Merced Wild and Scenic River Comprehensive Management Plan / DEIS

APPENDIX N 

DRAFT BIOLOGICAL ASSESSMENT 

APPENDIX N 

BIOLOGICAL ASSESSMENT 

Biological Assessment on the 

Merced River Plan/DEIS 

National Park Service 

Department of the Interior 

November 2012 
APPENDIX N. BIOLOGICAL ASSESSMENT

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Appendix N. Biological Assessment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-i

TABLE OF CONTENTS 

Chapter I. Introduction N-1 

Purpose and Need .................................................................................................................................. N-1 

U.S. Fish and Wildlife Service Consultation ....................................................................................... N-2 

Species Evaluated in this Biological Assessment ................................................................................ N-2 

Species Removed from Further Analysis ............................................................................................. N-6 

Critical Habitat ........................................................................................................................................ N-6 

Chapter II. Current Management Direction N-7 

Authorities ............................................................................................................................................... N-7 

Policy and Program Objectives ............................................................................................................. N-7 

Chapter III. The Merced River Plan/DEIS N-8 

The Preferred Alternative – Enhanced Visitor Experiences and Essential Riverbank 

Restoration ........................................................................................................................................... N-8 

Chapter IV. Existing Environment N-9 

Habitat Descriptions .............................................................................................................................. N-9 

Species Accounts .................................................................................................................................. N-14 

Federal Endangered Species ............................................................................................................... N-22 

Federal Threatened Species ................................................................................................................ N-23 

Federal Candidate Species ................................................................................................................... N-23 

California State Endangered Species ................................................................................................. N-27 

California State Threatened Species .................................................................................................. N-29 

California State Fully Protected Species ............................................................................................ N-30 

California State Rare Species ............................................................................................................... N-31 

California State Species of Special Concern ...................................................................................... N-32 

Park Rare Species .................................................................................................................................. N-49 

Chapter V. Environmental Effects N-60 

Methods Used to Assess Effects ......................................................................................................... N-60 

Federal Endangered Species ............................................................................................................... N-64 

Federal Threatened Species ................................................................................................................ N-65 

Federal Candidate Species ................................................................................................................... N-67 

California State Endangered Species ................................................................................................. N-72 

California State Threatened Species .................................................................................................. N-74 

California State Rare Species ............................................................................................................... N-78 

California State Species of Special Concern ...................................................................................... N-79 

Park Rare Species ................................................................................................................................ N-104 

Chapter VI. Determination of Effects on Federally Listed or candidate Species N-108 

Determinations for Federally Listed Threatened or Endangered Species ................................. N-109 

Determinations for Federal Candidate Species .............................................................................. N-109 

Chapter VII. References N-111 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-ii Merced Wild and Scenic River Comprehensive Management Plan /DEIS

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I. Introduction 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-1 

CHAPTER I. INTRODUCTION 

Purpose and Need 

The National Park Service in Yosemite has prepared the Merced Wild and Scenic River Comprehensive 

Management Plan/Draft Environmental Impact Statement (Merced River Plan/DEIS) to provide a 

comprehensive management plan for the protection of the Merced River’s free-flowing condition, 

water quality, and the values that make the river worthy of designation. The purpose of this Biological 

Assessment is to review the Merced River Plan /DEIS in sufficient detail to determine effects of the plan 

on federal and state-listed threatened or endangered species, federal and state species of concern, 

state-listed rare species, and species that are locally rare or threatened. All of these species are also 

referred to as special-status species throughout this document. 

The Merced River Plan/DEIS aims to protect and further restore degraded areas of the river to its 

natural free-flowing condition and encourage resource-based recreational and educational 

opportunities along the river corridor. The plan would contribute to subsequent planning that would 

manage crowding through careful design, relocation, or removal of specific facilities and by setting use 

limits, dispersing visitor impacts, and establishing other measures to protect river resources and the 

diversity of visitor experiences. The plan also proposes to reduce traffic congestion by identifying 

optimal road locations and facilities, parking areas, turnouts, and other transportation facilities in the 

river corridor. Many of these functions would move to the El Portal Administrative Site on the western 

boundary of the park. 

This Biological Assessment will evaluate the Preferred Alternative in the Merced River Plan/DEIS, 

Alternative 5. The areas that could be affected by the Preferred Alternative include East and West 

Yosemite Valley, Wawona, Merced Lake High Sierra Camp, El Portal and Old El Portal. These areas 

are designated as the project area. Detailed maps of the project area are available in Vol. I, Merced 

River Plan/DEIS. 

