol 

was detected in one well (domestic) in the Northeast Creek watershed and two wells (both 

bedrock monitoring wells) in the Bass Harbor watershed. 
111 

Figure 60. Total trace metal concentrations in streams and springs on MDI, June 2003. (From 

Peckenham et al. 2006)

Naturally occurring contaminants in well water supplies include arsenic and radon. Arsenic 

concentrations appear to be low on MDI – out of 117 well-water samples analyzed, 92 had 

<1μg/L arsenic while three had >30 μg/L (K. Bell, University of Maine, pers. comm.). 

Culbertson et al. (2007) detected arsenic in two domestic wells and two bedrock montoring wells 

in the Northeast Creek watershed. Concentrations in domestic wells were <5 μg/L, while those 

of bedrock wells were between 6.3 and 11.1 μg/L (the EPA maximum concentration in drinking 

water for arsenic is 10 μg/L.). 

Data presented by Kahl et al. (2000) suggest that radon levels in some wells on MDI may be a 

health hazard to humans. 

Marine Waters: Contaminant monitoring of coastal marine sediments indicates that 

contaminant concentrations in the MDI region are relatively low. Figure 51 displays data for Hg 

and arsenic. 

 

The Gulfwatch program monitors spatial and temporal patterns of trace metal and organic 

contaminants in the Gulf of Maine using the blue mussel (Mytilus edulis). Most contaminant 

levels were lower in the Gulf of Maine than median concentrations from all National Status and 

Trends (NST) Mussel Watch data (Chase et al. 1997). However, Hg concentrations at > 80% 

Gulf of Maine sites exceeded the median NST value. There are two Gulfwatch sites on the 

southwest sector of the MDI coast (www.gulfofmaine.org). 
112 

Emerging issues: Recently, concern has been raised about previously un-studied contaminants. 

Two such examples are fire retardants and pharmaceuticals. There is no specific information 

regarding these groups – or other emerging contaminant groups – at ACAD, but they have been 

found to be fairly ubiquitous at some other sites and warrant further investigation. 

Fire 

Key Issues Extent of Problem Information Base

Impacts on terrestrial systems: 

vegetation composition, soil structure 

and chemistry, Hg, beaver populations 

EP / PP / HP Good 

Impacts of Fire on Terrestrial Systems 

Patterson et al. (1983) list 10 major fires in the ACAD region during the century from the mid 

1800s. The largest of these burned approximately one third (6,875 ha) of MDI in 1947 (Figure 

14). In addition, there have been many smaller fires, generally affecting areas < 5 ha. Between 

1937 and 1974, for example, there were 136 documented smaller fires. 

Forest stands at ACAD have been classified into five fire-response groups (Patterson et al. 

1983): 

(i) Spruce and cedar stands, in which the natural fire cycle is tied to the maturation 

cycle of the dominant trees. 

(ii) Pine stands, composed of fire-adapted species for which fire enhances the 

establishment of seedlings. 

(iii) Birch-aspen stands – these often appear following fires which expose mineral 

soils. 

(iv) Red oak stands, which may benefit from moderate fires but are significantly 

affected by more intense fires. 

(v) Northern hardwood stands – these are less likely to burn than other forest types 

but, when ignited, are also more susceptible to forest damage. 

ACAD soils have been classified into four groups according to their susceptibility to fire damage 

(Patterson et al. 1983). Classification is based on a series of properties (slope, drainage, 

permeability, depth, texture and erodibility) that characterize a soil’s susceptibility to post-fire 

erosion and the rapidity with which revegetation would occur. 

More recently Devine et al. (2006) developed fire fuel load maps of ACAD using data from the 

Acadia Vegetation Mapping Project (Lubinski et al. 2003) and field-collected fuel load data. 

Figure 61 depicts fire fuel loads for MDI and vicinity using a “complacent” fire fuels model (i.e. 

little vegetative seasonal drying or “curing”). Used with data on stand height, canopy cover, 

canopy bulk density, slope, aspect and elevation, these fire fuel load data will enable future 

simulations of fire growth behavior. This is particularly important given Park policy of not 

removing fuel. 

Related topics: The 1947 fire affected extensive stands of softwood forests on eastern MDI and 

resulted in the regeneration of birch-aspen stands (Patterson et al. 1983). In addition to 
113 

vegetation composition, the 1947 fire influenced beaver, river otter and deer populations (Dubuc 

et al. 1988, 1990, 1991; Cunningham et al. 2006; D. Manski, NPS, pers. comm.) as well as soil 

structure and Hg dynamics (Johnson et al. 2003). These issues are covered in other sections of 

this report. 

Figure 61. Fire model output for MDI region based on vegetation map data. 

(Image from Devine et al. 2006) 
114 

Altered Hydrology 

Key Issues Extent of Problem Information Base

Lake water level fluctuations OK Good 

 - impacts on biota UNK Poor 

Stream discharge OK Poor 

Wetland hydrology EP Good 

Groundwater levels PP Fair 

- water availability & surface hydrology PP Poor 

Lake Water Levels 

Lake water levels are influenced by precipitation, evaporation and, in the case of four drinking 

water supply lakes, potable water demand. Use of water for fire control as well as human and 

beaver damming activity may also influence lake water levels (Seger et al. 2006). Stage data are 

available from eight lakes on MDI (Eagle, Bubble, Echo, Jordan, Seal Cove, Upper Hadlock, 

Witch Hole and the Tarn). The magnitude and pattern of lake drawdowns vary among years 

(Seger et al. 2006). Figure 62 shows stage data for MDI lakes in 2005, a year when there was 

relatively little rainfall during the summer months. Late spring-summer water level declines were 

greatest for Eagle and Echo Lakes (ca. 1.5 m) and least for Bubble and Upper Hadlock Ponds. 

Eagle Lake is a municipal water source, but Echo Lake is not. In years with greater summer 

precipitation (e.g. 2004, Seger et al. 2006), lake levels fluctuate less. 

Water withdrawals for Eagle Lake in summer months are about double the winter level (Figure 

62B), in part because of increased demand from the tourist population. The drought of 2001-

2002 did not have substantial effects on either lake levels or water quality of Eagle Lake 

(Schmitt 2003). 

There appears to be no information on the impacts of lake drawdown regimes on habitat quantity 

or quality for aquatic biota in ACAD lakes. Fluctuating water levels have been identified 

elsewhere as adversely impacting some bird species: black terns (Chlidonis niger), common 

loons (Gavia immer), pied-billed grebe (Podilymbus podiceps) – see Appendix 9 for more 

information. In some Maine lakes, human-influenced lower and/or fluctuating lake levels are 

known to negatively impact aquatic plant and fish populations (Vaux 2005). Instream flow below 

water control structures at lake outlets may be reduced when lake water levels fall below the 

outlet elevation (see below). Water level changes in lakes or wetlands, flooding, and frequent 

drying and wetting cycles increase the production of methylmercury (the toxic form of mercury) 

by increasing decomposition of organic matter and creating anoxic zones, both conducive to 

methylating bacteria (in the case of wetting) or oxidizing reduced sulfur (in the case of drying) 

which then leads to a spike in sulfur reduction when soils/sediments are subsequently re-wet 

(Munthe et al. 2007 and references therein). 

Stream Discharge 

The hydrological record for ACAD streams is insufficient to document any medium- to longterm trends in stream discharge. The longest-term records are for Cadillac and Hadlock Brooks, 

each with just seven years of data. There are also insufficient data to evaluate the effects of water 

control structures at lake outlets (Figure 9) on the hydrology of outflowing streams. Flows in the 
115 

outlet stream from Long Pond may be too low to permit effective passage of anadromous fish – 

and may be lower than permitted flows (D. Lamon, Somes-Meynell Wildlife Sanctuary, pers. 

comm. August 2007). The effects of stream barriers on habitat quality and connectivity are 

discussed below under Threats: Habitat Loss / Impairment.

(A) 

(B) 

Water Withdrawals from Eagle Lake, 1992-2002

0

50,000

100,000

150,000

200,000

250,000

300,000

Jan-92

Jul-92

Jan-93

Jul-93

Jan-94

Jul-94

Jan-95

Jul-95

Jan-96

Jul-96

Jan-97

Jul-97

Jan-98

Jul-98

Jan-99

Jul-99

Jan-00

Jul-00

Jan-01

Jul-01

Jan-02

Jul-02

cubic meters

Figure 62. Lake levels and water withdrawals. 

(A) Stage data from eight MDI lakes, and precipitation, April – December 2005. 

Precipitation bars represent cumulative rainfall for the periods since the previous date 

represented. Precipitation data are from the McFarland Hill NADP site. 

(Figure from Seger et al. 2006) 

(B) Water withdrawals from Eagle Lake, Bar Harbor (graph provided by C. Schmitt, University 

of Maine) 
116 

Wetland Hydrology 

As a result of road-building, filling, ditching and dredging, humans have been altering the 

hydrologic regimes MDI wetlands for over 250 years (Neckles et al. 2007). Bridges, causeways, 

dikes and other structures that cross wetlands restrict or impede the natural hydrologic regime at 

a number of locations in the Park (Kahl et al. 2000). Of particular concern are the following 

areas: 

• At Schoodic, just before Big Moose Island, the park loop road appears to be 

constricting the connection between the ocean and a small estuary. As a result of 

reduced tidal flows, upland vegetation has been encroaching into the former wetland 

(Kahl et al. 2000). 

• Remnants of an old rock dam at the mouth of Northeast Creek restrict tidal flow into 

and out of the estuary, especially during neap tides when there is little or no seawater 

input (Caldwell and Culbertson 2007). Bridge abutments at the Route 3 road crossing 

also constrict the outlet of Northeast Creek. 

• The outlet of Bass Harbor marsh is constricted by the Route 102 road crossings 

(Doering et al. 1995). 

• In Great Meadow, historic roads, berms and ditches restrict sheet flow into this 

wetland, causing changes in the vegetation community (D. Manski, NPS, pers. 

comm.). 

Jordaan (2006) noted that the presence of culverts affected all the estuarine sites surveyed for 

fish assemblages. Culvert location relative to mean tide is different for each site; this, combined 

with local topography, means that the structures have different influences on hydrologic 

dynamics. 

Groundwater Levels 

Increasing residential development in the Northeast Creek basin (northeastern part of MDI) has 

led to concerns about impacts on ground water quantity and quality. Nielsen (2002a) evaluated 

water use and groundwater recharge rates in the Northeast Creek basin and two adjacent 

watersheds. Approximately 20% of this area is within the ACAD boundary. Nielsen concluded 

that: 

 (i) Groundwater use in the study area during 2001 was less than water recharge to the 

study area. For example, using a medium recharge rate, water use represented 2.5% of the 

estimated recharge volume. Water use was 18% of the recharge rate in one small subwatershed (Liscomb Brook); in all others it was <7% (Figure 55A). 

(ii) Small changes in housing density would not substantially affect groundwater use 

relative to recharge. 

Nevertheless, members of the public on MDI continue to be concerned that residential 

development in the Northeast Creek watershed may adversely affect water supply from drilled 

wells (J. Disney, MDI Water Quality Coalition, pers. comm. July 2007). 

Ground water quality is discussed under Threats: Nutrient Enrichment. 
117 

Impacts of Hydrologic Changes on Rare Plant Species 

According to Greene et al. (2002), changes in hydrology are a potential stressor for 6 rare plant 

species (out of 20 species considered) (Table 7). These changes, although not detailed by Greene 

et al. (2002), probably refer to water level alterations in wetlands and lakes. To our knowledge, 

there is no information that quantitatively documents the impact of hydrologic changes on 

individual plant species at ACAD. 

Habitat Loss and Impairment 

(Notes: Changes in hydrology – see above – are closely related to habitat loss and impairment. 

Visitor use impacts on habitat quality are discussed in the following section.) 

Key Issues Extent of Problem Information Base

Stream barriers EP Fair 

Beaver impacts on wetlands OK Good 

Terrestrial habitat loss and 

fragmentation – impacts on biota 

PP Poor 

Shellfish harvest and boat mooring 

impacts on eelgrass beds 

PP Poor / Inferential 

Stream Barriers 

Most larger lakes in the ACAD region have water control structures at their outlets (Figure 9). 

The height of these structures is between 6 and 14 feet, while the hydraulic height is generally 1-

2 feet lower (data source: GIS database of Maine impoundments). 

In addition to these lake outlet structures, there are also numerous culverts, bridges, weirs and 

dams across MDI streams. Many of these reduce or impair habitat connectivity. ACAD scientists 

have recently surveyed 131 stream crossings on 48 streams in the Park to characterize the extent 

to which these structures are barriers to the passage of fish (B. Connery, NPS, pers. comm. 

October 2007). Draft conclusions from this survey include the following breakdown of number 

of sites by quality of aquatic organism passage (AOP): 

 Bad (blocks AOP): 34% 

 Fair (partially blocks AOP): 56% 

 Good (does not block AOP): 9% 

 

Reasons for obstructed passage include perched culverts and crossings blocked by debris. The 

survey also ranked streams for future restoration by considering, in addition to the extent of 

passage blockage, the amount of upstream habitat, land ownership and likely remediation costs. 

These survey data are being used to prioritize sites for restoration. In addition to AOP quality, 

factors considered during the prioritization process include cost, amount of ‘new’ habitat that 

would be gained from restoration, length of stream in Park lands, existing and historical 

fisheries, number of abutting land owners, and other aspects of stream condition. Streams with 

high priority restoration sites include: Cromwell Brook, Heath Brook, Hunters Brook, Kebo 

Stream, Lurvey Brook, Marshall Brook and Stanley Brook. 
118 

An ongoing restoration project is designed to improve fish passage for alewives (Alosa 

pseudoharengus), American eel (Anguilla rostrata) and sea lamprey (Petromyzon marinus) 

between Somes Sound and Long Pond (D. Lamon, Somes-Meynell Wildlife Sanctuary, pers. 

comm. September 2007). Historically, >200,000 adult sea-run alewives followed streams leading 

from Somes Sound through a mill pond to Somes Pond, Ripple Pond and then on to Long Pond. 

In the 1970s, the estimated harvest of alewives was >80,000 fish. Because of deterioration of the 

fish ladder on the lower dam, only 360 fish were counted passing the dam in 2005 (note, 

however, that 2005 was a poor year for alewife runs elsewhere in Maine). Run sizes in 2006 and 

2007 were >4,000 and >6,000 fish, respectively – still an order of magnitude lower than runs 

forty years ago. There are four water control structures and fishways between Somes Sound and 

Long Pond – two fishways were restored in 2006; work on other structures started in 2007. 

While none of these structures are on ACAD fee-owned lands, Long Pond is partially surrounded 

by ACAD (Figure 2). If the lake were made fully accessible to anadromous fish, it would provide 

almost 400 ha of freshwater habitat for these species. An additional key issue for fish passage in 

this system relates to dam management and ensuring minimum flows, particularly during fish 

immigration and emigration. 

Water control structures at lake outlets may contribute to low-flow conditions in some streams. 

For example, a ca. 500 m section of Jordan Stream immediately downstream of the Jordan Pond 

dam was completely dry in the summer of 2007 when low lake water levels prevented flow to 

the stream (D. Manski, NPS, pers. comm.). There are no data on the natural flow regime of this 

and other streams prior to installation of water control structures. 

Beaver Impacts on Wetlands 

Following the re-introduction of beaver to MDI in 1921, a natural disturbance regime was 

restored to the island (Cunningham et al. 2006). Beaver create a “shifting mosaic” of wetlands 

resulting from patterns of colonization and abandonment. Beaver activity on MDI has been 

especially pronounced in areas burned by the 1947 fire, where subsequent early successional tree 

species produced a highly favorable environment for this species. The number of ponded wetland 

units on eastern MDI increased by 89% between 1944 and 1997 as a result of the increasing 

beaver population (Cunningham et al. 2006). This increase represented newly flooded wetlands 

as well as conversion of forested to open water and emergent wetlands. In recent years, forest 

succession in burned areas has reduced habitat quality for beaver. This has resulted in a 

corresponding reduction in actively maintained beaver dams, even though many of these 

wetlands persist (Figure 27, Cunningham et al. 2006).

Beaver-created wetlands provide valuable habitat for pond-breeding amphibians (Cunningham et 

al. 2006). Conversely, wetland creation may potentially reduce habitat quality for some fish 

species (e.g. brook trout) as a result of elevated water temperatures relative to free-flowing 

streams. While the positive impacts on amphibian populations have been documented at ACAD 

(Cunningham 2003), potential negative impacts on fish remain undocumented. 
119 

Terrestrial Habitat Loss and Fragmentation 

A number of studies have examined faunal habitat characteristics, patch sizes and dispersal 

abilities on MDI. For example, Whitcomb (1993) found that spruce grouse (Falcipennis 

canadensis) occupied about one third of suitable habitat patches surveyed. However, marginal 

and unsuitable forest habitat between patches did not represent an inter-patch dispersal barrier 

for this species. Chilelli et al. (1994) used stochastic simulation modeling to study the effects of 

habitat quantity and quality (including connectivity) on population viability for three species: 

southern bog lemming (Synaptomys cooperi), fisher (Martes pennanti), and black bear (Ursus 

americanus). Interconnecting habitat fragments were found to be necessary for the maintenance 

of a viable metapopulation structure for southern bog lemmings. Demographic and 

environmental stochasticity were major influences on modeled population sizes of fisher on 

MDI. Simulated black bear populations on MDI were not large enough to maintain genetic vigor. 

Consequently, the island population of this species would have to be considered part of a viable 

mainland population. 

Residential and other development is ongoing in many areas around ACAD and is presumably 

contributing to habitat fragmentation and habitat loss. Between 1976 and 2002, the amount of 

urban land in and, especially, around ACAD increased by 117%, from 11,601 acres (469 ha) to 

25,160 acres (10,182 ha) (Table 3). Building and road densities in MDI watersheds are shown in 

Figure 5. The impacts of land cover change and habitat fragmentation on the flora and fauna of 

the region not been addressed quantitatively. 

Habitat loss was identified as a stressor for a few rare plant species at ACAD by Greene et al. 

(2002) (Table 7). Potential stressors on other plant species have not been compiled in a similar 

way. 

Habitat fragmentation and changes in land cover type (especially decline of early successional 

habitat) are potentially important stressors for many resident terrestrial bird species in and 

around ACAD (Appendices 8, 11). Supporting evidence comes from studies both in Maine and 

outside the state. However, this issue has been inadequately studied at ACAD. Consequently 

there is relatively little direct evidence of these factors operating in the Park. 

Loss of open habitat as a result of vegetation succession and/or fire suppression is known to be a 

significant factor adversely impacting colonial water bird species (Folger 1986). 

Impacts from Shellfish Harvesting and Boat Moorings on Eelgrass Beds 

Commercial mussel harvesting can physically disrupt beds of eelgrass (Zostera marina) (e.g. 

Neckles et al. 2003). There has been concern that mussel dragging may be adversely affecting 

eelgrass beds in Frenchman Bay (J. Disney, MDI Water Quality Coalition, pers. comm. 

September 2007). However, there are no quantitative data to document any impacts around MDI. 

Studies on eelgrass disturbance in southern Maine (Maquoit Bay; Neckles et al. 2003) indicated 

that grass beds severely damaged by mussel draggers would require an average of 11 years to 

recover. These results were based on data collected during a period of overall bed expansion in 
120 

the study area; recovery trajectories were predicted to be as high as 22 years under less favorable 

conditions for re-growth. 

Direct damage to seagrasses from dredge and fill operations (Thayer et al. 1984), boat propellers 

(Dawes et al. 1997), docks (Burdick and Short 1999), and anchors and mooring chains (Creed 

and Amado Filho 1999) have all been documented, but not for eelgrass in the MDI area, per se. 

Visitor Use and Habitat Disturbance 

Key Issues Extent of Problem Information Base

Impacts on terrestrial habitat EP Fair 

Impacts on birds EP Fair 

Impacts on freshwater systems PP Poor 

Impacts on inter-tidal areas PP Fair 

Visitor Impacts on Terrestrial Habitat 

Visitors to ACAD participate in a range of recreational activities, many of which have impacts 

on natural resources, including vegetation, soils, water and wildlife9. High-use areas include: 

Cadillac Mountain summit, Jordan Pond House area, Sand Beach to Otter Point, parking areas 

associated with Eagle Lake, Acadia Mountain and Cadillac North Ridge, and the Ship Harbor – 

Bass Harbor lighthouse corridor (NPS 2003). Multiple challenges confront visitor use 

management at ACAD, including: uncontrolled access from state and town roads, many entry 

points, large visitor numbers, and uneven temporal and spatial distribution of use (NPS 2003).

In a 1998 survey, 72% of visitor groups indicated that they hiked on trails, while 40% and 30% 

walked or biked, respectively, on carriage roads (Littlejohn 1999). Intensity of use of ACAD’s 

trail system is heterogeneous. Figure 8 summarizes August hiker census data for trails on MDI 

and Table 4 presents a compilation of selected visitor use statistics. This information has been 

discussed in the section on Human Utilization of Park Resources. 

Trampling on trails and campsites results in direct and indirect natural resource impacts, 

including: loss of ground vegetation, altered vegetation composition including introduction of 

non-native species, altered microclimate, soil compaction, loss of organic litter, increased water 

runoff and reduced soil fauna (see Table 1 in Marion 2006). According to Greene et al. (2002), 

trampling by hikers is one of the primary stressors likely affecting rare (and other) plant species 

at ACAD (Table 7).

Hiking and camping effects on vegetation occur along both designated and social (visitorcreated) trails. On Little Moose Island, soil erosion or compaction is common on 18% of 

undesignated trail length, with the trail surface being below ground level (Manning et al. 2006). 

 

9

 Use impacts also include those on visitor perceptions and experiences which, in turn, are related to carrying 

capacity. These issues are being studied at ACAD under the Visitor Experience and Resource Protection (VERP) 

planning and decision making framework (Manning et al. 2006). Although this research is an essential component 

of broader Park management, it does not directly relate to condition of natural resources per se. Hence the present 

report does not cover research on visitor perceptions, carrying capacity, and associated issues. 
121 

A further 4% of trails exhibit signs of incipient erosion and compaction. On IAH, even relatively 

low trail use (compared to many locations on MDI) has produced trail incision of >4 inches in 

some areas (Figure 63). Between 0.2 and 4% of IAH trail lengths display excessive erosion or 

muddiness. Ongoing trail assessments are documenting impacts on the designated and social 

trails of MDI. Additional research on the Cadillac Mountain summit is focused on assessing 

visitor impacts to soils and vegetation and in developing protocols to allow the NPS to evaluate 

its visitor management actions (D. Manski, NPS, pers. comm. September 2008). 

Figure 63. Frequency distribution of maximum incision in low- and high-use trail classes on 

IAH. (Figure from Marion 2006) 

Visitor Impacts on Birds 

Disturbance is a stressor potentially affecting a number of terrestrial, marsh and marine birds 

(Appendix 11). Because loons are especially sensitive to disturbance by visitors, a trail at Upper 

Hadlock Pond was recently closed to protect the nesting birds (D. Lamon, Somes-Meynell 

Wildlife Sanctuary, pers. comm. August 2007). Other trails are periodically closed to avoid 

disturbance of breeding peregrine falcons (Falco peregrinus) and nesting sea birds (Figure 64). 

Matz et al. (1997) documented the impact of disturbance on bald eagle (Haliaeetus 

leucocephalus) nests. They noted that there is risk of disturbance not only during the summer, 

when the birds are fledging, but also earlier in the season when nest abandonment may result. 

Wilson et al. (undated) note that people in canoes and kayaks in Bass Harbor Marsh (and to a 

lesser extent Northeast Creek) represent a source of intrusion on bird populations, a factor that is 

likely to be particularly disruptive during the breeding season. In addition, there is evidence that 

persons with all-terrain vehicles intrude on the salt marshes of Bass Harbor Marsh at low tide, 

compacting both vegetion and substrate and potentially disrupting both breeding and nonbreeding bird species. There are, however, no quantitative data on the extent of these impacts.

Visitor Impacts on Freshwater Systems 

As in upland areas, visitor use can have direct and indirect effects on freshwater systems, 

including erosion / sedimentation, habitat modification and contamination. However, there is 

little quantitative documentation of the extent of visitor-associated effects via erosion and habitat 
122 

modification. There is some evidence of nonpoint-source pollution associated with development 

(Kahl et al. 2000). 

Contamination issues associated with swimming beaches are addressed under Threats: Microbial 

Contamination. 

Visitor use can influence the aesthetic and visitor-experience characteristics of freshwater 

resources, including noise and crowding. Regulations passed by the Maine legislature in 1998 

include prohibition of internal combustion engines or limitation of engine horsepower on seven 

Great Ponds on MDI. ACAD became the first park unit in the National Park System to ban 

personal watercraft within the park (Kahl et al. 2000). 

Unauthorized introductions are modifying fish assemblages in many of Maine’s lakes and 

streams (Vaux 2005). Several fish species currently found in ACAD freshwaters are non-native 

to the area (Table 12). The number of non-native species may increase in the future as a result of 

unintended and/or intentional introductions, particularly of bait species, by anglers. 

Visitor Impacts on Intertidal Areas 

On-going studies (Olson 2007; J. Long, Northeastern University, pers. comm.) are examining 

visitor impacts on the inter-tidal fauna and flora at SCH. This research is documenting effects of 

trampling and habitat disruption, as well as providing valuable base-line data on the biodiversity 

of coastal habitats in this Park unit. 

Petraitis et al. (2001) evaluated visitor impacts at Anemone Cave, which has been a popular 

tourist attraction for many decades (although not currently publicized, it is still visited by many 

people). Visitor counts made in the late 1990s indicate that an average of 47 people entered the 

cave per 3-hour period around low tide between late May and late August (Jacobi 2000; Table 

4). In August, about one third of people entering the cave disturbed pools; in other months this 

number was much lower. The authors concluded that visitors (i) trample and may be injuring 

anemones and other species in the cave, and (ii) do not appear to substantially disrupt the 

freshwater lenses in the pool. Longer-term impacts of visitors on species composition and 

abundance are unclear. While trail use by visitors appears to reduce barnacle densities in the 

Anemone Cave area, this is not a significant impact in view of the ubiquity of this faunal group. 

Cammen and Larsen’s (1992) study of the intertidal resources of ACAD characterized the small 

infauna of rocky shore and mudflat areas on MDI. The authors indicated that there is no need to 

protect intertidal mudflats from normal visitor activity such as worming and clamming. The 

reasons given include (i) the fauna are fecund and (ii) movement over the mudflats is difficult, 

making it unlikely that these areas will be exposed to intense visitor traffic. 

MacArthur and Drury (1977) produced a semi-quantitative documentation of human impacts 

along coastal trails in the area from Sand Beach to Otter Cliffs. Some comparisons were made to 

trail status observations recorded a decade earlier by Barden (1970). The primary conclusion was 

that there had been a proliferation of trampled paths through vegetation. 
123 

Herbivory and Predation 

Key Issues Extent of Problem Information Base

Browsing impacts on terrestrial 

vegetation 

OK Good 

Predation impacts on mammals PP Fair 

Herbivore Impacts on Vegetation 

Several studies have investigated the damage caused to vegetation by white-tailed deer 

(Odocoileus virginianus) and other mammalian grazers, including snowshoe hare (Leptus 

americanus). 

Although deer numbers increased dramatically following the 1947 fire (D. Manski, NPS, pers. 

comm.), the population on MDI is currently stable or declining and is below forage carrying 

capacity (Long et al. 1998). Forage is not thought to limit deer populations on MDI, rather fawn 

and adult doe mortality (Fuller and Harrison 2002). Deer densities are greater on the eastern 

portion of MDI than in the western region. Browsing at ACAD declined from 1980 to 1989, 

paralleling reductions in the deer population (Saeki 1991). Past browsing has suppressed stem 

densities in species such as rose, cherry (Prunus spp.), serviceberry (Amelanchier canadensis) 

and white pine (Pinus strobus). Habitat use by deer is influenced by understory composition, 

while use by hare is based on the extent of canopy closure, especially in dense coniferous forests. 

Using exclosures, Saeki (1991 – see also Saeki and Harrison 1991) studied the effect of deer 

browsing at burned (from the 1947 fire) and unburned sites on MDI. Browsing influenced the 

height distribution of plants, particularly in the shrub height class (0.5 – 2.0 m) and this effect 

was dependent on fire history. Browsing also had a significant effect on plant species richness 

and densities. Overall, effects were greater in white cedar-dominated habitats than in hardwood 

habitats. 

Gilbert and Harrison (1982) investigated the influence of white-tailed deer browsing on the 

vegetation of MDI prior to the arrival of coyotes in 1981 (Canis latrans). Predation by coyotes 

subsequently led to a reduction in the deer population (see below). The most heavily utilized 

species included: cherry (Prunus spp.), red maple (Acer rubrum), striped maple (Acer 

pensylvanicum), wild raisin (Viburnum nudum var. cassinoides), winterberry (Ilex verticillata), 

birch (Betula spp.), red oak (Quercus rubra), and sumac (Rhus hirta). The authors concluded that 

none of the browsed species were over-browsed as to restrict regeneration or to cause 

deformation, defoliation or mortality, with the exception of sumac. Further, the researchers 

suggested that no management efforts were needed and that the status of habitat/grazing should 

be monitored again in 10 years. Similarly, McLaughlin (1968) conducted a vegetation survey 

and identified some local areas of over-browsing, yet concluded that ACAD, as a whole, was not 

over-browsed. Allen (1970) also noted that over-browsing occurred in deer wintering areas. 

Baird (1966) developed a detailed habitat evaluation on IAH, including composition of overstory 

and understory vegetation. The total amount of preferred browse was < 7 pounds per acre for the 

entire island. At that time, deer subsisted to a large extent on food sources other than woody 

plants. The author noted that serious habitat deterioration can occur from a density of >1 deer per 
124 

25 acres. Frequent complaints about deer problems on IAH from local residents suggest that deer 

densities could be high on this island at present (D. Manski, NPS, pers. comm.). 

Predation Effects on Mammal Populations 

White-tailed deer populations on MDI lacked a top predator for approximately 80 years 

following extermination of wolves from Maine in the early 1900s and until the arrival of coyotes 

in 1981 (Fuller and Harrison 2003). By 1989, coyotes were reproducing and had established 

territories on MDI. Until the early 1980s, the lack of a predator, coupled with the no-hunting 

regulation on MDI, resulted in historic overpopulation of deer on the island. 

Coyotes now are the major predator of deer and have contributed to recent declines in the deer 

population. Long (1995, see also Long et al. 1998) reported that the annual rate of fawn survival 

was 0.26. The leading cause of mortality was predation (at least 80% of predation was by 

coyote), followed by drowning and collisions with vehicles. Relative mortality rates for these 

three causes were, respectively, 0.52, 0.24 and 0.14. Recruitment to one year of age was lower 

than rates observed in other Maine deer populations. Low recruitment associated with multiple 

causes of fawn mortality may be limiting deer populations in some areas on MDI. Different rates 

of fawn survival across the island may explain an apparent patchy distribution of deer (Long et 

al. 1998). 

Vinck (1993) compiled information on automobile accidents on MDI involving deer and noted 

that, while accidents occurred island-wide, they were concentrated in three focus areas. 

 

Food use by coyote (the primary deer predator on MDI) was reported by O’Connell et al. (1992). 

The most common coyote foods were deer, raccoons (Procyon lotor), snowshoe hare and other 

small mammals (Cricetidae, Soricidae, Zapodidae), and fruits. Compared to the mainland 

populations, coyotes on MDI exhibited greater dietary diversity despite lower faunal diversity on 

the island. Predation on raccoons illustrates the ability of coyotes to expand their feeding niche in 

response to available resources on MDI. 

 

 

Harvest / Hunting / Take 

Key Issues Extent of Problem Information Base

Fisheries management: impacts on 

native populations 

PP Poor 

Effects of worming on shorebirds PP Poor 

Eel harvests: impacts on population 

status 

PP Poor 

Deer hunt – effects of possible adoption 

of hunt 

PP Fair 

Harvest of waterfowl EP Poor 

In general, there is little information on the effects of harvesting activities on the biological 

resources of ACAD. Freshwater fisheries are managed by MDIFW but little is known about how 

stocking and fishery regulations influence populations of native species. There is a thriving 

fishery for elvers (young eels) in several streams on MDI. The impacts from this fishery on eel 
125 

populations are essentially unknown; some researchers have suggested that there may be 

worldwide declines in eel population, but there are no long-term data to document such patterns 

(Gulf of Maine Council on the Marine Environment 2007). 

Worm and shellfish harvests occur in mudflats around MDI. Possible harvesting impacts on 

shorebirds have not been investigated. However, research elsewhere has shown that shellfish 

take by humans can influence bird populations through both exploitative and interference 

competition (e.g. Stillman et al. 2003). 

Some members of the public on MDI are lobbying for adoption of a deer hunt on the island – in 

part in response to perceived higher numbers of deer. However, while there may be higher 

concentrations of deer in peripheral areas of MDI, there is no evidence that the deer population is 

increasing; rather it appears to be stable or even declining (Fuller and Harrison 2002). Low fawn 

and adult doe survival are believed to be key factors influencing the current status of deer 

populations on MDI (Fuller and Harrison 2002). Park staff are concerned that by adding an 

additional mortality factor, a hunt could cause serious problems for the deer population on MDI 

(D. Manski, NPS, pers. comm.). 

Over-harvest of some bird species is considered to be an existing or potential problem, 

particularly for marsh and marine taxa (Appendix 11). 

Exotic Species 

Key Issues Extent of Problem Information Base

Terrestrial exotic plants EP Fair 

Freshwater invasive plants PP Good 

Competition for nesting habitat by nonnative birds PP Poor / Inferential 

Exotic freshwater fish PP / EP Good 

Exotic terrestrial invertebrates PP Poor 

Invasive terrestrial invertebrates EP Fair 

Invasive marine species EP Fair 

The NPS defines exotic species as “those species that occupy or could occupy park lands directly or 

indirectly as the result of deliberate or accidental human activities” (NPS 2006). An invasive species is 

one which outcompetes native species for space and resources and, by some definitions, causes 

economic or environmental harm. Only some exotic species are considered to be invasive. 

Terrestrial Exotic Plants 

Twenty five percent of all plant taxa (~290 taxa) at ACAD are considered non-native to Maine 

(Greene et al. 2005). This compares to a figure of 30% statewide (Campbell et al. 1995). Nine 

percent of the 290 non-native species of ACAD are on the Draft List of Invasive Plant Species of 

Maine (Maine Natural Areas Program 2004). Out of the 40 taxa on this list, 24 occur at ACAD 

(Greene et al. 2004), primarily on MDI. Aggressively invasive plant species include Norway 

maple (Acer platanoides), Japanese and common barberry (Berberis thunbergii and B. vulgaris), 

oriental bittersweet (Celastrus orbiculata), honeysuckles (Lonicera x bella, L. morrowii, L. 
126 

xylosteum), and purple loosestrife (Lythrum salicaria) – all most likely intentionally introduced 

to MDI. Garlic mustard (Alliaria petiolata), a more recent invasive, was most likely 

unintentionally introduced. All currently recognized invasive species are much more abundant on 

the eastern side of MDI than on the unburned (and less-populated, less-visited) west side (Figure 

65; also see below). 

Aggressively invasive species such as shrubby St. Johnswort (Hypericum prolificum) and 

ninebark (Physocarpus opulifolius), while native further south, are in Maine only as garden 

escapees (Haines and Vining 1998). Forest woodrush (Luzula luzuloides) is another potentially 

invasive species. All three species are found adjacent to basin wetlands within the areas burned 

in the 1947 fire. These species could expand their distributions in response to further disturbance, 

or decline if pre-fire communities become more prevalent. 

In an extensive survey of invasive species, Reiner and McLendon (2002) listed, described, and 

ranked exotic species that threaten ACAD and suggested options and management protocols for 

these species. The goals of their study were to (i) estimate potential effects of non-native species 

on native plant communities within ACAD, (ii) rank non-native species based on their potential 

impacts on native plant species and their communities, and (iii) develop management protocols 

to manage non-native species at levels that will protect native plant communities. Their ranking 

process involved literature reviews and field surveys. The initial screening list produced 45 taxa 

considered to be exotic at ACAD. An additional 25 taxa were identified that, while currently not 

present in the park, may occur there in the future. The authors note that 76% of ACAD exotic 

species originated in Eurasia, and 11% in North America. Their final assessment identified 16 

species of concern and 8 species were recommended for highest management priorities at 

ACAD. The 8 species and their priority ranks are listed below. 

Priority 1: Lonicera japonica, Lonicera morrowii, Lonicera x bella – all honeysuckles 

Priority 2: Celastrus orbiculata, Frangula alnus, Berberis thunbergii, Lythrum salicaria, Rosa 

multiflora

Since 1988, purple loosestrife (Lythrum salicaria) has been actively managed on MDI (Chase et 

al. 2002; Figure 64). Active management appears to keep the plant from spreading too rapidly. 

To date, this species has not been recorded at SCH or IAH. 

Greene et al. (2004) followed the Reiner and McLendon (2002) survey and further documented 

the distribution and abundance of invasive species at ACAD. They noted that of the 600 species 

that could be viewed as being potentially invasive, only 33 are considered to be invasive in 

Maine (Cameron 2000). From this list, Greene et al. focused on 24 invasive taxa; these included 

11 species from the Reiner and McLendon (2002) study plus an additional 13 species. Alder 

buckthorn (Rhamnus alnifolia), non-native honeysuckles (Lonicera spp.) and Japanese barberry 

(Berberis thunbergii) occurred at more sites than any other invasive species. The majority of the 

documented species were on the eastern side of the island, within the extent of the 1947 fire 

(Figure 65). Invasive species were concentrated around Great Meadow and Sieur du Monts 

Spring. The density of plants was higher at these sites than in any other part of ACAD. Greene et 

al. (2004) suggested that the best strategy for management of invasive species at ACAD is by 
127 

site rather than by species. Exotic species are considered a significant stressor for nine rare plant 

species (out of 20 considered) (Table 7). 

Stubbs et al. (2005) investigated the influence of two invasive plant species (Japanese barberry 

and glossy buckthorn) on pollinator visitation patterns. The researchers concluded that the 

invasive species do not compete with native species for pollinators. 

Figure 64. Selected management activities at ACAD. 

(Data source: GIS coverages from ACAD Office of GIS) 
128 

Figure 65. Distribution of invasive plants on MDI. The map shows the number of species in each 

watershed for which there were survey sites. Map is based on survey data in Greene et al. (2004). 

This survey was restricted to sites within ACAD. Additional data (courtesy of K. Anderson, 

ACAD Office of GIS) are shown for lupine and purple loosestrife records. 

Recent data from sites monitored by the Northeast Temperate Network monitoring program 

suggest that there are fewer invasive plants at ACAD than at all seven other parks in the network 

(B. Mitchell, NPS, pers. comm.; see Assessment of Condition). 

Freshwater Exotic Plants 

Four invasive aquatic plant species (plus a milfoil hybrid) are currently known to exist in Maine: 

Eurasian milfoil (Myriophyllum spicatum), variable milfoil (M. heterophyllum), hydrilla 
129 

(Hydrilla verticillata) and curly-leaf pondweed (Potamogeton crispus). As of March, 2007, all 

occurrences of these plants are to the south and west of MDI (MDEP 2007). There are currently 

no invasive exotic freshwater plants in the ACAD region. Park staff conduct annual surveys to 

ensure early detection of any invasives that might arrive at ACAD. In their survey of plants on 

MDI, Greene et al. (1997) recorded only one non-native aquatic species – the water lily 

Nymphaea tuberosa which is naturalized at Little Long Pond in Seal Harbor. The authors noted 

that there was no evidence that the plant was spreading to other waterbodies on the island. 

Exotic Birds 

Non-native species such as starlings and house sparrows may be impacting some native bird 

populations via competition for nesting habitat (Appendix 11). However, data on these 

interactions in the ACAD region are largely absent.

Exotic Fish 

Manipulations of freshwater fish communities in the ACAD region have occurred since before 

the creation of the Park (Stone et al. 2007). Manipulations include “stocking, bait introductions, 

and illegal, accidental, and intentional transfers of species by humans”. 

Most MDI lakes currently harbor species that are thought to be non-native to the waters of MDI 

(Figure 28). Just under 50% (12/29) of fish species in ACAD lakes and streams are not native to 

MDI (Table 12). Many of the species not native to MDI are, however, native to Maine. Fish 

species in the ACAD region that are not native to Maine include the black basses and brown 

trout. 

Stone et al. (2007) note that non-indigenous fish species are now prominent members of the fish 

community in Eagle Lake (common shiner, Luxilus cornutus), Echo Lake (fallfish, Semotilus 

corporalis), Jordan Pond (common shiner), and Round Pond (smallmouth bass, Micropterus 

dolomieu). In each case, the “introduced species is now the most abundant or one of the most 

abundant species in the lake or pond (based on catch-per-unit data from surveys in 1998 and 

1999)”. 

Transfer of baitfish into ACAD waters is a continuing threat in the Park. These introductions are 

leading to the increased homogenization of freshwater fish assemblages in ACAD lakes as well 

as in waters throughout much of Maine (Vaux 2005). The broader ecological ramifications of 

many of the non-predator introductions are not well understood. Three exotic predator species 

that are today causing concern because of their colonization of an increasing number of lakes and 

rivers in Maine are: smallmouth bass, largemouth bass (Micropterus salmoides) and Northern 

pike (Esox lucius). Smallmouth bass occurs in five ACAD lakes. Largemouth bass occurs in one 

MDI lake outside ACAD. The closest population of Northern pike to the ACAD region is in the 

lower Penobscot watershed. 
130 

Exotic Terrestrial Invertebrates 

There are insufficient baseline survey data on ACAD invertebrates to permit estimation of the 

number of exotic species in the Park. Some new appearances of non-native taxa have been 

recorded in recent years, for example the European hammock spider, Linyphia triangularis, 

which occurs at SCH (Jennings et al. 2002). Recent research by Jakob et al. (2005) has 

addressed the impacts of this species on native spiders at ACAD. Final results from this work are 

not currently available. 

The European fire ant (Myrmica rubra) is a pestiferous invasive species that is currently causing 

concern to residents on MDI. It was first recorded from the MDI area in the late 1960s. Since 

1993, the number of complaints from the public about this stinging species has increased 

dramatically, with most complaints coming from MDI and the mid-coast area of the state 

(Groden et al. 2005). The fire ant has a patchy distribution on MDI (Figure 66). Nests are 

typically found in downed woody debris, leaf litter and soil under tree roots. This species is not 

only pestiferous to humans but also negatively impacts native ant fauna (Garnas 2004). Almost 

complete displacement of native ants by the colonizer reduces species richness and diversity. 

Fire ants appear to have few impacts on non-ant arthropods. 

Figure 66. Distribution of European fire ant (Mymica rubra) on MDI. 

(Figure from Groden et al. 2005, used with permission)
131 

Invasive Marine Species 

As of 2004, 33 marine introduced species had become established in Maine’s coastal waters 

(Carlton 2004). Among them were seven species of algae, 25 invertebrate species, and one 

protista species. Ballast water is generally considered the most prevalent vector of marine 

introductions, but in Maine vectors such as fouling communities on vessel hulls, fishing and 

seafood trades practices, research activities, and other vectors may pose equal threats (Thayer 

and Stahlnecker 2006). 

The following are among the most notable marine invasives in Maine (after Thayer and 

Stahlnecker 2006)10. 

Codium fragile, a spongy green alga also known as “oyster thief”, is present in a number of 

locations along the Maine coast. It can smother beds of oysters and other shellfish. 

The invasive bryozoan Membranipora membranacea has been present in the Gulf of 

Maine since 1987. It promotes kelp breakage by making the kelp blades more brittle and 

susceptible to wave damage.

Marine invasives include the Asian shore crab (Hemigrapsus sanguineus), a species that was first 

recorded in the U.S. in New Jersey in 1988. It reached Maine by 2001 and is now found as far 

north as the Schoodic Peninsula. The green crab, Carcinus maenas, is Maine’s most destructive 

and costly invader. Despite extensive efforts to eradicate this invasive species, it has caused a 

substantial reduction in the population of soft-shelled clam (Mya arenaria) (Thayer and 

Stahlnecker 2006). 

Invasive colonial tunicates have become problematic in many parts of the world because the 

rapid spread of colonies alters marine habitats and threatens to interfere with fishing, 

aquaculture, and other coastal and offshore activities. In Maine, Didemnum spp. have been 

present in the Damariscotta River area since the early 2000s, and recently (2007) appeared in 

Cobscook Bay. 

Species that have not yet been reported in Maine but are considered to be possible future 

threats include the Chinese mitten crab (Eriocheir sinensis), the Pacific oyster (Crassostrea 

gigas), and the veined Rapa whelk (Rapana venosa). 

Ongoing research at ACAD is focusing on approaches to forecasting the spread of marine 

invasive species and monitoring their status (Delaney 2006). 

 

10 A number of monitoring efforts have been developed over the past several years to help track the advance of 

invasives along the coast, and to help identify new invasives. Currently, five different data contributors within the 

Gulf of Maine list their data with the Massachusetts Institute of Technology Marine Invader Tracking Information 

System (http://chartis.mit.edu/mitis/), which in turn contributes to the International Nonindigenous Species Database 

Network (http://www.nisbase.org/nisbase). 
132 

Pests and Pathogens 

Key Issues Extent of Problem Information Base

Pests/pathogens of terrestrial vegetation PP Poor / Inferential 

Pests/pathogens of wetland fauna EP Fair 

Pests/pathogens of bird fauna PP Poor / Inferential 

Pests and Pathogens of Terrestrial Vegetation 

Pathogens/pests could have detrimental short-term and long-term effects on plant species within 

ACAD. In addition to species-level effects, pests/pathogens can have impacts on ecosystem 

processes such as productivity, nutrient cycling, and support of consumer food webs. Pests and 

pathogens could be even more important than climate change in causing species transitions in 

eastern forests over the next few decades (Lovett et al. 2006). 

Current or immediate threats to ACAD include gypsy moth (Lymantria dispar; target species: 

oak and aspen), beech bark disease (scale insect Cryptococcus fagisuga and pathogenic fungus 

Neonectria; target species: beech), hemlock wooly adelgid (Adelges tsugae; target species: 

hemlock). 

The hemlock wooly adelgid, a small aphid-like insect introduced from Japan, has caused 

widespread hemlock mortality throughout the mid-Atlantic and southern New England region 

over the last 20 years (Orwig et al. 2002). Major trends associated with the decline in hemlock 

include shifts in canopy dominance to oak and mixed hardwoods, considerable understory 

development, including greater herb richness and abundance and increased density of clonal 

saplings, and expansion of several invasive shrub and woody vines (Small et al. 2005; Runkle 

2005; Bailo et al. 2004). Although the pest has not been documented within ACAD, it was 

recently reported on private property outside the Park (J. Hazen Connery, NPS, pers. comm.). 

Although it is unclear if the pest managed to spread from infested nursery stock to trees outside 

the property, the findings suggest careful monitoring is essential to keep the situation under 

control. Orwig (2002) has noted the potential for movement of this pest northward along the east 

coast. 

Additional pests and pathogens that could potentially affect ACAD resources include: Asian 

longhorned beetle (Anoplophora glabripennis), a wood-boring beetle that can affect red maple, a 

common species at ACAD. The emerald ash-borer (Agrilus planipennis; target species: Fraxinus

spp.- ash) also can exert heavy mortality in white ash, a species common at ACAD. Like sugar 

maple, white ash is able to produce soil organic matter with a low C:N ratio and high nitrification 

rates (Venterea et al. 2003), so the loss of this species due to a pest such as the emerald ash-borer 

could also have significant effects on C and N cycles within the region. Phytophthora ramorum, 

the pathogen responsible for sudden oak death, has recently spread to eastern North America 

(Lovett et al. 2006). Red oak, a dominant species at ACAD, is known to be susceptible. Oaks 

also have unique foliar and litter properties that affect C and N cycling, producing litter with low 

decomposition rates, and, unlike white ash and sugar maple, soils with low rates of nitrification 

(Lovett et al. 2004). This leads to low nitrate leaching into surface waters and high retention of 

atmospherically deposited N. Widespread attack on oaks could have significant effects on 
133 

ecosystem processes and subsequently on species composition of various vegetated 

communities. 

Unpredictability of new introductions combined with the lack of knowledge about currently 

threatening pests and pathogens limit the ability to confidently forecast the nature and scope of 

change that could occur at ACAD in the presence of one or more of these pests/pathogens. 

Historically, there were efforts over many decades to control white pine blister rust and beech 

bark disease (as documented in numerous reports in the ACAD bibliographic database). Beech 

bark disease is currently widespread at ACAD where beeches occur. For example, of the 18 

beech trees that are in NETN forest plots at ACAD (from 4 plots), all trees were clearly affected 

by the disease, except the two smallest (B. Mitchell, NPS, pers. comm.). 

Pests and Pathogens of Wetland Fauna 

Disease is one of several stressors known or thought to be impacting ACAD amphibian 

populations. Five major amphibian diseases have been documented at ACAD: ranavirus (Figure 

67), chytridiomycosis (Bd), Ichthyophonus, Saprolegnia, and a Perkinsus-like organism (Gahl 

2007). Disease screenings of ACAD amphibians indicated that three of these diseases 

(Ichthyophonus, Bd and Saprolegnia) were benign and thus may have natural controls on MDI. 

Some amphibian die-off events have been linked to ranavirus and the Perkinsus-like organism. 

However, in general, Gahl (2007) concluded that “disease events do not seem to exacerbate 

natural breeding population fluctuations” (see also Calhoun and Gahl 2006). Because no spatial 

autocorrelation of ranavirus disease events was detected, Gahl (2007) concluded that epizootics 

were not clustered and thus that landscape and within-pond stressors were likely to be more 

influential in ranavirus occurrence than movement of vectors. High catchment position was the 

primary landscape feature associated with ranavirus-caused larval mortality events. Aluminum 

and temperature were identified as potential environmental stressors associated disease events 

caused by ranavirus, Perkinsus-type organism and Ichthyophonus (Gahl 2007). Other water 

chemistry attributes appeared to be substantially unassociated with mortality events. 

Figure 67. Ranavirus-associated amphibian die-off events on MDI. 

(Figure courtesy of M. Gahl, University of Maine, Orono) 
134 

In their study of Hg concentrations in frog tadpoles, Bank et al. (2007b) noted that there had 

been amphibian disease outbreaks / dieoffs at three of their nine ACAD study sites. However, 

these authors noted that there is no known link between Hg and amphibian disease. 

In 2001, water molds (Saprolegniasis) were detected in spotted salamander (Ambystoma 

maculatum) egg masses in ACAD, but it could not be determined if the eggs were alive or dead 

at the time the fungi invaded them (NEARMI 2007). 

Most anuran amphibian populations in Maine are infected with the chytrid fungus 

Batrachachytrium dendrobatidis. However, to date there have been no die-offs attributable to 

this disease (NEARMI 2007). 

Pests and Pathogens of Birds 

There is some concern that avian cholera, avian botulism and other pathogens may impact bird 

populations in the ACAD region. However, there is currently little evidence to suggest current 

problems in the Park (Appendix 11). 

Giardia and Beaver Populations 

Giardiasis is a commonly diagnosed intestinal disease in humans (O’Connell 2003). Beaver are 

frequently thought of as a vector of Giardia. At least one of the water utilites on MDI has 

expressed concern that beaver presence in water supply lakes may jeopardize the utility’s 

filtration waiver – this waiver is in effect because the supply lake is largely surrounded by 

ACAD. O’Connell (2003) reviewed the role of beaver in Giardia transmission and concluded 

that the connection between humans and beaver in relation to human cases of giardiasis is not 

clear. According to this author, removal of beaver from ACAD lakes to protect drinking water 

supplies is unwarranted. He notes that 20 mammal species inhabiting ACAD are known (from 

research elsewhere) to be capable of hosting Giardia. 

Climate Change 

Key Issues Extent of Problem Information Base

Sea level rise EP Good 

Other impacts, modeled for ACAD PP Inferential 

Although there is a growing literature on the potential impacts of climate change on ecosystems 

of the Northeastern U.S., there appear to be no published studies that use climate change models 

to explicity explore impacts on the biological resources of ACAD. Many species are at or near 

their range extents in the Acadia region. Consequently, climate change could have significant 

effects on the composition of plant and animal communities in the Park. Although some of the 

potential impacts of climate change on forest community structure have been mentioned in 

earlier sections of this report, an in-depth literature review of climate change research and 

possible implications for the Acadia region is outside the scope of this report. 
135 

Huntington et al. (2004) found that, for 11 sites across New England, there had been less snow 

over the period 1949-2000, including coastal sites. 

Several studies have addressed the issue of sea-level rise in Maine (e.g. USEPA 1995). Mean sea 

level is expected to rise about 60 cm (2 feet) along most of the U.S. Gulf and Atlantic Coast in 

the next century (USEPA 1995). A recent map displaying areas in the ACAD region susceptible 

to two different sea level rise scenarios is shown in Figure 68. 

Figure 68. Impact of sea level rise on MDI. Areas shown in red and orange would be inundated 

by a sea level rise of 1 and 6 meters, respectively. 

(Figure courtesy of Natural Resource Council of Maine and Colby College.)
136 

Light Pollution 

The impact of residential, municipal and commercial lighting on the night sky on MDI has 

recently become a topic of public interest. There are no known implications for non-human 

inhabitants of the ACAD region. Figure 69 shows a map of night sky illumination. 

Figure 69. Map of MDI showing illumination in the night sky. Higher values indicate darker sky. 

(Map courtesy of N. Bacon and A. Gehlot, College of the Atlantic) 
137 

Multiple Stressors 

Key Issues Extent of Problem Information Base

Synergistic effects of multiple stressors PP Poor 

The effect of multiple stressors acting simultaneously or sequentially on organisms is a topic that 

is currently of considerable interest to many researchers and resource managers. A few studies at 

ACAD have referenced the potential roles of multiple stressors at ACAD. Examples include (i) 

the impacts of acid fog and ozone on conifers; and (ii) impacts of UV-B radiation, mercury, 

disease and landscape position on amphibians. However, there has been very little research 

specifically targeting possible synergistic effects of multiple stressors. Additional issues include 

the possible influence of nitrogen enrichment (from atmospheric sources) on susceptibility of 

terrestrial plant communities to invasion by exotic species, and the coupled impacts of N-rich 

and acidic deposition on terrestrial plant communities. Researchers have identified the issue of 

multiple stressors as an important area for future study at ACAD. 

Threat Asssessments: A Summary 

The resource – stressor matrix shown in Table 21 provides an overview of the stressors acting on 

the natural resources of ACAD. The matrix also shows the richness of the information resources 

associated with each stressor and resource category. This matrix comes with a note of caution. 

Since it attempts to summarize a lot of information within individual matrix cells, the table 

inevitably involves significant consolidation and ‘averaging’ of conclusions. Consequently, it is 

important that the reader consult the separate matrices presented above for each stressor. In these 

matrices, the various key issues associated with each stressor are identified and reviewed 

separately. 

Two further summaries of the threats status and information richness are provided in Figures 70 

and 71 – both are based on the resource / stressor matrix in Table 21. 

Terrestrial systems, lakes, and streams – in particular their abiotic compontents – are the 

resources for which there is most information at ACAD, as shown by the number of threats for 

which the problem status is classed as “Existing Problem” or “OK”. For the wetlands, estuaries 

and marine resource groups, a large proportion of the threats are classified as “Potential 

Problem” or “Unknown”. These observations reflect the relative amounts of research effort 

invested in the ACAD region. Future research will likely provide information on the extent to 

which issues, currently considered to be potential problems, influence the natural resources of 

ACAD. 

The following section of this report, Assessment of Condition, provides an additional synthesis of 

some of the material presented under our assessment of threats – information that relates 

specifically to metrics and other descriptors of resource condition. 
138 

Table 21. Resource stressor matrix showing extent of problem and knowledge base. 

THREAT / 

STRESSOR 

RESOURCE – COMPONENT 

Terrestrial Lakes & 

Streams 

Wetlands & 

Estuaries 

Grnd

water 

Marine 

Abiotic Biotic Abiotic Biotic Abiotic Biotic Abiotic Abiotic Biotic 

UV radiation -- -- Inf -- Inf -- -- 

Visibility G -- -- -- -- -- -- -- -- 

Ozone G G -- -- -- -- -- -- -- 

Atm. deposition: 

acidity etc. 

G G G Inf Inf -- 

Nutrient enrichment G Inf G G F G P Inf 

Mercury G P G F F P G 

Other contaminants P P P P P P P 

Microbial contam. -- -- F P P F 

Fire G G -- -- -- -- -- -- -- 

Altered hydrology -- -- F P P F -- -- 

Habitat 

loss/impairment 

-- Inf -- F -- F -- -- Inf 

Visitor use F F P -- F F 

Herbivory & predation -- G -- -- -- -- Inf 

Exotic species -- F -- G -- P -- -- Inf 

Harvest / hunt / take -- F -- P -- -- -- P 

Pests & pathogens -- P -- -- F -- -- 

Climate change Inf Inf Inf Inf Inf Inf Inf G Inf 

Synergistic effects 

from multiple 

stressors 

-- Inf -- Inf -- Inf -- -- Inf 

KEY 

Extent of problem OK EP: Existing problem PP: Potential problem Unk: Unknown 

Knowledge base G = Good F = Fair P = Poor Inf = Inferential 
139 

Figure 70. Summary of “extent of problem” for threats / stressors at ACAD, by resource. Data 

are derived from matrix in Table 21 and represent proportion of each threat category within each 

abiotic / biotic resource group. 

Key: 

Extent of problem 

OK 

EP: Existing 

problem 

PP: Potential 

problem 

Unk: Unknown 

Terr: Abiotic

OK

EP

P P UNK

Terr: Biotic

OK

EP

PP

UNK

L&S: Abiotic

OK

EP

P P

UNK

L&S: Biotic

OK

EP

P P

UNK

Wet/Est: Abiotic

OK EP

P P

UNK

Wet/Est: Biotic

OK

EP

PP

UNK

Marine: Abiotic

OK

EP

P P

UNK

Marine: Biotic

OK EP

P P

UNK

Grnd: Abiotic

OK

EP

P P

UNK
140 

Figure 71. Summary of information richness for threats / stressors 

at ACAD, by resource. Data are derived from matrix in Table 21 and represent proportion of 

each information category within each abiotic / biotic resource group. 

Key: 

Information richness 

Good 

Fair 

Poor 

Inf: Inferential

Terr: Abiotic

Good

Fair

Poor

Inf

Terr: Biotic

Good

Poor Fair

Inf

L&S: Abiotic

Good

Fair

Poor

Inf

L&S: Biotic

Good

Fair

Poor

Inf

Wet/Est: Abiotic

Good

Fair

Poor

Inf

Wet/Est: Biotic

Good

Fair

Poor

Inf

Marine: Abiotic

Good

Fair

Poor

Inf

Marine: Biotic

Good

Fair

Inf Poor

Grnd: Abiotic

Good

Poor Fair

Inf
141 

Assessment of Condition 

Introduction 

This section brings together information about metrics and other attributes that we have used to 

describe the condition of natural resources in the ACAD region. Most of this information has 

already been presented in some detail in the Resource Characterization and Assessment of 

Threats sections of this report. 

As discussed previously, this Assessment used an information base that is very heterogeneous in 

terms of both quantity and quality. Consequently, a consistent and fully quantitative assessment 

of resource conditions was an unrealistic goal. Our selection of metrics and other condition 

attributes was based on (i) ecological theory, (ii) our threats assessment, (iii) the list of Vital 

Signs adopted by the Northeast Temperate Network (Mitchell et al. 2006), and (iv) information 

presented elsewhere, for example the ACAD water resource management plan (Kahl et al. 2000). 

Vital Signs metrics are generally included in our lists, regardless of whether or not there are 

currently data associated with the metrics. Absence of data serves to underscore information 

gaps. In some cases, we include more than a single metric to describe an aspect of condition. 

For some attributes, it was only possible to make general, qualitative, statements about condition 

– these were generally based on discussions with Park resource management staff and other 

researchers. In some cases, we had to conclude that insufficient information was available to 

assess condition at any level of confidence at the present time. 

However, for other attributes, we were able to use better defined benchmarks against which to 

compare ACAD data. Categories of benchmarks include: 

● Park-desired conditions (explicit or inferred, regardless of attainability) 

e.g. No exotic species. 

● External criteria and reference conditions 

e.g. State of Maine water quality classes and levels of attainment based on stream 

macroinvertebrates. 

Lake trophic state. 

Mercury body burdens (from Mercury Study Report to Congress 1997, Evers et 

al. 2005, others). 

Stream water quality reference conditions proposed by New England Wadeable 

Streams project (NEWS: Snook et al. 2007) 

● Historical data (i.e. trends) 

 e.g. Lake water transparency and dissolved oxygen. 

● Spatial frameworks (state, ecoregion / biophysical region, national 

e.g. Lake water transparency and chemistry, mercury in biota, atmospheric deposition. 
142 

Condition summaries by resource group 

In the following series of matrices, each metric or other descriptor is given a condition rank. We 

used three ranking statements: “Good”, “Caution”, and “Significant Concern”. For several of the 

air quality metrics, our rank of “Caution” equates to the “Moderate” rank used by the National 

Park Service (NPS 2006). For some NETN metrics with available data, ranks have been 

numerically defined (B. Mitchell, NPS, pers comm.) – we have used these metric classes. 

However, for many other metrics, rank was assigned using best professional judgment following 

review of the available data. 

Supporting information is included alongside the ranking statement – often these data reference 

figures or tables in the Resource Characterization and Assessment of Threats sections of this 

report. 

Where trend data are available, they are noted. Not all NETN-designated metrics have NETN 

data associated with them in these matrices – generally because the data were not available by 

the time of report preparation. 

There are seven matrices summarizing condition data by resource group; a final table includes 

metrics associated with climate change: 

• Air Quality 

• Terrestrial 

• Streams 

• Lakes and Ponds 

• Wetlands + Estuaries 

• Groundwater 

• Marine Intertidal and Coastal 

• Climate Change Metrics 

An asterisk (*) by a metric indicates that the metric is from the list of adopted Vital Signs 

(Mitchell et al. 2006). A cross (†) indicates the metric is a proposed Vital Signs metric. 

One approach to summarizing overall condition within each resource group would be to simply 

state the number of metrics assigned to each condition rank. However, this is potentially 

misleading and inaccurate, since the study used a very heterogeneous information base – one that 

made it impossible to conduct a fully quantitative and consistent condition assessment. 

Furthermore, there is not a consistent number of metrics used for each thematic area – for 

example, within lakes, these areas might be water quality, structure and integrity of biological 

assemblages, contaminant levels in biota, and habitat issues. Finally, the selection of individual 

metrics to incorporate into an overall index of condition, and the weighting given to each metric, 

can greatly influence the final index value. 
143 

Nonetheless, with this caveat in place, we provide a summary of metric rankings as follows: 

Air: 

Good (0); Caution (4); Significant Concern (5); Insufficient data (0). 

Terrestrial: 

Good (9); Caution (10); Significant Concern (1); Insufficient data (5). 

Streams: 

Good (7); Caution (3); Significant Concern (3); Insufficient data (1). 

Lakes and Ponds: 

Good (12); Caution (4); Significant Concern (1); Insufficient data (0). 

Wetlands/Estuaries: 

Good (3); Caution (2); Significant Concern (2); Insufficient data (7). 

Groundwater: 

Good (4); all other ranks (0). 

Marine: 

Good (2); Caution (2); Significant Concern (3); Insufficient data (3). 

The reader is strongly urged to consult information for each metric before using the above 

summary. 
144 

Air Quality 

Metric Condition Data Summaries and/or Refs. 

Ozone 

3 year average of 

annual 4thhighest 8-hour 

ozone 

concentration* 

CAUTION 

(concentration within range 68-84 ppb) 

• Although there is no trend or a decreasing 

trend, exceedences are heavily dependent 

on meteorology, which is unpredictable. 

• Higher elevation, coastal sites – 

specifically the Cadillac summit – have 

exceedences at greater frequencies than 

elsewhere in Maine.

NPS 2006 

Ozone 

# 8-hr 

exceedences 

CAUTION

• 1983-2005: Mean = 5.2 / yr 

Annual number of 8-hour ozone exceedances at 

six park units (Table 17) 

Visibility 

Haze index* 

CAUTION 

• Highly significant improving trend (clean 

days) 

• Significant improving trend (dirty days) 

NPS 2006 

Visibility 

Standard Visual 

Range 

CAUTION 

• Benchmark: natural conditions on the 

20% best days (ACAD/NPS/MANE-VU's 

goal through the Regional Haze Rule). 

• At ACAD, visibility conditions on the 

20% best days are improving and are 

statistically significant. 

• On the 20% worst days, there is an 

improving trend at ACAD but it is not 

statistically significant. 

(H. Salazer, NPS, pers. comm.) 

(Fig 36)

Wet deposition 

of Ammonium* 

SIGNIFICANT CONCERN 

• No Trend 

• NADP deposition data ranged 0.73 

kg/ha/yr (2001, a drought year) to 1.87 

(2002) during the most recent 10 years 

available (1997-2006); all values except for 

2001 were greater than the NETN reference 

condition of < 1 kg/ha/yr. (Fig. 37) 
145 

Wet deposition 

of Nitrate* 

SIGNIFICANT CONCERN 

• No Trend 

• NADP deposition data ranged 5.98 

kg/ha/yr (2001, a drought year) to 12.01 

(2000) during the most recent 10 years 

available (1997-2006); all values were 

several times greater than the NETN 

reference condition of < 1 kg/ha/yr. (Fig. 37) 

Wet deposition 

of Sulfate* 

SIGNIFICANT CONCERN 

• Improving Trend 

• There has been a decline in deposition 

since the 1980s. NADP ranged 6.38 

kg/ha/yr (2001, a drought year) to 17.6 

kg/ha/yr (1998) during the most recent 10 

years available (1997-2006); all values were 

several times the reference condition. (Fig. 37) 

Sulfur and 

Nitrogen total 

deposition 

SIGNIFICANT CONCERN (S) 

CAUTION (N) 

(rankings by NPS 2006) 

• S and N total deposition are dependent on 

vegetation type and site elevation. Hotspots 

of deposition were located at mountain 

summits and in areas of coniferous 

vegetation. 

Mercury wet + 

dry deposition 

SIGNIFICANT CONCERN 

• Total deposition (throughfall) is typically 

2-3 times wet-only deposition at Acadia. 

Wet-only deposition exceeded the likely 

‘pre-industrial’ Hg deposition value of less 

than approximately 2 μg/m2

/yr11; 

throughfall deposition approached or 

exceeded the estimate of pre-industrial total 

deposition. 

(Fig. 44) 

 

11 (Roos-Barraclough et al. 2006) 
146 

 Terrestrial Resources 

Metric Condition Data Summaries and/or Refs. 

Forest patch 

size 

GOOD 

• Patch size at ACAD is > 50 ha and, based 

on research elsewhere, is considered 

adequate to support invertebrates, 

mammals, and most bird species. 

Tierney et al. (in press) 

Anthropogenic 

land-use 

GOOD 

• 96% of watersheds inside the park (23 of 

24) have <10% anthropogenic land use and 

the same 96% have <40% anthropogenic 

land use. 

• 60% of watersheds partly or entirely 

outside the park (78 of 131) have <10% 

anthropogenic land use; 90% of watersheds 

partly or entirely outside the park meet the 

NETN benchmark of <40% anthropogenic 

land use. 

• The value <10% is the benchmark used 

by Snook et al. (2007) to characterize 

reference watersheds. 

• The value <40% is the benchmark used 

by NETN Vital Signs to characterize park 

condition. 

+ Tierney et al. (in press) 

Landcover 

Change 

CAUTION 

• 117% increase in urban lands within Park 

+ 5-km buffer over period 1976-2002 

Landcover change in the ACAD region, 1976-

2002 (Table 3) 

Forest 

Structure: Snag 

abundance* 

(NETN data) 

GOOD 

• ≥ 10% all standing trees are snags and ≥

10% all medium-large standing trees are 

snags 

(Plot-level data not available) 

Tierney et al. (in press) 

Forest 

Structure: 

CWD volume* 

(NETN data)

CAUTION 

• 19% plots GOOD 

• 24% plots CAUTION 

• 57% plots SIG. CONCERN 

Forest plot-level data for four condition metrics 

(Table 18) 

Forest 

Structure: 

Stand structural 

class* 

CAUTION / SIGNIFICANT CONCERN 

• Measures proportion of late-successional 

stands; rank criteria depend on forest type. 

(Plot-level data not available)

Tierney et al. (in press) 

Tree condition* 

(NETN data) 

GOOD 

• 61% plots GOOD 

• 34% plots CAUTION 

Forest plot-level data for four condition metrics 

(Table 18) 
147 

• 5% plots SIGNIFICANT CONCERN 

Tree Health 

(Other data) 

CAUTION 

• ≤22% of trees in Cadillac and Hadlock 

watersheds had signs of damage, measured 

using Forest Health Monitoring Protocol. 

• Hemlock woody adelgid – 2 recent 

outbreaks on MDI (trees removed). Other 

potential pest spp. (see p. 71). 

• Ozone causes leaf damage in several spp. 

and impacts radial growth in white pine. 

Ozone exposure causes reduced growth rate 

and/or tissue biomass in 3 out of 8 spp. 

tested. 

• Red spruce damaged by acid fog and rain. 

See Threats sections: Ozone; Atmospheric 

Deposition and Related Chemistry; Pests and 

Pathogens of Terrestrial Vegetation

Terrestrial 

Invasive & 

Exotic Plants 

(Other data) 

CAUTION 

• 25% ACAD plants are exotic (slightly less 

than value for entire state). Most of these 

exotic spp. are not aggressively invasive. 

• Invasive spp. more abundant on east side 

of MDI. 

• 24 spp. of potential concern as invasives 

(2004 study). 

• However, invasive plant density in 

monitored plots is lower at ACAD than at 

other parks in NETN (Tierney et al. in 

press) 

+ Table 8; Fig. 64 

Status of Rare 

Plant 

Populations 

CAUTION 

• ACAD supports rare plant taxa, some of 

which occur nowhere else in Maine. 

• Although population trend data are not 

available for most rare species, the status of 

these plant populations is potentially 

threatened by a range of stressors. Trend 

data on rare plant populations is a critical 

need. 

Table 7 

Terrestrial 

Invasive Fauna 

CAUTION 

• European fire ant established at multiple 

sites on MDI. 

 (Fig. 66) 

Forests: Deer 

Browse* 

GOOD / CAUTION 

• Deer population currently below forage 

carrying capacity (but browsing impacts 

See Threats: Herbivory and Predation
148 

plant height, species richness and densities 

in some areas). 

(NETN plot-level data not available) 

Forest 

Sensitivity to 

Nitrogen & 

Sulfur 

Deposition 

GOOD 

• ACAD region generally not sensitive 

(Fig. 41) 

Soil Chemistry: 

Acid Stress – 

Ca:Al ratio* 

(NETN data) 

CAUTION 

• 32% plots: GOOD 

• 21% plots: CAUTION 

• 46% plots: SIGNIFICANT CONCERN 

Forest plot-level data for four condition metrics 

(Table 18) + Tierney et al. (in press) 

Soil Chemistry: 

Nitrogen 

Saturation – 

C:N ratio* 

(NETN data) 

GOOD 

• 81% plots: GOOD 

• 16% plots: CAUTION 

• 3% plots: SIGNIFICANT CONCERN 

Forest plot-level data for four condition metrics 

(Table 18) + Tierney et al. (in press) 

Soil Chemistry: 

Hg 

CAUTION 

• Most Hg is found in the organic horizon of 

soils; soils at burned sites had less Hg than 

soils at undisturbed sites which can have 

relatively large stocks of Hg. Soil Hg 

concentrations are within the range of other 

Northeastern sites (e.g., Grigal 2002, 

Demers et al. 2007); however, atmospheric 

deposition of Hg is elevated in the 

Northeast so these values could be 

considered high for rural sites. 

Summary of Hg concentrations in 

environmental media (Fig. 47) 

Birds: IBI 

Metrics * 

(Data not available) 

Birds: 

Frequency of 

Occurrence * 

(Data not available)

Birds: Species 

Diversity * 

(Data not available)

Birds: 

Population 

Trends (resident 

spp.) 

UNKNOWN 

• Increasing populations in 13% MDI spp. 

Decreasing populations in 2% spp. 

Insufficient data for 68% spp. 

Resident birds: summary of population trends 

and information quality (Table 8) 

Mammals: Deer 

Population 

Trends* 

CAUTION

• Deer population may be declining on 

MDI. 

See Threats: Herbivory and Predation
149 

Mammals: 

Other 

Population 

Trends 

UNKNOWN 

Amphibian 

Population 

Trends 

SIGNIFICANT CONCERN

• Declining populations for 3 spp. (out of 

12+ spp present in the Park). 

(1 salamander, 2 frogs). 

(Fig. 15) 

Contaminants: 

Mercury and 

PCBs in Birds 

CAUTION 

• The range of Hg in eagle blood (0.03 - 

0.15 ppm, wet weight) was well below the 

threshold of 1 ppm. 

• The range of Hg in tree swallow eggs 

(0.097 - 1.313 ppm, wet weight) included 

some values that exceeded the threshold of 

0.8 ppm. 

• High PCB levels in nesting bald eaglet 

blood and feathers (Matz et al. 1997) 0 0.2 0.4 0.6 0.8 1 1.2 1.4

s

Max

Mean

Min

tree swallow eggs

eagle blood

See Tables 19 and 20 for more information 

Contaminants: 

Mercury in 

mammals 

GOOD 

• The range of Hg in mink and otter fur 

(1.14 - 9.9 ppm, wet weight) was well 

below the proposed threshold of 30 ppm. 

0 5 10 15 20 25 30

Max

Min

mink& otter fur

See Tables 19 and 20 for more information 
150 

Streams 

Metric Condition Data Summaries and/or Refs. 

pH* GOOD / CAUTION 

• 1 out of 14 streams exhibits pH 

consistently < 6.0. 

• Episodic acidification documented for 

several streams. 

 (Fig 22) 

ANC* CAUTION 

• Many streams have ANC < 40 ueq/L, the 

tolerance criterion of DuPont et al. (2005) 

for aquatic organisms (especially fish). 

However, NETN uses a more protective 

threshold of 100 ueq/L. (Fig. 23)

Sulfate GOOD 

• Most sites exhibit lower SO4

concentrations than NEWS reference 

condition of 104 ueq/L 12. 

• Concentrations declining since 1980s 

(Kahl et al. 2004) 

0

2

4

6

8

10

12

14

16

18

35‐60 61‐80 81‐103 104‐120 120‐135

Spring

Fall

Streamwater

Sulfate (μeq/L)

NEWS

(See Fig. 42 for full data) 

Conductivity* GOOD 

• 12 / 14 streams typically exhibit 

conductivities < 100 μS/cm 13. Natural 

condition. 

(NETN data not available) 

 (Fig. 22) 

 

12 Threshold value (equivalent to 5 mg/L) that was judged to characterize “minimally stressed background sites” in 

New England Wadeable Streams Project, NEWS (Snook et al. 2007), based on human disturbance in a watershed, 

physical-chemical parameters, and biological responses. 

13 Threshold value used by NEWS to characterize minimally disturbed sites. See footnote above for sulfate for more 

information. 
151 

Total Nitrogen* CAUTION 

• N concentrations in some streams are 

chronically elevated. 

• TN in 12/14 streams generally > 0.25 

mg/L 14. 

• TN in 3/14 streams consistently <0.38 

mg/L. 

 (NETN data not available)

• Research at paired watersheds suggests 

some N saturation may occur at 

undisturbed, conifer-forested sites. 

 (Fig. 22) 

Minimum DO* GOOD 

• Streams generally well oxygenated. 

 (Fig. 22) 

Water 

Temperature 

GOOD 

• No evidence that temperature regimes 

differ from the natural condition. 

Trend in Flow* UNKNOWN 

Mercury in 

Water 

SIGNIFICANT CONCERN 

• 0/28 sampled streams exhibited Hg 

concentrations ≥ 7.5 ng/L; however, 10/28 

had Hg concentrations greater than the 

average for Hadlock Brook, a site with 

elevated Hg in amphibians. 

• Hg is strongly related to DOC and 

episodic high flows and may exceed the 

NEWS reference condition; Hg at Hadlock 

Brook ranged up to 8 ng/L during high flow 

events. 

• Highest MDI concentrations are ~70% of 

maximum values observed in statewide 

survey. 

• Both Cadillac and Hadlock watersheds 

exceeded the MeHg level presumed to lead 

to biota body burdens >0.3 ppm during 

some periods (maxima: 0.28 ng/L (Cadillac) 

and 0.68 ng/L (Hadlock). 

 (+ Fig. 47) 

 

14 NETN reference condition is <0.38 mg/L. NEWS reference condition is <0.25 mg/L as NO3 + NO2. 
152 

Mercury in 

Salamanders 

SIGNIFICANT CONCERN 

• Average Hg in salamanders ranged 0.036-

0.167 ppm (ww). In several watersheds, 

body burdens exceeded the 0.077 ppm 

criterion that most likely affords protection 

to predators of these species. 

 (Fig. 48) 

Other 

Contaminants 

GOOD 

• VOCs and trace metal concentrations 

below detection and below acceptable 

ecological limits, respectively, in sampled 

streams. 

• Leachate from closed landfills is a threat 

to water quality in 2 streams. 

 (Fig. 60) 

Macroinvertebrates 

GOOD / CAUTION 

• Bioassessments indicate that quality at 

many sites, although generally good, is 

slightly lower than the AA class designation 

for all ACAD streams. Two streams, Heath 

B. and Otter C., are degraded, based on the 

macroinvertebrate data. 

Stream water quality attainment based on 

macroinvertebrate biomonitoring data (Table 

14) 

Fish Barriers SIGNIFICANT CONCERN 

• 34% stream barriers block passage by 

aquatic organisms. 56% partially block 

passage. 

See Threats: Habitat Loss and Impairment

Fish 

Assemblages 

CAUTION

• 1/3 stream fish species are non-native to 

MDI. 

• Diadromous species runs thought to be 

much smaller than historically. 

Freshwater fishes in lakes and streams (Table 

12) 
153 

Lakes and Ponds 

Metric Condition Data Summaries and/or Refs. 

pH* GOOD / CAUTION

• Most lakes have pH > 6.0. Of the 2 ponds 

with pH < 5.0, one is naturally acidic. 

• No significant change in pH of ACAD 

lakes 1990-2000 despite sulfur emission 

reductions. 

 (Fig. 16) 

Alkalinity / 

ANC* 

CAUTION 

• Alkalinity in most lakes is < 10 mg/L 

• Many lakes are naturally dilute; however, 

ANC has not increased in most lakes 

despite decreased acidic deposition. This is 

inconsistent with many lakes elsewhere in 

Maine and New England. 

0.1

1

10

100

1000

0 1 10 100 1,000 10,000 100,000

Lake Area (ha)

Alkalinity (mg/L)

Maine

ACAD

(Fig. 19) 

Transparency GOOD

• Most lakes are mesotrophic or oligotropic 

based on Secchi depths. 

• Larger ACAD lakes have higher 

transparencies than statewide population of 

surveyed lakes. 

0

2

4

6

8

10

12

14

16

0 1 10 100 1,000 10,000 100,000

Lake Area (ha)

Secchi Depth (m)

Maine

ACAD

(Fig. 19; see also Fig. 21) 

Chlorophyll GOOD 

• Lakes are mesotrophic or oligotropic 

based on chlorophyll concentrations. 

0.1

1

10

100

1000

0 1 10 100 1,000 10,000 100,000

Lake Area (ha)

Chlorophyll (ug/L)

Maine

ACAD

(Fig. 19) 

Total 

Phosphorus* 

GOOD

• Epilimnetic TP concentrations generally < 

10 ug/L. 

• No evidence of increasing phosphorus 

concentrations. 1

10

100

1000

0 1 10 100 1,000 10,000 100,000

Lake Area (ha)

Total Phosphorus (ug/L)

Maine

ACAD

(Fig 15) 

Total Nitrogen* GOOD 

• TN in 7/11 lakes < 0.24 mg/L. 

• TN in all lakes < 0.50 mg/L (except for 

marine-influenced Seawall Pond). 

Seger et al. (2006) 
154 

Sulfate GOOD

• Significant decline in period 1900-2000, 

but less than in broader population of 

sensitive lakes in Maine. 

Trends in selected lake water quality 

parameters (Table 12) 

Surface 

Dissolved 

Oxygen* 

GOOD

• Surface waters are well oxygenated. 

Hypolimnetic 

Dissolved 

Oxygen* 

GOOD

• While some lakes exhibit low 

hypolimnetic DO in summer, there is no 

indication that levels of hypoxia have 

changed over the past 60 years. 

 (Fig. 53) 

Lake Water 

Levels* 

GOOD (?) 

• No evidence for temporal trends in extent 

of drawdowns. 

• No evidence for adverse impacts on lake 

ecology from water level fluctuations, but

there has been little research on this topic. (Fig. 62) 

Loon 

Populations 

CAUTION

• Concern about reproductive rates on some 

lakes. 

Loon populations on ACAD and Maine lakes 

(Fig. 26) 

Fish: Species 

Richness 

CAUTION 

• Some evidence that numbers of species in 

smaller ACAD lakes are higher than in 

similarly-sized lakes in southern Maine. 

 (Fig. 29) 

% Non-Native 

Fish 

CAUTION 

• 15 / 28 ACAD species are thought to be 

non-native to MDI. 

• Illegal fish introductions are significant 

threat. 

0 5 10 15 20

Long P

Eagle L

Seal Cove P

Echo L

Jordan P

Somes P

Long P (IAH)

Hamilton P

Lower Hadlock P

Little Long P

Round P

Upper Hadlock P

Hodgdon P

Aunt Betty P

Bubble P

Witch Hole P

Breakneck Ponds

LakeWood

The Tarn

Duck P

The Bowl

Halfmoon P

Sargent Mountain P

Number of Species

Historically present Probable natives

(Fig. 25; see also Table 12) 
155 

Mercury in Fish SIGNIFICANT CONCERN

• Fish in ACAD lakes typically exhibit 

elevated tissue Hg concentrations, at levels 

higher or lower than statewide averages, 

depending on species. 

• All surveyed ACAD lakes had at least one 

fish sample for which fillet concentrations 

exceeded Maine advisory for human 

consumption. 

See Tables 19 and 20 for full information 

Organic 

Contaminants 

in Fish 

GOOD (?)

• Low concentrations of PCBs and 

pesticides in 1993-94 survey. Entire park is 

at risk from organochlorines, but data are 

inadequate for full assessment. 

Invasive Plants* GOOD 

• No aquatic invasive species currently in 

ACAD lakes. 

• Only one aquatic plant species appears to 

be non-native. 

 
156 

Wetlands (Freshwater and Saltwater) 

Metric Condition Data Summaries and/or Refs. 

Plant Spp. 

Richness* 

UNRANKED 

• However, plant species richness higher in 

undisturbed wetlands. 

Neckles et al. (2008) 15

Water Quality* UNRANKED 

• Conductivity and pH are both higher in 

disturbed wetlands – surface and ground 

water. 

Neckles et al. (2008) 

Mercury in 

Amphibians 

GOOD / CAUTION 

• Hg in green frog (0.025±0.001 ppm, ww) 

and bullfrog (0.019±0.007 ppm ww) 

tadpoles was below the the 0.077 ppm 

criteria that most likely affords protection to 

predators of these species. However, 

population-level effects of these Hg burdens 

are unknown. 

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08

Max

Mean

Min

bullfrog tadpoles

green frog tadpoles

See Tables 19 and 20 for full information 

UV dosimetry GOOD / CAUTION 

• UV dose to ACAD wetlands is lower than 

at wetlands in five other national parks. 

• However, there do not appear to be 

published data on impacts on UV in ACAD 

wetlands. 

 (Fig. 35) 

Amphibian 

Disease 

CAUTION 

• Five major amphibian diseases recorded at 

ACAD. 

• Amphibian die-offs have been recorded 

and are apparently disease-related. 

 (Fig. 67) 

Multiple 

Stressors 

UNRANKED 

• Neckles et al. (2008) used a multiparametric index (SumRel) of 

anthropogenic stressors to classify all 

watersheds on MDI. Index includes 

following parameters: % agriculture, % 

urban, population density, road density, 

impervious surface. However, data are 

available only in draft report, so are not 

presented here. For selected observations of 

characteristics of reference vs. disturbed 

Neckles et al. (2008) 

 

15 The report by Neckles et al. (2008) is a draft; although referenced here, we do not include extensive data examples 

from this document. 
157 

wetlands, see Plant Species Richness and 

Water Quality, above. 

Nutrient 

Loading to 

Wetlands and 

Estuaries 

SIGNIFICANT CONCERN / CAUTION 

/ GOOD 

• Eutrophication trend documented in Bass 

Harbor Marsh. 

• Potential for eutrophication, leading to 

degraded conditions, in Northeast Creek as 

a result of future development in watershed. 

• Anthropogenic nutrient loading and 

nutrient levels in Somes Sound do not 

represent a problem. Water quality in this 

estuary is good. 

Nutrient loading and algal biomass in Bass 

Harbor Marsh (Fig. 54) 

Groundwater use and nitrate concentrations in 

selected sub-watersheds of the Northeast Creek 

system (Fig. 55) 

Macoalgae 

Abundance in 

Estuaries 

SIGNIFICANT CONCERN 

• Increasing abundance in Bass Harbor 

Marsh

Other NETN metrics for freshwater wetlands: Published data not available

Invasive plants. Landscape connectivity. Vegetation structure. Organic matter accumulation. Soil disturbance. 

 
158 

Groundwater 

Metric Condition Data Summaries and/or Refs. 

Level* GOOD 

• No evidence for trends of increasing depth 

to groundwater. 

 (Fig. 24)

Specific 

Conductance* 

GOOD 

• No evidence for increasing conductance in 

groundwater. 

Contaminants GOOD 

• Most domestic and monitoring well 

samples from Bass Harbor Marsh and 

Northeast Creek watersheds contain few, if 

any, detectable contaminants (phenol is 

only contaminant detected). 

• Most well water samples contain arsenic at 

levels below the EPA maximum 

concentration. 

• Leachate from 2 landfills presumably 

present in surrounding groundwater (see 

item under Streams, above). 

Nutrients GOOD / CAUTION 

• Groundwater in shallow, hyporheic zone, 

of Northeast Creek and Bass Harbor 

watersheds has elevated concentrations of 

dissolved nitrogen, perhaps indicating 

contamination from septic systems.

• Nitrate concentrations in Northeast Creek 

watershed wells are below human health 

limit of 10 mg/L. except in one subwatershed. 

• There is concern that increasing 

development may increase groundwater 

nitrogen levels in NEC and possibly other 

areas.

See Threats: Nutrient Enrichment.
159 

 Marine Intertidal 

Metric Condition Data Summaries and/or Refs. 

Algal species† UNKNOWN 

• Limited evidence of changes in vertical 

distribution limit for some taxa at one series 

of sites. 

• Insufficient data to document temporal 

trends in assemblage composition.

Algal Blooms CAUTION 

• Blooms occur and influence the 

shellfishing industry in the Gulf of Maine.

 (Fig. 57) 

Shellfish 

Closures 

SIGNIFICANT CONCERN 

• Areas are closed to shellfishing because of 

sewage-based contaminants and, at times, 

toxins from algal blooms.

 (Fig. 59) 

Invertebrate 

Community 

Composition † 

UNKNOWN 

• No information on temporal trends in 

marine invertebrate communities or 

populations. 

• Ongoing studies will provide important 

base data.

Human 

trampling† 

(excl. caves) 

UNKNOWN 

• Ongoing studies will provide important 

base data. 

Invertebrate 

Communities of 

Cave Tide Pools 

SIGNIFICANT CONCERN 

• Trampling visitors likely impacts 

anemones and other species in Anenome 

Cave. 

See Threats: Visitor Impacts on Intertidal 

Areas

Invasive species SIGNIFICANT CONCERN 

• Several marine invasives currently exist in 

or near the ACAD area, including the Asian 

shore crab and green crab.

See Threats: Invasive Marine Species
160 

Eelgrass CAUTION 

• Some evidence (anecdotal) from MDI area 

that eelgrass beds have been disrupted by 

mussel dragging and other activites. 

• Documentation of reduced eelgrass beds 

in the neighboring Penobscot Bay. (Fig. 32) 

Sediment 

Contaminants 

(off-shore) 

GOOD 

• Levels of measured contaminants 

generally low in the MDI area.

Metal: Mercury

2000-2003 Northeast NCA Data State = ME

ERL/ERM threshold limits are in effect

ERL = 0.15 ppm

ERM = 0.71 ppm

State map Symbols designate condition as defined in legend below.

Pie diagram & statistics table indicate percentage of estuarine area in state in 4 condition categories

State pie chart: 

State statistics:

Percentage of Estuarine Area in ME

Good 87.8%

Fair 12.2%

Poor 0.0%

Missing 0.0%

42.5

43.0

43.5

44.0

44.5

45.0

45.5

-71.2 -70.7 -70.2 -69.7 -69.2 -68.7 -68.2 -67.7 -67.2 -66.7

ME Mercury

Good, 

88%

Fair, 12%

Poor, 0%

Missing, 

0%

Good: <0.15 ppm

Fair: 0.15 to 0.71

Poor: >0.71 ppm

Missing

 (Fig. 51) 

Fish 

Assemblages 

GOOD (?) 

• No evidence from available data that fish 

assemblages are in ‘degraded’ form.
161 

 Climate - Related 

Metric Condition Data Summaries and/or Refs. 

Precipitation 

patterns 

(changes in total 

amount and 

temporal 

distribution) 

Unranked

 (Fig. 10) 

Precipitation 

type (proportion 

of snow to rain)

Unranked

Temperature Unranked 

Sea level rise† SIGNIFICANT CONCERN 

(Fig. 68)

Phenology 

(plant, bird, 

amphibian)† 

No data 

Climate-induced 

species range 

shifts 

No data for ACAD 
162 

Conclusions and Information Needs 

This section addresses information richness and information needs as they relate to the natural 

resources of the Acadia region. We first provide an overview of the ‘status’ of resource 

inventories. Secondly, we identify a series of key data gaps which, if filled, would improve 

understanding of the interrelationships between stressors and ecosystem responses at ACAD. 

This added information would also make possible a more rigorous and quantitative assessment of 

status and trends in resource condition based on a broad range of ecosystem attributes. 

Biological resource inventories 

Based on our review of available information, and discussions with ACAD staff and external 

researchers, we have attempted to characterize the level of completeness for biological resource 

inventories at ACAD, as well as information on trends in species composition and relative 

abundance. 

Terrestrial Plants: Inventory of MDI vascular plants is relatively complete. Plant species lists 

for SCH and IAH are incomplete. Lichens have been well inventoried. Knowledge of mosses and 

ferns is sparse. Overall, there is little information on species-habitat relationships at ACAD. 

While rare plants have been well surveyed on MDI, there is little follow-up information on the 

status of rare plant populations. 

Freshwater Plants: Vascular macrophytes were well surveyed over a decade ago; 

contemporary information is sparse. There are no contemporary macrophyte data from Long 

Pond on IAH. Populations of the several rare aquatic plant species have generally not been resurveyed to document current status. There is little information on lake phytoplankton 

populations. 

Wetland and Estuarine Plants: Species lists are probably relatively complete for the ACAD 

region as a whole. Until recently, quantitative data on community composition and relative 

abundance at individual wetlands or for wetland classes has been less available. As part of the 

NPS Vital Signs Monitoring Program, the Northeast Temperature Network has developed 

detailed freshwater wetland monitoring protocols that will now produce good information on 

status and trends of wetland vegetation and water chemistry (Neckles et al. 2007). For estuarine 

systems, plants in Bass Harbor Marsh were surveyed over a decade ago. More recent data are 

available for plants in Northeast Creek, and methods for assessing the condition of submerged 

aquatic vegetation in Bass Harbor Marsh and Northeast Creek estuaries are under development. 

Marine Algae: Detailed surveys of rocky intertidal and mudflat algae have been completed at a 

few sites on MDI. The degree to which these sites are representative of the entire ACAD region 

is unknown. Ongoing surveys are developing information on coastal flora at SCH. Little is 

known about the marine flora at IAH and other islands. 

Birds: The species list is relatively complete for the ACAD region. However, new surveys may 

find additional owl species – indeed, compared to other groups, we probably know the least 
163 

about the owls of the ACAD region. For most bird species, there is little information on 

population sizes and trends, as well as responses to many environmental stressors. 

Mammals: The species list is probably complete for the ACAD region. There is information on 

population size and trends for some species but not for many others. 

Amphibians and Reptiles: The species list for the ACAD region is likely complete. Recent 

survey data, including information on relative abundance, are available. 

Freshwater Fish: Presence/absence survey data are available from most lakes, ponds and 

streams on MDI. Population size and trend data are incomplete and the information is generally 

less readily accessible. Current monitoring of freshwater fish assemblages may not be 

sufficiently frequent or rigorous to detect species additions (for example, bait-bucket 

introductions). 

Estuarine Fish: Three studies have investigated fish assemblages in Bass Harbor Marsh; two of 

these are over a decade old, while more recent data are those of Jordaan (2006). Information 

includes both species lists and relative abundance, as well as a number of other assemblage and 

population-level data. Fewer data are available from the Northeast Creek estuary, although some 

collections were made in the late 1990s. 

Intertidal and Marine Fish: Intertidal and tidepool fish assemblages were surveyed in the early 

2000s. There are detailed survey data on sub-tidal fish assemblages, including relative abundance 

(catch per unit effort) for many taxa. 

Aquatic Invertebrates: Survey data on stream macroinvertebrates are available from a few sites 

on MDI. These data are collected with a standardized methodology, potentially permitting future 

inter-site and inter-year comparisons as the database expands. Data on lake benthic 

macroinvertebrates are very sparse – most of the information is from >50 years ago and these 

data are, for the most part, at the family or genus level. Damselflies and dragonflies (Odonata) 

have been reasonably well surveyed on MDI; many data have been collected in the past 10 years. 

Mayflies (Ephemeroptera) were well surveyed in the 1990s. (Note that most odonate and mayfly 

specimens have been collected as adults and therefore not in their aquatic life stage.) Some 

freshwater mussel collections have been made. Although many waterbodies have not been 

surveyed, it is likely that the mussel species list for the ACAD region is complete because of the 

relatively low species richness of this group. Data on the macroinvertebrates of wetlands and 

estuaries are sparse. Intertidal invertebrates have been quantitatively surveyed at a few sites on 

MDI. There are ongoing surveys of intertidal invertebrates at SCH. There is little information 

from IAH. 

Current research is developing zooplankton data for some ACAD lakes. There are virtually no 

historical assemblage-level zooplankton data – data collected in the early 1940s are of limited 

use in terms of temporal comparisons since most identifications were, at the best, only to the 

genus level. 
164 

Data on groups of invertebrates that are associated with freshwaters have been integrated into a 

composite database (that has statewide coverage) (Vaux 2005). However, other invertebrate data 

from the Park do not currently reside in a centralized database, including the NPSpecies 

database. 

Terrestrial Invertebrates: The Procter surveys from over 60 years ago are a rich information 

base on terrestrial invertebrates. Changes in taxonomy, however, complicate comparisons to 

more contemporary data sources (for example, for mayflies). Recent bioblitzes have generated 

useful species lists for ants, beetles, butterflies, flies, true bugs, and spiders. Except for ants 

(collections made on MDI), these bioblitzes have all occurred at SCH over a short time period. 

Their data, while valuable, may not represent a complete picture of species richness for these 

groups for ACAD as a whole. Relatively contemporary data on other invertebrate groups is 

patchy. 

Trends in Species Composition and Relative Abundance: For virtually all floral and faunal 

groups, there is a dearth of information on trends in species composition and relative abundance 

for individual habitats. For example, over 20% of taxa in the catalogue of the vascular plants of 

the Acadia region are historic records and have not been documented in the area since 1980 

(Greene et al. 2005). Trends in population sizes of birds and many other faunal groups are also 

largely undocumented. Understanding “natural” patterns of variance in the composition and 

relative abundance of species assemblages is critical to being able to evaluate status and trends. 

Currently, there is very little known about components of variance in plant and animal 

populations at ACAD. 

Rare Species: Although there are relatively detailed survey data on rare plant taxa, there is little 

information on temporal trends in the presence and status of individual populations. Of particular 

importance is the impact of Park use by visitors on rare plants. For non-vascular plant groups, 

there is a need to better understand the distribution and status of rare species. 

Threat and Condition Assessments: Information Needs 

We developed a list of information needs through (i) discussions with ACAD and external 

researchers, (ii) a series of meetings organized by Acadia Partners and NPS to provide input to 

the development of a research opportunities catalogue for ACAD, and (iii) our review of the 

scientific literature. The latter includes several review documents that include statements of 

information needs, for example Haines and Webber (1999), Maniero and Breen (2003), Kahl et 

al. (2000) and Connery (1998). Note that the information needs reviewed here focus principally 

on issues related to the assessment of threats and resource condition. 

For some threats and stressors, available information is largely limited to measures of their 

presence and, sometimes, spatial and/or temporal patterns; there is often little known about the 

effects of a stressor or the mechanisms whereby these effects are occurring. For example, loading 

of contaminants transported to the Acadia region via the atmosphere are, in general, fairly well 

known. The effects of these contaminants on the biota of ACAD are much less well understood. 

Mercury is one contaminant for which there is a reasonable amount of information on tissue 
165 

concentrations. Nonetheless, there is little quantitative documentation of the impacts of mercury 

body burdens on faunal physiology, behavior, population dynamics and community-level 

interactions. Another example is exotic plants, for which there are relatively extensive survey 

data. However, the ways in which these species affect non-native taxa are, on the whole, poorly 

documented. 

Whereas the MDI unit of the park is well-studied, very little information exists for other areas of 

the Park. The Schoodic peninsula, in particular, is under-studied. Streams, wetlands, and ponds 

on SCH have very little baseline monitoring, and represent interesting systems very closely 

coupled to the marine environment. In addition, there is currently some development pressure on 

park boundaries at SCH (as on MDI) and the effects of land-use change on in-Park resources for 

the Schoodic section have not been modeled to the same extent as those on MDI (if at all). 

For some threats, research currently in progress (or recently completed but not yet published) 

will likely fill some key information gaps. Examples include the trampling effects of visitors on 

rocky intertidal flora and fauna, the landscape-level attributes of disease patterns in amphibians, 

and stream barriers that impede passage by fish and other aquatic organisms. 

The following list of key information needs is largely structured around the series of threats 

addressed earlier in this report. However, it should be underscored that there are many interrelationships among many of the topics. 

Contaminants: Many of the contaminant-related information needs address issues associated 

with the inter-relationships between contaminants, watershed geochemistry, and landscape 

structure, including changes in land use and land cover. 

Ozone: Data on the ozone impacts on terrestrial vegetation derive principally from sites on the 

eastern-facing sites of MDI. Data are needed from sites with other aspects since these may 

represent greater exposure to ozone (Haines and Weber 1999). 

Mercury: Fog at Acadia has never been studied for Hg. Evidence from Nova Scotia indicates 

very high concentrations of Hg in fog on islands and the coast as compared to an inland site. This 

potentially large contribution of Hg to ACAD’s ecosystems is unknown at this point. 

There is a strong record of research regarding Hg in biota (body burdens) and in watershed 

components such as soil, litter, precipitation, and streams. However, the link between high levels 

of Hg in the environment and population-level effects of these high levels has not yet been made. 

Park Service officials have expressed interest in knowing whether the high Hg levels observed at 

the Park are having an observable effect. Further investigation into the mobility and 

transformations of Hg in Acadia’s ecosystems could help us to understand whether there is cause 

for concern at sites that otherwise may be predicted to have low Hg deposition. 

ACAD presents a unique template for Hg research, because of the marine influence. Some 

species of Hg in the environment include chloride, and could be affected by proximity to the 

ocean. It is unknown at this point whether proximity to the ocean affects Hg deposition, mobility, 

or processing in the terrestrial environment. In addition, some researchers have proposed that Hg 
166 

may be re-emitted from oceans. To date, no research has identified the relative contribution of 

Hg from oceans as compared to Hg from inland sources. 

Road salt: Recent research elsewhere has focused on the effects of road salting. Though studies 

on road salt have been conducted at ACAD, some research suggests that there could be temporal 

changes in road salt application methods and amounts that might be resulting in changes in salt 

loads. In addition, other research suggests that increases in salt loads may occur where there is 

increased housing/residential development. Developing a salt budget for Acadia will determine 

whether road salt might be an issue for the park, or if the proximity to the ocean makes this 

concern a non-issue. 

Other contaminants: Some contaminants at ACAD have been little researched. Organochlorines 

are one example. 

Hydrology and Water Quality: Several sites in the park have had stream gauges, lake level 

monitoring stations, or groundwater monitoring wells. However, in general, basic information 

regarding surface and groundwater hydrology is quite sparse. 

The Park has an extensive water chemistry database for streams and lakes. However, long-term 

monitoring of streams is limited – streams have more typically been surveyed (temporal 

snapshot) or monitored for a few years, then programs are discontinued. Measuring the response 

to climate change, chemical interactions, and loading of pollutants requires ongoing monitoring 

without major changes in methodology. 

Nutrient Enrichment: Atmospheric deposition is a major source of N for terrestrial and aquatic 

systems. Impacts of nitrogen enrichment on ACAD forests need to be better understood. The 

ecosystem-level ramifications of elevated N levels in ACAD streams are poorly understood. 

Primary production in many ACAD lakes would appear to be limited by P, rather than by N. 

Nutrient bioassays are needed to quantify nutrient limitation in freshwater ecosystems. Although 

there has been some work looking at the impacts of development on nutrient loading, much more 

needs to be known about how the spatial distribution and scale of various land-use classes 

influences nutrient loading to freshwater and estuarine systems. The potential impacts of finfish 

aquaculture in the ACAD region need to be better understood. 

Wetlands Extent and Condition: Acadia’s landcover includes a large proportion of wetlands 

and many vernal pools that are not always counted in wetland maps/analyses. Improved 

document and monitoring of the spatial distribution of vernal pools is of particular importance. 

The chemistry of wetlands is largely unknown, particularly as compared to streams and lakes. 

Data collected during development of a wetlands monitoring protocol (Neckles et al. 2008) and 

to be collected by the Northeast Temperate Network’s monitoring program will fill some of this 

gap. 

Exotic Species: There is a need to know which exotic species represent threats to native fauna 

and flora, and what the competitive mechanisms are. This information is critical for developing 
167 

and prioritizing management strategies. Rapid bioassessments for invasive species provide a 

potentially valuable tool for detecting problems at ACAD. 

Management of Native Fauna: The impacts of current and future management activities on the 

status native animals in the Park need study. Examples include freshwater and diadromous 

fisheries and deer. Harvest (creel census) data are needed for MDI’s lake fisheries. 

Disease: Emerging patterns of disease transmission into and among ACAD fauna and flora need 

increased research. This includes monitoring of forest pests – about which there is currently very 

little information – and a better understanding of the susceptibility to disease of forest stands of 

differing age and composition. 

Habitat Fragmentation: The impacts of habitat fragmentation and circum-Park development 

on the biological resources of the Park are likely multi-dimensional and do not appear to have 

been substantively addressed. One exception is the impacts of land-use change on water quality 

and habitat integrity of the Northeast Creek system. Fish passage is an example of an issue where 

data already exist on the extent of fragmentation (by dams and poorly constructed and/or 

maintained culverts). Initial stream crossing evaluations have not only evaluated crossing 

structures, but have also characterized the extent of upstream habitat, as well as various 

economic and ownership attributes. This information provides an excellent foundation for further 

investigating and prioritizing stream restoration in the Acadia area. 

Ecosystem-Level Linkages between Park and Non-Park Lands: Since many watersheds on 

MDI cross park boundaries, there is a need to better understand and quantify how land 

management activities on non-park lands influence park resources. Nutrient loading from 

development has been mentioned above. Another example is the role of private lands in 

providing connectivity between habitat patches on park lands. 

Synergistic Effects from Multiple Stressors: This is significant area of research which has 

been scarcely tapped at ACAD. 

Effects of Climate Change: Recent research in Maine has suggested that there has been less 

snow and a warming trend, based on 50 years of climate and hydrologic data (Huntington et al. 

2004, Huntington 2003, Hodgkins et al. 2003). We are not aware of any studies that explore 

what the effects of these climate changes might be on Acadia’s ecosystems. Because the Park is 

located at an ecotone, with many species being either at their southernmost boundary or their 

northernmost boundary, species shifts could potentially occur. It is important to identify unique 

habitats in and around ACAD that are likely to be especially vulnerable to climate change. 

Restoration Opportunities, Approaches and Evaluations: Effective approaches for restoring 

degraded plant and animal populations merit investigation and evaluation; candidate approaches 

need to be implemented and compared. The example of fish passage in streams, noted above, is 

an excellent example of restoration opportunities, backed by a methodology that provides a 

quantitative basis for prioritization. 
168 

Literature Cited 

Aber, J.D., K. Nadelhoffer, P. Steudler and J. Melillo. 1989. Nitrogen saturation in northern 

forest ecosystems. BioScience 39: 378-386. 

Aber, J., W. McDowell, K. Nadelhoffer, A. Magill, G. Berntson, M. Kamakea, S. McNulty, W. 

Currie, L. Rustad and I. Fernandez. 1998. Nitrogen Saturation in Temperate Forest 

Ecosystems BioScience 48 (11): 921-934. 

Aber, J., C. Goodale, S. Ollinger, M. Smith, A. Magill, M. Martin, R. Hallett and J. Stoddard. 

2003. Is nitrogen deposition altering the nitrogen status of northeastern forests? 

Bioscience 53: 375-389. 

Allen, T.J. 1970. Telemetry studies of deer movements and habitat utilization at Acadia National 

Park. M.S. thesis, University of Maine, Orono. 

Ames, E. 1997. Cod and haddock spawning grounds of the Gulf of Maine from Grand Manan to 

Ipswich Bay. Pages 55-64 in: The implications of localized fishery stocks. Natural 

Resource, Agriculture, and Engineering Service, Ithaca, New York, USA. 

Ames, E. 2004. Atlantic cod stock structure in the Gulf of Maine. Fisheries 29: 1. 

Amirbahman, A., P. L. Ruck, et al. 2004. The effect of fire on mercury cycling in the soils of 

forested watersheds: Acadia National Park, Maine, USA. Water Air and Soil Pollution 

152: 313-331. 

Andersen, J. L. 1984. Potential impact of acid precipitation and poor air quality on the 

resources of Acadia National Park. National Park Service, North Atlantic Region, Office 

of Scientific Studies, OSS 85-1. pp. 15-62. 

Bailo, B. G. et al. 2004. Thirty-six years of change in an eastern hemlock-white pine stand in 

western Massachusetts. Rhodora 106: 273-286. 

Baird, J.C. 1966. Some ecological aspects of the white-tailed deer on Isle au Haut, Maine. M.S. 

thesis, University of Maine, Orono. 115 p. 

Bank, M.S., C. Loftin and R. Jung. 2005. Mercury bioaccumulation in Northern two-lined 

salamanders from streams in the Northeastern United States. Ecotoxicology 14(1-2): 

181-191. 

Bank, M.S., J.B. Crocker, S. Davis, D.K. Brotherton, R. Cook, J. Behler and B. Connery. 2006. 

Population decline of northern dusky salamanders at Acadia National Park, Maine, USA. 

Biological Conservation 130: 230-238. 
169 

Bank, M.S., J. Burgess, D.Evers and C. Loftin. 2007a. Mercury contamination of biota from 

Acadia National Park, Maine: a review. Environmental Monitoring and Assessment 

126(1-3): 105-115. 

Bank, M.S., J. Crocker, B. Connery and A. Amirbahman. 2007b. Mercury bioaccumulation in 

green frog (Rana clamitans) and bullfrog (Rana catesbeiana) tadpoles from Acadia 

National Park, Maine, USA. Environmental Toxicology and Chemistry 26(1): 118-125. 

Barden, L. 1970. Management of heavily used land along Ocean Drive, Acadia National Park. 

Unpublished report, Acadia National Park. 48 p. 

Bartholomay, G. A., R. T. Eckert, and K.T. Smith. 1997. Reductions in tree-ring widths of 

white pine following ozone exposure at Acadia National Park, Maine, USA. Canadian 

Journal of Forest Research 27: 361-368. 

Benjamin, P. and R. Hiebert. 2004. Assessing the invasive plant issue. Park Science 22: 27-31. 

Bergstrom, A., P. Blomqvist and M. Jansson. 2005. Effects of atmospheric nitrogen deposition 

on nutrient limitation and phytoplankton biomass in unproductive Swedish lakes. 

Limnology and Oceanography 50(3): 987-994. 

Bricker, S., C. Clement, D. Pirhalla, S. Orlando, and D. Farrow. 1999. National Estuarine 

Eutrophication Assessment: effects of nutrient enrichment in the nation’s estuaries. 

NOAA, National Ocean Service, Special Projects Office and the National Centers for 

Coastal Ocean Science, Silver Spring, MD. 71 p. 

Bricker, S., B. Longstaff, W. Dennison, A. Jones, K. Boicourt, C. Wicks, and J. Woerner. 2007. 

Effects of nutrient enrichment in the nation’s estuaries: a decade of change. NOAA’s 

Coastal Ocean Program Decision Analysis Series No. 26. National Centers for Coastal 

Ocean Science, Silver Spring, MD. 328 p. 

Brower, A. E. 1949. The Beech Scale and Beech Bark Disease in Acadia National Park. Journal 

of Economic Entomology 42: 226-228. 

Brumback, W. E. et al. 1996. Flora Conservanda: New England. The New England Plant 

Conservation Program (NEPCoP) list of plants in need of conservation. Rhodora 98: 

233-361. 

Burdick, D. and F. Short. 1999. The effects of boat docks on eelgrass beds in coastal waters of 

Massachusetts. Environmental Management 23: 231-240. 

Burgess, J. 1997. Mercury contamination in fishes of Mount Desert Island: A comparative food 

chain mercury study. M.S. thesis, University of Maine, Orono. 58 p. 
170 

Burian, S.K. and K.E. Gibbs. 1991. Mayflies of Maine: An Annotated Faunal List. Technical 

Bulletin 144. Maine Agricultural Experiment Station, University of Maine, Orono. 109 

pp. 

Burian, Steven K., K. Blackburn, and L. Juentes-Molack. 1995. An update on the occurrence of 

three species of mayflies (Ephemeroptera) in Maine. Maine Naturalist 3(1): 49-54. 

Caldwell, J. and C. Culbertson. 2007. Hydrologic data summary for the Northeast Creek / Fresh 

Meado estuary, Acadia National Park, Maine, 2000-2001. U.S. Geological Survey OpenFile Report 2007-1035. 

Calhoun, A. and M. Gahl. 2006. Spatial and temporal patterns of amphibian diseases in Acadia 

National Park wetlands: causal factors and potential management strategies. 

Investigator’s annual report posted at 

http://rprs.nps.gov/research/ac/search/iars/IarSearch. 

Calhoun, A., J. Cormier, R. Owen, A. O’Connell, C. Roman and R. Tiner. 1994. The wetlands of 

Acadia National Park and vicinity. Maine Agricultural and Forest Experiment Station 

Miscellaneous Publication 721. 108 pp. 

Cameron, D.. 2000. Invasive Plant Survey Atlas. Maine Natural Areas Program, Department of 

Conservation, Augusta, Maine. 

Cammen, L. and P. Larsen. 1992. An ecological characterization of intertidal resources of 

Acadia National Park: macrofauna. Technical Report NPS/NAROSS/NRT-92/06, 

National Park Service. 

Campbell, C. and 13 others. 1995. Checklist of Vascular Plants of Maine, 3rd Rev. Bull. 844, 

Maine Agricultural and Forest Experiment Station, Orono, ME. 

Campbell, J. and 12 others. 2004. Input-output budgets of inorganic nitrogen for 24 forest 

watersheds in the northeastern United States: a review. Water, Air, and Soil Pollution 

151: 373-396. 

Cameron, D. 2000. Aquatic vegetation survey for selected Maine lakes. Maine Natural Areas 

Program, Department of Conservation. Augusta. 134 p. 

Carlton, J. 2004. A checklist of the introduced marine and estuarine organisms on the coast of 

Maine, USA. Unpublished report. Marine Studies Program, Williams College, Mystic, 

Connecticut. Accessible at www.seagrant.umaine.edu/documents/pdf/invchk.pdf. 

Carlton, J., G. Vermeij, D. Lindberg, D. Carlton and E. Dudley. 1991. The first historical 

extinction of a marine invertebrate in an ocean basin: the demise of the eelgrass limpet 

Lottia alveus. Biological Bulletin 180(1): 72-80. 
171 

Caron, H.J. 2005. Groundwater hydrology and chemistry of Fresh Meadow Wetland, Acadia 

National Park, Maine, USA. M.S. thesis, University of Maine, Orono. 97 p. 

Castro, M.S. and C.T. Driscoll. 2002. Atmospheric nitrogen deposition to estuaries in the midAtlantic and northeastern United States. Environmental Science and Technology 36: 

3242-3249. 

Chalmers, R. 2004. Wetland and Nest Scale Habitat Use by the Four-toed Salamander 

(Hemidactylium scutatum) in Maine, and a Comparison of Survey Methods. M.S. thesis, 

University of Maine, Orono. 

Chalmers, R. and C. Loftin. 2006. Wetland and habitat use by nesting four-toed salamanders in 

Maine. Journal of Herpetology 40(4): 478-485. 

Chappelka, A.H. and L.J. Samuelson. 1998. Ambient ozone effects on forest trees of the eastern 

United States: a review. New Phytologist 139 (1): 91-108. 

Chase, G. E., L.L. Gregory, and J. Halperin. 2002. Acadia National Park Purple Loosestrife 

Management Program. 2001 Annual Summary. Acadia National Park Natural Resources 

Report # 2002-01. 

Chase, J.E., and 11 others. 1997. Gulfwatch: monitoring spatial and temporal patterns of trace 

metals and organic contaminants in the Gulf of Maine (1991-1997) with the blue mussel 

(Mytilus edulis L.). Marine Population Bulletin 42: 491-505. 

Chilelli, M., J.R. Gilbert, B. Griffith and A. O’Connell. 1994. Analysis of factors affecting 

population viability and reintroduction attempts of native mammals in Acadia National 

Park. Report to Acadia National Park. 

Coleman, M.A. and S.H. Brawley. 2005. Spatial and temporal variability in dispersal and 

population genetic structure of a rockpool alga. Marine Ecology Progress Series 300, 63-

77. 

Connery, B. 1998. A compilation of wildlife research recommendations at Acadia National Park. 

Unpublished report, Acadia National Park. 

 

Cowardin, L.M., V. Carter, F.C. Golet and E.T. LaRoe. 1979. Classification of wetlands and 

deepwater habitats of the United States. FWS/OBS-79/31. Washington D.C: U.S. Fish 

and Wildlife Service. 103p. 

Creed, J. and G. Amado Filho. 1999. Disturbance and recovery of the macroflora os a seagrass 

(Halodule wrightii Ascherson) meadow in the Abrohos Marine National Park, Brazil: an 

experimental evaluation of anchor damage. Journal of Experimental Marine Biology and 

Ecology 235: 285-306. 
172 

Culbertson, C.W., T.G. Huntington and J.M. Caldwell. 2007. Nutrient enrichment in estuaries 

from discharge of shallow ground water, Mt. Desert Island, Maine. U.S. Geological 

Survey Scientific Investigations Report 2007-5188. 34 p. ONLINE ONLY 

Cunningham, J.M. 2003. Pond-breeding amphibian distributions in a beaver-modified landscape, 

Acadia National Park, Mount Desert Island, ME. M.S. thesis, University of Maine, 

Orono. 

Cunningham, J.M., A. Calhoun and W. Glanz. 2006. Patterns of beaver colonization and wetland 

change in Acadia National Park. Northeastern Naturalist 13(4): 583-596. 

Davies,, S., L. Tsomides, J. DiFranco and D. Courtemanch. 1999. Biomonitoring retrospective: 

fifteen year summary for Maine rivers and streams. Maine Dept. of Environmental 

Protection, Augusta, Maine. 

Dawes, C., J. Andorfer, C. Rose, C. Uranowski, and N. Ehringer. 1997. Regrowth of the seagrass 

Thalassia testudinum into propeller scars. Aquatic Botany 59: 139-155. 

Decker, K. L. and R. E. J. Boerner. 1997. Ca:Al ratio effects on growth and competitive 

interactions of northern Red Oak (Quercus rubra) and yellow poplar (Liriodendron 

tulipifera). Journal of the Torrey Botanical Society 124: 286-296. 

Delaney, D. 2006. Predicting and monitoring the spread of marine invasive species: development 

of approaches and application to the European green crab and the Asian shore crab. 

Investigator’s annual report, accessed at 

http://rprs.nps.gov/research/ac/search/iars/Iar?reportId=37291. 

Devine, H.A., W.A. Millinor, E. Eastman. 2006. Acadia National Park fire fuels database. 

Final Technical Report to National Park Service, Cooperative Agreement 4560C0027, 

Task Agreement 006. North Carolina State University. 

Diamond, S. and 13 others. 2005. Estimated ultraviolet radiation doses in wetlands in six 

national parks. Ecosystems 8: 462-477. 

Dieffenbacher-Krall, A.C. 1998. Aquatic plants in quaternary science. Ph.D. thesis. University 

of Maine, Orono. 205 p. 

Doering, P.H. and C.T. Roman. 1994. Nutrients in Somes Sound and the associated watershed, 

Mount Desert Island, Maine. Technical report NPS/NAROSS/NRTR-94/22. National 

Park Service, North Atlantic Region. 

Doering, P.H., C.T. Roman, L.L. Beatty, A.A. Keller and C.A. Oviatt. 1995. Water quality and 

habitat evaluation of Bass Harbor Marsh, Acadia National Park, Maine. Technical 

Report NPS/NESORNR/NRTR/95-31. 
173 

Doggett, L.F., P. Larsen and S. Sykes. 1978. Intertidal bedrock areas of high species diversity in 

Maine, and their relevance to the Critical Areas Program. Maine State Planning Office 

Planning Report No. 55, Augusta, Maine. 

Driscoll, C.T., Y-J. Han, C.Y. Chen, D.C. Evers, K.F. Lambert, T.M. Holsen, N. Kamman, R.K. 

Munson. 2007. Mercury Contamination in Forest and Freshwater Ecosystems in the 

Northeastern United States. BioScience 57(1): 17-28. 

Dubuc, L.J., R. Owen and W. Krohn. 1988. Ecology of river otter on Mount Desert Island, 

Maine. National Park Service, Boston, MA. 

Dubuc, L., W. Krohn and R. Owen. 1990. Predicting occurrence of river otters by habitat on 

Mount Desert Island, Maine. Journal of Wildlife Management 54: 595-599. 

Dubuc, L., R. Owen, W. Krohn and C. Schell. 1991. Foods and distribution of river otters on 

Mount Desert Island, Maine. Trans. N.E. Sect. Wildlife Society 48: 104-112. 

Dudley, R.W., V.G. Panchang, and C.R. Newell. 2000. Application of a comprehensive 

modeling strategy for the management of net-pen aquaculture waste transport. 

Aquaculture 187: 319-349. 

Eckert, R., R. Kohut, R., T. Lee, T. and K. Stapelfeldt. 1997. Studies to assess the effects of 

ozone on native vegetation of Acadia National Park. 1996 Annual Report. University of 

New Hampshire and Boyce Thompson Institute for Plant Research, Ithaca NY. 

Eckhoff, J. D., G.B. Wiersma and J. A. Elvir. 2003. Forest vegetation monitoring in Acadia 

National Park. Maine Agricultural and Forest Experiment Station, The University of 

Maine. Technical Bulletin 187. 

Ericksen, J. A. et al. 2003. Accumulation of atmospheric mercury in forest foliage. 

Atmospheric Environment 37: 1613-1622. 

Evers, D. C. 2005. Mercury connections: The extent and effects of mercury pollution in 

northeastern North America. Biodiversity Research Institute, Gorham, Maine. 

Farris, C.N. and C.A. Oviatt. 1999. Changes in metabolic rates under fluctuating salinity regimes 

for two subtidal estuarine habitats. Estuaries 22: 126-137. 

Fefer, S.I. and P.A. Schettig. 1980. An Ecological Characterization of Coastal Maine (North and 

East of Cape Elizabeth), Volume 1–4. FWS/OBS-80/29. U.S. Fish and Wildlife Service, 

Newton Corner, Massachusetts. 

Fernandez, I.J., L.E. Rustad, S.A. Norton, J.S. Kahl and B.J. Cosby. 2003. Experimental 

acidification causes soil base-cation depletion at the Bear Brook Watershed in Maine. 

Soil Science Society of America Journal 67: 1909-1919. 
174 

Finzi, A. G. et al. 1998. Canopy tree-soil interactions within temperate forests: Species effects 

on pH and cations. Ecological Applications 8: 447-454. 

Folger, D.C. 1986. Acadia National Park colonial waterbird inventory: 1985. Unpublished report 

to Acadia National Park. 

Fuller, A. and D. Harrison. 2002. Deer use on Mount Desert Island. Report to Acadia National 

Park. 42 p. 

Fuller, A. and D. Harrison. 2003. Occurrence, distribution, and survey methods for native 

terrestrial mammals in Acadia National Park, Mount Desert Island, Maine. Maine 

Agricultural and Forest Experiment Station, Miscellaneous Publication 752. 

Fuller, J.L. and G.P. Cooper. 1946. A biological survey of the lakes and ponds of Mount Desert 

Island, and the Union and Lower Penobscot river drainage systems. Maine Department 

of Inland Fisheries and Game. 

Frescholtz, T. F. et al. 2003. Assessing the source of mercury in foliar tissue of Quaking Aspen. 

Environmental Toxicology and Chemistry 22: 2114-2119. 

Gahl, M. 2007. Spatial and temporal patterns of amphibian disease in Acadia National Park 

wetlands. Ph.D. dissertation, University of Maine, Orono. 

Garnas, J. 2005. European fire ants on Mount Desert Island,Maine: population structure, 

mechanisms of competition and community impacts of Myrmica rubra L. (Hymenoptera: 

Formicidae). M.S. thesis, University of Maine, Orono, ME. 

Gilbert, J. R. and J. A. Harrison. 1982. Influence of white-tailed deer on vegetation of Mt. Desert 

Island, Acadia National Park. US Department of the Interior, National Park Service, 

North Atlantic Region. 

Goldman, C.R. 1988. Primary productivity, nutrients, and transparency during the early onset of 

eutrophication in ultra-oligotrophic Lake Tahoe, California-Nevada. Limnology and 

Oceanography 33: 1321-1333. 

Graydon, J.A., V. St. Louis, S. Lindberg, H. Hintelmann and D.P. Krabbenhoft. 2007. 

Investigation of Mercury Exchange between Forest Canopy Vegetation and the 

Atmosphere Using a New Dynamic Chamber. Environmental Science and Technology 

40: 4680-4688. 

Greene, C.W., C.B. Hellquist, and L.Gregory, Linda. 1997. Survey of freshwater aquatic 

vegetation of Acadia National Park. National Park Service, College of the Atlantic. Bar 

Harbor, Maine. 76 pp. 
175 

Greene, C. W., J.E. Weber, and S. C. Rooney. 2002. Rare Plant Monitoring in Acadia National 

Park. Technical Report NPS/BSO-RNR/NRTR/2002-10, Department of the Interior, 

Acadia National Park, Boston Support Office. 

Greene, C. W., J.E. Weber, S.C. Rooney, and K. B. Anderson. 2004. Invasive plant species 

distribution and abundance in Acadia National Park. Unpublished Technical Report. 

Greene, C. W., Gregory, L. L., Mittelhauser, G. H., Rooney, S. L., and J. E. Weber. 2005. 

Vascular flora of the Acadia National Park region, Maine. Rhodora 107: 117-185. 

Grigal, D.F. 2002 Inputs and outputs of mercury from terrestrial watersheds: a review. 

Environmental Reviews 10: 1-39. 

Groden, E., F.A. Drummond, J. Garnas and A. Francecour. 2005. Distribution of an invasive ant, 

Myrmica rubra (Hymenoptera: Formicidae), in Maine. Journal of Economic Entomology 

98(6): 1774-1784. 

Gulf of Maine Council on the Marine Environment. 2007. American Eels: Restoring a Vanishing 

Resource in the Gulf of Maine. www.gulfofmaine.org. 12 pp. 

Haines, A. and T. F. Vining.1998. Flora of Maine. A manual for idenitification of native and 

naturalized vascular plants of Maine. V. F. Thomas and Co., Bar Harbor, ME. 

Haines, T. and H. Webber. 1999. An assessment of contaminant threats at Acadia National Park. 

Report submitted to National Park Service. 74 p. 

Heath, R. H., J. S. Kahl, et al. 1992. Episodic Stream Acidification Caused by Atmospheric 

Deposition of Sea Salts at Acadia National-Park, Maine, United-States. Water Resources 

Research 28: 1081-1088. 

Heath, R.H., J.S. Kahl, S.A. Norton and W.R. Brutsaert. 1993. Elemental mass balances and 

episodic and ten-year changes in the chemistry of surface water, Acadia National Park, 

Maine: final report. Technical Report NPS/NAROSS/NRTR-93/16. National Park 

Service, North Atlantic Region, Boston, Massachusetts. 111 p. 

Hintelmann, H., R.H.A. Harris, J.P. Hurley, C.A. Kelly, D.P. Krabbenhoft, S. Lindberg, J.W.M. 

Rudd, K.J. Scott, V.L. St. Louis. 2002. Reactivity and mobility of new and old mercury 

deposition in a boreal forest ecosystem during the first year of the METAALICUS study. 

Environmental Science and Technology 36: 5034–5040. 

Hodgkins, G., R. Dudley, and T. Huntington. 2003. Changes in the timing of high river flows in 

New England over the 20th century. Journal of Hydrology 278: 244–252. 

Hunter, M., A. Calhoun and M. McCullough. 1999. Maine Amphibians and Reptiles. University 

of Maine Press, Orono, Maine. 
176 

Huntington, T. 2003. Climate warming could reduce runoff significantly in New England. 

Agricultural and Forest Meteorology 117: 193-201. 

Huntington, T., G. Hodgkins, B. Keim and R.Dudley. 2004. Changes in the proportion of 

precipitation occurring as snow in New England (1949–2000). Journal of Climate 17(13): 

2626–2636. 

Jacobi, C. 2000. Visitor use of Anemone Cave – Summer 1999. ANP Natural Resources 

Report 2000-4. 

Jacobi, C. 2001(a). A census of vehicles and visitors to Cadillac Mountain, Acadia National 

Park, August 14 2001. ANP Natural Resources Report Number 2001-11. 

Jacobi, C. 2001(b). Hiker use of mountain summits in Acadia National Park: 1999, 2000, and 

2001. ANP Natural Resources Report 2001-8. 

Jacobi, C. 2003(a). A census of vehicles and visitors to Cadillac Mountain, Acadia National 

Park, August 1, 2002. ANP Natural Resources Report 2002-05. 

Jacobi, C. 2003(b). Monitoring visitor capacity for Acadia National Park carriage roads, 2002. 

ANP Natural Resource Report 2003-02. 10 p. 

Jacobi, C. 2003(c). Hiker use of mountain summits in Acadia National Park, 2002-2003. ANP 

Natural Resouce Report 2003-15. 

Jacobi, C. 2003(d). A census of hiking trail use in Acadia National Park, August 5 and 6, 2003. 

ANP Natural Resources Report 2003-10. 12 p. 

Jagels, R., J. Carlisle, R. Cunningham, S. Serreze and P. Tsai. 1989. Impact of fog and ozone in 

coast red spruce. Water, Soil and Air Pollution 48: 193-208. 

Jagels, R., M. Jiang, et al. 2002. Red spruce canopy response to acid fog exposure. 

Atmospheric Research 64: 169-178. 

Jakob, E., D. Jennings and J. Houser. 2005. Linyphia triangularis: An Exotic Spider with 

Potential Adverse Impacts on the Invertebrate Fauna of Acadia National Park. 

Investigator’s Annual Report, accessed at 

http://rprs.nps.gov/research/ac/search/iars/Iar?reportId=33909. 

Jaworski, N., R. Howarth and L. Hetling. 1997. Atmospheric deposition of nitrogen oxides onto 

the landscape contributes to coastal eutrophication in the Northeastern United States. 

Environmental Science and Technology 31(7): 1995-2004. 

Jennings, D.T., K.M. Catley and F. Graham. 2002. Linyphia triangularis, a palearctic spider 

(Araneae, Linyphiidae) new to North America. Journal of Arachnology 30: 455-460. 
177 

Jiang, M. and R. Jagels. 1999. Detection and quantification of changes in membrane-associated 

calcium in red spruce saplings exposed to acid fog. Tree Physiology 19: 909-916. 

Johnson, D. and A. Skutch. 1928a. Littoral vegetation on a headland of Mt. Desert Island, Maine. 

Submersible or strictly littoral vegetation. Ecology 9: 188-215. 

Johnson, D. and A. Skutch. 1928b. Littoral vegetation on a headland of Mt. Desert Island, 

Maine. II. Tidepools and the environment and classification of submersible plant 

communities. Ecology 9: 307-338. 

Johnson, D. and A. Skutch. 1928c. Littoral vegetation on a headland of Mt. Desert Island, Maine. 

III. Adlittoral or non-submersible region. Ecology 9: 429-450. 

Johnson, K.B. 2002. Fire and its effects on mercury and methylmercury dynamics for two 

watersheds in Acadia National Park, Maine. M.S. Thesis, University of Maine, Orono, 

Maine. 

Johnson, K. B., T.A. Haines, J.S. Kahl, S.A. Norton, A. Amirbahman, and K.D. Sheehan. 2007. 

Controls on mercury and methylmercury deposition for two watersheds in Acadia 

National Park, Maine. Environmental Monitoring and Assessment 126: 55-67. 

Johnson, D.W., J.A. Benesch, M.S. Gustin, D.S. Schorran, S.E. Lindberg and J.S. Coleman. 

2003. Experimental evidence against diffusion control of Hg evasion from soils. The 

Science of the Total Environment 304: 175-184.

Jones, S.H., and P.G. Wells. 2002. Gulf of Maine Environmental Quality Monitoring 

Workshop: Summary Report. Gulf of Maine Council on the Marine Environment, 

www.gulfofmaine.org. 

Jordaan, A. 2006. Determining environmental drivers of fish community structure along the 

coast of Maine. Ph.D. dissertation, University of Maine, Orono.

Kahl, J.S., S.A. Norton, T.A. Haines, E.A. Rochette, R.H. Heath and S.C. Nodvin. 1992. 

Mechanisms of episodic acidification in low-order streams in Maine, USA. 

Environmental Pollution 78: 37-44. 

Kahl, J.S., D. Manski, M. Flora and N. Houtman. 2000. Water resources management plan, 

Acadia National Park. National Park Service. 

Kahl, J.S, I. Fernandez, S. Norton, G.B. Wiersma and G. Jacobson. 2003. Final integrated report: 

Establishing paired gauged watersheds at Acadia National Park for long-term research on 

acidic deposition, nitrogen saturation, forest health, and mercury biogeochemistry (1998-

2002). University of Maine, Orono. 

Kahl, J.S., S.J. Nelson, J.L. Stoddard, S.A. Norton and T.A. Haines. 2004. Lakewater chemistry 

at Acadia National Park, Maine, in response to declining acidic deposition. In: D. 
178 

Harmon, B.M. Kilgore, and G.E. Vietzke, eds. Protecting Our Diverse Heritage: The 

Role of Parks, Protected Areas, and Cultural Sites. The George Wright Society. 

Kahl, J.S., J.L. Stoddard, S.G.,Haeuber, S.G. Paulsen, F.A. Deviney, J.R. Webb, D.R. DeWalle, 

W. Sharpe, C.T. Driscoll, A.T. Herlihy, J.H. Kellogg, P.S. Murdoch, K. Roy, K.E. 

Webster and N.S. Urquhart. 2004. Have U.S. surface waters responded to the 1990 Clean 

Air Act Amendments? Environmental Science and Technology 38 (24): 484A-490A. 

Kahl, J.S., S.J. Nelson, I. Fernandez, T. Haines, S. Norton, G.B. Wiersma, G. Jacobson, A. 

Amirbahman, K. Johnson, M. Schauffler, L. Rustad, K. Tonnessen, R. Lent, M. Bank, J. 

Elvir, J. Eckhoff, H. Caron, P. Ruck, J. Parker, J. Campbell, D. Manski, R. Breen, K. 

Sheehan and A. Grygo. 2007a. Watershed Nitrogen and Mercury Geochemical Fluxes 

Integrate Landscape Factors in Long-term Research Watersheds at Acadia National Park, 

Maine, USA. Environmental Monitoring and Assessment 126 (1-3): 9-25. 

Kahl, J.S., S.J. Nelson and I.J. Fernandez. 2007b. Understanding Atmospheric Deposition to 

Complex Landscapes at Acadia National Park, Maine 2002-2005. Technical Report 

NPS/NER/NRTR—2007/080. National Park Service. Boston, MA. 

Keats, R.A. 2002. The Effect of Nitrogen Loading on an Estuarine Faunal Community: A Stable 

Isotope Approach. M.S. Thesis, University of Maine, Orono, ME. 

Kimball, K. D., R. Jagels, G. A. Gordon, K. C. Weathers, and J. Carlisle. 1988. Differences 

between New England coastal fog and mountain cloud water chemistry. Water Air Soil 

Pollution 39:383-393.

Kinney, E.H. and C.T. Roman. 1998. Response of primary producers to nutrient enrichment in 

a shallow estuary. Marine Ecology Progress Series 163: 89-98.

Kittredge, L. 1996. A geochemical analysis of lake waters and soils associated with three 

granites of variable fluoride concentration in Maine and New Hampshire, USA. M.S. 

thesis, Univerisity of Maine, Orono. 95 p. 

Kohut, R., J. Laurence, P. King and R. Raba. 2000. Identification of bioindicator species for 

Ozone and assessment of the responses to Ozone of native vegetation at Acadia National 

Park. Department of the Interior, National Park Service. 

Letcher, B., M. Gallagher, B. Connery, M. O’Donnell, J. Zydlewski, J. McKenna and T. 

Dubreuil. 2006. Scoping project for sea-run brook trout studies. Investigator’s annual 

report, accessed at http://rprs.nps.gov/research/ac/search/iars/Iar?reportId=38777. 

Lindberg, S.E., J.G. Owens and W.J. Stratton. 1994. Application of Throughfall Methods to 

Estimate Dry Deposition of Mercury. In: Watras, C.J. and Huckabee, J.W. (eds), Mercury 

as a Global Pollutant: Integration and Synthesis, Lewis Publishers, Boca Raton, pp. 261-

271. 
179 

Lindberg, S., R. Bullock, R. Ebinghaus, D. Engstrom, X. Feng, W. Fitzgerald, N. Pirrone, E. 

Prestbo and C. Seigneur. 2007 A synthesis of progress and uncertainties in attributing the 

sources of mercury in deposition. Ambio 36 (1): 19-32. 

Little, A.M. 2005. The effects of beaver inhabitation and anthropogenic activity on freshwater 

wetland plant community dynamics on Mount Desert Island, Maine, USA. Ph.D. 

dissertation, University of Wisconsin-Madison, Madison, WI. 

Littlejohn, M. 1999. Acadia National Park: Visitor Study. Summer 1998. Visitor Services 

Project, Cooperative Park Studies Unit, University of Idaho. 

http://psu.uidaho.edu/files/vsp/reports/108_ACAD_rept.pdf

Long, R.A. 1995. Annual survival and cause-specific mortality of white-tailed deer fawns, and 

relative abundance of snowshoe hare on Mount Desert Island, Maine. M.S. thesis, 

University of Maine, Orono. 

Long, R.A., A.F. O’Connell and D.J. Harrison. 1998. Mortality and survival of white-tailed 

deer, Odocoileus virginianus, fawns on a north Atlantic coastal island. Wildlife Biology 

4: 237-247. 

Longcore, J.R., R. Dineli and T.A. Haines. 2007a. Mercury and Growth of Tree Swallows at 

Acadia National Park, and at Orono, Maine, USA. Environmental Monitoring and 

Assessment 126 (1-3): 117-127. 

Longcore, J.R., T.A. Haines and W.A. Halteman. 2007b. Mercury in Tree Swallow Food, Eggs, 

Bodies, and Feathers at Acadia National Park, Maine, and an EPA Superfund Site, Ayer, 

Massachusetts. Environmental Monitoring and Assessment 126 (1-3): 129-143. 

Lovett, G. M. and M. J. Mitchell. 2004. Sugar maple and nitrogen cycling in the forests of 

eastern North America. Frontiers in Ecology and the Environment 2: 81-88. 

Lovett, G. M. et al. 2004. Nitrogen cycling in a northern hardwood forest: Do species matter? 

Biogeochemistry 67: 289-308. 

Lovett, G. M. et al. 2006. Forest ecosystem responses to exotic pests and pathogens in eastern 

North America. BioScience 56: 395-405. 

Lubinski, S., K. Hopp and S. Gawler. 2003. U.S. Geological Survey – National Park Service 

vegetation mapping program. Acadia National Park. U.S. Geological Survey, Upper 

Midwest Environmental Sciences Center, La Crosse, Wisconsin. Maine Natural Areas 

Program, Augusta, Maine. 274p. http://biology.usgs.gov/npsveg/acad/report.pdf

Lyon, J. and W. E. Sharpe. 1999. An assessment of the Ca:Al ratios of selected Pennsylvania 

forest soils. Water, Air, and Soil Pollution 109: 53-65. 

MacArthur, H. and W. Drury. 1977. A preliminary study of human impact on a shoreline area 

of Acadia National Park. Unpublished report, College of the Atlantic, Bar Harbor. 19 p. 
180 

Mack, R.G. 1988. A survey of the mayflies (Ephemeroptera) of Acadia National Park, Mount 

Desert Island, Maine. M.S. thesis, University of Maine, Orono. 102 pp. 

Maine Natural Areas Program. 2004. Draft List of Invasive Plant Species of Maine. On-line 

data accessed in 03/07 from 

http://www.mainenaturalareas.org/docs/rare_plants/links/plant_list.pdf. 

Maniero, T. and B. Breen. 2004. Acadia National Park: Assessment of long-term air quality 

programmatic, monitoring and research needs. National Park Service, Acadia National 

Park. 75 p. 

Manning, R., C. Jacobi and J.L. Marion. 2006. Recreation monitoring at Acadia National Park. 

The George Wright Forum 23(2): 59-72. 

Manski, D. 1998. Resource management plan, Acadia National Park. National Park Service. 

38 p. 

Marion, J. 2006. Monitoring protocols and indicators for assessing campsite and trail 

conditions: Isle au Haut, Acadia National Park. Research / Natural Resources 

Management Report, draft. National Park Service. 98 p. 

Mathieson, A. C., C. J. Dawes, & E. J. Hehre. 1998. Floristic and zonation studies of seaweeds 

from Mount Desert Island, Maine: An historical comparison. Rhodora 100(904): 333-

379. 

Matz, A.C., S.E. Dooling, and J.R. Gilbert. 1997. Disturbance at selected Bald Eagles nests in 

and near Acadia National Park, 1993-1994. Technical Report NPS/NESO-RNR/NRTR 

97-05. National Park Service, Boston, MA. 

McLaughlin, F. L. 1968. Ecological relationships of white-tailed deer and vegetation at Acadia 

National Park. M.S. Thesis. University of Maine, Orono. 106p. 

McNulty, S. G. et al.. 1991. Spatial changes in forest floor and foliar chemistry of spruce-fir 

forests across New England. Biogeochemistry 14: 13-29. 

McNulty, S.G., J.D. Aber, T.M. McLellan and S.M., Katt. 1990. Nitrogen cycling in high 

elevation forests of the northeastern US in relation to nitrogen deposition. Ambio 19: 38-

40. 

McNulty, S. G., J. Boggs, et al. 2005. Red spruce ecosystem level changes following 14 years of 

chronic N fertilization. Forest Ecology and Management 219: 279-291. 

MDDS. 2005. Maine Damselfly and Dragonfly Survey database, provided to Maine Aquatic 

Biodiversity Project database by P. Brunnelle, P. DeMaynadier and R. Butler. 
181 

MDEP. 2004. 2004 integrated water quality monitoring and assessment report. Maine 

Department of Environmental Protection, Augusta. Document # DEPLW0665. 243 pp. + 

app. 

MDEP. 2007. Biomonitoring internet mapping project Web site 

(http://www.maine.gov/dep/blwq/docmonitoring/biomonitoring/biomaps/index.htm). ME 

Dept. of Environmental Protection. Accessed 8/2007. 

MDEP. 2007. Known locations of invasive aquatic plants in Maine. On-line map accessed May 

2007: http://www.maine.gov/dep/blwq/topic/invasives/invasivesmap.pdf. 

Miller, E., A. Vanarsdale, G. Keeler, A. Chalmers, L. Poissant, N. Kamman and R. Brulotte. 

2005. Estimation and Mapping of Wet and Dry Mercury Deposition Across Northeastern 

North America. Ecotoxicology 14: 53-70. 

Miller, E.K. 2006. Assessment of Forest Sensitivity to Nitrogen and Sulfur Deposition in Maine. 

Report to Maine Department of Environmental Protection by Ecosystems Research 

Group, Ltd. Norwich, VT, December 16, 2006. 20 pp. 

Mitchell, B., W. Shriver, F. Dieffenbach, T. Moore, D. Faber-Langendoen, G. Tierney, P. 

Lombard, and J. Gibbs. 2006. Northeast Temperate Network Vital Signs Monitoring 

Plan. Technical Report NPS/NER/NRTR--2006/059. National Park Service, Northeast 

Temperate Network, Woodstock, Vermont. 

Mittelhause, G. and D. Kelly. 2007. Inventory of marine flora in Frenchman Bay and Blue Hill 

Bay, Maine, 1926-1932: catalogue of William Procter’s marine collections. Maine 

Natural History Observatory, Gouldsboro, Maine. 

Mittelhauser, G., J. Connery and J. Jacobs. 1996. Inventories of selected flora and fauna on 10 

islands of Acadia National Park, Maine. Natural Resources Technical Report 

NPS/NESO-RNR/NRTR/96-01, National Park Service, New England System Support 

Office, Boston, MA. 

Muhlin, J.F. 2007. Reproductive ecology and characterization of population genetic structure of 

Fucus vesiculosus Linnaeus in the Northwestern Atlantic. Ph.D. dissertation, University 

of Maine, Orono. 

Muhlin, J.F., C.R. Engel, R. Stessel, R. A. Weatherbee, and S.H. Brawley. 2008. The influence 

of coastal topography, circulation patterns, and rafting in structuring populations of an 

intertidal alga. Molecular Ecology 17, 1198 – 1210. 

Munthe, J., R.A. Bodaly, B.A. Branfireun, C.T. Driscoll, C.C. Gilmour, R. Harris, M. Horvat, M. 

Lucotte and O. Malm. 2007. Recovery of Mercury-Contaminated Fisheries. Ambio 36(1): 

33-44. 
182 

National Park Service (NPS). 1992. General management plan, Acadia National Park, ME. 

United States Department of the Interior, National Park Service, North Atlantic Region. 

Boston, MA. 

National Park Service (NPS). 1997. The Visitor Experience and Resource Protection (VERP) 

framework: A handbook for planners and managers (Publication No. NPS D-1215). 

Denver, CO:USDI National Park Service, Denver Service Center. 

National Park Service (NPS). 2003. A visitor use management strategy for the Mount Desert 

Island section of Acadia National Park. Acadia National Park Natural Resource Report 

2003-03. 11 p. 

National Park Service (NPS). 2004. Revised land protection plan, Acadia National Park. 

National Park Service. 

National Park Service. 2006 (NPS). Air quality trends and conditions in national parks: 2006 

annual performance and progress report, October 2007. 

http://www2.nature.nps.gov/air/Pubs/pdf/gpra/GPRA_AQ_ConditionsTrendReport2006.

pdf

Neal, B.P., S. Fitzhenry, K. Porter, H. Backman, P. Gasperini, R. Alley and S. Alley. 2003. 

Eastern Gulf of Maine Atlantic Herring Spawning Area Survey: Project Year 6 

Summary. Island Institute, Rockland, Maine. 

NEARMI. 2007. Northeast Amphibian and Research and Monitoring Initiative, United States 

Geological Survey, Website. http://www.pwrc.usgs.gov/nearmi/ (accessed 8/2007). 

Neckles, H.A., F.T. Short, S. Barker and B. Kopp. 2003. Effects of commercial fishing on 

eelgrass in New England: characterization of impacts and measurements of regrowth. 

Report to USGS Eastern Regional Office – State Partnership Project. Maine Department 

of Marine Resources Project Report, Project No. 00HQAG0021. 

Neckles, H., A. Gilbert, G. Guntenspergen, N. Danz, T. Hollenhorst, A. Little and J. Olker. 2007. 

Protocol for monitoring freshwater wetlands in national parks of the Northeast Temperate 

Network. Draft report. U.S. Department of the Interior and U.S. Geological Survey. 

Nedeau, E.J., M. McCollough and B. Swartz. 2000. The Freshwater Mussels of Maine. Maine 

Department of Inland Fisheries and Wildlife, Augusta, Maine. 118 p. 

Nelson, S.J. 2002. Determining atmospheric deposition inputs to two small watersheds at Acadia 

National Park. M.S. thesis, University of Maine, Orono, Maine. 163 p. 

Nelson, S.J., K. Johnson, J.S. Kahl, T. Haines, and I. Fernandez. 2007. Mass balances of mercury 

and nitrogen in burned and unburned forested watersheds at Acadia National Park, 

Maine. Environmental Monitoring and Assessment 126(1-3): 69-80. 
183 

Nelson, S.J., K.B. Johnson, K.C. Weathers, C.S. Loftin, I.J. Fernandez, J.S. Kahl and D.P. 

Krabbenhoft. 2008. A comparison of winter mercury accumulation at forested and nocanopy sites measured with different snow sampling techniques. Applied Geochemistry 

23(3): 384-398. 

Nielsen, M. 2002a. Estimated quantity of water in fractured bedrock units on Mt. Desert Island, 

and estimated ground-water use, recharge, and dilution of nitrogen in septic waste in the 

Bar Harbor area, Maine. Open-file report 02-435. U.S. Geological Survey, Augusta, 

Maine. 45 p. 

Nielsen, M.G. 2002b. Water budget for and nutrient loads to Northeast Creek, Bar Harbor, 

Maine. U. S. Geological Survey Water-Resources Investigations Report 02-4000 (p. 32). 

Augusta, Maine: U.S. Geological Survey. 

Nielsen, M., J.M. Caldwell, C.W. Culbertson and M. Handley. 2002c. Hydrologic data collected 

in small watersheds on Mount Desert Island, Maine, 1999-2000. United States 

Geological Survey, Augusta, Maine. Open File Report 02-416. 10 p + app. 

Nielsen, M.G., G.R. Guntenspergen and H.A. Neckles. 2006. Using hydrogeomorphic criteria to 

classify wetlands on Mt. Desert Island, Maine—approach, classification system, and 

examples. U.S. Geological Survey Scientific Investigations Report 2005-5244. 27 p.

Nielsen, M. and J.S. Kahl. 2007. Nutrient export from watersheds on Mt. Desert Island, Maine, 

as a function of land use and fire history. Environmental Monitoring and Assessment 

126: 81-96. 

Nieratko, D.P. 1992. Factors controlling phosphorus loading to lakes in Maine: a statistical 

analysis. M.S. thesis, University of Maine, Orono. 

National Oceanic and Atmospheric Administration (NOAA). 1997. NOAA’s estuarine 

eutrophication survey. Volume 3: North Atlantic Region. Silver Spring, MD: Office of 

Ocean Resources, Conservation and Assessment. 45 p. 

Norton, S.A., G.C. Evans and J.S. Kahl. 1997. Comparison of Hg and Pb fluxes to hummocks 

and hollows of ombrotrophic Big Heath Bog and to nearby Sargent Mt. Pond, Maine, 

USA. Water, Air and Soil Pollution 100: 271-286. 

O’Connell, A.F. 2003. Giardia, giardiasis, and evaluation of the role of wildlife in transmission 

into human populations at Acadia National Park, Maine. National Park Sevice, Boston, 

MA. 

O’Connell, A.F., D.J. Harrison, B. Connery and K.B. Anderson. 1992. Food use by an insular 

population of coyotes. Northeast Wildlife 49: 36-42. 
184 

Olson, D.E. 2007. Characterization of a rocky intertidal shoreline within Acadia National Park: 

impact of short-term trampling and the implications for management. M.S. thesis 

proposal, University of Maine, Orono. 

Orwig, D. A. 2002. Ecosystem to regional impacts of introduced pests and pathogens: historical 

context, questions, and issues. Journal of Biogeography 29:1471-1474. 

Orwig, D. A. et al. 2002. Landscape patterns of hemlock decline in New England due to the 

introduced Hemlock Wooly Adelgid. Journal of Biogeography 29:1475-1487. 

Parker, J. L., I. J. Fernandez, et al. 2001. Effects of nitrogen enrichment, wildfire, and 

harvesting on forest-soil carbon and nitrogen. Soil Science Society of America Journal 

65: 1248-1255. 

Patterson, W. A. et al. 1983. Fire regimes of the coastal Maine forests of Acadia National Park. 

Publication OSS 83-3, US Dept. of the Interior, National Park Service, Boston, MA. 

Peckenham, J.M., J.S. Kahl and B. Mower. 2003. Background mercury concentrations in river 

water in Maine, U.S.A. Environmental Monitoring and Assessment 89: 129-152. 

Peckenham, J.M., J.S. Kahl and A. Amirbahman. 2006. The impact of vehicular traffic on water 

quality in Acadia National Park. Technical report NPS/NER/NRTR-2006/035. National 

Park Service, Boston, MA. 

Peckenham, J.M., J.S. Kahl, S.J. Nelson, K.B. Johnson and T.A. Haines. 2007. Landscape 

Controls on Mercury in Streamwater at Acadia National Park, USA. Environmental 

Monitoring and Assessment 126(1-3): 97-104. 

Percy, K.E., R. Jagels, S. Marden, C.K. McLaughlin and J. Carlisle. 1993. Quantity, chemistry, 

and wettability of epicuticular waxes on needles of red spruce along a fog-acidity 

gradient. Canadian Journal of Forest Research 23: 1472-1479. 

Perrin, S. 1996. Watersheds of Mount Desert Island, Maine. Unpublished report, Acadia 

National Park. 

Petraitis, P.S., S.R. Fegley and B.F. Beal. 2002. Ecological assessment of the Anemone Cave in 

Acadia National Park. Technical Report NPS/BSO-RNR/NRTR/2002-11. 

Pettigrew, N.R., D.A. Kistner, G.P. Barbin, A.K. Laursen, W. David and J. Christensen. 1997. 

Somes Sound: fjord or well-mixed estuary? Northeastern Naturalist 4: 35-44. 

Procter, W. 1946. Biological survey of the Mount Desert Region; Part VII. The Insect Fauna. 

Winstar Press, Philadelphia, PA. 
185 

Rea, A.W., S.E. Lindberg and G.J. Keeler. 2000. Assessment of dry deposition and foliar 

leaching of mercury and selected trace elements based on washed foliar and surrogate 

surfaces. Environmental Science and Technology 34: 2418-2425. 

Reeb, C.K. 1992. Distribution and ecology of river otter on Eastern Mount Desert Island, Maine. 

Unpublished Thesis (B.A.), University of Maine, 27 pp. 

Reid, J.M., J.A. Reid, C.J. Jenkins, M.E. Hastings, S.J. Williams, and L.J. Poppe. 2005. 

usSEABED: Atlantic Coast offshore surficial sediment data release: U.S. Geological 

Survey Data Series 118, version 1.0. (http://pubs.usgs.gov/ds/2005/118/). 

Reiner, D. and T. McLendon. 2002. Assessment of exotic plant species of Acadia National 

Park. Evaluation of potential impacts of known exotic plants and summary of 

management options for species of concern. Technical Report NPS/BSORNR/NRTR/2002-5. The Department of the Interior, National Park Service, Boston 

Support Office. 

Richardson, D.T. 1973. Distribution and abundance of harbor and gray seals, Acadia National 

Park area. Final report to National Park Service, contract # 14-10-9-900-380. 

Ritchie, C.D., W. Richards and P.A. Arp. 2006. Mercury in fog on the Bay of Fundy (Canada). 

Atmospheric Environment 40: 6321–6328. 

Roberts, V. A. and R.G. Dearborn, R. G. 1999. Light trapping as a measure of diversity and to 

monitor pest species in Acadia National Park, Bar Harbor, ME. Unpublished report 

(available at ACAD library). 

Rohweder, J.J., T.J. Fox, G.R. Guntenspergen, M.G. Nielsen and H.A. Neckles. 2004. Acadia 

National Park nutrient load and estuarine response decision support system: user’s 

manual. United States Geological Survey. May 2004 release. 74 p. 

Roman, C.T., N. Jaworski, F.T. Short, S. Findlay and R. Warren. 2000. Estuaries of the 

northeastern United States: Habitat and land use signatures. Estuaries 23: 743-764. 

Ross, D. S. et al. 2004. Mineralization and nitrification patterns at eight northeastern USA 

forested research sites. Forest Ecology and Management 188: 317-335. 

Rowe, E. C. et al. 2006. Vegetation type affects the relationship between soil carbon to nitrogen 

ratio and nitrogen leaching. Water, Air, and Soil Pollution 177: 335-347. 

Ruck, P.L. 2002. Cycling and speciation of mercury in soils at Cadillac Brook and Hadlock 

Brook Watersheds, Acadia National Park, Maine. M.S. Thesis, University of Maine, 

Orono, ME, 114 pp. 

Runde, J.M. 2007. "Draft Review of the Acadia National Park Lake Monitoring Program Part 

1: Statistical Overview." Natural Resource Report NPS/NRPC/NRTR—2007/xxx. 
186 

Runkle, J. R. 2005. Twenty-four years of change in an old Tsuga canadensis woods affected by 

beech bark disease. Journal of the Torrey Botanical Society 132: 483-491. 

Rutledge, C. R. and T. McLendon. 1996. An assessment of exotic plant species of Rocky 

Mountain National Park. Department of Rangeland Ecosystem Science, Colorado State 

University. 

Saeki, M. 1991. Influence of browsing by white-tailed deer and snowshoe hare on vegetation at 

Acadia National Park, Maine. M.S. thesis, University of Maine, Orono. 120 pp. 

Saeki, M. and D.J. Harrison. 1991. Effects of white-tailed deer on post-fire plants. Unpublished 

report to Acadia National Park. 

Schauffler, M., S.J. Nelson, J.S. Kahl, G.L. Jacobson, T.A. Haines, W.A. Patterson and K.B. 

Johnson. 2007. Paleoecological Assessment of Watershed History in PRIMENet 

Watersheds at Acadia National Park, USA. Environmental Monitoring and Assessment 

126 (1-3): 39-53. 

Schmitt, C. 2003. The effects of the 2001-2002 drought on maine surface water supplies. M.S. 

thesis, University of Maine, Orono.

Seger, E., W.G Gawley and R.M. Breen. 2006. Lake monitoring report: 2002-2005. National 

Park Service, Acadia National Park. 19p + app. 

Sheehan, K. D. 2005. Vegetative and landscape influences on forest litter mercury at Acadia 

National Park. MS Thesis. The University of Maine, Orono, ME, USA. 

Sheehan, K. D., I. J. Fernandez, et al. 2006. Litterfall mercury in two forested watersheds at 

Acadia National Park, Maine, USA. Water Air and Soil Pollution 170: 249-265. 

Sherman, S., K. Stepanek, J. Sowles, D. Grout and R. Tetrault. 2005. Fall 2003 and Spring 2004 

Maine-New Hampshire Inshore Trawl Survey. Final report submitted to The Northeast 

Consortium. Maine DMR Research Reference Document 05/02. 

Small, M.J. et al. 2005. Changes in a hemlock-dominated forest following wooly adelgid 

infestation in southern New England. Journal of the Torrey Botanical Society 132: 458-

470. 

Snook, H., S.P. Davies, J. Gerritsen, B.K. Jessup, R. Langdon, D. Neils, E. Pizutto. 2007. The 

New England Wadeable Stream Survey (NEWS): Development of Common Assessments 

in the Framework of the Biological Condition Gradient. Report to: USEPA Office of 

Science and Technology and USEPA Office of Watersheds Oceans and Wetlands, 

Washington, D.C. 20 pp. plus appendices. 

Stillman, R., A. West, J. Goss-Custard, R. Caldow, S. McGrorty, S. Durell, M. Yates, P. 

Atkinson, N. Clark, M. Bell, P. Dare and M. Mander. 2003. An individual behaviour-
187 

based model can predict shorebird mortality using routinely collected shellfishery data. 

Journal of Applied Ecology 40: 1090-1101. 

Stoddard, J., J. S. Kahl, F. Deviney, D. DeWalle, C. Driscoll, A. Herlihy, J. Kellogg, P. 

Murdoch, J. Webb and K. Webster. 2003. Response of surface water chemistry to the 

Clean Air Act Amendments of 1990. EPA/620/R-03/001, U.S. Environmental Protection 

Agency, Washington, DC. 78 pp. 

Stone, J., B. Le and J. Moring. 2007. Freshwater fishes of Acadia National Park, Mount Desert 

Island, Maine. Northeastern Naturalist 8(3): 311-318. 

Stubbs, C., F. Drummond and H. Ginsberg. 2005. Effects of invasive plant species on pollinator 

service and reproduction in native plants at Acadia National Park. Investigator’s annual 

report, accessed at http://rprs.nps.gov/research/ac/search/iars/Iar?reportId=36316. 

Stubbs, C.S., R. Jagels and R. Homola. 1988. Biomonitoring environmental quality: lichen 

distribution and health on red spruce (Picea rubens L.) in Maine. American Journal of 

Botany 75: 10-11. 

Sullivan, T.J. 1996. The lichens of Acadia National Park, Maine. Ph.D. dissertation, University 

of Minnesota, Minneapolis, MN. 

 

Thayer, G., W. Kenworthy, and M. Fonseca. 1984. The ecology of eelgrass meadows of the 

Atlantic coast: a community profile. U.S. Fish and Wildlife Service FWS/OBS-94/02, 

Washington, DC. 

Thayer, P.E. and J. Stahlnecker. 2006. Non-native invasive marine species in Maine. A report to 

the Maine State Legislature, Marine Resources Committee and Natural Resources 

Committee, February 1, 2006. ME Division of Marine Resources and Dept. of 

Environmental Protection.

Theisen, A.F., B.N. Rock and R.T. Eckert. 1994. Detection of changes in steady-state 

chlorophyll fluorescence in Pinus strobus following short-term ozone exposure. Journal 

of Plant Physiology 144: 410-419. 

Tierney, G. and D. Faber-Langendoen, 2006. 

http://www1.nature.nps.gov/im/units/netn/downloads/Phase3/Protocol_Forest_Condition.

pdf. 

Tierney, G.L., D. Faber-Langendoen, B.R. Mitchell, W.G. Shriver and J.P. Gibbs. In Press. 

Monitoring and evaluating the ecological integrity of forest ecosystems. Frontiers in 

Ecology and the Environment. 

Town of Bar Harbor. 2005. Draft comprehensive plan update. Unpublished report. 
188 

Townsend, D.W., N.R. Pettigrew and A.C. Thomas. 2005. On the nature of Alexandrium 

fundysense blooms in the Gulf of Maine. Deep-Sea Research II 52: 2603-2630. 

Turco, R.P. 2002. Earth under siege: from air pollution to global change. (2nd ed). Oxford 

University Press. 

USEPA. 1995. Anticipatory planning for sea-level rise along the Maine coast. U.S. 

Environmental Protection Agency. EPA-230-R-95-900. 

USEPA. 2001. Ambient water quality criteria recommendation. Information supporting the 

development of State and Tribal nutrient criteria--Rivers and streams in ecoregion VIII: 

U.S. Environmental Protection Agency Office of Water Publication number EPA 822-B01-015. 129 p. 

USGS. 2007. Bird checklists of the United States: Acadia National Park. Accessed from 

www.npwrc.usgs.gov/resource/birds/chekbird/r5/acadia.htm 7/20/2007. 

Vaux, P. 2005. Freshwater biodiversity in Maine: an assessment of aquatic systems and their 

ecological communities. Final report, Maine Aquatic Biodiversity Project. The Nature 

Conservancy, Maine Department of Environmental Protection, Maine Department of 

Inland Fisheries & Wildlife. 299 pp. + app. 

Venterea R, T. et al. 2003. Landscape patterns of net nitrification in a northern hardwoodconifer forest. Soil Science Society of America Journal 67:527-539. 

Vinck, J. 1993. Deer / automobile accidents. Unpublished thesis, College of the Atlantic, Bar 

Harbor, Maine. 

Wang, Y.Q., J. Nugranad-Marzilli and G. Bonynge. 2006. Impacts of land-cover change on the 

National Parks of the Northeast Temperate Network. Draft report, University of Rhode 

Island, National Park Service. 

Weathers, K.C., G.M. Lovett, G.E. Likens and R. Lathrop. 2000. The effect of landscape features 

on deposition to Hunter Mountain, Catskill Mountains, New York. Ecological 

Applications 10 (2): 528-540. 

Weathers, K.C., S.M. Simkin, G.M., Lovett and S.E. Lindberg. 2006. Empirical modeling of 

atmospheric deposition in mountainous landscapes. Ecological Applications 16(4): 1590–

1607. 

Webber, H.M. and T. Haines. 2003. Mercury effects on predator avoidance behavior of a forage 

fish, golden shiner (Notemigonus chyrsoleucas). Environmental Toxicology and 

Chemistry 22: 1556-1561. 

Wenner, N.G. and W. Merrill. 1998. Pathological anatomy of needles of Pinus strobus exposed 

to carbon-filtered aire or to three times ambient ozone concentrations, or infected by 

Canavirgella banfieldii. Canadian Journal of Botany 76: 1331-1339. 
189 

Wetmore, C.M. 1984. Lichens and air quality in Acadia National Park. Report for contract CX 

0001-2-0034. National Park Service, Denver CO. 

Whitcomb, S.D. 1993. Population characteristics patch occupancy and fall dispersal of spruce 

grouse on Mount Desert Island Maine. M.S. thesis, University of Maine, Orono. 

White, Harold B. 1989. Dragonflies and damselflies (Odonata) of Acadia National Park and 

vicinity, Maine. Entomological News 100: 89-103. 

Wilson, P., J. Longcore, J. Sauer and K. Anderson. Undated. Avian use of Northeast Creek and 

Bass Harbor Marsh on Mount Desert Island, Maine, 2001-2002. Unpublished draft 

report, provided by Acadia National Park. 

Xue, H., F. Chai and N. Pettigrew. 2000. A model study of the seasonal circulation in the Gulf of 

Maine. Journal of Physical Oceanography 30: 1111-1135. 
190 

Appendices 
Appendix 1. 

Land use / land cover statistics by watershed cluster. 

Watershed clusters are groups of small watersheds – cluster level C in Figure 4. Except 

for some coastal watersheds, clusters are defined by hydrology. 

Small watersheds include named and unnamed watersheds (Perrin 1996). For MDI 

watersheds, the following list identifies named watersheds by their cluster number in the 

table, below. (For each cluster, individual watersheds appear in order of size.) 

Land use/cover data are derived from the USGS / NPS Vegetation Mapping Project 

(Lubinski et al. 2003). 

________________________________________________________________________ 

MD1:1 Jones Marsh, North Coast 

MDI:2 Customhouse, Schooner Head, Great Head, Meadow Brook, Bar Harbor, 

Compass Harbor, Eddie Brook. 

MDI:3 Little Hunters Brook, Seal Harbor, Blackwoods, Otter Point, Northeast 

Harbor. 

MDI:4 Brown Mountain, Sargent Cove, Browns Brook, Monument Cove 

Drainage, Norumbega, Squantum Point. 

MDI:5 Somesville, Man o’War Brook, Valley Cove, Acadia Mountain. 

MDI:6 Seawall Pond, Fernald & Norwood Cove, Hutchins Brook, Southwest 

Harbor. 

MDI:7 Halfway Brook, Cousins Creek, Webster Brook, Richtown, Tinker Brook, 

Moosehorn Brook, Duck Cove Brook, Seal Cove, Bernard, Bass Harbor 

Head, Goose Cove. 

MDI:8 Stewart Cove South, Pretty Marsh, Goose Marsh, Bartlett Narrows. 

MDI:9 Smiths Brook, Meadow Brook, Prays Brook, Western Bay. 

MDI:10 Faun Pond, Lake Wood, French Hill Pond & Brook, Aunt Betsey’s Brook, 

Hamilton Pond & Stony Brook, Old Mill Brook, Fresh Meadow Marsh. 

MDI:11 Breakneck Ponds, Breakneck Brook. 

MDI:12 Halfmoon Pond, Duck & Witch Hole Brooks, Witch Hole Pond, Bubble 

Pond, New Mill Meadow, Eagle Lake. 

MDI:13 Cromwell Brook, The Tarn, Great Meadow, Kebo Brook. 

MDI:14 Bear Brook Pond, Bear Brook. 

MDI:15 The Bowl, Otter Creek & Canon Brook. 

MDI:16 Hunters Brook. 

MDI:17 Stanley Brook. 

MDI:18 Sargent Mountain Pond, Little Long Pond, Jordan Pond. 

MDI:19 Little Harbor Brook. 

MDI:20 Hadlock Brook, Lower Hadlock Pond, Upper Hadlock Pond. 

MDI:21 Sargent Brook. 

MDI:22 Chasm Brook, Gilmore Meadow, Heath Brook & Sunken Brook, 

Richardson Brook, Aunt Betty Pond. 

191
MDI:23 Tavern Brook, Babson Creek, Kitteredge Brook. 

MDI:24 Mill Pond, Ripple Pond, Duck Pond & Brook, Round Pond, Little Round 

Pond, Great Brook, Somes Pond, Long Pond. 

MDI:25 Little Echo Pond, Echo Lake. 

MDI:26 Lurvey Brook, Heath Brook, Buttermilk Brook, Bass Harbor Marsh, 

Adams Brook, Marshall Brook. 

MDI:27 Flyes Brook, Steward Brook, Hodgdon Brook & Pond, Seal Cove Pond. 

 

192
Watershed 

Cluster Area 

Residential, 

Commercial, 

Transportation,

Built-up 

(11+12+14+16+17) 

Agricultural, 

Rangeland 

(shrub, brush) 

(24+31+32) 

Rock, Quarries, 

etc. (74+75)

Deciduous 

Forest (41) 

Evergreen 

Forest (42) 

 

Whole 

Cluster 

(ha) 

% 

Park 

% 

Whole % Park 

% 

Whole 

% 

Park 

% 

Whole 

% 

Park 

% 

Whole 

% 

Park 

% 

Whole 

% 

Park 

MDI:1 1221 9.9 23.1 10.0 4.8 0.3 1.4 0.0 4.3 9.1 17.3 22.2 

MDI:2 950.5 56.6 31.8 2.4 1.2 2.1 1.7 2.3 33.1 53.2 5.2 8.2 

MDI:3 1148.8 38.3 33.0 7.0 1.2 1.6 1.7 3.0 3.6 8.4 31.2 44.7 

MDI:4 814 55.5 10.5 1.9 3.2 1.0 0.1 0.0 0.6 0.6 48.8 62.8 

MDI:5 717.9 33.1 12.6 0.1 4.0 2.2 2.1 0.4 1.2 2.7 26.8 40.0 

MDI:6 1432.5 22.0 32.2 7.9 4.2 3.0 0.8 0.5 0.1 0.0 27.2 36.7 

MDI:7 1813.2 12.3 20.6 1.5 9.1 2.8 1.4 2.3 0.0 0.0 50.8 81.5 

MDI:8 989.5 4.0 6.8 0.8 5.3 0.0 0.7 0.0 0.3 0.0 51.1 59.0 

MDI:9 1238.2 0.0 7.8 0.0 2.5 0.0 0.6 0.0 1.9 0.0 41.5 0.0 

MDI:10 2584 27.5 4.7 0.1 8.0 1.3 1.6 0.0 9.7 18.2 11.8 5.2 

MDI:11 382.3 97.9 0.7 0.1 1.2 1.3 0.0 0.0 34.0 34.1 5.7 5.8 

MDI:12 1480.8 85.7 1.4 1.6 3.1 3.6 0.2 0.2 18.0 20.9 21.9 25.5 

MDI:13 757.5 79.6 11.1 2.1 2.8 2.2 0.2 0.2 44.3 51.1 17.8 21.6 

MDI:14 142.7 64.4 11.8 2.1 0.1 0.1 0.0 0.0 39.6 47.4 18.4 26.1 

MDI:15 901.5 83.7 8.2 1.0 7.6 8.6 0.1 0.1 37.0 39.6 18.1 20.6 

MDI:16 587 94.7 0.6 0.5 2.6 2.8 0.5 0.5 6.8 7.1 38.0 38.8 

MDI:17 378.6 63.4 11.3 3.2 1.2 1.3 0.4 0.3 3.1 4.8 44.4 40.4 

MDI:18 834.2 62.9 1.3 0.8 9.9 13.9 0.4 0.7 11.8 18.8 33.1 35.4 

MDI:19 356.1 61.0 0.2 0.0 7.5 12.3 0.0 0.0 2.2 3.6 24.5 23.8 

MDI:20 548.2 79.7 5.9 1.3 7.5 9.4 0.0 0.0 0.9 1.1 46.0 49.8 

MDI:21 379.2 70.4 2.3 0.0 2.7 3.5 0.7 0.0 6.5 6.6 18.0 22.1 

MDI:22 976.4 83.5 2.5 0.7 3.4 2.4 0.1 0.1 21.1 23.4 14.7 16.8 

MDI:23 759.3 7.8 4.5 0.1 4.2 0.0 1.2 0.0 2.8 22.1 22.9 5.0 

MDI:24 2338.3 33.9 3.9 0.1 1.7 0.5 0.2 0.1 3.7 2.1 25.3 46.7 

MDI:25 833.9 38.7 6.9 2.3 2.9 0.5 0.9 0.0 3.3 3.1 23.7 49.3 

MDI:26 2173.9 63.9 4.3 0.3 1.9 0.8 2.4 0.0 0.0 0.0 45.9 45.3 

MDI:27 1249 60.1 4.2 0.3 4.7 2.1 0.2 0.0 0.4 0.1 44.0 50.7 

MDI:Total 

27988.5 

** 44.8 10.4 1.4 4.2 3.1 0.9 0.4 8.4 15.4 29.4 33.2 

 

SCH:50 *** 1961.9 41.2 3.9 2.9 4.2 7.1 2.2 4.0 0.7 0.2 70.0 75.7 

IAH:60 2297.1 46.1 3.3 0.1 1.6 0.6 2.0 2.0 0.1 0.0 70.6 77.0 

Islands:70 264 2.1 8.1 7.2 3.5 49.6 

193
Watershed 

Cluster 

Mixed Forest 

(43) 

Forested 

Wetland (61) 

Nonforested 

Wetland, Bays 

and Estuaries 

(62, 54) 

Lakes 

(52) * 

Great 

Ponds 

(>10 

acres) 

* 

 

% 

Whole 

% 

Park 

% 

Whole 

% 

Park 

% 

Whole 

% 

Park 

% 

Whole 

% 

Whole 

MDI:1 39.8 50.5 3.8 0.4 5.5 7.5 0.0 1.0 

MDI:2 21.6 22.8 3.0 5.3 2.5 3.7 0.0 0.0 

MDI:3 26.7 33.2 1.0 1.1 1.6 1.0 0.0 0.0 

MDI:4 30.9 29.7 3.5 3.3 2.4 0.7 0.0 0.0 

MDI:5 49.3 51.2 3.0 2.3 1.1 1.1 0.0 0.0 

MDI:6 26.3 32.2 8.1 18.3 1.2 1.5 0.0 0.0 

MDI:7 12.5 6.5 3.1 3.7 2.6 1.8 0.0 0.0 

MDI:8 28.1 36.9 3.5 2.1 4.1 1.2 0.4 0.0 

MDI:9 40.3 0.0 2.9 0.0 2.4 0.0 0.0 0.0 

MDI:10 48.4 46.6 11.7 21.0 4.1 7.7 0.0 0.9 

MDI:11 49.9 50.1 3.6 3.7 4.8 4.9 0.0 2.2 

MDI:12 36.1 42.0 4.0 4.6 3.6 1.6 11.9 13.4 

MDI:13 16.5 14.7 4.2 5.2 3.2 2.8 0.0 1.0 

MDI:14 23.4 15.3 1.4 1.3 5.2 7.7 0.0 0.0 

MDI:15 25.1 26.3 2.4 1.9 1.6 1.8 0.0 0.5 

MDI:16 51.1 49.9 0.4 0.3 0.2 0.2 0.0 0.0 

MDI:17 37.6 46.8 1.5 2.4 0.5 0.7 0.0 0.0 

MDI:18 29.2 28.2 2.2 1.1 3.0 0.7 9.0 10.7 

MDI:19 64.7 60.0 0.8 0.2 0.0 0.0 0.0 0.0 

MDI:20 31.7 35.4 1.8 2.0 6.3 1.0 0.0 5.5 

MDI:21 67.3 65.9 1.9 1.0 0.7 0.8 0.0 0.0 

MDI:22 44.3 41.7 11.3 12.1 2.6 2.9 0.0 1.3 

MDI:23 52.0 67.1 12.2 5.8 0.1 0.0 0.0 0.0 

MDI:24 41.7 46.8 4.4 3.1 0.7 0.0 18.7 18.9 

MDI:25 48.2 42.4 2.0 2.1 0.7 0.0 11.4 12.0 

MDI:26 30.8 35.4 10.7 14.6 3.9 3.5 0.0 0.0 

MDI:27 32.0 42.2 4.1 4.1 0.7 0.3 9.7 9.7 

MDI:Total 35.6 38.0 5.2 6.2 2.5 2.2 3.2 3.7 

 

SCH:50 *** 9.6 1.8 2.0 3.6 3.8 4.7 0.0 0.4 

IAH:60 15.8 13.4 4.3 5.0 2.1 1.7 1.2 1.2 

Islands:70 22.4 0.4 6.6 0.0 

* The NPS vegetation map classifies lakes and ponds as mix of nonforested wetlands (smaller waterbodies) and lakes 

(larger waterbodies). The column "Great Ponds" provides data on all lakes >10 acres (0.4 ha) - these data were derived 

from a separate GIS coverage of hydrography and should not be summed with vegetation map landcover classes. 

** Total area for MDI excludes small 'sliver' polygons in GIS coverage that are not incorporated into the cluster 

framework. 

*** Vegetation map landcover data do not include entire watersheds; thus landcover percentages do not sum to 100%. 

194
Appendix 2 

Legislative background and management objectives

Acadia National Park was established in 1916 as the Sieur de Monts National Monument. 

In 1919, the park was renamed Lafayette National Park, and again in 1929 when it was 

given its current name. The 1929 legislation also authorized expansion of the park, and in 

1986 the permanent boundary was established. Legislation in 2001 authorized ‘the reincorporation into ACAD of lands that were formerly part of the Park but which were 

subsequently used for military purposes’ on the Schoodic Peninsula (National Park 

Service 2004). The National Park Service acquired land on IAH in 1943 (Marion 2006). 

The following discussion is taken from Kahl et al. (2000) with updates. 

Federal Legislation 

• National Park Service Organic Act (1916) - The Organic Act specifies that the National 

Park Service is responsible for the preservation and conservation of natural resources in 

all park lands under its jurisdiction. This act was reinforced by Congress in 1970 with 

legislation stating that all park lands are united by a common purpose, regardless of title 

or designation. Hence, all water resources in the National Park System are protected by 

federal law, and it is the fundamental duty of the National Park Service to protect those 

resources unless otherwise indicated by Congress. 

• Federal Water Pollution Control Act (Clean Water Act) 1972 and Amendments (1977, 

1987) - This law is designed to restore and maintain the chemical, physical and biological 

integrity of the nation's waters. As part of the act, Congress recognizes the primary role 

of the states in managing and regulating the nation's water quality within the general 

framework developed by Congress. All federal agencies must comply with the 

requirements of state law for water quality management, regardless of jurisdictional 

status or land ownership. States are directed to implement the protection of water quality 

through best management practices and water quality and technology-based standards. 

 

• The 1990 Clean Air Act Amendments were designed to reduce acid rain and improve 

public health by reducing emissions of sulfur dioxide (SO2) and oxides of nitrogen (NOx) 

from industrial sources. Phase 1 reductions were implemented in 1995 and Phase II was 

implented in 2000. U.S. EPA reports that as of 2005, power plant emission reductions 

were >7 million tons, representing 41% reductions from 1980 levels (www.epa.gov).

ACAD region lakes and streams are generally poorly buffered and sensitive to acidic 

deposition. Therefore, they have been monitored to characterize ‘recovery’ from acidic 

deposition, both by academic researchers and the NPS resource management division.

• Safe Drinking Water Act (1974) and Amendments (1986) - This act sets national 

minimum water quality standards and requires regular testing for developed public 

drinking water supplies. Most significantly for MDI, the act requires filtration for all 

195
uncovered public surface drinking water supplies. Waivers from filtration require 

evidence of adequate watershed control and protection. This requirement affects one 

municipal and three private water companies on MDI who draw their waters from lakes 

and watersheds within or adjacent to the park boundary. 

• Coastal Zone Management Act (1972) and Amendments (1990) - This federal act 

provides assistance and encouragement to coastal states in the effective protection and 

careful development of the coastal zone. Maine's coastal program was approved in 1978 

and is administered by the Maine State Planning Office (SPO), with other regulatory 

functions carried out by the Department of Environmental Protection, Department of 

Marine Resources, and Department of Economic and Community Development. In 

Maine, all federal properties are excluded from the state's designated coastal zone. 

However, any park activity with an off-site impact on the coastal zone must be consistent 

with Maine's coastal zone management plans. 

• Water Quality Improvement Act (1970) - This act requires federally regulated activities 

to have state certification that they will not violate water quality standards. 

• Endangered Species Act (1973) - This act provides for the conservation, protection, 

restoration, and propagation of selected native species that are threatened with extinction. 

All entities using federal funding must consult with the Secretary of the Interior (through 

the U.S. Fish and Wildlife Service) on activities that potentially affect federally listed 

flora and fauna. 

• National Environmental Policy Act (1969) - This law requires systematic analysis of 

major federal actions, including a consideration of reasonable alternatives and an analysis 

of short- and long-term irretrievable, irreversible, and unavoidable impacts. Specifically, 

NEPA requires that an environmental impact statement (EIS) be prepared as part of the 

review and approval process by federal agencies of major actions which significantly 

affect the quality of the human environment. 

 

• Executive Orders on Wetlands and Floodplain Management (1977) - Executive Order 

11990, the "Protection of Wetlands," requires all federal agencies to minimize the 

destruction, loss or degradation of wetlands, and to preserve and enhance the natural and 

beneficial values of wetlands. 

State Legislation 

• Great Ponds - Great Ponds are defined in Maine Statutes as any inland body of water 

which in its natural state has a surface area in excess of 10 acres (4 ha) or impoundments 

more than 30 acres (12 ha) in size (Title 38, Chapter 3, 1973, c. 608 Article 1-A, 

subsection 381). Maine law currently recognizes the 1641-1647 Colonial Ordinance of 

the Massachusetts Bay Colony in common law. Under this ordinance, rights to fishing, 

fowling, and navigation of Great Ponds (codified in Maine statute) as well as of the 

intertidal zone of the coastline (under the so-called Public Trust doctrine), are held by the 

public in perpetuity. 

196
• Classification of Maine Waters - The federal Clean Water Act requires Maine to 

establish water quality standards for all water bodies in the state. Maine's antidegradation policy gives the Maine Department of Environmental Protection the 

authority to classify waters in national and state parks as "an outstanding national 

resource (where) water quality must be maintained and protected". Streams within the 

boundaries of ACAD are currently classified as AA "outstanding natural resources", a 

designation which requires aquatic life to be "as naturally occurs", meaning they must 

have essentially the same physical, chemical and biological characteristics as found in 

situations with similar habitats free of measurable effects of human activity. All Great 

Ponds and natural lakes and ponds less than 10 acres in size in the State of Maine are 

classified GPA, a designation which bans new discharge of pollutants or the erosion of 

materials placed on lakeshores into the water. 

• Management jurisdiction for coastal areas is complicated by the fact that the Park’s 

deeded authority extends to low tide in some areas and only to high tide in others areas 

(Table A2.1). The deeded boundary in other coastal sections is unclear. 

While marine waters beyond low tide are outside National Park Service jurisdiction, they 

are an integral part of the park's setting. The State of Maine classifies marine waters 

directly adjacent to park owned shoreline as "SA" which requires estuarine and marine 

life, dissolved oxygen and bacteria levels to be as naturally occurs. No direct discharges 

of pollutants are allowed in "SA" waters. Marine waters within 500 feet of privately 

owned shoreline on Mount Desert Island, Isle au Haut and the Cranberry Isles are 

classified "SB", a classification which allows existing discharges as long as they do not 

impair naturally occurring habitats or exceed bacterial standards. 

• Land Use Regulations - Although Maine towns have home rule authority, water 

management policies outside the park generally stem from both local zoning and state 

laws. The Maine Department of Environmental Protection oversees the adoption of 

mandatory shoreland zoning regulations, and the Department of Economic and 

Community Development oversees comprehensive planning which recognizes water 

quality objectives. 

• Maine's Nonpoint Source Management Plan identifies projects for future consistency 

review purposes. The plan calls for projects at the park to be reviewed by the Maine State 

Planning Office for their effects on water quality and their consistency with the state 

plan. 

• The Maine Natural Resources Protection Act recognizes "resources of state 

significance". These include Great Ponds, outstanding river segments, coastal wetlands, 

fragile mountain areas and significant wildlife habitat. The National Park Service at 

Acadia makes every effort to comply with the Natural Resources Protection Act to 

protect soil and water resources and respect the state's desire to protect resources of state 

significance. 

197
Management Objectives 

As stated by ACAD’s Resource Management Plan (Manski 1998): 

“Resource management at ACAD is focused on protecting the integrity of natural 

resources, preserving cultural heritage, and maintaining quality visitor 

experiences. Consistent with current Park strategic planning documents, resource 

management program activities emphasize: a) development of knowledge about 

and the identification of threats to Park ecosystems, cultural resources, and visitor 

experiences; b) application of scientific study in formulating solutions to Park 

issues; c) participation with other entities in the implementation of appropriate 

management actions to meet Park stewardship responsibilities; d) compliance 

with applicable federal, State, and local laws, and; e) communication of the 

results of our work with others to achieve the Park’s mission”. 

Kahl et al. (2000) provide a detailed review of water resources management objectives at 

ACAD, including the following: 

“National Park Service policy (National Park Service, 1988) calls for water 

resources to be maintained in their natural condition free from pollutants 

generated by human activity. The General Management Plan for Acadia (National 

Park Service, 1992) includes water resources in the overall management zoning 

scheme. Offshore islands and all wetlands are placed in the "Protected Natural 

Area Subzone" which seeks to perpetuate "geological or ecological values 

without any or with minimal human intrusion". However, the plan creates special 

use zones which include, among other areas, municipal water supply pump 

stations, dams and the 14 Great Ponds within or adjacent to park boundaries. 

Acadia shares management responsibilities in these zones with other 

organizations.” 

Table A2.1. Park ownership of intertidal areas (from Kahl et al. 2000) 

Park boundaries clearly deeded to the low tide line 

 Bar Island (western half), Bar Harbor 

 Otter Cove to Hunter’s Brook 

 Somes Sound (shoreline adjacent to Norumbega, Flying, and Acadia Mountains) 

 Seawall picnic area to Bass Head Harbor 

Park boundaries clearly deeded to end at high tide 

 Oak Hill Cliff near Schooner Head Overlook, Bar Harbor 

 Seawall Pond 

 Pretty March picnic area 

Park boundaries requiring deed inspection and/or clarification of intertidal ownership 

 All remaining shoreline areas in Acadia National Park 

198
Appendix 3. 

Migrant birds in the Acadia National Park region. 

Scientific Name Abundance MDI IAH SCH 

Ammodramus caudacutus 

Saltmarsh Sharp-tailed Sparrow

Rare Unconfirmed in Park

Anas acuta 

Northern Pintail 

Rare Present in Park Unconfirmed in Park 

Anas americana 

American Wigeon 

Uncommon Present in Park 

Anas clypeata 

Northern Shoveler 

Rare Unconfirmed in Park

Anas strepera 

Gadwall 

Rare Present in Park 

Anthus rubescens 

American Pipit 

Common Present in Park Present in Park 

Ardea alba 

Great Egret 

Occasional Present in Park 

Arenaria interpres 

Ruddy Turnstone 

Common Present in Park Unconfirmed in Park Present in Park 

Aythya affinis 

Lesser Scaup 

Rare Unconfirmed in Park

Bartramia longicauda 

Upland Sandpiper 

Rare Present in Park 

Branta bernicla 

Brant 

Occasional Historic Unconfirmed in Park Unconfirmed in Park 

Calidris alba 

Sanderling 

Occasional Unconfirmed in Park Unconfirmed in Park

Calidris alpina 

Dunlin 

Rare Unconfirmed in Park

Calidris canutus 

Red Knot 

Common Unconfirmed in Park

Calidris fuscicollis 

White-rumped Sandpiper 

Uncommon Present in Park Unconfirmed in Park Historic 

Calidris melanotos 

Pectoral Sandpiper 

Rare Present in Park 

Calidris minutilla 

Least Sandpiper 

Common Present in Park Historic Present in Park 

Calidris pusilla 

Semipalmated Sandpiper 

Abundant Present in Park Historic Historic 

Calonectris diomedea

Cory’s Shearwater 

Rare 

Catharus bicknelli 

Bicknell’s Thrush 

Rare Present in Park Present in Park 

Catharus minimus 

Gray-cheeked Thrush 

Rare Present in Park 

Charadrius melodus 

Piping Plover 

Rare Unconfirmed in Park

Charadrius semipalmatus 

Semipalmated Plover 

Common Unconfirmed in Park Unconfirmed in Park Historic 

Egretta thula 

Snowy Egret 

Occasional Present in Park Present in Park 

Fulica americana 

American Coot 

Rare Present in Park Present in Park 

Limnodromus griseus 

Short-billed Dowitcher 

Abundant Present in Park Present in Park 

Morus bassanus 

Northern Gannet 

Common Unconfirmed in Park Unconfirmed in Park Unconfirmed in Park 

Numenius borealis 

Eskimo Curlew 

Extinct Unconfirmed in Park 

Historic 

Historic 

Numenius phaeopus 

Whimbrel 

Rare Present in Park Historic 

Oxyura jamaicensis 

Ruddy Duck 

Rare Unconfirmed in Park Unconfirmed in Park 

Passerella iliaca 

Fox Sparrow 

Common Historic Unconfirmed in Park Unconfirmed in Park 

199
Phalaropus lobatus 

Red-necked Phalarope 

Rare Unconfirmed in Park Unconfirmed in Park Unconfirmed in Park 

Pluvialis dominica 

American Golden-plover 

Rare Unconfirmed in Park

Pluvialis squatarola 

Black-bellied Plover 

Common Present in Park Unconfirmed in Park Historic 

Puffinus gravis 

Greater Shearwater 

Rare Unconfirmed in Park Unconfirmed in Park Unconfirmed in Park 

Puffinus griseus 

Sooty Shearwater 

Rare Unconfirmed in Park Unconfirmed in Park Unconfirmed in Park 

Puffinus puffinus 

Manx Shearwater 

Rare Unconfirmed in Park Unconfirmed in Park Unconfirmed in Park 

Tringa flavipes 

Lesser Yellowlegs 

Uncommon Present in Park Unconfirmed in Park Present in Park 

Tringa melanoleuca 

Greater Yellowlegs 

Common Present in Park Historic 

Tringa solitaria 

Solitary Sandpiper 

Common Present in Park Unconfirmed in Park Historic 

Vireo philadelphicus 

Philadelphia Vireo 

Uncommon Present in Park Present in Park 

Zonotrichia leucophrys 

White-crowned Sparrow 

Common Historic Present in Park 

(Appendix 3, continued) 

200
Appendix 4. 

Methods used to assess condition, population trends 

and threats for the resident bird species of ACAD1

. 

CONDITION ASSESSMENT 

For each species, we summarized residency, abundance, and distribution information 

within ANP. We relied on existing information to summarize the abundance and 

distribution of birds in ANP. In addition, for each species we recorded the accuracy and 

reliability of the reported population status and distribution information using the 

following data quality codes: 1) Poorly known: little or no effort to discern population 

status or distribution throughout ANP; 2) Scattered reports: existing information may or 

may not correctly estimate status or distribution; 3) Generally well known: scattered 

anecdotal reports likely reflects status and distribution, but only poor or incomplete data 

available; 4) Reliable data: park-wide survey with good status and distribution 

information. 

POPULATION TRENDS 

Population trends of each resident species within ANP were determined by three methods 

(if available): Christmas Bird Count (CBC), Breeding Bird Surveys (BBS), and 

anecdotal population trends reported in a publication. Data for the CBC have been 

collected every December/January (with few exceptions) on Mount Desert Island since 

1934 and on Schoodic Peninsula since 1957; we used these data to assess long-term

changes in bird populations in the ANP region. These data are available online at 

National Audubon Society (2006). Only species recorded during 5 or more surveys were 

included in the analyses. Because these count data are strongly influenced by yearly 

count effort (Root 1988), we used the number of individuals reported per hour of search 

effort to assess population trends. To determine species that are declining on these 

counts, we used Spearman Correlation of count year vs. individuals reported per hour of 

effort. Exact p values for Spearman correlations were estimated by Monte Carlo 

simulations. Breeding bird Surveys were conducted by the same observer along a set 

route (3 separate legs) on Mount Desert Island for three consecutive years (1995-1997). 

Because of the limited number of surveys conducted, trend analysis was not possible on 

these data. Instead, we documented species where the relative abundance (RA) declined 

or increased in a linear manner during the three years of surveys. Anecdotal information 

was accessed through the park’s NPSpecies database, the park’s annotated bibliography 

of research, and through study of published and unpublished reports. 

SPECIES OF CONSERVATION CONCERN IN ACADIA NATIONAL PARK 

To determine the species of potential conservation concern in the ANP region, we relied 

on multiple regional assessments because the list of species of conservation concern in 

the ACAD region are not universally accepted among various agencies and organizations 

(US Fish and Wildlife Service 1995, 2006; Rosenberg and Wells 1999; Rosenberg and 

Hodgman 2000; Hodgman and Rosenberg 2000; Panjabi et al. 2005; Maine Department 

of Inland Fisheries and Wildlife 2005). Our goal was to err on the side of including all 

 

1

 Prepared by G. Mittelhauser 

201
species of potential conservation concern in the ACAD region. Four criteria (listed 

below) were used to assess the population status of each species and place it onto the list 

of species of conservation concern in ACAD. The review excluded species that are not 

native to Maine and those that occur as migrants or irregularly as vagrants. Overall, this 

approach ensured that all species that cannot be described as secure over the long term in 

the region are considered of Conservation Concern in ACAD, and not only those with a 

relatively high extinction risk. 

• MAINE CONSERVATION STATUS: Birds assessed as endangered, threatened, 

of special concern, or listed as priority code 1 (high potential for state extirpation 

without management intervention or protection) or priority code 2 (moderate to 

high potential for state extirpation without management intervention or 

protection) by Maine Department of Inland Fisheries and Wildlife (2005); also 

birds listed as Endangered, Threatened, or of Special Concern in Maine. 

• DECLINING SPECIES: Birds whose breeding or non-breeding population 

declined, or whose range contracted in the ACAD region. Species that historically 

declined but have recovered substantially were not included. 

• ATLANTIC NORTHERN FOREST REGION STATUS: Birds of conservation 

priority in the Atlantic Northern Forest Bird Conservation region (Dettmers 

2007). 

• WATERBIRDS OF CONSERVATION CONCERN: Species of North American 

waterbirds whose populations are of conservation concern in the mid-Atlantic, 

New England, and Maritimes region (Parsons et al. 2007). 

STRESSOR ASSESSMENT 

Rather than list potential stressors for all resident birds in the ACAD region, we detailed 

information on species of conservation concern in the region as outlined above. We 

relied on the ‘Birds of North America’ series to document potential stressors in a species, 

regardless of whether the stressors have been documented within ACAD. To document 

known stressors within ACAD, we relied on park reports and publications as well as 

other reports and publications from the local region. 

202
Appendix 5. 

Condition assessment for breeding and resident land bird 

populations in Acadia National Park. 

Species in bold letters are considered of potential conservation concern in Acadia National Park. 

Locations referred to in table refer to Mount Desert Island (MDI), Isle au Haut (IAH), Schoodic 

Peninsula (SCH), and small offshore islands (ISL). 

203
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK 

DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Accipiter cooperii Cooper’s Hawk

Breeding MDI: Occasional; Breeding recently 

reported at Compass Harbor (Witt 1997) 

SCH: Unconfirmed breeder 

1 0 3-SC 2

Accipiter gentilis Northern Goshawk 

Breeding Winter 

MDI: Rare, breeding recently reported at 

Aunt Betty’s Pond 

SCH: Probable breeder 

1 MDI CBC – Increasing (P = 0.006) (mean 

= 1.0, n = 16) 

SCH CBC – Increasing (P = 0.01) (mean 

= 1.0, n = 6)

5 3-SC MODERATE 2

Accipiter striatus Sharp-shinned 

Hawk

Breeding Winter 

MDI - Uncommon in summer, occasional in 

winter, breeding recently reported at Ship 

Harbor and Seawall Campground (Witt 

1997) 

SCH: Uncommon breeder, uncommon in 

winter 

IAH: Uncommon during summer and 

winter; Breeding suspected (Jones 1987) 

but not confirmed 

ISL: Observed on Schoodic Island during 

summer (Mittelhauser et al. 1992), but breeding not confirmed 

1 MDI CBC – No Change (+) (P = 0.13) 

(mean = 1.2, n = 26) 

MDI – Decreased sharply as a breeding 

bird in the last 30 years (Russell 1984) 

SCH CBC – Increasing (P = 0.05) (mean 

= 1.0, n = 11) 

3 2

Aegolius acadicus Northern Saw-whet 

Owl

Breeding Winter 

MDI: Rare to uncommon summer and 

winter, breeding reported for MDI 

although no records of nesting within park 

SCH: Rare in winter; no summer records; 

Breeding not confirmed 

IAH: Uncommon, Breeding suspected but 

not confirmed 

1 0 4

Archilochus colubris Ruby-throated 

Hummingbird

Breeding MDI: Common breeder on MDI; BBS 

average RA = 0.04% 

SCH: Occasional in summer; Breeding not 

confirmed 

IAH: Uncommon, Breeding suspected 

(Jones 1987) but not confirmed 

ISL: Uncommon; Breeding suspected 

(Mittelhauser et al. 1992) but not confirmed 

1 MDI BBS – No change 2 4 

Asio otus Long-eared Owl 

Breeding 

(historic) 

Winter 

MDI: Rare summer and winter, has bred on 

MDI (Russell 1984) 

2 0 2 HIGH 3

204
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Bombycilla cedrorum Cedar Waxwing 

Breeding Winter 

MDI – Abundant in summer, rare in winter, 

breeding on MDI, breeding suspected but not confirmed within park boundaries; 

BBS average RA = 3.3% 

SCH: Common; breeding suspected but not 

confirmed 

IAH: Common during summer, no winter

records; Breeding suspected (Jones 1987) but not confirmed 

ISL: Occasional in summer, nesting 

confirmed on Schoodic Island 

(Mittelhauser et al. 1992), no winter records 

1 MDI CBC – Increasing (P = 0.01) (mean 

= 30.3, n = 12) 

MDI BBS – RA increasing 0.8%/year 

5 4

Bombycilla garrulus Bohemian Waxwing 

Winter MDI: Occasional

SCH: Uncommon 

1 MDI CBC – Increasing (P < 0.001) (mean 

= 27.2, n = 12) 

5 4

Bonasa umbellus Ruffed Grouse 

Breeding Winter 

MDI: Common, breeding at many areas on 

MDI; BBS average RA = 0.1% 

SCH: Uncommon summer and winter; 

breeding not confirmed but likely 

IAH: Rare in winter on IAH; no summer 

records 

2 MDI CBC – No Change (-) (P = 0.30) 

(mean = 5.8, n = 60) 

MDI BBS – No Change SCH CBC – No Change (-) (P = 0.52) 

(mean = 2.6, n = 32) 

2 3 MODERATE 2

Bubo virginianus Great Horned Owl 

Breeding Winter 

MDI: Rare to uncommon breeder and winter 

resident, breeding reported for MDI (Long 

1987) 

SCH: Uncommon in summer and winter; 

Breeding not confirmed 

IAH: Uncommon, Breeding suspected 

(Pierson 1983) but not confirmed 

1 MDI CBC – No Change (+) (P = 0.44) 

(mean = 1.1, n = 11) 

2 4

Buteo jamaicensis Red-tailed Hawk 

Breeding MDI: Occasional, no recent records of 

breeding in recent years, last record of breeding confirmed in 1961 (Bond 1971) 

SCH: Unconfirmed in summer 

1 0 4

Buteo lagopus Rough-legged Hawk 

Winter MDI: Occasional

SCH: Rare in winter 

1 MDI CBC – No Change (+) (P = 0.24) 

(mean = 1.1, n = 15) 

SCH CBC – Declining (P = 0.04) (mean = 

1.0, n = 6) 

3 4

Buteo lineatus Red-shouldered 

Hawk

Summer MDI: Rare; Breeding not confirmed 

although Tyson and Bond (1941) report that this species may nest occasionally on 

MDI and Sullivan (1937) and Pellew (1927) report this species as common during the summer 

SCH: Unconfirmed IAH: One historic summer record (Manville 

1964), no other summer records 

1 MDI – formerly common on MDI (Pellew 

1927) 

1 3 3

205
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Buteo platypterus Broad-winged Hawk 

Breeding MDI: Common, Breeding confirmed at Seal 

Cove, Northeast Creek, and Seawall (Witt 1997); BBS average RA = 0.04% 

SCH: Unconfirmed breeder 

IAH: At least some summer records 

(Manville 1964, Pierson 1983, Jones 

1987); breeding suspected (Jones 1987) but not confirmed within park boundaries 

1 MDI BBS – No Change 

MDI – Reported as formerly a common 

breeder on MDI (Eliot 1931) 

2 3 2

Calcarius lapponicus Lapland Longspur

Winter MDI: Very rare

SCH: Unconfirmed 

1 0 4

Caprimulgus 

vociferus 

Whip-poor-will 

Breeding MDI – Common, nesting near Echo Lake 

(Tyson and Bond 1941); BBS average RA = 0.04% 

IAH: Uncommon, Breeding reported on 

island (Jones 1987) 

1 MDI BBS – No Change 

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

1 2 MODERATE 2

Cardinalis cardinalis Northern Cardinal

Breeding Winter 

MDI – Common winter and summer, nesting 

reported for MDI; BBS average RA = 0.07% 

SCH: Uncommon to rare in winter; no 

confirmed summer records 

IAH: Record of species from early June 

1983 on island (Pierson 1983) is only record for island 

1 MDI CBC – Increasing (P < 0.001) (mean 

= 4.5, n =31) 

MDI BBS = RA Increasing 0.1%/year 

SCH CBC – Increasing (P = 0.02) (mean 

= 1.1, n = 15) 

5 4

Carduelis flammea Common Redpoll 

Winter MDI: Irregular in winter 

SCH: Variable populations from year to 

year 

1 MDI CBC – No Change (+) (P = 0.36) 

(mean = 52.6, n = 30) 

SCH CBC – No Change (+) (P = 0.29) 

(mean = 76.2, n = 15) 

2 4

Carduelis pinus Pine Siskin 

Breeding Winter 

MDI Common breeder, uncommon in 

winter, breeding reported at Ship Harbor (Witt 1997); BBS average RA = 1.7% 

SCH: Uncommon in winter; breeding not 

confirmed 

IAH: Common in summer, uncommon in 

winter; Breeding suspected (Jones 1987) but not confirmed 

ISL: Unconfirmed; breeding suspected (Witt 

1997) but not confirmed 

1 MDI CBC – No Change (+) (P = 0.07) 

(mean = 32.2, n = 45) 

MDI BBS – No Change 

SCH CBC – No Change (+) (P = 0.79) 

(mean = 18.0, n = 18) 

2 4

Carduelis tristis American Goldfinch 

Breeding Winter 

MDI – Common in summer, irregular in 

winter, considered a common breeder on 

MDI; BBS average RA = 2.1% 

SCH: Common in winter; breeding not 

confirmed 

IAH: Common in summer, uncommon in 

winter, Breeding suspected (Jones 1987) but not confirmed 

1 MDI CBC – Increasing (P < 0.001) (mean 

= 59.2, n = 52) 

MDI BBS – No Change SCH CBC – No Change (+) (P = 0.19) 

(mean = 43.5, n = 32) 

SCH – Decline reported (1995-96) (Glanz 

and Connery 1999) 

3 4

206
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Carpodacus 

mexicanus 

House Finch

Breeding Winter 

MDI: Common in summer, irregular in 

winter, considered a common breeder around towns and villages (Witt 1997); BBS average RA = 0.2% 

SCH: Uncommon in winter; breeding not 

confirmed 

IAH: Uncommon in summer, rare in winter, 

Breeding suspected (Jones 1987) but not confirmed 

1 MDI CBC – Increasing (P < 0.001) (mean 

= 13.0, n = 16) 

MDI BBS – RA Decreasing 0.06%/year 

SCH CBC – Increasing (P = 0.008) (mean 

= 8.3, n = 9) 

3 4

Carpodacus 

purpureus 

Purple Finch 

Breeding Winter 

MDI: Common in summer, irregular in 

winter, breeding reported from summit of 

Cadillac Mountain (Long 1987); BBS average RA = 1.8% 

SCH: Uncommon in winter; breeding not 

confirmed 

IAH: Uncommon during summer and 

winter, Breeding suspected (Jones 1987) but not confirmed 

1 MDI CBC – Increasing (P < 0.001) (mean 

= 5.8, n = 38) 

MDI BBS – RA Increasing 0.2%/year 

SCH CBC – No Change (+) (P = 0.11) 

(mean = 3.9, n = 16) 

SCH – Increase reported (1995-96) (Glanz 

and Connery 1999) 

3 2 HIGH 1

Cathartes aura Turkey Vulture

Summer MDI: Common, breeding status is uncertain 

(Witt 1997) 

1 MDI – Numbers have steadily increased 

since the 1970’s (Witt 1997) 

1 4

Catharus fuscescens Veery 

Breeding MDI: Common breeder, breeding at Sieur de 

Monts Spring and Great Meadow (Witt 1997); BBS average RA = 0.6% 

SCH: Uncommon; Breeding not confirmed 

IAH: Uncommon, Breeding suspected 

(Jones 1987) but not confirmed 

1 MDI BBs – No change 

REGION – Declining in the eastern 

spruce-hardwood forest region of the 

northeast (Rosenberg and Hodgman 2000) 

3 2 HIGH 1

Catharus guttatus Hermit Thrush 

Breeding MDI: Common breeder throughout MDI; 

BBS average RA = 3.3% 

SCH: Uncommon; Breeding not confirmed IAH: Uncommon, Breeding suspected 

(Pierson 1983) but not confirmed 

1 MDI BBS – No Change 

MDI – Steadily diminishing in numbers, 

‘perhaps discouraged by too many

Rockefeller roads’ 

2 4

Catharus ustulatus Swainson’s Thrush 

Breeding MDI: Common breeder throughout MDI; 

BBS average RA = 1.1% 

SCH: Common breeder (Glanz and Connery 

1999) 

IAH: Uncommon, Breeding suspected 

(Pierson 1983) but not confirmed 

ISL: Unconfirmed 

1 MDI BBS – No Change 

SCH – Decline noted 1995-96 (Glanz and 

Connery 1999) 

3 4

Certhia americana Brown Creeper

Breeding Winter 

MDI: Common summer and winter, 

breeding on MDI; BBS average RA = 

0.2% 

SCH: Occasional; breeding not confirmed 

but probable 

IAH: Uncommon during summer, rare 

during winter, Breeding suspected (Pierson 1983) but not confirmed 

1 MDI CBC – No Change (+) (P = 0.06) 

(mean = 5.3, n = 59) 

MDI BBS – RA Increasing 0.2%/year 

SCH CBC – No Change (+) (P = 0.53) 

(mean = 2.2, n = 31) 

3 MODERATE 2

207
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Chaetura pelagica Chimney Swift

Breeding MDI: Common, Breeding confirmed on 

MDI (all nests reported in chimneys), no 

breeding records specific to ANP; BBS average RA = 0.05% 

SCH: Unconfirmed breeder IAH: Reported on island in summer, 

Breeding suspected but not confirmed 

1 MDI BBS – No Change 

MDI – Diminishing species, long ago 

most cottage chimneys harbored a nest 

or two (Eliot 1931)

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

3 2 HIGH 2

Charadrius 

vociferus 

Killdeer

Breeding MDI: Common, breeding occurs on many 

areas on MDI; BBS average RA = 0.03% 

SCH: Unconfirmed breeder IAH: No summer records 

1 MDI BBS – No Change 2 3 MODERATE 2 

Chordeiles minor Common 

Nighthawk 

Breeding MDI: Common breeder, nesting on south 

ridge of Cadillac Mountain (Tyson and 

Bond 1941); BBS average RA = 0.06% 

SCH: Occasional; Breeding not confirmed IAH: Uncommon, Breeding suspected 

(Jones 1987) but not confirmed 

1 MDI BBS – No Change 

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

2 2 HIGH 1

Circus cyaneus Northern Harrier 

Breeding MDI: Occasional, Breeding reported at New 

Mill Meadow and Northeast Creek (Witt 1997) 

SCH: Unconfirmed breeder IAH: No confirmed summer records 

1 0 3 MODERATE 2

Cistothorus platensis Sedge Wren

Breeding MDI: Rare, Breeding reported on MDI (Witt 

1997, Russell 1984, Long 1987), but no 

nesting records within park boundaries; 

species reaches northeastern most edge of breeding range in Maine 

2 0 1-E 3

Coccothraustes 

vespertinus 

Evening Grosbeak

Breeding Winter 

MDI: Occasional in summer, common in 

winter, breeding reported on MDI (Witt 

1997); BBS average RA = 0.08% 

SCH: Occasional in winter; breeding not 

confirmed 

IAH: Uncommon during summer and 

winter, Breeding not confirmed 

1 MDI CBC – No Change (-) (P = 0.88) 

(mean = 133.9, n = 42) 

MDI BBS – No Change MDI – Has become common only in the 

last 25 years (Russell 1984) 

SCH CBC – No Change (-) (P = 0.45) 

(mean = 59.4, n = 29) 

MAINE – increasing its eastern range 

over last 90 years (Palmer 1949) 

2 3 4

Coccyzus 

erythropthalmus 

Black-billed Cuckoo

Breeding MDI: Uncommon, breeding reported on 

Cadillac Mountain (Bond 1969); BBS average RA = 0.02% 

SCH: Rare in summer; breeding not 

confirmed 

IAH: No summer records 

1 MDI BBS – RA Decreasing 0.01%/year 

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

4 2 MODERATE 2

208
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Colaptes auratus Northern Flicker

Breeding MDI: Common Breeder throughout MDI; 

BBS average RA = 0.2% 

SCH: Common; Breeding suspected but not 

confirmed 

IAH: Common, Breeding suspected (Pierson 

1983) but not confirmed 

1 MDI BBS – No Change 

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

3 2 MODERATE 2

Colinus virginianus Northern Bobwhite

Summer Winter 

MDI: Locally common, no evidence of 

breeding reported; BBS average RA = 0.04% 

1 MDI BBS – No Change 2 4 

Columba livia Rock Dove

Breeding Winter 

MDI: Common, breeding recorded for MDI; 

BBS average RA = 0.07% 

SCH: Common; breeding not confirmed 

ISL: Common, breeding not confirmed 

1 MDI CBC – Increasing (P < 0.001) (mean 

= 80.4, n = 39) 

MDI BBS – RA Increasing 0.06%/year 

SCH CBC – Increasing (P < 0.001) (mean 

= 38.2, n = 30) 

5 4

Contopus cooperi Olive-sided 

Flycatcher 

Breeding MDI: Occasional, nesting at Sieur de Monts 

Spring (Long 1987); BBS average RA = 0.03% 

SCH: Uncommon; Breeding not confirmed IAH: Uncommon, Breeding suspected 

(Jones 1987) but not confirmed 

1 MDI BBS – No Change 

MDI – Formerly more common (Witt 

1997) 

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999)

2 2-SC HIGH 1

Contopus virens Eastern WoodPewee 

Breeding MDI: Common breeder throughout MDI; 

BBS average RA = 0.4% 

SCH: Occasional; Breeding not confirmed 

IAH: Uncommon, Breeding suspected 

(Pierson 1983) but not confirmed 

ISL: Uncommon; Breeding suspected 

(Mittelhauser et al. 1992) but not 

confirmed 

1 MDI BBS – No Change 

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

3 3 HIGH 1

Corvus 

brachyrhynchos 

American Crow

Breeding Winter 

MDI: Common, breeding suspected but not 

confirmed within park boundaries; BBS 

average RA = 4.0% 

SCH: Common; breeding not confirmed 

IAH: Common summer and winter, breeding 

confirmed on island (Pierson 1983) 

ISL: Common summer and winter, breeding 

suspected but not confirmed 

1 MDI CBC – Increasing (P < 0.001) (mean 

= 218.5, n = 62) 

MDI BBS – RA Increasing 0.6%/year 

SCH CBC – No Change (-) (P = 0.65) 

(mean = 84.6, n = 46) 

3 4

Corvus corax Common Raven 

Breeding Winter 

MDI: Common breeding suspected but not 

confirmed within park boundaries; BBS 

average RA = 0.5% 

SCH: Historic record of nesting (Sullivan 

1937); no recent breeding confirmed 

IAH: Uncommon summer and winter, 

breeding confirmed on island (Manville 1964, Pierson 1983) 

ISL: Occasional summer and winter, 

breeding not confirmed 

1 MDI CBC – Increasing (P = 0.002) (mean 

= 27.5, n = 61) 

MDI BBS – No Change SCH CBC – No Change (-) (P = 0.28) 

(mean = 15.0, n = 46) 

3 4

209
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Cyanocitta cristata Blue Jay 

Breeding Winter 

MDI: Very common summer and winter; 

Breeding throughout island; BBS average RA = 2.0% 

SCH: Uncommon; Breeding not confirmed IAH: Common in summer, uncommon in 

winter; Breeding suspected (Jones 1987) but not confirmed 

1 MDI CBC – Increasing (P = 0.01) (mean 

= 121.4, n = 55) 

MDI BBS – No Change SCH CBC – No Change (+) (P = 0.91) 

(mean = 43.0, n = 45) 

3 4

Dendroica 

caerulescens 

Black-throated Blue 

Warbler 

Breeding MDI: Common, breeding reported within 

park (Witt 1997); BBS average RA = 

0.1% 

SCH: Uncommon; Breeding not confirmed 

AH: Uncommon during summer, Breeding I

suspected (Jones 1987) but not confirmed 

1 MDI BBS – No Change 2 2 HIGH 1 

Dendroica castanea Bay-breasted 

Warbler 

Breeding MDI: Common, considered an erratic 

breeder on MDI (Witt 1997), breeding records exist from within park; BBS average RA = 0.3% 

SCH: Uncommon; Breeding not confirmed 

IAH: Uncommon, Breeding suspected 

(Pierson 1983) but not confirmed 

1 MDI BBS – No Change 2 2 HIGHEST 1 

Dendroica coronata Yellow-rumped 

Warbler 

Breeding MDI: Common breeder throughout island, 

nesting in the Ship Harbor area (Bond 

1955); BBS average RA = 2.4% 

SCH: Common breeder (Witt 1997, Glanz 

and Connery 1999) 

IAH: Common during summer, Breeding 

confirmed on island (Pierson 1983) 

ISL: Occasional in summer, breeding 

suspected (Witt 1997) but not confirmed 

1 MDI BBS – No Change 2 4

Dendroica fusca Blackburnian 

Warbler 

Breeding MDI: Common, breeding reported at Bass 

Harbor Head and Otter Point (Witt 1997); BBS average RA = 1.5% 

SCH: Common breeder (Glanz and Connery 

1999)

IAH: Uncommon, Breeding confirmed on 

island (Pierson 1983) 

1 MDI BBS – No Change 

REGION – Declining in the northern New 

England region (Hodgman and 

Rosenberg 2000) 

3 2 MODERATE 2

Dendroica magnolia Magnolia Warbler 

Breeding MDI: Common breeder on MDI, breeding 

reported at Ship Harbor (Bond 1955); BBS average RA = 2.2% 

SCH: Common breeder (Glanz and Connery 

1999)

IAH: Uncommon, Breeding confirmed on 

island (Pierson 1983) 

1 MDI BBS – No Change 2 4 

210
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Dendroica 

palmarum 

Palm Warbler

Breeding MDI: Common breeder on MDI, breeding 

reported at Seawall and Wonderland (Witt 1997) and Ship Harbor (Bond 1955); BBS 

average RA = 0.04% 

SCH: Uncommon; Breeding not confirmed IAH: Uncommon, Breeding not confirmed 

1 MDI BBS – No Change 2 3 MODERATE 2 

Dendroica 

pensylvanica 

Chestnut-sided 

Warbler 

Breeding MDI: Common breeder, nesting in the Ship 

Harbor area (Bond 1955); BBS average 

RA = 1.4% 

SCH: Uncommon; breeding not confirmed 

but suspected 

IAH: Uncommon, Breeding suspected 

(Jones 1987) but not confirmed 

1 MDI BBS – No Change 

MDI – Species has increased on MDI 

since the fire of 1947 (Bond 1969) 

REGION – Declining in the northern New 

England region (Hodgman and 

Rosenberg 2000) 

3 2 HIGH 1

Dendroica petechia Yellow Warbler 

Breeding MDI: Common breeder on MDI, nesting in 

the heath near Seawall (Bond 1955); BBS average RA = 0.8% 

SCH: Uncommon; breeding suspected but 

not confirmed 

IAH: Common, Breeding suspected (Pierson 

1983) but not confirmed 

ISL: Occasional; breeding confirmed 

1 MDI BBS – RA Increasing 0.06%/year 2 3 4 

Dendroica pinus Pine Warbler

Breeding MDI: Locally common breeder, breeding 

reported for MDI but no confirmed 

records of nesting within park boundaries 

SCH: Uncommon; breeding not confirmed IAH: Unconfirmed (Manville 1964) 

1 0 4

Dendroica striata Blackpoll Warbler 

Breeding MDI: Rare breeder, nesting along the 

shoreline at Wonderland (Witt 1997); BBS 

average RA = 0.03% 

SCH: Uncommon breeder (Glanz and

Connery 1999) 

IAH: Few summer records, Breeding 

suspected (Manville 1964) but not confirmed 

ISL: Unconfirmed; breeding suspected 

(Pellew 1927, Witt 1997) but not 

confirmed 

1 MDI BBS – No Change 2 3 MODERATE 2 

Dendroica tigrina Cape May Warbler 

Breeding MDI: Common to occasional breeder, 

breeding confirmed in the Ship Harbor 

area (Bond 1955); BBS average RA = 

0.1% 

SCH: Uncommon; Breeding not confirmed IAH: Uncommon, Breeding not confirmed 

1 MDI BBS – No Change 

MDI – Commonly bred in the 1930s and 

1940s during the large spruce budworm outbreaks, and for many years after 

have not been known to breed (Russell 1984); species is again common and breeding on MDI (Witt 1997) 

2 2 HIGH 1

211
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Dendroica virens Black-throated 

Green Warbler 

Breeding MDI: Very Common breeder throughout 

MDI; BBS average RA = 18.9% 

SCH: Common Breeder (Glanz and Connery 

1999) 

IAH: Abundant, Breeding confirmed on 

island (Pierson 1983) 

ISL: Unconfirmed; breeding suspected but 

not confirmed 

1 MDI BBS – No Change 2 2 MODERATE 2 

Dolichonyx 

oryzivorus 

Bobolink 

Breeding MDI: Common but local breeder on MDI, 

breeding on MDI but no confirmed nests within park; BBS average RA = 0.5% 

SCH: Unconfirmed IAH: Uncommon, Breeding suspected 

(Pierson 1983) but not confirmed 

1 MDI BBS – RA Increasing 0.07%/year 2 2 HIGH 2 

Dryocopus pileatus Pileated Woodpecker

Breeding Winter 

MDI: Common summer and winter, 

breeding reported on MDI; BBS average RA = 0.2% 

SCH: Unconfirmed 

IAH: Unconfirmed (Manville 1964) 

1 MDI CBC – Increasing (P < 0.001) (mean 

= 2.0, n = 31) 

MDI BBS – No Change SCH CBC – Increasing (P = 0.01) (mean 

= 2.1, n = 23) 

5 4

Dumetella 

carolinensis 

Gray Catbird 

Breeding MDI: Common, breeding at Western Point 

(Allen 1969); BBS average RA = 0.5% 

SCH: Uncommon; Breeding not confirmed 

IAH: Uncommon, Breeding suspected 

(Pierson 1983) but not confirmed 

1 MDI BBS – No Change 

MDI – Increased as a summer resident on 

MDI since the fire of 1947 (Bond 1969)

2 4

Empidonax minimus Least Flycatcher 

Breeding MDI: Common breeder, breeding at Sieur de 

Monts Spring (Long 1987); BBS average RA = 0.04% 

SCH: Uncommon; Breeding not confirmed 

IAH: Uncommon, Breeding suspected 

(Jones 1987) but not confirmed 

1 MDI BBS – No Change 2 3 4

Eremophila alpestris Horned Lark

Summer Winter 

MDI: Uncommon in winter, no summer 

records, no records of breeding 

SCH: Uncommon migrant, no summer or 

winter records 

ISL: Unconfirmed, but reportedly most 

frequently found on the outer islands 

1 REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

1 2 MODERATE 3

Euphagus carolinus Rusty Blackbird

Summer MDI: Rare in summer, no breeding records 

on MDI to date (Witt 1997) 

SCH: Unconfirmed ISL: Rare, no evidence suggesting breeding 

1 0 2-SC HIGH 3

Falcipennis 

canadensis 

Spruce Grouse 

Breeding Winter 

MDI: Rare summer and winter, breeding 

within park (Whitcomb et al. 1994) 

SCH: Uncommon breeder and in winter; 

population of 34 estimated during 1992 

(Whitcomb et al. 1994). 

4 MDI – Relatively common on MDI until 

1910 when numbers gradually declined until the early 1930s (Barden 1970); MDI population in 1993 estimated at 56 

birds (Whitcomb et al. 1994) 

1 3 2

212
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Falco columbarius Merlin

Summer MDI: Occasional in summer, sightings of 

birds have occurred regularly during the 

summer, but no other direct evidence of 

breeding 

SCH: Unconfirmed breeder IAH: No summer records 

1 0 3 4

Falco peregrinus Peregrine Falcon 

Breeding MDI: Locally common, Breeding at 3 

locations within the park; BBS average 

RA = 0.06% 

SCH: Uncommon during summer; no 

records of breeding 

IAH: No summer records 

4 MDI BBS – No Change 

MDI – extirpated as a breeding population 

during the past decade (Bond 1969), recent reintroduction efforts have been successful 

3 1-E 1

Falco sparverius American Kestrel

Breeding MDI: Uncommon, Breeding reported on 

MDI (Witt 1997) but no details of nesting within park boundaries; BBS average RA = 0.03% 

SCH: Unconfirmed breeder 

IAH: No summer records 

1 MDI BBS – No Change 2 4 

Geothlypis trichas Common 

Yellowthroat 

Breeding MDI: Very Common breeder throughout 

MDI; BBS average RA = 3.7% 

SCH: Common; breeding suspected but not 

confirmed 

IAH: Common, Breeding confirmed on 

island (Pierson 1983) 

ISL: Occasional on islands, breeding 

confirmed (Mittelhauser et al. 1992) 

1 MDI BBS – No Change 2 3 4 

Haliaeetus 

leucocephalus 

Bald Eagle 

Breeding Winter 

MDI: Common breeder and winter resident, 

breeding confirmed; BBS average RA = 

0.01% 

SCH: Common in summer and winter 

IAH: Nesting on island; commonly observed 

both summer and winter 

ISL: Common in summer and winter; 

nesting on many park islands 

4 MDI CBC – Increasing (P = 0.02) (mean 

= 5.2, n = 62) 

MDI BBS – No Change SCH CBC – Increasing (P = 0.009) (mean 

= 4.0, n = 41) 

5 2-T MODERATE 1

Hirundo rustica Barn Swallow 

Breeding MDI: Common Breeder on MDI, breeding 

at Anemone Cave (Long 1987); BBS average RA = 0.4% 

SCH: Uncommon; Breeding not confirmed 

IAH: Common, Breeding confirmed on 

island (Pierson 1983) 

ISL: Uncommon, nesting on Baker Island 

(Russell 1984) 

2 MDI BBS – No Change 2 2 MODERATE 2 

Hylocichla 

mustelina 

Wood Thrush

Breeding MDI: Common Breeder, breeding reported 

at Sieur de Monts Spring (Witt 1997); BBS average RA = 0.09% 

IAH: Uncommon, Breeding suspected 

(Pierson 1983) but not confirmed 

1 MDI BBS – No Change 

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

3 2 HIGHEST 1

213
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Icterus galbula Baltimore Oriole 

Breeding MDI: Uncommon breeder, breeding at Sieur 

de Monts Spring area (Witt 1997); BBS average RA = 0.02% 

SCH: Unconfirmed IAH: Uncommon, Breeding suspected 

(Jones 1987) but not confirmed 

1 MDI BBS – No Change 

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

3 2 2

Junco hyemalis Dark-eyed Junco 

Breeding Winter 

MDI: Very Common breeder throughout 

MDI; BBS average RA = 1.9% 

SCH: Uncommon in summer and winter; 

breeding suspected but not confirmed 

IAH: Uncommon in summer and winter, 

Breeding confirmed on island (Pierson 1983) 

1 MDI CBC – No Change (+) (P = 0.11) 

(mean = 41.8, n = 67) 

MDI BBS – No Change 

SCH CBC – No Change (+) (P = 0.97) 

(mean = 22.4, n = 37) 

2 4

Lanius excubitor Northern Shrike 

Winter MDI: Uncommon in winter 

SCH: Uncommon IAH: Rare in winter 

1 MDI CBC – No Change (+) (P = 0.31) 

(mean = 1.5, n = 38) 

SCH CBC – No Change (+) (P = 0.29) 

(mean = 1.7, n = 25) 

2 4

Loxia curvirostra Red Crossbill 

Breeding Winter 

MDI: Irregular abundance, breeding reported 

at Otter Point and Ship Harbor (Long 1987); BBS average RA = 0.4% 

SCH: Variable; breeding not confirmed 

IAH: Uncommon summer and winter, 

Breeding suspected (Jones 1987) but not confirmed 

1 MDI CBC – No Change (-) (P = 0.45) 

(mean = 16.4, n = 18) 

MDI BBS – RA Increasing 0.4%/year 

MDI – extremely rare in summer from 

1920 to 1940, since then it has become occasionally abundant (Bond 1969) 

SCH CBC – No Change (+) (P = 0.84) 

(mean = 24.1, n = 10) 

3 2 2

Loxia leucoptera White-winged 

Crossbill

Breeding Winter 

MDI; Irregularabundance, breeding reported 

from Otter Point and Ship Harbor (Witt 1997, Long 1987); BBS average RA = 

0.1% 

SCH: Variable; breeding not confirmed IAH: Occasional during summer and winter, 

Breeding suspected (Jones 1987) but not confirmed 

1 MDI CBC – No Change (+) (P = 0.43) 

(mean = 49.9, n = 41) 

MDI BBS – RA Decreasing 0.1%/year 

SCH CBC – No Change (+) (P = 0.84) 

(mean = 37.2, n = 17) 

3 3 4

Meleagris gallopavo Wild Turkey

Breeding Winter 

MDI: Rare, no evidence of breeding SCH: Rare year round IAH: Occasional to common based on 

recent introduction of wild stock to island, Breeding suspected but not confirmed 

1 0 3

Melospiza lincolnii Lincoln’s Sparrow 

Breeding MDI: Uncommon breeder, nesting reported 

at Big Heath (Long 1987) 

SCH: Uncommon; Breeding not confirmed 

IAH: Present on island during early June 

1983 (Pierson 1983), no other records 

1 0 4

214
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Melospiza melodia Song Sparrow

Breeding MDI: Abundant breeder throughout MDI; 

BBS average RA = 1.7% 

SCH: Uncommon; Breeding not confirmed IAH: Common, Breeding suspected (Pierson 

1983) but not confirmed 

ISL: Common, Breeding confirmed on 

Schoodic Island (Mittelhauser et al. 1992) 

1 MDI BBS – No Change 2 4

Mimus polyglottos Northern 

Mockingbird

Breeding Winter 

MDI: Occasional in summer and winter, 

breeding reported on MDI although no breeding records exist for within the park 

1 MDI – Recorded with increasing 

frequency in the last 10 years (Russell 

1984) 

1 4

Mniotilta varia Black-and-white 

Warbler 

Breeding MDI: Common breeder, breeding at Sieur de 

Monts Spring (Witt 1997); BBS average RA = 1.8% 

SCH: Uncommon; Breeding suspected but 

not confirmed 

IAH: Common, Breeding confirmed on 

island (Pierson 1983) 

1 MDI BBS – RA Increasing 0.5%/year 

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999)

3 2 2

Molothrus ater Brown-headed 

Cowbird 

Breeding MDI: Very Common breeder throughout 

MDI; BBS average RA = 0.5% 

SCH: Occasional; Breeding suspected but 

not confirmed 

IAH: Common, Breeding suspected (Jones 

1987) but not confirmed 

1 MDI BBS – No Change 

MDI – Increasing in numbers (Pellew 

1927) 

3 4

Myiarchus crinitus Great Crested 

Flycatcher 

Breeding MDI: Common but local breeder, breeding 

at Sieur de Monts Spring (Long 1987);

BBS average RA = 0.4% 

SCH: Uncommon; Breeding not confirmed IAH: Uncommon, Breeding suspected 

(Jones 1987) but not confirmed 

ISL: Rare, Breeding not confirmed 

1 MDI BBS – RA Increasing 0.04%/year 

MDI – Species has extended its range on 

MDI in recent years, likely a result of the fire of 1947 (Bond 1969) 

2 2 2

Nyctea scandiaca Snowy Owl 

Winter MDI: Rare in winter 

SCH: Rare ISL: Rare in winter 

2 0 4

Oporornis 

philadelphia 

Mourning Warbler

Breeding (Historic) 

MDI: Rare in summer, has bred in the park 

in past years but no recent breeding records (Witt 1997); BBS average RA = 0.03% 

SCH: Uncommon; Breeding not confirmed 

1 MDI BBS – No Change 2 4 

Parula americana Northern Parula 

Breeding MDI: Common breeder throughout MDI; 

BBS average RA = 2.3% 

SCH: Occasional; breeding suspected but 

not confirmed 

IAH: Abundant, Breeding confirmed on 

island (Pierson 1983) 

1 MDI BBS – No Change 2 2 MODERATE 2

215
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Passer domesticus House Sparrow

Breeding Winter 

MDI: Locally common summer and winter, 

breeding reported for MDI but no breeding records for the park 

SCH: Unconfirmed 

1 MDI CBC – No Change (-) (P = 0.78) 

(mean = 49.4, n = 57) 

SCH CBC – No Change (-) (P = 0.52) 

(mean = 12.1, n = 24) 

2 4

Passerculus 

sandwichensis 

Savannah Sparrow 

Breeding MDI: Common Breeder, breeding at Bass 

Harbor Marsh (Witt 1997); BBS average RA = 0.2% 

SCH: Uncommon; breeding not confirmed 

IAH: Uncommon, Breeding suspected 

(Jones 1987) but not confirmed 

ISL: Common, Breeding on Baker (Witt 

1997) and Schoodic (Mittelhauser et al. 1992) Islands 

1 MDI BBS – No Change 2 4

Passerina cyanea Indigo Bunting

Summer MDI: Occasional, no nests discovered on 

MDI, but breeding is suspected; BBS average RA = 0.01% 

1 MDI BBS – No Change 2 4 

Perisoreus 

canadensis 

Gray Jay 

Breeding Winter 

MDI: Very rare summer and winter, 

breeding reported near Bass Harbor Marsh 

(Bond 1969), Great Heath (Witt 1997), and Town Hill (Long 1987) 

SCH: Uncommon; Breeding on Big Moose 

Island (Glanz and Connery 1999) 

1 MDI CBC – No Change (+) (P = 0.30) 

(mean = 1.7, n = 20) 

MDI – Decreased greatly in numbers 

during the past 100 years (Bond 1949) 

SCH CBC – No Change (-) (P = 0.41) 

(mean = 4.1, n = 16) 

2 MODERATE 3

Petrochelidon 

pyrrhonota 

Cliff Swallow 

Breeding MDI: Common breeder on MDI, breeding at 

Anemone Cave (Witt 1997); BBS average RA = 0.3% 

SCH: Historically nested (Goodridge 1962), 

no recent breeding records 

IAH: Uncommon, Breeding suspected 

(Pierson 1983) but not confirmed 

1 MDI BBS – RA Declining 0.3%/year 2 2 

Phasianus colchicus Ring-necked 

Pheasant

Breeding Winter 

MDI: Rare, no evidence of breeding SCH: Historic record; no indication if 

population is established 

IAH: Uncommon based on previous 

introductions to island (Manville 1964); breeding suspected but not confirmed 

within park boundaries.

1 MDI CBC – No Change (-) (P = 0.14) 2 4 

Pheucticus 

ludovicianus 

Rose-breasted 

Grosbeak 

Breeding MDI: Uncommon breeder, breeding at Sieur 

de Monts Spring (Long 1987); BBS average RA = 0.1% 

SCH: Uncommon; breeding not confirmed 

IAH: Uncommon, Breeding suspected 

(Jones 1987) but not confirmed 

1 MDI BBS – RA Increasing 0.04%/year 2 2 MODERATE 2 

216
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Picoides arcticus Black-backed 

Woodpecker

Breeding Winter 

MDI: Rare breeder and rare in winter, 

breeding in the upper part of Bass Harbor Head (Long 1987)

SCH: Uncommon in summer and winter 

IAH: Uncommon in winter, no summer 

records 

1 MDI CBC – No Change (+) (P = 0.23) 

(mean = 1.3, n = 9) 

2 3 MODERATE 2

Picoides pubescens Downy Woodpecker 

Breeding Winter 

MDI: Very common breeder throughout 

MDI, common in winter; BBS average RA = 0.4% 

SCH: Common in summer and winter; 

Breeding suspected but not confirmed 

IAH: Uncommon, Breeding suspected 

(Jones 1987) but not confirmed 

1 MDI CBC – No Change (+) (P = 0.39) 

(mean = 26.7, n = 64) 

MDI BBS – No Change 

SCH CBC – No Change (-) (P = 0.25) 

(mean = 8.0, n = 45) 

2 4

Picoides villosus Hairy Woodpecker 

Breeding Winter 

MDI: Common breeder throughout MDI, 

common in winter; BBS average RA = 0.3% 

SCH: Uncommon summer and winter; 

Breeding suspected but not confirmed 

IAH: Common in summer, uncommon in 

winter, Breeding confirmed on island 

(Pierson 1983)

1 MDI CBC – No Change (+) (P = 0.43) 

(mean = 17.8, n = 60) 

MDI BBS – No Change 

SCH CBC – No Change (+) (P = 0.68) 

(mean = 5.3, n = 40) 

2 4

Pinicola enucleator Pine Grosbeak

Winter MDI: Irregular abundance 

SCH: Uncommon ISL: Rare, Breeding not confirmed 

1 MDI CBC – Declining (P = 0.004) (mean 

= 36.7, n = 34) 

SCH CBC – No Change (-) (P = 0.78) 

(mean = 19.5, n = 17) 

3 3 MODERATE 3

Pipilo 

erythrophthalmus 

Eastern Towhee 

Breeding MDI: Common breeder, breeding reported 

on the slopes of Cadillac Mountain (Witt 1997); BBS average RA = 0.1% 

SCH: Uncommon; breeding not confi med r

IAH: Uncommon, Breeding suspected 

(Pierson 1983) but not confirmed 

1 MDI BBS – No Change 

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

3 2 2

Piranga olivacea Scarlet Tanager 

Breeding MDI: Uncommon breeder, breeding at Sieur 

de Monts Spring (Witt 1997); BBS average RA = 0.08% 

SCH: Uncommon; breeding not confirmed 

1 MDI BBS – No Change 2 2 2 

Plectrophenax 

nivalis 

Snow Bunting

Winter MDI: Uncommon to rare 

SCH: Uncommon to rare IAH: Rare in winter 

1 MDI CBC – No Change (+) (P = 0.58) 

(mean = 11.3, n = 19) 

SCH CBC – No Change (-) (P = 0.25) 

(mean = 14.9, n = 7) 

2 4

Poecile atricapilla Black-capped 

Chickadee 

Breeding Winter 

MDI: Common breeder throughout MDI; 

BBS average RA = 3.7% 

SCH: Common in summer and winter; 

Breeding suspected but not confirmed 

IAH: Common summer and winter, 

Breeding suspected (Jones 1987) but not confirmed 

ISL: Unconfirmed 

1 MDI CBC – Increasing (P = 0.006) (mean 

= 313.6, n = 68) 

MDI BBS – No Change SCH CBC – No Change (+) (P = 0.64) 

(mean = 110.0, n = 46) 

3 4

217
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Poecile hudsonica Boreal Chickadee 

Breeding Winter 

MDI: Uncommon breeder and uncommon in 

winter, breeding at Bass Harbor Light 

(Witt 1997)

SCH: Common but local breeder (Glanz and 

Connery 1999), uncommon to occasional 

in winter 

IAH: Uncommon and local, summer and 

winter, Breeding confirmed on island 

(Palmer 1949, Pierson 1983) 

ISL: Unconfirmed but likely present (Long 

1987)

1 MDI CBC – Declining (P = 0.04) (mean = 

6.4, n = 26) 

SCH CBC – Declining (P = 0.03) (mean = 

6.6, n = 23)

5 HIGH 1

Pooecetes gramineus Vesper Sparrow 

Summer MDI: Rare in summer, no evidence of 

nesting on MDI (Witt 1997) 

SCH: Rare in summer 

IAH: Unconfirmed (Manville 1964) 

1 REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

1 2-SC MODERATE 3

Progne subis Purple Martin

Breeding (Historic) 

MDI: Unconfirmed during summer, 

historically nested on MDI (Long 1987)

SCH: Rare; no historic breeding records IAH: Rare; formerly nested on island 

(Manville 1964) 

2 MDI – Formerly abundant on MDI 

(Pellew 1927) 

1 2 3

Quiscalus quiscula Common Grackle

Breeding MDI: Common in summer, breeding 

throughout MDI; BBS average RA = 1.0%

SCH: Uncommon; breeding not confirmed 

IAH: Common, Breeding suspected (Pierson 

1983) but not confirmed 

1 MDI BBS – No Change 2 4

Regulus calendula Ruby-crowned 

Kinglet 

Breeding MDI: Common breeder on MDI breeding at 

Otter Point (Davis 1961); BBS average RA = 0.6% 

SCH: Occasional in summer; Breeding 

suspected but not confirmed 

IAH: Uncommon, Breeding suspected 

(Pierson 1983) but not confirmed 

1 MDI BBS – No Change 

MDI – Formerly very rare on MDI, now 

common and widespread (Tyson and 

Bond 1941) 

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

3 4

Regulus satrapa Golden-crowned 

Kinglet 

Breeding Winter 

MDI: Common breeder throughout MDI, 

common in winter; BBS average RA = 1.6% 

SCH: Common breeder (Glanz and Connery 

1999), common in winter 

IAH: Common summer and winter, 

Breeding confirmed on island (Pierson 1983) 

1 MDI CBC – Increasing (P < 0.001) (mean 

= 20.1, n = 62) 

MDI BBS – No Change SCH CBC – No Change (+) (P = 0.22) 

(mean = 11.7, n = 40) 

SCH – Decline noted 1995-96 (Glanz and 

Connery 1999) 

3 4

Riparia riparia Bank Swallow

Breeding MDI: Common breeder on MDI (Witt 1997), 

no confirmed breeding within park boundaries 

SCH: Rare in summer; Breeding not 

confirmed 

ISL: Uncommon, Breeding on Schoodic 

Island (Mittelhauser et al. 1992) 

1 0 3 MODERATE 2

218
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Sayornis phoebe Eastern Phoebe 

Breeding MDI: Common breeder, nesting at Sieur de 

Monts Spring (Witt 1997); BBS average RA = 0.3% 

SCH: Unconfirmed IAH: Uncommon, Breeding suspected 

(Jones 1987) but not confirmed 

1 MDI BBS – RA Decreasing 0.1%/year 2 4 

Scolopax minor American 

Woodcock 

Breeding MDI: Common, Breeding in many areas on 

MDI; BBS average RA = 0.01% 

SCH: Occasional; breeding unconfirmed IAH: Uncommon during summer; Breeding 

historically reported (Hebard 1959)

1 MDI BBS – No Change 

REGION – Declining in the eastern 

spruce-hardwood forest region of the 

northeast (Rosenberg and Hodgman 2000)and the northern New England region (Hodgman and Rosenberg 2000)

3 2 HIGHEST 1

Seiurus aurocapillus Ovenbird

Breeding MDI: Common breeder throughout MDI; 

BBS average RA = 4.8% 

SCH: Occasional; Breeding suspected but 

not confirmed 

IAH: Common, Breeding confirmed on 

island (Pierson 1983) 

1 MDI BBS – No Change 2 3 MODERATE 2 

Seiurus 

noveboracensis 

Northern 

Waterthrush 

Breeding MDI: Uncommon breeder on MDI, breeding 

suspected within the park; BBS average 

RA = 0.1% 

SCH: Uncommon; Breeding suspected (Witt 

1997) but not confirmed 

IAH: Uncommon to rare, Breeding 

suspected (Pierson 1983) but not 

confirmed 

1 MDI BBS – No Change 2 4 

Setophaga ruticilla American Redstart

Breeding MDI: Common breeder throughout MDI; 

BBS average RA = 1.7% 

SCH: Common; Breeding suspected but not 

confirmed 

IAH: Common, Breeding confirmed on 

island (Pierson 1983) 

1 MDI BBS – No Change 

SCH – Increase noted during 1995-96 

(Glanz and Connery 1999) 

3 3 HIGH 2

Sialia sialis Eastern Bluebird 

Breeding MDI: Rare breeder on MDI, breeding 

confirmed on MDI, but no breeding records confirmed within park; BBS average RA = 0.01% 

1 MDI BBS – No Change 

MDI – formerly more common on MDI, a 

slight increase during the late 1960s (Bond 1969) 

3 4

Sitta canadensis Red-breasted 

Nuthatch 

Breeding Winter 

MDI: Very common breeder throughout 

MDI and common during winter; BBS average RA = 1.8% 

SCH: Uncommon in summer and winter; 

Breeding not confirmed 

IAH: Common, Breeding suspected (Pierson 

1983) but not confirmed 

ISL: Uncommon, breeding suspected 

(Mittelhauser et al. 1992) but not confirmed 

1 MDI CBC – Increasing (P < 0.001) (mean 

= 40.1, n = 62) 

MDI BBS – No Change 

SCH CBC – No Change (+) (P = 0.11) 

(mean = 15.5, n = 41) 

3 4

219
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Sitta carolinensis White-breasted 

Nuthatch

Breeding Winter 

MDI: Locally common summer and winter, 

breeding reported for MDI although no breeding records exist for within the park 

SCH: Uncommon in winter, no summer 

records; Breeding not confirmed 

IAH: Uncommon, Breeding not confirmed 

1 MDI CBC – No Change (+) (P = 0.18) 

(mean = 8.3, n = 45) 

SCH CBC – No Change (+) (P = 0.26) 

(mean = 1.5, n = 21) 

2 4

Sphyrapicus varius Yellow-bellied 

Sapsucker

Breeding? MDI: Common, breeding on MDI although 

no records of breeding from within park; 

BBS average RA = 0.01% 

SCH: Unconfirmed IAH: Uncommon in summer; no evidence of 

breeding 

1 MDI BBS – No Change 2 2 HIGH 1 

Spizella arborea American Tree 

Sparrow 

Winter MDI: Common in winter 

SCH: Unconfirmed IAH: Unconfirmed 

1 MDI CBC – No Change (-) (P = 0.68) 

(mean = 52.7, n = 61) 

SCH CBC – No Change (-) (P = 0.08) 

(mean = 21.0, n = 41) 

2 4

Spizella passerina Chipping Sparrow 

Breeding MDI: Common breeder on MDI; BBS 

average RA = 0.4% 

SCH: Uncommon; Breeding not confirmed IAH: Uncommon in summer, Breeding 

suspected (Pierson 1983) but not 

confirmed 

1 MDI BBS – No Change 2 4 

Spizella pusilla Field Sparrow 

Breeding MDI: Rare breeder on MDI, breeding 

suspected within park boundaries 

SCH: Unconfirmed in summer 

1 MDI – Southern species that has become 

established as a summer resident since the fire of 1947 (Bond 1969) 

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

1 2 3

Stelgidopteryx 

serripennis 

Northern Roughwinged Swallow

Breeding (Historic) 

MDI: Rare, Historically bred on MDI, but no 

recent records (Witt 1997); BBS average 

RA = 0.06% 

1 MDI BBS – No Change 

MDI – This southern species has been 

steadily spreading northward and now appears regularly on MDI (Bond 1969) 

3 3 3

Strix varia Barred Owl 

Breeding Winter

MDI: Uncommon breeder and winter 

resident, breeding on MDI (Witt 1997) 

SCH: Rare during summer and winter; 

Breeding not confirmed 

IAH: Uncommon, Breeding not confirmed 

1 MDI CBC – No Change (+) (P = 0.44) 

(mean = 1.0, n = 9) 

2 2 2

Sturnella magna Eastern 

Meadowlark

Breeding (Historic) 

MDI: Rare breeder on MDI, no recent 

breeding records within park (Witt 1997) 

SCH: Unconfirmed in summer 

1 REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

0 2-SC 3

220
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Sturnus vulgaris European Starling

Breeding Winter 

MDI: Common summer and winter, 

breeding throughout MDI; BBS average RA = 1.1% 

SCH: Common in summer and winter; 

Breeding not confirmed 

IAH: Common summer, uncommon in 

winter, Breeding confirmed on island 

(Pierson 1983)

ISL: Occasional; Breeding on Schoodic 

Island (Mittelhauser et al. 1992) 

1 MDI CBC – No Change (+) (P = 0.17) 

(mean = 148.6, n = 63)

MDI BBS – No Change MDI – Recently become a regular and 

common summer resident on MDI 

(Tyson and Bond 1941) 

SCH CBC – No Change (+) (P = 0.85) 

(mean = 87.0, n = 46) 

3 4

Tachycineta bicolor Tree Swallow 

Breeding MDI: Common breeder throughout MDI; 

BBS average RA = 1.3% 

SCH: Uncommon in summer; Breeding not 

confirmed 

IAH: Common, Breeding confirmed on 

island 

1 MDI BBS – RA Declining 0.6%/year 2 3 2 

Toxostoma rufum Brown Thrasher 

Breeding MDI: Common breeder on MDI; BBS 

average RA = 0.1% 

SCH: Uncommon; breeding not confirmed 

IAH: Uncommon, Breeding not confirmed 

1 MDI BBS – RA Declining 0.04%/year 

MDI – Rarely seen on MDI before the fire 

of 1947, now they occur on the burnt 

lands (Bond 1969)

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

2 2 2

Troglodytes aedon House Wren

Breeding? MDI: Uncommon to rare, breeding 

confirmed on MDI (Bond 1969) but no records within park boundaries; BBS 

average RA = 0.01% 

SCH: Unconfirmed IAH: Unverified historic record of nesting 

on island (Manville 1964) 

1 MDI BBS – No Change 2 3 4 

Troglodytes 

troglodytes 

Winter Wren 

Breeding MDI: Common, Breeding at many areas on 

MDI; BBS average RA = 1.4% 

SCH: Occasional; breeding not confirmed 

but likely 

IAH: Uncommon during summer, Breeding 

suspected (Pierson 1983) but not confirmed 

1 MDI BBS – No Change 2 4 

Turdus migratorius American Robin 

Breeding Winter 

MDI: Very Common breeder throughout; 

BBS average RA = 4.9% 

SCH: Occasional; Breeding suspected but 

not confirmed 

IAH: Common in summer, Rare in winter, 

Breeding suspected (Pierson 1983) but not confirmed 

1 MDI CBC – Increasing (P = 0.05) (mean 

= 12.7, n = 56) 

MDI BBS – No Change SCH CBC – No Change (+) (P = 0.61) 

(mean = 8.9, n = 32) 

SCH – Decline noted from 1995-96 

(Glanz and Connery 1999) 

3 4

221
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Tyrannus tyrannus Eastern Kingbird

Breeding MDI: Occasional; breeding at Breakneck 

and Beaverdam Ponds (Russell 1984); BBS average RA = 0.1% 

SCH: Unconfirmed IAH: Uncommon, Breeding suspected 

(Pierson 1983) but not confirmed 

1 MDI BBS – No Change 

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999) 

3 2 2

Vermivora peregrina Tennessee Warbler 

Breeding MDI: Uncommon breeder, breeding in the 

Lurvey Spring and Marshall Brook area 

(Bond 1969, 1971); BBS average RA = 0.04% 

SCH: Uncommon; breeding not confirmed 

1 MDI BBS – No Change 2 3 4 

Vermivora 

ruficapilla 

Nashville Warbler 

Breeding MDI: Common breeder on MDI, Breeding 

near Wonderland (Bond 1955); BBS average RA = 2.6% 

SCH: Common breeder (Glanz and Connery 

1999)

IAH: Uncommon, Breeding confirmed on 

island (Pierson 1983) 

1 MDI BBS – No Change 2 4

Vireo gilvus Warbling Vireo

Breeding MDI: Rare, nesting at Sieur de Monts Spring 

(Long 1987); BBS average RA = 0.01% 

1 MDI BBS – No Change 2 4 

Vireo olivaceus Red-eyed Vireo 

Breeding MDI: Common breeder, breeding at many 

locations on MDI; BBS average RA = 

3.8% 

SCH: Uncommon; Breeding not confirmed IAH: Common, Breeding suspected (Pierson 

1983) but not confirmed 

1 MDI BBS – No Change 2 4 

Vireo solitarius Blue-headed Vireo 

Breeding MDI: Common breeder throughout MDI; 

BBS average RA = 1.0% 

SCH: Uncommon; Breeding not confirmed IAH: Uncommon, Breeding suspected 

(Jones 1987) but not confirmed 

1 MDI BBS – No Change 

SCH – Decline noted 1995-96 (Glanz and 

Connery 1999) 

3 4

Wilsonia canadensis Canada Warbler 

Breeding MDI: Common breeder on MDI, breeding 

near The Bowl (Tyson and Bond 1941); 

BBS average RA = 0.4% 

SCH: Uncommon; breeding not confirmed IAH: Uncommon, Breeding confirmed on 

island (Manville 1964) 

1 MDI BBS – RA Increasing 0.01%/year

REGION – Significant declines noted in 

region (Rosenberg and Wells 1999)

3 2 HIGHEST 1

Wilsonia pusilla Wilson’s Warbler 

Breeding MDI: Occasional breeder, no breeding 

reported in the last couple of years (Witt 

1997); BBS average RA = 0.02% 

SCH: Uncommon; Breeding not confirmed 

IAH: Uncommon, Breeding suspected 

(Pierson 1983) but not confirmed 

1 MDI BBS – No Change 

MDI – No breeding reported in the last 

couple of years (Witt 1997) 

3 4

222
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION IN 

ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

PROPOSED ANP PRIORITY6

Zenaida macroura Mourning Dove 

Breeding Winter 

MDI: Common in summer and winter, 

breeds sparingly near developed areas (Witt 1997); BBS average RA = 2.8% 

SCH: Common summer and winter; 

breeding not confirmed 

IAH: Uncommon during summer, rare 

during winter; Breeding suspected 

(Pierson 1983) but not confirmed 

1 MDI CBC – Increasing (P < 0.001) (mean 

= 226.1, n = 43) 

MDI BBS – No Change SCH CBC – Increasing (P < 0.001) (mean 

= 66.5, n = 35) 

SCH – Declines reported from 1995-1996 

Glanz and Connery 1999) (

3 4

Zonotrichia albicollis White-throated 

Sparrow 

Breeding Zenaida macroura 

Mourning Dove 

1 MDI BBS – No Change 2 3 4

1 DATA QUALITY: 1) Poorly known: little or no effort to discern population status or distribution throughout ANP; 2) Scattered reports: existing information 

may or may not correctly estimate status or distribution; 3) Generally well known: scattered anecdotal reports likely reflects status and distribution, but 

only poor or incomplete data available; 4) Reliable data: park-wide survey with good status and distribution information. 

2. POPULATION TREND: To calculate the mean number of birds observed during CBCs, only counts where the species was observed were included. If a 

species was not reported during a count in a year, that years data was not included in calculating the mean. Sample size reported (n) is the number of 

years a species was reported. 

3 TREND CONFIDENCE: 0: no data available for assessment of trends; 1: anecdotal evidence or no easily discernable trends; 2: slight or no trends evident 

based on surveys; 3: trends possible or vary over time, mixed evidence; 4: trends significant, based on <10 years data; 5: trends significant, based on > 10 years data. 

4 MAINE PRIORITY STATUS: Maine Fish and Wildlife priority codes(Maine Department of Inland Fisheries and Wildlife 2005): 1: high potential for state 

extirpation without management intervention and/or protection; 2: moderate to high potential for state extirpation without management intervention and/or protection; 3 low to moderate potential for state extirpation, yet, there are some remaining concerns regarding restricted distribution, status, and/or extreme habitat specialization. T: Threatened in Maine; E: Endangered in Maine; SC: ‘Special Concern’ in Maine (Maine Department of Inland 

Fisheries and Wildlife 1996). 

5. REGIONAL CONCERN: Conservation priority categories for birds in BCR 14 (Dettmers 2007). 

6. Proposed ANP Priority birds for research: 1. Highest; 2. High; 3. Moderate or peripheral; 4. Low. 

223
Appendix 6. 

Condition assessment for breeding and resident marsh bird 

populations in Acadia National Park. 

Species in bold letters are considered of potential conservation concern in Acadia National Park. 

Locations referred to in table refer to Mount Desert Island (MDI), Isle au Haut (IAH), Schoodic 

Peninsula (SCH), and small offshore islands (ISL). 

224
SPECIES R E S I D E N C Y ABUNDANCE & D

IN ACADIA NATIONAL PARKDATA QUALITY

ISTRIBUTION DATA 

QUALITY

1

POPULATION TREND2

TREND CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

WATERBIRD CONSERVATION CONCERN6

PROPOSED ANP PRIORITY7

Agelaius 

eus 

Breeding ng at many 

SCIS

al. 

1 MDI BBS – RA 

/year phoenic

Red-winged 

Blackbird 

MDI: Common, breedi

areas on MDI; BBS average RA =1.6% 

H: Uncommon; no confirmed 

breeding 

IAH: Common during summer; 

breeding confirmed on island (Pierson 1983) 

L: Uncommon, breeding 

suspected (Mittelhauser et 1992) but not confirmed 

increasing 0.3%

MDI – Increasing on 

t MDI during the pas

60 years (Long 1987) 

2 4 

Aix sponsa Breeding M

t 

2 MDI – ‘increasing’ 

%/year 

2 MODERATE 2 

Wood Duck

DI – Occasional but local; 

breeding likely, but no recennesting reported within the park; BBS average RA = 0.2% 

1927-1987 (Long 1987) 

MDI BBS – RA 

increasing 0.05

Ammodramus 

iled 

Breeding M eeding 

SCIA

2 2 2 HIGHEST 1 

nelsoni 

Nelson’s 

ta SharpSparrow

DI: Common but local, br

at Bass Harbor Marsh (Witt 

1997); BBS average RA = 0.05% 

H: Common but local; Breeding 

in salt marsh along park road 

(Witt 1997) 

H: Unconfirmed (Manville 1964) 

MDI BBS – No change 

Anas crecca Breeding 

ll 

SC

1 0 3 4 

Green-winged

Teal 

Winter 

MDI: Occasional breeder and 

g has occasional in winter, breedin

been historically reported (Russe

1984); southern limit of breeding

range is reached in Maine (Adamus 1987) 

H: Unconfirmed 

IAH: Rare in winter 

Anas discors Breeding eeding 

Witt 

1 0 3 4 

Blue-winged 

Teal 

MDI: Uncommon, Br

confirmed at Seawall Pond (1997)

SCH: Unconfirmed IAH: Unconfirmed 

Anas 

yrhynchos 

Breeding mmer and 

SC

1 MDI CBC – Increasing 

S

5 3 MANAGEMENT 4 

plat

Mallard 

Winter 

MDI: Common in su

winter, Breeding confirmed at Northeast Creek and Lower 

Breakneck Pond (Witt 1997); BBS average RA = 0.1% 

H: Present 

med in summer IAH: Unconfir

(P < 0.001) (mean = 102.3, n = 45) 

CH CBC – Increasing 

(P < 0.001) (mean = 

28.7, n = 33) 

CONCERN 

225
SPECIES R E S I D E N C Y ABUNDANCE & DISTRIBUTION 

IN ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2

TREND CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

WATERBIRD CONSERVATION CONCERN6

PROPOSED ANP PRIORITY7

Anas rubripes Breeding MDI: Common summer and winter, 

SC

 and 

s 

IS

1 MDI CBC – Increasing 

SR

3 2 HIGHEST 1 

American 

uck Black D

Winter breeding confirmed at many 

locations 

H: Common in winter, 

unconfirmed in summer 

IAH: Uncommon in summer

winter; Breeding suspected (Jone1987) but not confirmed 

L: Common in winter, Breeding 

suspected but not confirmed (Hebard 1959) 

(P = 0.008) (mean = 494.3, n = 63) 

CH CBC – Declining 

(P = 0.02) (mean = 

240.5, n = 46) 

EGION – Declining 

(Rosenberg and Hodgman 2000)

Ardea herodias Breeding 

) 

M eeding 

es 

SC

1 0 2 HIGH 2 

Great Blue 

Heron

(historic

DI: Common in summer, br

historically reported at SomSound (Farley 1935), no breeding 

records since 

H: Uncommon to occasional in 

summer 

IAH: Uncommon during summer

ISL: Uncommon during summer; 

Historically nested on Heron Island (Folger 1986), no current 

breeding records from park islands 

Aythya collaris Breeding M 1 0 3 4 

Ring-necked 

Duck 

DI: Occasional, Breeding reported 

at many ponds 

Botaurus 

lentigino

American 

sus 

Breeding M many 1 0 2 MODERATE HIGHEST 1 

Bittern 

DI: Common, breeding at 

locations 

Branta 

ens canad

Canada Goose

is 

Breeding? MDI: Rare in summer and winter; 

SC

mmer; 

IS , 

1 MDI CBC – Increasing 3 3 MANAGEMENT 4 

Winter no recent reports of nesting 

although nesting is recorded for 

the island (Bond 1969) 

H: Rare in winter 

 in su IAH: Status unknown

rare in winter; Breeding not confirmed 

L: Rare in summer and winter

Breeding not confirmed but a summer record exists (Favour1974) 

(P < 0.001) (mean = 66.2, n = 29) 

SCH CBC – No Change 

(+) (P = 0.06) (mean = 

10.9, n = 15) 

CONCERN 

226
SPECIES R E S I D E N C Y ABUNDANCE & DISTRIBUTION 

IN ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2

TREND CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

WATERBIRD CONSERVATION CONCERN6

PROPOSED ANP PRIORITY7

Butorides 

n

Breeding MDI: Rare, Only record of breeding 

ing 

SC

1 0 3 MODERATE 3 

virescens

Green Hero

(Historic) was on Hamilton Pond dur

1968 (Bond 1969); species 

approaches the northern edge of its breeding range in Maine 

H: Unconfirmed in summer 

IAH: Historic reference to species 

on island (Hebard 1959), no recent records 

Ceryle alcyon Belted 

Breeding 1 MDI BBS – No Change 2 4 

Kingfisher 

MDI: Common, breeding in many 

areas on MDI (Witt 1997); BBS 

average RA = 0.03% 

SCH: Occasional; breeding not 

confirmed 

IAH: Uncommon during summer;

breeding not confirmed 

Chlidonias 

niger 

Summer 2 0 1-E HIGH 3 

Black Tern

MDI: Unconfirmed in summer, one 

summer record 

ISL: Rare, breeding not confirmed 

Cistothorus 

palustris 

n Marsh Wre

REGION – Significant 

declines noted in 

3 Breeding? MDI: Rare, Pair and male nests with 

no eggs observed at Beaverdam 

g Pond in 1968 (Bond 1969, Lon

1987), no other evidence of 

breeding; species reaches northeastern most edge of 

breeding range in Maine 

2 

region (Rosenberg andWells 1999) 

0 2 

Empidonax 

alnorum 

Breeding M

d 

1 MDI BBS – No Change 2 4 

Alder 

Flycatcher

DI: Common breeder, breeding at

Sieur de Monts Spring (Long 

1987); BBS average RA = 2.2% 

SCH: Occasional; Breeding not 

confirmed 

ed IAH: Common, Breeding suspect

(Pierson 1983) but not confirme

Empidonax 

flaviventris 

d 

Breeding 1 MDI BBS – No Change 

MDI – Formerly 

2 MODERATE 2 

Yellow-bellie

Flycatcher

MDI: Common breeder throughout 

MDI; BBS average RA = 0.4% 

SCH: Occasional; Breeding not 

confirmed 

IAH: Uncommon, Breeding not 

confirmed 

considered local on MDI, now well

distributed on the western half of MDI (Long 1953) 

Empidonax 

traillii 

Summer 

(Witt 1997); BBS 

1 M 2 2 3 

Willow 

Flycatcher

MDI: Rare, breeding not detected 

on MDI average RA = 0.01% 

SCH: Rare; Breeding not confirmed

DI BBS – No Change 

227
SPECIES R E S I D E N C Y ABUNDANCE & DISTRIBUTION 

IN ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2

TREND CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

WATERBIRD CONSERVATION CONCERN6

PROPOSED ANP PRIORITY7

Gallinago Breeding? MDI: Occasional; Breeding is 

987) 

SC

1 0 MODERATE 2 

delicata 

Wilson’s Snipe

suspected (Witt 1997, Long 1but not confirmed 

H: Breeding not confirmed 

IAH: No summer records 

Gavia immer 

n 

Breeding er 

SCIAIS

2 MDI CBC – Increasing 

M

3 2 MODERATE HIGHEST 1 

Common Loo Winter 

MDI: Common breeder and wint

resident, breeding reported at many locations 

H: No records of breeding; 

Uncommon in summer, 

Occasional to common in winter 

H: Common in winter and 

no occasional during summer; 

records suggesting breeding 

L: Common in winter, breeding 

not confirmed 

(P < 0.001) (mean = 35.5, n = 61) 

DI – Reproductive 

success low on MDI

SCH CBC – No Change

(-) (P = 0.30) (mean = 

33.2, n = 46) 

Ixobrychus 

rn 

Breeding 

) 

m 

.)

 (B

1 0 2-SC HIGHEST 3 

exilis 

Least Bitte

(historic

MDI: Rare, breeding on island at 

Beaver Dam Pond in 1968 and 

1969; recent breeding record froBass Harbor Marsh (tributary “2 

Moose Pond” in 2000; T. Hodgman, MDIFW, pers. comm

ond 1969); species reaches 

northern edge of its breeding range in Maine 

Lophodytes 

cucullatus 

Breeding 

(historic) 

as 

) 

SC

1 0 4 

Hooded 

Merganser 

MDI: Rare in summer; Breeding h

been reported from Breakneck 

Ponds and Echo Lake (Witt 1997but no recent evidence of breeding 

H: Unconfirmed 

Melospiza 

georgiana 

Breeding M

 average 

1 MDI BBS – No Change 2 4 

Swamp 

Sparrow 

DI: Very Common breeder

BS throughout MDI; B

RA = 0.7% 

SCH: Uncommon; Breeding not 

confirmed 

IAH: Uncommon, Breeding 

suspected (Pierson 1983) but not 

confirmed 

Mergus 

merganser 

Breeding 1 0 4 

Common

Merganser 

MDI: Rare, breeding on Jordan 

Pond and Bubble Pond (Witt 

1997) 

SCH: Unconfirmed 

228
SPECIES R E S I D E N C Y ABUNDANCE & DISTRIBUTION 

IN ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2

TREND CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

WATERBIRD CONSERVATION CONCERN6

PROPOSED ANP PRIORITY7

Nycticorax 

ed 

Breeding MDI: Rare, Several nesting colonies 

n MDI 

ered 

941)

IS

1 MDI – Historically 

us 

1 2 HIGH HIGHEST 3 

nycticorax

Black-crown

Night-heron

(Historic) were historically reported o

when the species was consid

numerous (Tyson and Bond 1

L: Rare in summer; Historically 

nested on Heron Island (Folger 1986) and possibly one of the Porcupine Islands (Allen 1899), breeding not recently confirmed 

considered numeroin summer (Tyson and Bond 1941), now 

considered rare (Witt 1997) 

Pandion 

haliaetus 

Breeding M

IA

1 MDI – Declining (Long 

1987) 

1 3 

Osprey

DI: Common, Breeding reported 

on island, but no confirmed nesting within park reported 

SCH: Uncommon breeder 

H: Nesting directly adjacent to

rkers, island on navigational ma

commonly observed in summer 

ISL: Locally common in summer,

Historic breeding on park islands (Farley 1935, Russell 1984), no recent records for nesting on park islands 

Podilymbus 

podiceps 

Breeeding (Historic) 

M

at 

s 

SC

2 0 2 HIGHEST 3 

Pied-billed 

Grebe 

DI: Occasional, No records of 

breeding recently (Witt 1997), 

Historically reported as nesting Seal Cove Pond and Aunt Betty’Pond (Palmer 1949, Bond 1969) 

H: Unconfirmed during breeding 

season 

 records IAH: No confirmed summer

Porzana 

carolina 

Sora

Summer eeding 1 0 3 HIGH 3 MDI: Uncommon to rare, br

suspected but not confirmed 

SCH: Breeding not confirmed; 

species present as a migrant 

Rallus limicola 

ia Ra Virgin il 

1 0 3 RATE 2 Breeding MDI: Uncommon, Breeding at 

Great Meadow (Witt 1997) andSeal Cove area (Bond 1969) 

MODE

1 1) Poorly known: population status or distribution throughout ANP; 2) Scattered reports: existing information may or 

ay not correctly estimate stat rally well known: scattered anecdotal reports likely reflects status and distribution, but only poor or 

complete data available; 4) Reliable data: park-wide survey with good status and distribution information. 

 DATA QUALITY: little or no effort to discern

us or distribution; 3) Gene m

in

2. POPULATION TREND: To calculate the mean number of birds observed during CBCs, only counts where the species was observed were included. If a species was

not reported during a count in a year, that years data was not included in calculating the mean. Sample size reported (n) is the number of years a species was 

reported. 

229
3 TREND CONFIDENCE: 0: no data available for assessment of trends; 1: anecdotal evidence or no easily discernable trends; 2: slight or no trends evident based on 

surveys; 3: trends possible or vary over time, mixed evidence; 4: trends significant, based on <10 years data; 5: trends significant, based on > 10 years data. 

E PRIORITY STATUS: Maine Fish and Wildlife priority codes(Maine Department of Inland Fisheries and Wildlife 2005): 1: high potential for state 4 MAIN

life 

5. REGI

6. WAT

7. Propo

extirpation without management intervention and/or protection; 

2: moderate to high potential for state extirpation without management intervention and/or 

protection; 

3 low to moderate potential for state extirpation, yet, there are some remaining concerns regarding restricted distribution, status, and/or extreme 

Wild habitat specialization. 

T: Threatened in Maine; 

E: Endangered in Maine; SC: ‘Special Concern’ in Mai

ne (Maine Department of Inland Fisheries and 

1996). 

ONAL CONCERN: Conservation priority categories for birds in BCR 14 (Dettmers 2007). 

ERBIRD CONSERVATION CONCERN: Regional waterbird population priorities in the mid-Atlantic, New England, and Maritimes region of North America.

sed ANP Priority birds for research: 1. Highest; 2. High; 3. Moderate or peripheral; 4. Low. 

230
Appendix 7. 

Condition assessment for breeding and resident marine bird 

populations in Acadia National Park. 

Species in bold letters are considered of potential conservation concern in Acadia National Park. 

Locations referred to in table refer to Mount Desert Island (MDI), Isle au Haut (IAH), Schoodic 

Peninsula (SCH), and small offshore islands (ISL). 

231
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION 

IN ACADIA NATIONAL PARK DATA QUALITY

DATA QUALITY

1

POPULATION TREND2 TREND 

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

WATERBIRD CONSERVATION CONCERN6

PROPOSED ANP PRIORITY7

Actitis macularia Spotted Sandpiper

Breeding MDI: Common, many nests found 

on MDI (Witt 1997) 

SCH: Occasional; no confirmed 

breeding 

IAH: Occasional during summer, 

Breeding suspected (Pierson 1983) 

but not confirmed 

ISL: Common to occasional during 

summer, breeding suspected 

(Mittelhauser et al. 1992, Witt 1997) but not confirmed 

1 0 4

Alca torda Razorbill

Summer Winter 

MDI: Rare in summer and winter SCH: Rare in summer, uncommon 

in winter 

ISL: Rare in summer and winter 

2 SCH CBC – Increasing (P 

= 0.02) (mean = 5.1, n = 10) 

4 2-T HIGH HIGH 3

Alle alle Dovekie

Winter MDI: Uncommon

SCH: Uncommon IAH: Uncommon in winter 

1 MDI CBC – No Change (-) 

(P = 0.98) (mean = 3.0, n 

= 15) 

SCH CBC – Declining (P = 

0.04) (mean = 3.4, n = 

14) 

4 LOW 3

Aythya marila Greater Scaup 

Winter MDI: Common winter resident 

SCH: Sporadic numbers, 

occasionally common 

IAH: Rare in winter; no winter 

records from within park boundaries 

ISL: Locally common in winter 

adjacent to park islands (Favour 

1970, Witt 1997). 

2 MDI CBC – No Change (-) 

(P = 0.94) mean = 478.8, (

n = 51)

SCH CBC – No Change (-) 

(P = 0.53) (mean = 18.1, n = 17)

2 2 MODERATE 2

Bucephala 

albeola 

Bufflehead 

Winter MDI: Abundant in winter 

SCH: Common in winter IAH: Common in winter ISL: Locally common in winter 

1 MDI CBC – No Change (+) 

(P = 0.46) (mean = 336.0, n = 62)

SCH CBC – No Change (-) 

(P = 0.06) (mean = 235.1, n = 46)

2 4

Bucephala 

clangula 

Common 

Goldeneye

Winter MDI: Common in winter; said to 

have once nested on MDI (Tyson 

and Bond 1941) although the ANP region is far out of its breeding 

range 

SCH: Uncommon in winter IAH: Uncommon to Occasional in 

winter 

ISL: Locally common to occasional 

in winter 

1 MDI CBC – No Change (-) 

(P = 0.37) (mean = 265.9, 

n = 59)

SCH CBC – Declining (P = 

0.01) (mean = 195.0, n = 46) 

3 3 MODERATE 2

232
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION 

IN ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND 

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

WATERBIRD CONSERVATION CONCERN6

PROPOSED ANP PRIORITY7

Bucephala 

islandica 

Barrow’s 

Goldeneye

Winter MDI: Rare in winter 

SCH: Rare in winter IAH: Unconfirmed 

2 MDI CBC – No Change (-) 

(P = 0.27) (mean = 6.0, n = 32) 

SCH CBC – No Change (+) 

(P = 0.92) (mean = 3.7, n = 22)

2 2-SC HIGHEST 3

Calidris maritima Purple Sandiper 

Winter MDI: Common 

SCH: Common IAH: Common during winter ISL: Common during winter 

4 MDI CBC – No Change (+) 

(P = 0.27) (mean = 120.0, n = 41)

SCH CBC – No Change (-) 

(P = 0.29) (mean = 99.8, n = 38)

2 2 HIGHEST 1

Catoptrophorus 

semipalmatus 

Willet

Summer MDI: Unconfirmed within the park 

during summer (Witt 1997) 

SCH: Unconfirmed within the park 

during summer (Glanz and 

Connery 1999) 

1 0 2 MODERATE 3

Cepphus grylle Black Guillemot 

Breeding Winter 

MDI: Common in summer and 

winter, nesting at Otter Cliffs (Long 1987) 

SCH: Common in winter; no record 

of breeding on peninsula 

IAH: Common summer and winter, 

no records suggesting breeding on island 

ISL: Common in summer and 

winter, common breeder on manyislands 

3 MDI CBC – Increasing (P 

< 0.001) (mean = 31.1, n = 58) 

SCH CBC – No Change (+) 

(P = 0.29) (mean = 19.1, 

n = 46)

3 3 HIGH MODERATE 1

Charadrius 

melodus 

Piping Plover

Summer MDI: No evidence of breeding 

within park; summer records exist in region 

1 0 1-E HIGHEST 3

Clangula 

hyemalis 

Long-tailed 

Duck 

Winter MDI: Abundant in winter

SCH: Common in winter IAH: Common in deeper waters ISL: Common in deeper waters 

adjacent to park islands 

2 MDI CBC – No Change (+) 

(P = 0.14) (mean = 615.6, 

n = 63)

SCH CBC – Declining (P < 

0.001) (mean = 353.6, n 

= 46) 

REGION – Declines noted 

in the region (Sea Duck Joint Venture Management Board 

2006) 

3 3 MODERATE 2

Fratercula 

arctica 

Atlantic Puffin

Summer Winter 

MDI: Rare in summer and winter; 

reportedly used to breed on MDI 

(Palmer 1949) 

SCH: Rare in summer and winter 

2 0 2-T MODERATE MODERATE 3

233
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION 

IN ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND 

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

WATERBIRD CONSERVATION CONCERN6

PROPOSED ANP PRIORITY7

Fulmarus 

glacialis 

Northern Fulmar

Winter MDI: Rare

SCH: Unconfirmed IAH: Extremely rare during winter 

2 0 LOW 4

Gavia stellata Red-throated 

Loon

Winter MDI: Occasional in winter 

SCH: Uncommon in winter 

1 MDI CBC – No Change (-) 

(P = 0.13) (mean = 2.0, n = 27)

SCH CBC – No Change (+) 

(P = 0.66) (mean = 2.0, n = 23)

2 3 MODERATE HIGHEST 2

Histrionicus 

histrionicus 

Harlequin Duck

Winter MDI: Uncommon in winter 

SCH: Uncommon in winter IAH: Common in winter ISL: Locally common adjacent to 

some islands 

4 IAH – Declining until 

1992, then increasing 

SCH CBC – Increasing (P 

= 0.04) (mean = 3.6, n = 

7) 

3 2-T HIGHEST 1

Larus argentatus Herring Gull 

Breeder Winter 

MDI: Abundant in summer and 

winter; no confirmed breeding 

SCH: Abundant in summer and 

winter; no confirmed breeding 

IAH: Abundant summer and winter; 

no confirmed breeding 

ISL: Abundant summer and winter, 

Breeding on many park islands 

1 MDI CBC – Increasing (P 

= 0.03) (mean = 1201.0, 

n = 63) 

SCH CBC – No Change (-) 

(P = 0.13) (mean = 

1018.1, n = 45)

3 3 HIGH HIGH 1

Larus atricilla Laughing Gull 

Summer MDI: Common; no confirmed 

breeding 

SCH: Common; no confirmed 

breeding 

IAH: Uncommon; no records 

suggesting breeding on island 

ISL: Occasional to locally common, 

no confirmed breeding 

1 0 3-SC HIGH 3

Larus 

delawarensis 

Ring-billed Gull 

Winter MDI: Uncommon in winter 

SCH: Uncommon in winter 

1 MDI CBC – Increasing (P 

< 0.001) (mean = 41.6, n 

= 40) 

SCH CBC – Increasing (P 

< 0.001) (mean = 19.3, n 

= 31) 

5 LOW 4

Larus glaucoides Iceland Gull 

Winter MDI: Uncommon to rare in winter 

SCH: Uncommon to rare in winter IAH: Occasional in winter 

1 MDI CBC – No Change (+) 

(P = 0.35) (mean = 1.3, n = 9) 

SCH CBC – Increasing (P 

< 0.001) (mean = 3.3, n = 

25) 

3 LOW 4

234
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION 

IN ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND 

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

WATERBIRD CONSERVATION CONCERN6

PROPOSED ANP PRIORITY7

Larus 

hyperboreus 

Glaucous Gull 

Winter MDI: Uncommon in winter 

SCH: Rare in winter IAH: Rare in winter ISL: Rare win winter 

1 MDI CBC – No Change (+) 

(P = 0.31) (mean = 1.0, n = 10)

SCH CBC – No Change (+) 

(P = 0.08) (mean = 1.6, n = 10)

2 LOW 4

Larus marinus Great Blackbacked Gull 

Breeder Winter 

MDI: Common to abundant yearround; no confirmed breeding 

SCH: Common year-round; no 

confirmed breeding 

IAH: Common summer and winter 

ISL: Common summer and winter, 

breeding on park islands 

1 MDI CBC – Increasing (P 

= 0.001) (mean = 76.7, n 

= 62)

SCH CBC – No Change (-) 

(P = 0.09) (mean = 68.7, 

n = 46)

IAH – Numerous and 

increasing by 1958 

(Hebard 1959) 

3 3 LOW 4

Larus 

philadelphia 

Bonaparte’s Gull 

Winter MDI: Uncommon, found further 

offshore (Russell 1984) 

ISL: Uncommon to rare in winter 

SCH: Uncommon in winter 

1 MDI CBC – No Change (+) 

(P = 0.06) (mean = 5.1, n = 21)

SCH CBC – Increasing (P 

= 0.02) (mean = 10.4, n = 

7) 

3 2 breed-ing MODERATE 3

Melanitta fusca White-winged 

Scoter 

Winter MDI: Abundant in winter 

SCH: Common in winter IAH: Common in winter ISL: Locally common in winter 

1 MDI CBC – Increasing (P 

= 0.002) (mean = 492.6, 

n = 62) 

SCH CBC – Decreasing (P 

= 0.004) (mean = 532.1, n = 44) 

REGION – Declines noted 

in the region (Sea Duck Joint Venture Management Board 

2006) 

3 3 3

Melanitta nigra Black Scoter 

Winter MDI: Uncommon in winter 

SCH: Uncommon in winter IAH: Uncommon in winter, but 

numbers can vary greatly from

year to year 

ISL: Locally occasional in winter 

1 MDI CBC – Decreasing (P 

= 0.03) (mean = 49.6, n = 

45) 

SCH CBC – No Change (+) 

(P = 0.70) (mean = 15.2, 

n = 29)

REGION – Declines noted 

in the region (Sea Duck 

Joint Venture Management Board 2006) 

3 3 HIGH 1

235
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION 

IN ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND 

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

WATERBIRD CONSERVATION CONCERN6

PROPOSED ANP PRIORITY7

Melanitta 

perspicillata 

Surf Scoter 

Winter MDI: Uncommon in winter 

SCH: Uncommon in winter IAH: Uncommon in winter ISL: Uncommon but local in winter 

1 MDI CBC – Decreasing (P 

= 0.02) (mean = 20.0, n = 

41) 

SCH CBC – No Change (+) 

(P = 0.16) (mean = 9.1, n 

= 33)

REGION – Declines noted 

in the region (Sea Duck 

Joint Venture Management Board 2006) 

3 3 MODERATE 1

Mergus serrator Red-breasted 

Merganser 

Breeding Winter 

MDI: Occasional breeder, common

in winter, Breeding on Little Long 

Pond, Jordan Pond, and Eagle 

Lake (Witt 1997) 

SCH: Common in winter 

IAH: Common in winter, Breeding 

historically reported (Manville 

1964) 

ISL: Common in winter, breeding 

not confirmed on park islands 

1 MDI CBC – Increasing (P 

< 0.001) (mean = 56.1, n = 61) 

SCH CBC – No Change (+) 

(P = 0.54) (mean = 49.0, 

n = 45)

3 3 (breeding) 4

Oceanites 

oceanicus 

Wilson’s StormPetrel 

Summer MDI: Uncommon, more common 

offshore 

ISL: Uncommon 

2 0 LOW 4

Oceanodroma 

leucorhoa 

Leach’s StormPetrel

Breeding MDI: Very rare

SCH: Very rare 

IAH: Uncommonly observed from 

shore during the day 

ISL: Uncommon, breeding on Heron 

Island and Schoodic Island 

2 0 3-SC MODERATE MODERATE 2

Phalacrocorax 

auritus 

Double-crested 

Cormorant 

Breeding MDI: Abundant 

SCH: Common to abundant 

IAH: Common during summer ISL: Abundant during summer, 

breeding on Schoodic Island 

2 ISL: Only established 

breeding colonies here since about 1920 (Bond 1969)

1 LOW 4

Phalacrocorax 

carbo 

Great 

Cormorant 

Summer Winter 

MDI: Occasional in summer, 

common in winter 

SCH: Uncommon in summer,

occasional in winter 

IAH: Uncommon during summer, 

common to occasional in winter 

ISL: Uncommon in summer, 

common to occasional in winter, 

breeding not confirmed 

2 MDI CBC – No Change (-) 

(P = 0.15) (mean = 27.7, 

n = 57)

SCH CBC – Declining (P < 

0.001) (mean = 17.7, n = 46) 

3 2-SC HIGHEST HIGH 2

236
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION 

IN ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND 

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

WATERBIRD CONSERVATION CONCERN6

PROPOSED ANP PRIORITY7

Podicips auritus Horned Grebe 

Winter MDI: Common 

SCH: Common IAH: Common during winter ISL: Common during winter 

1 MDI CBC – No Change (+) 

(P = 0.14) (mean = 84.3, n = 62)

SCH CBC – Declining (P < 

0.001) (mean = 58.9, n = 46) 

3 3 MODERATE HIGHEST 1

Podicips 

grisegena 

Red-necked 

Grebe 

Winter MDI: Occasional 

SCH: Uncommon to occasional IAH: Occasional during winter, 

numbers can vary from year to 

year 

ISL: Occasional during winter 

1 MDI CBC – Increasing (P 

< 0.001) (mean = 32.1, n 

= 58) 

SCH CBC – No Change (+) 

(P = 0.07) (mean = 21.4, 

n = 45)

3 HIGH HIGH 1

Rissa tridactyla Black-legged 

Kittiwake 

Winter MDI: Uncommon, generally found 

further offshore 

SCH: Uncommon although a good 

place to observe this species 

IAH: Uncommon in winter 

1 MDI CBC – No Change (+) 

(P = 0.10) (mean = 8.2, n 

= 11)

SCH CBC – Increasing (P 

< 0.001) (mean = 4.8, n = 

23) 

3 MODERATE LOW 3

Somateria 

mollissima 

Common Eider 

Breeding Winter 

MDI: Abundant during summer and 

winter 

SCH: Abundant during summer and 

winter 

IAH: Abundant during summer and 

winter 

ISL: Abundant during summer and 

winter; Breeding on Schoodic 

Island and Heron Island 

(Mittelhauser 1992, Folger 1986) 

2 MDI CBC – Increasing (P 

< 0.001) (mean = 3078.5, 

n = 61) 

SCH CBC – No Change (-) 

(P = 0.45) (mean = 

1768.7, n = 46)

3 2 HIGHEST 1

Sterna dougallii Roseate Tern 

Summer MDI: Rare 

SCH: Uncommon to rare ISL: Locally rare, breeding not 

confirmed 

3 0 1-E HIGH HIGHEST 3

Sterna hirundo Common Tern 

Summer MDI: Common 

SCH: Common IAH: Uncommon during summer ISL: Common, breeding not 

confirmed 

3 IAH – Used to be abundant, 

now less so in the area (Hebard 1959)

1 2-SC HIGH HIGHEST 3

Sterna 

paradisaea 

Arctic Tern 

Summer MDI: Uncommon

SCH: Uncommon IAH: Uncommon in summer 

ISL: Uncommon, breeding not 

confirmed 

3 0 2-T HIGH HIGHEST 3

Uria aalge Common Murre 

Winter MDI: Uncommon to rare in winter 

ISL: Rare in winter 

1 0 2 MODERATE 2

237
SPECIES RESIDENCY ABUNDANCE & DISTRIBUTION 

IN ACADIA NATIONAL PARK DATA QUALITY 

DATA QUALITY

1

POPULATION TREND2 TREND 

CONF3

MAINE PRIORITY STATUS4

REGIONAL CONCERN5

WATERBIRD CONSERVATION CONCERN6

PROPOSED ANP PRIORITY7

Uria lomvia Thick-billed 

Murre 

Winter MDI: Occasional to uncommon 

SCH: Uncommon IAH: Rare during winter ISL: Rare in winter 

1 0 LOW 4

1 DATA QUALITY: 1) Poorly known: little or no effort to discern population status or distribution throughout ANP; 2) Scattered reports: existing information 

may or may not correctly estimate status or distribution; 3) Generally well known: scattered anecdotal reports likely reflects status and distribution, but 

only poor or incomplete data available; 4) Reliable data: park-wide survey with good status and distribution information. 

2. POPULATION TREND: To calculate the mean number of birds observed during CBCs, only counts where the species was observed were included. If a 

species was not reported during a count in a year, that years data was not included in calculating the mean. Sample size reported (n) is the number of 

years a species was reported. 

3 TREND CONFIDENCE: 0: no data available for assessment of trends; 1: anecdotal evidence or no easily discernable trends; 2: slight or no trends evident 

based on surveys; 3: trends possible or vary over time, mixed evidence; 4: trends significant, based on <10 years data; 5: trends significant, based on > 10 years data. 

4 MAINE PRIORITY STATUS: Maine Fish and Wildlife priority codes(Maine Department of Inland Fisheries and Wildlife 2005): 1: high potential for state 

extirpation without management intervention and/or protection; 2: moderate to high potential for state extirpation without management intervention and/or protection; 3 low to moderate potential for state extirpation, yet, there are some remaining concerns regarding restricted distribution, status, and/or extreme habitat specialization. T: Threatened in Maine; E: Endangered in Maine; SC: ‘Special Concern’ in Maine (Maine Department of Inland 

Fisheries and Wildlife 1996). 

5. REGIONAL CONCERN: Conservation priority categories for birds in BCR 14 (Dettmers 2007). 

6. WATERBIRD CONSERVATION CONCERN: Regional waterbird population priorities in the mid-Atlantic, New England, and Maritimes region of North 

America. 

7. Proposed ANP Priority birds for research: 1. Highest; 2. High; 3. Moderate or peripheral; 4. Low. 

238
Appendix 8. 

Potential threats to land bird populations of conservation 

concern in Acadia National Park. 

Topics in bold are considered a potentially important threat in Acadia National Park, deserving 

additional study. 

239
SPECIES HABITAT DISRUPTION CONTAMINANTS, SPILLS, DISEASE, 

PARASITISM 

OTHER INDICATORS OR STRESSORS 

Accipiter cooperii Cooper’s Hawk 

Bioaccumulation of pesticides and other 

contaminants (Curtis and Rosenfield 2006) 

DDE (e.g., dieldrin, PCBs, mercury and other heavy 

metals reported in eggs with unknown effects (Curtis and Rosenfield 2006) 

Collisions with man-made objects (Curtis and 

Rosenfield 2006) 

Shooting and trapping (Curtis and Rosenfield 2006) 

Accipiter gentilis Northern Goshawk 

Timber harvest is primary threat to nesting populations 

(Squires and Reynolds 1997) 

Harvest methods that create large areas of reduced forest 

canopy cover (<35–40%) (Squires and Reynolds 1997) 

Human disturbance and development near nest site 

(Squires and Reynolds 1997) 

Asio otus Long-eared Owl 

Loss of open habitats to urbanization and forest succession 

(Marks et al. 1994) 

Contaminants including heptachlor and dieldrin 

(Marks et al. 1994) 

Bonasa umbellus Ruffed Grouse 

Loss of early-successional deciduous forests (Rusch et al. 

2000) 

Pesticides including DDT can cause mortality or 

reduce survival (Rusch et al. 2000) 

Overharvest (Rusch et al 2000) 

Buteo lineatus Red-shouldered Hawk 

Forest fragmentation (Crocoll 1994) DDE, DDD, DDT, dieldrin, heptachlor epoxide, 

hexochlorobenzine, mercury, chlordane, dieldrin, 

Furadan 10, and organochlorine and polychlorinated biphenyls detected in some populations (Crocoll 1994) 

Human disturbance near nest (Crocoll 1994) 

Buteo platypterus Broad-winged Hawk 

Habitat alteration, fragmentation, or elimination, 

particularly on wintering range (Goodrick et al. 1996) 

Increased use of DDT south of U.S. may affect birds 

with a diet of insects (Goodrick et al. 1996) 

Caprimulgus vociferus Whip-poor-will 

Habitat loss to agriculture and closing of forest openings

(Cink 2002) 

Vehicle collisions (Cink 2002) 

Carpodacus purpureus Purple Finch 

Reduction of habitat quality (Dettmers 2007) Predation at nests (Wootton 1996) 

Human disturbance occasionally causes nest 

abandonment (Wootton 1996) 

Catharus fuscescens Veery 

Loss of dense understory in maturing forests; browsing 

by white-tailed deer may be significant (MDIFW 2005, 

Bevier et al. 2004) 

Loss or degradation of wintering habitat (Bevier et al. 2004) 

Nest parasitism by Brown-headed Cowbird

(Bevier et al. 2004) 

Nocturnal collisions with human-made towers 

(Bevier et al. 2004) 

Certhia americana Brown Creeper 

Loss of old growth forests and forest fragmentation (Hejl et 

al. 2002) 

Affected by spraying of DDT (Hejl et al. 2002) Collisions (Hejl et al. 2002) 

Chaetura pelagica Chimney Swift 

Loss of nesting habitat – new or rebuilt chimneys too 

narrow for nesting (MDIFW 2005, Cink and Collins 2002) 

Aerial spraying for spruce budworm (Choristoneura 

fumiferana) has been implicated in declines of prey species (Cink and Collins 2002) 

Gas from fires in chimneys during the nesting 

season (Cink and Collins 2002) 

Collisions with vehicles (Cink and Collins 2002) 

Charadrius vociferus Killdeer 

Susceptible to pollutants, pesticides, and oil 

(Jackson and Jackson 2000) 

Killed by hunters who mistake them for Mourning 

Doves (Jackson and Jackson 2000) 

Prone to collisions with human-made towers and 

vehicles (Jackson and Jackson 2000) 

Chordeiles minor Common Nighthawk 

Pesticide spraying for control of mosquitoes 

implicated in population declines in species 

(Poulin et al. 1996) 

Susceptible to predators, especially domestic cats 

(Poulin et al. 1996)

Collisions with vehicles (Poulin et al. 1996) 

Circus cyaneus Northern Harrier 

Loss of open habitat and degradation of habitat through 

increasing predators are the primary causes of the population decline (MacWhirter and Bildstein 1996) 

Organochloride pesticide contamination 

documented in species (MacWhirter and Bildstein 1996) 

Terrestrial mammals appear to be important 

predators of eggs and nestlings (MacWhirter and Bildstein 1996) 

Human disturbance at nest sites (MacWhirter and 

Bildstein 1996) 

240
SPECIES HABITAT DISRUPTION CONTAMINANTS, SPILLS, DISEASE, 

PARASITISM 

OTHER INDICATORS OR STRESSORS 

Cistothorus platensis Sedge Wren 

Habitat loss through development and agriculture practices 

and wetland alteration (MDIFW 2005) 

Draining and degradation of wetlands and wet-grass 

habitats (Herkert et al. 2001)

Adverse weather on wintering grounds (MDIFW 

2005)

Predation appears to be a major source of nest 

failure (Herkert et al. 2001) 

Coccyzus erythropthalmus Black-billed Cuckoo 

May be susceptible to habitat fragmentation or modification 

(Hughes 2001) 

Potentially susceptible to pesticide-residue 

accumulation (Hughes 2001) 

Species closely tied to fluctuations in tent caterpillar 

populations (MDIFW 2005) 

Collisions with towers and buildings (Hughes 2001) 

Colaptes auratus Northern Flicker 

Loss of mature trees and suitable nest cavities (MDIFW 

2005, Moore 1995) 

Any removal of snags, dead limbs, and diseased trees 

(Moore 1995) 

Competition for nest sites with starlings (MDIFW 

2005, Moore 1995) 

Collisions with vehicles a potential threat (Moore 

1995) 

Contopus cooperi Olive-sided Flycatcher 

Habitat loss on wintering grounds (MDIFW 2005, Altman 

and Sallabanks 2000) 

Decline of postfire habitat (Altman and Sallabanks 2000) 

No data, but spraying of pesticides may be 

detrimental to food supply (Altman and 

Sallabanks 2000)

Increasing predation rates at edge habitats

(MDIFW 2005) 

Contopus virens Eastern Wood-Pewee 

Potentially susceptible to forests sprayed with the 

insecticide diflubenzuron (to control gypsy moth 

Lymantria dispar) (McCarty 1996) 

High populations of deer (> 4–8 deer/km2) may 

lower breeding populations (McCarty 1996) 

Dendroica caerulescens Black-throated Blue Warbler 

Removal of forest shrub layers or reduction of relatively 

complete canopy cover (Holmes et al. 2005) 

Human disturbance during nest building (Holmes et 

al. 2005) 

Dendroica castanea Bay-breasted Warbler 

Loss of mature spruce-fir habitat (MDIFW 2005, Williams 

1996) 

Forest fragmentation (MDIFW 2005) 

Spraying (especially fenitrothion) for spruce 

budworm may be partially responsible for recent 

population declines (Williams 1996) 

Global climate change (MDIFW 2005) 

Population is naturally cyclic with spruce budworm

outbreaks (MDIFW 2005) 

Collisions with towers and lighthouses (Williams 

1996) 

Dendroica fusca Blackburnian Warbler 

Loss of Hemlock stands because of the introduced Hemlock 

Wooly Adelgid (Adelges piceae) (MDIFW 2005, Morse 

2004) 

Forest fragmentation or removal of large conifers (Morse 

2004)

Deforestation on tropical wintering grounds (Morse 2004)

Persistent pesticides, DDT application, and 

application of fenitrothian for spruce budworm 

control (Morse 2004) 

Dendroica palmarum Palm Warbler 

Disturbance of habitat (Wilson 1996) Collisions (Wilson 1996) 

Predation (Wilson 1996) 

Dendroica pensylvanica Chestnut-sided Warbler 

Habitat loss because of development and decline of early 

successional habitat (MDIFW 2005) 

Fenitrothion, Bt (Bacillus thuringiensis), and other 

insecticides may decrease productivity or cause 

abandonment of area (Richardson and Brauning 1995) 

Predation (MDIFW 2005) Collisions with towers (Richardson and Brauning 

1995) 

Dendroica striata Blackpoll Warbler 

Collisions with towers, lighthouses, and other tall 

structures (Hunt and Eliason 1999) 

Dendroica tigrina Cape May Warbler 

Loss of mature conifer forest perhaps through climate 

change or shortened harvest rotations (MDIFW 2005) 

Aerial spraying of spruce forests with 

organophosphate insecticides (phosphamidon, trichlorfon, fenitrothion) (Baltz and Latta 1998) 

Spruce budworm suppression efforts (MDIFW 

2005) 

Collisions with towers and other tall structures 

(Baltz and Latta 1998) 

Dendroica virens Black-throated Green Warbler 

Fragmentation of forests (Morse and Poole 2005) DDT applications and application of fenitrothian in 

spruce budworm control (Morse and Poole 2005) 

241
SPECIES HABITAT DISRUPTION CONTAMINANTS, SPILLS, DISEASE, 

PARASITISM 

OTHER INDICATORS OR STRESSORS 

Dolichonyx oryzivorus Bobolink 

Loss of nesting fields (Martin and Gavin 1995) Increased predation rates because of habitat 

fragmentation (MDIFW 2005) 

Mowing nesting fields before young have fledged

(Martin and Gavin 1995) 

Shooting and trapping on wintering grounds (Martin 

and Gavin 1995) 

Eremophila alpestris Horned Lark 

Habitat loss by reforestation of agricultural lands and 

development (COSEWIC 2003, MDIFW 2005) 

Sensitive to Fenthion, an organophosphorus 

cholinesterase-inhibiting insecticide (Beason 1995) 

Predation (COSEWIC 2003) Human disturbance (COSEWIC 2003) 

Euphagus carolinus Rusty Blackbird 

Loss of wet forested habitat (MDIFW 2005; Avery 1995) Competition from other species for open habitat 

(MDIFW 2005) 

Falcipennis canadensis Spruce Grouse 

Loss of habitat (Boag and Schroeder 1992) Nest predation by red squirrels (Tamiasciurus 

hudsonicus) (Boag and Schroeder 1992) 

Falco peregrinus Peregrine Falcon 

Organochlorine pesticides, particularly DDT and 

HEOD (dieldrin, aldrin); also PCBs, mercury,

and lead (White et al. 2002) 

Human disturbance or aircraft at nest sites

(MDIFW 2005; White et al. 2002) 

Electrocutions and wire strikes (White et al. 2002) 

Collision with buildings or moving vehicles (White 

et al. 2002) 

Haliaeetus leucocephalus Bald Eagle 

Loss of habitat (MDIFW 2005, Buehler 2000) Declining water quality (MDIFW 2005) 

Organophosphorus and carbamate pesticides, 

heavy metals, and other environmental contaminants (DDT, Dieldrin, PCBs, mercury, 

lead (Buehler 2000) 

Human disturbance (MDIFW 2005, Buehler 2000) Human caused deaths in injuries (MDIFW 2005) 

Oil Spills (Buehler 2000) 

Hirundo rustica Barn Swallow 

Loss of open barns for nesting (MDIFW 2005, Brown and 

Brown 1999) 

Hylocichla mustelina Wood Thrush 

Forest fragmentation (Roth et al. 1996) Loss of breeding habitat – scrub understory layer

(MDIFW 2005)

Loss of wintering habitat (MDIFW 2005) 

Ca+ depletion via acid rain (MDIFW 2005) 

Contaminants (MDIFW 2005) 

Collisions with towers or windows (Roth et al. 

1996) 

Icterus galbula Baltimore Oriole 

Sensitive to DDT, Sevin, and arsenate of lead 

(Rising and Flood 1998) 

Collisions with towers (Rising and Flood 1998) 

Loxia curvirostra Red Crossbill 

Forest fragmentation and loss of old growth habitats 

(MDIFW 2005, Adkisson 1996) 

Boreal forest habitat degradation and change (COSWIC 

2004) 

Exotic pests of conifers such as Hemlock Wooly Adelgid 

(MDIFW 2005) 

Competition with and predation by red squirrels 

(COSEWIC 2004) 

Predation by Gray Jays (Adkisson 1996) 

Vehicle collisions (COSEWIC 2004) 

Mniotilta varia Black-and-white Warbler 

Habitat loss and forest fragmentation resulting in patches 

<10 ha in size (Kricher 1995) 

Pesticides such as fenitrothion and phosphamidon; 

chlorinated hydrocarbons (Kricher 1995) 

Myiarchus crinitus Great Crested Flycatcher 

Loss of dead snags and natural nesting cavities (MDIFW 

2005, Lanyon 1997) 

Aerial spraying of pesticides (Lanyon 1997) Potential competition for nest sites with other 

cavity nesters (Starlings) (MDIFW 2005)

Parula americana Northern Parula 

Air pollution has adversely affected the growth of the 

epiphytic lichens used for nest construction in some 

regions of the northeast (MDIFW 2005, Moldenhauer and 

Regelski 1996) 

Susceptible to DDT (Moldenhauer and Regelski 

1996)

Collisions with towers (Moldenhauer and Regelski 

1996) 

Perisoreus canadensis Gray Jay 

Very vulnerable to traps set for terrestrial furbearers 

(Strickland and Ouellet 1993) 

242
SPECIES HABITAT DISRUPTION CONTAMINANTS, SPILLS, DISEASE, 

PARASITISM 

OTHER INDICATORS OR STRESSORS 

Petrochelidon pyrrhonota Cliff Swallow 

Competition with House Sparrows (Brown and 

Brown 1995) 

Pheucticus ludovicianus Rose-breasted Grosbeak 

Loss of edge habitat and young forests (MDIFW 2005, 

Wyatt and Francis 2002) 

Decline of hardwood species (Dettmers 2007) 

Collisions with towers and lighthouses (Wyatt and 

Francis 2002) 

Picoides arcticus Black-backed Woodpecker 

Fire suppression (Dixon and Saab 2000) 

Pinicola enucleator Pine Grosbeak

Deforestation (Adkisson 1999) Collisions with cars in winter (Adkisson 1999) 

Pipilo erythrophthalmus Eastern Towhee 

Loss of early successional habitat (Greenlaw 1996) Predation on ground nests (Greenlaw 1996) 

Piranga olivacea Scarlet Tanager 

Sensitive to forest fragmentation on breeding grounds 

(Mowbray 1999, MDIFW 2005) 

High rates of nest predation and brood 

parasitism by cowbirds (Mowbray 1999)

Poecile hudsonica Boreal Chickadee 

Availability of winter habitat (especially old black spruce 

stands) (Ficken et al. 1996) 

Pooecetes gramineus Vesper Sparrow 

Human activities that remove vegetation cover (MDIFW 

2005) 

Loss of grasslands (Jones and Cornely 2002)

Declines have been attributed to pesticides (Jones 

and Cornely 2002) 

Progne subis Purple Martin 

Displacement from nesting sites by House 

Sparrows and European Starlings (Brown 1997) 

Riparia riparia Bank Swallow 

Loss or stabilization of bank habitat (Garrison 1999) 

Scolopax minor American Woodcock 

Habitat loss and degradation through forest maturation

MDIFW 2005) (

Human development (Dettmers 2007) 

High levels of DDT, dieldrin, PCBs, mercury, 

heptachlor epoxide, and mirex have been reported 

in some populations (MDIFW 2005, Keppie and Whiting 1994) 

Migration barriers (MDIFW 2005) Predation (MDIFW 2005) Over-hunting (Keppie and Whiting 1994) 

Seiurus aurocapillus Ovenbird 

Forest fragmentation (Van Horn and Donovan 1994) Predation (Van Horn and Donovan 1994) 

Setophaga ruticilla American Redstart 

Ageing of forests (Sherry and Holmes 1997) DDT spraying (Sherry and Holmes 1997) Collisions (Sherry and Holmes 1997) 

Nest predators (Sherry and Holmes 1997) 

Sphyrapicus varius Yellow-bellied Sapsucker 

Loss of nesting cavities (MDIFW 2005) Loss of early-successional habitats (Walters et al. 2002) 

Spizella pusilla Field Sparrow 

Loss of suitable habitat (Carey et al. 1994) Sensitive to human disturbance during nest building 

(Carey et al. 1994) 

Strix varia Barred Owl 

Habitat loss through deforestation, timber harvesting, and 

forest fragmentation (Mazur and James 2000) 

Significant levels of organochlorines and PCBs 

detected in some regions; possibly sensitive to heptachlor (Mazur and James 2000) 

Sturnella magna Eastern Meadowlark 

Loss of grassland, agricultural, and old field habitats

(MDIFW 2005) 

Mowing of fields before August, or mowing of fields 

more often than every 3-5 years (Lanyon 1995)

Pesticides (Lanyon 1995) Disturbance at nesting sites; extremely sensitive 

to the presence of humans in breeding territory

(MDIFW 2005, Lanyon 1995) 

243
SPECIES HABITAT DISRUPTION CONTAMINANTS, SPILLS, DISEASE, 

PARASITISM 

OTHER INDICATORS OR STRESSORS 

Tachycineta bicolor Tree Swallow 

Loss of standing dead snags for nest sites (Robertson et al. 

1992) 

Mercury, PCBs, and DDE (Longcore and Haines 

1998, Robertson et al. 1992) 

Acid precipitation may reduce reproductive success 

of some populations (Robertson et al. 1992) 

Displacement from nest sites by European 

Starling and House Sparrow populations (Robertson et al. 1992) 

Toxostoma rufum Brown Thrasher 

Loss of shrubby, edge habitats through maturation of 

forests (Cavitt and Haas 2000) 

Organophosphate or carbamate pesticides (Cavitt 

and Haas 2000)

Collisions with cars and towers (Cavitt and Haas 

2000)

Disturbance at nest sites during incubation (Cavitt 

and Haas 2000) 

Tyrannus tyrannus Eastern Kingbird 

Habitat loss resulting from human development, 

Reforestation of abandoned farmland, and natural 

plant succession (MDIFW 2005, Murphy 1996) 

Pesticides (Murphy 1996) Collisions with automobiles (Murphy 1996) 

Wilsonia canadensis Canada Warbler 

Habitat loss and fragmentation (MDIFW 2005, Conway 

1999) 

Appears sensitive to reduction of understory vegetation 

by forest ungulates or forest management practices(MDIFW 2005, Conway 1999) 

244
Appendix 9. 

Potential threats to marsh bird populations of conservation 

concern in Acadia National Park. 

Topics in bold are considered a potentially important threat in Acadia National Park, deserving 

additional study. 

245
SPECIES HABITAT DISRUPTION CONTAMINANTS, SPILLS, DISEASE, 

PARASITISM 

OTHER INDICATORS OR STRESSORS 

Aix sponsa Wood Duck 

Loss of forested wetlands (Hepp and Bellrose 1995) Overharvest (Hepp and Bellrose 1995) 

Ammodramus caudacutus Saltmarsh Sharp-tailed Sparrow 

Management activities in saltmarshes (MDIFW 2005) Marsh degradation and loss due to development, diking, and 

drainage (Greenlaw and Rising 1994) 

Contaminants especially methyl mercury

(MDIFW 2005) 

Oil spills (MDIFW 2005) 

Ammodramus nelsoni Nelson’s Sharp-tailed Sparrow 

Loss and degradation of saltmarsh habitat (MDIFW 2005) 

Sea level rise (MDIFW 2005) Marsh degradation and loss due to development, diking, and 

drainage (Greenlaw and Rising 1994) 

Oil spills (MDIFW 2005) Industrial discharge (MDIFW 2005) 

Contaminants, mercury (MDIFW 2005) 

Anas rubripes American Black Duck 

Loss and degradation of wetland habitat (MDIFW 2005, 

Longcore et al. 2000) 

Sea level rise (MDIFW 2005) 

Contaminants (MDIFW 2005) Duck plague (duck virus enteritis) caused by a 

herpesvirus, avian botulism (Clostridium 

botulinum), and avian cholera (Pasteurella 

multocida) (Longcore et al. 2000) 

Blooms (red tide) of the dinoflagellate Gonyaulax 

tamarensis can cause significant mortality (Longcore et al. 2000) 

Lead shot ingestion (Longcore et al. 2000) 

Overharvest (Longcore et al. 2000) 

Sensitive to human disturbance at breeding sites 

(Longcore et al. 2000) 

Disturbance at wintering habitats during severe 

weather (MDIFW 2005) 

Competition with Mallards suspected (MDIFW 

2005) 

Aquaculture (MDIFW 2005) 

Ardea herodias Great Blue Heron 

Contaminants including DDE, PCB, dioxins, 

dieldrin, and endrin (Butler 1992) 

Human disturbance and construction within 300 

meters of breeding colonies (Butler 1992) 

Predation by Bald Eagles (MDIFW 2005) 

Nest-site predators (Parsons et al. 2007) 

Botaurus lentiginosus American Bittern 

Marshland invasion by purple loosestrife (Lythrum 

salicaria), may substantially alter habitat, but how this 

effects bitterns has not been assessed (Gibbs et al. 1992a) 

Loss of wetland habitat and habitat degradation (Gibbs et al.

1992a) 

Prey species may be vulnerable to agricultural 

pesticides (Gibbs et al. 1992a) 

Avian disease (Parsons et al. 2007) Contaminants (Parsons et al. 2007)

Human disturbance (Parsons et al. 2007) Over-harvest (Parsons et al. 2007) 

Butorides virescens Green Heron 

Contaminants (Parsons et al. 2007) Nest-site predators (Parsons et al. 2007) 

Human disturbance (Parsons et al. 2007) 

Chlidonias niger Black Tern 

Fluctuating water levels (MDIFW 2005) Overwinter survival may be limited by declines in fish 

populations (MDIFW 2005) 

Loss and/or degradation of wetlands (Dunn and Agro 1995) 

Pesticides may reduce favored insect foods (Dunn 

and Agro 1995) 

Chick predation (MDIFW 2005) 

Cistothorus palustris Marsh Wren 

Loss or degradation of marsh habitat (Kroodsma and Verner 

1997) 

Nest predation thought to be significant

(Kroodsma and Verner 1997) 

Collisions with towers and other structures during 

migration (Kroodsma and Verner 1997) 

Empidonax flaviventris Yellow-bellied Flycatcher 

Forest fragmentation that leads to dessication of ground 

cover (Gross and Lowther 2001)

Empidonax traillii Willow Flycatcher 

Breeding Habitat destruction or degradation (Sedgwick 

2000) 

Collisions with towers and other tall structures 

(Sedgwick 2000) 

Gallinago delicata Wilson’s Snipe 

Loss of wetland habitat (Mueller 2005) Contaminants (Mueller 2005) Overharvest (Mueller 2005) 

Collisions (Mueller 2005) 

246
SPECIES HABITAT DISRUPTION CONTAMINANTS, SPILLS, DISEASE, 

PARASITISM 

OTHER INDICATORS OR STRESSORS 

Gavia immer Common Loon 

Human disturbance and boat traffic near nest sites

(McIntyre and Barr 1997, Parsons et al. 2007)

Extreme shoreline development (T. Hodgman, MDIFW, 

pers. comm.) 

Fluctuation of water level during breeding season

(Parsons et al. 2007) 

Oil spills (MDIFW 2005) Contaminants – PCBs (McIntyre and Barr 1997) Heavy metals: mercury, lead poisoning (MDIFW 

2005, Evers et al. 2003, McIntyre and Barr 1997) 

Avian disease (Parsons et al. 2007) 

By-catch in commercial fisheries (MDIFW 2005) 

Ixobrychus exilis Least Bittern 

Destruction or alteration of wetland habitat (large (>10 ha), 

shallow wetlands with dense growth of robust, emergent vegetation) (Gibbs et al. 1992b, MDIFW 2005) 

Invasion of wetlands by purple loosestrife (Lythrum 

salicaria) and phragmites (Phragmites australis) (Gibbs et al. 1992b, MDIFW 2005) 

Avian disease (Parsons et al. 2007) Contaminants (Parsons et al. 2007) 

Collisions with motor vehicles and transmission 

lines (Gibbs et al. 1992b) 

Nycticorax nycticorax Black-crowned Nightheron 

Habitat loss (MDIFW 2005) Coastal marsh degradation (Parsons et al. 2007) 

Organochlorines, PCBs, and heavy metals are 

potentially a problem (Davis 1993) 

Human disturbance (MDIFW 2005) 

Nest-site predators (Parsons et al. 2007) 

Podilymbus podiceps Pied-billed Grebe 

Loss of large (>10 ha) wetland habitats (Muller and Storer 

1999) 

Large fluctuations of water level (T. Hodgman, MDIFW, 

pers. comm.) 

Invasive plants (Parsons et al. 2007) 

Significant DDE and PCB residues detected in eggs 

(Muller and Storer 1999) 

High mercury concentrations in some populations 

(Muller and Storer 1999) 

Over-harvest (Parsons et al. 2007) 

Porzana carolina Sora 

Inland wetland loss (Parsons et al. 2007) Invasive plants (Parsons et al. 2007) 

Collisions (Parsons et al. 2007) Human disturbance (Parsons et al. 2007) 

Rallus limicola Virginia Rail 

Inland wetland loss (Parsons et al. 2007) Invasive plants (Parsons et al. 2007) Coastal marsh degradation (Parsons et al. 2007)

Contaminants (Parsons et al. 2007) Collisions (Parsons et al. 2007) 

Human disturbance (Parsons et al. 2007) 

247
Appendix 10. 

Potential threats to marine bird populations of conservation 

concern in Acadia National Park. 

Topics in bold are considered a potentially important threat in Acadia National Park, deserving 

additional study.

248
SPECIES HABITAT DISRUPTION CONTAMINANTS, SPILLS, DISEASE, 

PARASITISM 

OTHER INDICATORS OR STRESSORS 

Alca torda Razorbill 

Reduced integrity of nesting islands as development, 

recreational use, timber harvesting, and aquaculture 

increase (Hipfner and Chapdelaine 2002) 

Changes in food availability (MDIWW 2005) 

Oil pollution represents most serious threat (Hipfner 

and Chapdelaine 2002) 

Butyltin, a component of antifouling paints used on 

large ships, found to accumulate in Razorbill 

livers, but consequences unknown (Hipfner and Chapdelaine 2002) 

Contaminants (Parsons et al. 2007) 

Predation from gulls (MDIFW 2005) Limited numbers and distribution of breeding 

colonies (MDIFW 2005) 

Entanglement in fishing gear (Hipfner and 

Chapdelaine 2002) 

Very sensitive to human disturbance; approaching 

tour boats cause adults to abandon nests (at least 

temporarily (Hipfner and Chapdelaine 2002) 

Alle alle Dovekie 

Highly vulnerable to oil – spills or illegally 

discharged from vessels when pumping bilges (Montevecchi and Stenhouse 2002) 

DDT and PCB contaminants and heavy metals 

detected in liver, kidney, muscle, and fat, consequences unknown (Montevecchi and Stenhouse 2002)

Entanglement in fishing gear (Montevecchi and 

Stenhouse 2002) 

Aythya marila Greater Scaup 

Pesticides and other contaminants/toxins (MDIFW 

2005) 

Fuel oil and other hydrocarbons transported by 

commercial vessels a constant risk (Kessel et al. 2002) 

Organochlorine compounds (including DDE and 

PCBs), Aroclor 1260, and heavy metals detected in some populations (Kessel et al. 2002) 

Sensitive to human disturbance (Kessel et al. 2002) Overharvest (MDIFW 2005) 

Bucephala clangula Common Goldeneye 

Declines in habitat quality on both breeding and wintering 

grounds (Eadie et al. 1995) 

Contaminants including PCBs, DDE, and 

mercury (Eadie et al. 1995) 

Overharvest (Eadie et al. 1995) 

Bucephala islandica Barrow’s Goldeneye 

Displacement from foraging areas by aquaculture 

development (MDIFW 2005) 

Habitat degradation through alterations of river beds, 

increased sediment loads from agricultural and industrial 

practices, and loss of coastal and interior wetlands (Eadie et al. 2000) 

Oil spills (MDIFW 2005) Oil spills and pollutant exposure are a potential 

threat (Eadie et al. 2000) 

Overharvest (Eadie et al. 2000, MDIFW 2005) 

Calidris maritima Purple Sandiper 

Oil spills (MDIFW 2005, Payne and Pierce 2002) High levels of organochlorine contaminants (HCH, 

HCB, PCB, and particularly DDT) reported in this 

species (Payne and Pierce 2002) 

Human disturbance (MDIFW 2005) Limited number and distribution of global 

populations (MDIFW 2005) 

Rockweed (Ascophyllum nodosum) harvesting may

be degrading feeding habitat (Payne and Pierce 

2002) 

Catoptrophorus semipalmatus Willet 

Development (MDIFW 2005) Ditching of wetlands (Lowther et al. 2001) 

Oil spills (MDIFW 2005) Botulism outbreaks (bacterium Clostridium 

botulinum type C) reported in some populations 

(Lowther et al. 2001) 

Arsenic (elevated levels), selenium, mercury, DDE, 

and other organochlorines have been reported in some populations (Lowther et al. 2001) 

Human disturbance (MDIFW 2005) Collisions with vehicles (Lowther et al. 2001) 

Cepphus grylle Black Guillemot 

Contaminants such as mercury, pesticides, and 

other residues (Parsons et al. 2007, Eadie et al. 1995) 

Oil spills (Eadie et al. 1995) 

Nest site predators (Parsons et al. 2007) 

Human disturbance on nest sites (Eadie et al. 1995) 

249
SPECIES HABITAT DISRUPTION CONTAMINANTS, SPILLS, DISEASE, 

PARASITISM 

OTHER INDICATORS OR STRESSORS 

Charadrius melodus Piping Plover 

Loss and degradation of habitat at staging areas from 

development and contaminants (MDIFW 2005) 

Oil spills (MDIFW 2005) Human disturbance (MDIFW 2005) 

Avian and mammalian predators during nesting 

(Haig and Elliott-Smith 2004) 

Clangula hyemalis Long-tailed Duck 

Fowl cholera (Pasterulla multocida) and an 

adenovirus have been implicated in large die-offs 

(Robertson and Savard 2002) 

Increasing cadmium, selenium, and mercury 

levels have been reported (Robertson and Savard 

2002) 

Vulnerable to oil (Robertson and Savard 2002) 

High levels of butyltin (active ingredient in 

antifouling marine paint) reported in liver of this 

species (Robertson and Savard 2002) 

Ingestion of lead shot (Robertson and Savard 2002) 

Overharvest (Robertson and Savard 2002) 

By-catch in commercial fishing (Robertson and 

Savard 2002) 

Fratercula arctica Atlantic Puffin 

Habitat loss (MDIFW 2005) Collapse of fish stocks (especially of prey species such as 

herring) near breeding colonies (Lowther et al. 2002) 

Oil spills (MDIFW 2005) Mercury (in some populations), high mercury load 

not found in Gulf of Maine populations (Lowther 

et al. 2002) 

Predation from gulls (MDIFW 2005) 

Nest predators such as rats, mink, gulls, Incidental take during fishing (MDIFW 2005) Limited number and distribution of nesting sites 

(MDIFW 2005) 

Human disturbance during incubation (Lowther et 

al. 2002) 

Gavia stellata Red-throated Loon 

Marine oil spills (Parsons et al. 2007) Contaminants such as mercury (Parsons et al. 

2007, Barr et al. 2000) 

Collisions (Parsons et al. 2007) 

Histrionicus histrionicus Harlequin Duck 

Wintering habitat degradation from shoreline development, 

aquaculture, and algae-harvesting are concerns 

(Robertson and Goudie 1999) 

Oil spills (Wickett 1999, Robertson and Goudie 

1999)

Bioaccumulation of heavy metals (Robertson and 

Goudie 1999) 

Factors lowering adult survival rates (MDIFW

2005)

Limited distribution (MDIFW 2005) 

Human disturbance (Wickett 1999) 

Larus argentatus Herring Gull 

Contaminants (Parsons et al. 2007) Nest-site predators (Parsons et al. 2007) 

Human disturbance (Parsons et al. 2007) 

Larus atricilla Laughing Gull 

Susceptible to Organochlorine compounds, lead, 

and mercury (Burger 1996) 

Human intrusions at colonies (Burger 1996) 

Competition for nesting habitat with Herring Gulls 

(Burger 1996) 

Melanitta nigra Black Scoter 

Increasing commercial harvest of mussels (Bordage and 

Savard 1995) 

High levels of lead, cadmium, PCBs, DDE, and 

mercury have been detected in some populations 

(Bordage and Savard 1995) 

Very susceptible to oil spills (Bordage and Savard 

1995) 

Over-hunting (Bordage and Savard 1995) 

Melanitta perspicillata Surf Scoter 

High levels of cadmium and mercury detected in 

some populations (Savard et al. 1998) 

Susceptible to oil spills (Savard et al. 1998) 

Over-hunting (Savard et al. 1998) 

Oceanodroma leucorhoa Leach’s Storm-Petrel 

Vulnerable to pollution from organochlorine 

compounds (Huntington et al. 1996) 

Oil spills (Huntington et al. 1996) Heavy metals including selenium and mercury

(Huntington et al. 1996) 

Species is vulnerable to introduction of predatory 

mammals (Huntington et al. 1996) 

Trampling of burrows or erosion resulting from 

human visitors or domestic sheep (Huntington

et al. 1996) 

250
SPECIES HABITAT DISRUPTION CONTAMINANTS, SPILLS, DISEASE, 

PARASITISM 

OTHER INDICATORS OR STRESSORS 

Phalacrocorax carbo Great Cormorant 

Habitat loss (MDIFW 2005) Changes in food availability (MDIFW 2005) 

Oil spills (Hatch et al. 2000) Predation from gulls and eagles (MDIFW 2005) 

Very susceptible to disturbance, especially where 

nesting in mixed colonies with gulls (Hatch et al. 

2000, MDIFW 2005) 

Birds drowned in fishing gear (Hatch et al. 2000) 

Podicips auritus Horned Grebe 

Marine oil spills (Parsons et al. 2007, Stedman 

2000) 

Avian disease (Parsons et al. 2007) Contaminants including DDE (Stedman 2000) 

Podicips grisegena Red-necked Grebe 

Marine oil spills (Parsons et al. 2007) Avian disease (Parsons et al. 2007) Contaminants including organochorines, 

mercury, and other heavy metals (Parsons et al.

2007, Sout and Nuechterlein 1999) 

Over-harvest (Parsons et al. 2007) 

Rissa tridactyla Black-legged Kittiwake 

Marine oil spills (Parsons et al. 2007) Contaminants (Baird 1994) 

Somateria mollissima Common Eider 

Habitat loss (MDIFW 2005) Commercial harvesting of blue mussels, sea urchins, and 

marine algae (Goudie et al. 2000, MDIFW 2005)

Oil spills, especially during molt (MDIFW 2005, 

Goudie et al. 2000) 

Fowl cholera (Pasturella multocida) outbreaks 

(Spencer 1980, Goudie et al. 2000) 

Heavy metals (Goudie et al. 2000) 

Over-hunting (MDIFW 2005, Goudie et al. 2000) Human disturbance of nesting islands (MDIFW 

2005) 

Aquaculture development (MDIFW 2005) 

Predation by Great Black-backed Gulls and Bald 

Eagles (MDIFW 2005) 

Sterna dougallii Roseate Tern 

Habitat loss (MDIFW 2005) Changes in food availability (MDIFW 2005) 

Oil spills (MDIFW 2005) Organochlorines, PCBs, lead, mercury, 

cadmium, and selenium detected in some 

colonies (Gochfeld et al. 1998) 

Predation by gulls and mink (MDIFW 2005) Predation by Peregrine Falcons (Drennan 1986) Human disturbance on nesting islands (MDIFW 

2005, Gochfeld et al. 1998) 

Limited number and distribution of breeding 

colonies (MDIFW 2005) 

Sterna hirundo Common Tern 

Habitat loss (MDIFW 2005) Competition for nesting sites with gulls (MDIFW 2005) Changes in food availability (MDIFW 2005) Human development, building, recreational activity, and 

other degradation of habitat (Nisbet 2002) 

High levels of DDE, PCBs, other 

Organochlorines, mercury (Hg), lead (Pb), 

cadmium (Cd), chromium (Cr), and selenium (Se) reported from some populations; especially sensitive to embryotoxic effects of DDE and dioxin-like toxic effects of PCBs (Nisbet 2002) 

Predation from gulls and mink (MDIFW 2005) Predation by Peregrine Falcons (Drennan 1986) Human disturbance on nesting islands (MDIFW 

2005)

Limited number and distribution of breeding 

colonies (MDIFW 2005) 

Sterna paradisaea Arctic Tern 

Habitat loss and disturbance (MDIFW 2005, Hatch 2002) Competition for nesting sites with gulls (MDIFW 2005) 

Changes in food availability; competition with commercial 

fisheries (MDIFW 2005, Hatch 2002) 

DDE, PCBs, oxychlordane, Mercury (Hg), and 

Cadmium detected at some populations (Hatch 

2002)

Predation and displacement by gulls (MDIFW 2005, 

Hatch 2002) 

Predation by Peregrine Falcons (Drennan 1986) 

Limited number and distribution of breeding 

colonies (MDIFW 2005) 

Uria aalge Common Murre 

High levels of DDE, PCB, dieldrin, and mercury

reported in some populations (Ainley et al. 2002)

Significant mortality from oil pollution and spills 

(Ainley et al. 2002) 

Mortality associated with commercial fishing nets 

(Ainley et al. 2002) 

Direct conflict with commercial fisheries (Ainley et 

al. 2002) 

251
Appendix 11. Stressors affecting or partially affecting 

resident birds in ACAD. 

Codes are as follows: 

EP – existing problem based on direct evidence 

PP – potential problem but not backed up with data or documentation 

OK – Not currently or expected to be a problem 

? = not enough information available to assess threat level 

Blank = not applicable

252
STRESSOR LAND BIRDS MARSH BIRDS MARINE BIRDS 

HABITAT ALTERATION, LOSS, DEGRADATION  Aquaculture, commercial fishing ? ?  Collisions with made-made objects ? ? ? 

 Loss of open habitats through succession or fire suppression PP PP EP3

 Loss of old chimneys or open barns as nesting habitat ? 

 Loss of hemlock stands from non-native adelgid ?  Mowing fields before young have fledged ? 

PESTICIDES / HERBICIDES  Organochlorine contaminants EP1 PP PP Organophosphate contaminants PP ? ? OTHER CONTAMINANTS  Oil spills PP PP EP4 Heavy metals EP2 PP PPDISTURBANCE  Approaching too close (boat or on foot) PP PP PP DISEASE /PARASITISM  Avian cholera, avian botulism, virus ? ? PP5 Red tide blooms ? ? 

 Parasitism by Brown-headed Cowbirds ? 

PREDATION 

 By Gulls EP4

 By Mink PP 

 By Eagles ? PP  By domestic cats ? ? OK 

STRESSOR LAND BIRDS MARSH BIRDS MARINE BIRDS 

HARVEST  Overharvest through hunting PP EP EP  Illegal shooting ? OK ? COMPETITION  For nesting habitat (gulls) EP6 For nesting habitat (starlings, House Sparrows) PP 1. Based on study of organochlorines in Bald Eagles by Matz (1998) and Welch (1992). 

253
2. Based on study by Longcore and Haines (1998) on bioaccumulation of mercury in Tree Swallows on Mount Desert Island and mercury in Bald Eagles by 

Welch (1992). 3. Folger (1986) describes park islands with nesting seabirds and threats to each colony. 4. See Shenton (1973) for a summary of local oil and gas spills in the region. 5. Cholera has been problematic in local seabird colonies in the past (Spencer 1980, Korschgen et al. 1978, Elliot 1983). 6. See Folger (1986). In 1952, 1103 gull eggs were destroyed by being sprayed with an oil mixture on Schoodic Island to assist in Gull Control (Maine

Department of Inland Fisheries and Wildlife 1969). 

254
Appendix 12. 

Growth and physiological response to varying levels of ozone. Responses are measured via photosynthesis (Pn), stomatal conductance (gs), dark respiration (Rs), and carbon allocation of common 

tree species found in ACAD. (Based on Chappelka and Samuelson 1998 Tables 1, 2). Ambient ozone levels range from 0.02-0.045 μl l-1 (National Research 

Council 1991). Species Ozone Treatment 

(~ 0.05 – ~ 1.00 μl l-1 over 1-3 growing seasons) 

Physiological Response (multiple studies) 

Acer rubrum (red maple) ~0.05 μl l-1 and up to 2 x 77 μl 

l-1

No effect on growth to 15% decrease in growth; 25% decrease in Pn; 30% decrease in gs

Acer saccharum (sugar maple) Up to 4 x 1.85 μl l-1 No effect on growth; no influence on Pn and Rs; Pn reduced by 

56%; reduced chlorophyll concentrations; increased foliar Rs

Quercus rubra (red oak) Up to 2 X ~ 0.04 μl l-1 No effect on growth; No effect on Pn and gs on seedlings; Pn

reduced up to 50% in mature trees; reduced foliar starch, foliar nitrogen and increased foliar carbon; no effect on foliar Rs; no effect on fine root respiration to reduction in fine root production 

Picea rubens (red spruce) ~ 1.00 μl l-1 No effect on growth; no ozone effects on Pn, gs or chlorophyll 

nutrition/chlorophyll and wax content in seedlings and mature trees; Reduction in Pn seedlings and mature trees; no effect on 

needle or whole tree Pn and water-use efficiency 

255
Species Ozone Treatment 

(~ 0.05 – ~ 1.00 μl l-1 over 1-3 growing seasons) 

Physiological Response (multiple studies) 

Populus tremuloides (quaking aspen) 

~0.05 μl l-1; 0.073 to 50 and 2 x 

50 μl l-1

12-24% reduction in above-ground biomass; 18-55% decline in Pn; higher rates of decline associated with nutrient and water stress; clone, leaf age, date reflect response level 

Prunus serotina (black cherry) ~0.05 μl l-1 No effect on growth to 30% decrease in shoot biomass; 

premature senescence; decline in root/shoot ratio; up to 50% decline in Pn

Pinus strobus (white pine) ~0.05 μl l-1 20% decrease in height Robinia pseudoacacia (black locust) 

~0.05 μl l-1 18% decrease in height to no effect on growth 

(Appendix 12, continued) 

256
The Department of the Interior protects and manages the nation’s natural resources and cultural heritage; provides scientific and 

other information about those resources; and honors its special responsibilities to American Indians, Alaska Natives, and 

affiliated Island Communities. 

NPS D-344, November 2008
National Park Service 

U.S. Department of the Interior 

Natural Resource Program Center 

1201 Oakridge Drive, Suite 150 

Fort Collins, CO 80525 

www.nature.nps.gov 

EXPERIENCE YOUR AMERICA TM