This Biological Assessment will: 

 Evaluate and document the effects of the Preferred Alternative on special-status species or 

their critical habitat that are known to be or could be present within the project area 

 Determine the need for consultation and conference with the U.S. Fish and Wildlife Service 

(USFWS) 

 Conform to requirements of the Endangered Species Act (19 USC 1536 [c], 50 CFR 402) and 

the National Environmental Policy Act (42 USC 4321 et seq., implemented at 40 CFR Parts 

1500-1508) 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-2 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

U.S. Fish and Wildlife Service Consultation 

The Endangered Species Act (Section 7 [a][2]) directs federal agencies to consult with the responsible 

agency (in this case, the USFWS) to determine whether proposed actions are likely to jeopardize the 

continued existence of a listed species or destroy or adversely modify critical habitat. The NPS 

initiated informal consultation with the USFWS and obtained an updated species list from the USFWS 

on October 18, 2012. NPS obtained lists of federally listed endangered or threatened species within the 

Mount Lyell, Merced Peak, Sing Peak, Timber Know, Half Dome, El Capitan, Wawona, Mariposa 

Grove, El Portal, and Kinsley U.S. Geological Survey quadrangles that may be present or may be 

affected by actions proposed in the Merced River Plan/DEIS. Based on these lists and professional 

judgment by the park staff, seven federally listed threatened, endangered, proposed, or candidate 

species have been identified as known to occur or as having the potential to occur in the study area: 

one invertebrate species, two amphibian species, and three mammal species, and one plant species (see 

table N-1). Consultation with the USFWS will continue throughout the environmental compliance 

process for the Merced River Plan, and the NPS will consult with the USFWS to obtain an updated list 

of federally endangered or threatened species prior to project implementation. 

Other species considered in this biological assessment include species identified by the California 

Department of Fish and Game (CDFG) as endangered, threatened, or a candidate species; and CDFG 

species of concern, rare species, or fully protected species. Additionally, species considered rare by the 

National Park Service are also included in this biological assessment. Based on these lists, previous 

studies, recent surveys, and professional judgment by the park staff, 33 special status wildlife species 

are known to occur or have the potential to occur in the study area: one invertebrate species (beetle), 

one fish species, three amphibian species, 14 bird species, and 14 mammal species. 

Botanical surveys have identified one federal candidate plant species and two state-listed plants within 

the Merced River corridor in Yosemite. Therefore, for purposes of this analysis, special status plant 

species generally include mainly those species identified as such by the park. Park-designated sensitive 

plant species are those that have (1) extremely limited distributions in the park and may represent 

relict populations from past climatic or topographic conditions; or (2) may be at the extreme extent of 

their range in the park or represent changes in species genetics. These species may be included on lists 

such as the CNPS Inventory of Rare and Endangered Plants. 50 special status plant species are known 

to occur or have the potential to occur in the study area. 

Species Evaluated in this Biological Assessment 

Federally Listed Species 

The Endangered Species Act defines an endangered species as any species that is in danger of 

extinction throughout all or a significant portion of its range. A threatened species is defined as any 

species that is likely to become an endangered species within the foreseeable future throughout all or a 

significant portion of its range. Of the Federally listed species that could be affected by the Merced 

River Plan/DEIS, one is endangered: Sierra Nevada bighorn sheep (Ovis canadensis sierrae); and one is 

threatened: Valley elderberry longhorn beetle (Desmocerus californicus dimorphus). 
I. Introduction 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-3 

TABLE N-1: SPECIES CONSIDERED IN THIS BIOLOGICAL ASSESSMENT

Federal Threatened Species 

Invertebrates 

Valley elderberry longhorn beetle (Desmocerus californicus dimorphus)

Federal Candidate Species 

Mammals 

Pacific fisher (Martes pennanti pacifica) 

Reptiles and Amphibians 

Yosemite toad (Bufo canorus) 

Sierra Nevada yellow-legged frog (Rana sierrae) 

Plants 

Whitebark pine (Pinus albicaulis)

California State Endangered Species 

Birds 

Willow flycatcher (Empidonax traillii) 

Bald eagle (Haliaeetus leucocephalus) 

Mammals 

Sierra Nevada bighorn sheep (Ovis canadensis sierrae)

California State Threatened Species 

Mammals 

California wolverine (Gulo gulo) 

Sierra Nevada red fox (Vulpes vulpes necator) 

California State Fully Protected Species 

Birds 

Golden eagle (Aquila chrysaetos) 

Peregrine Falcon (Falco peregrinus) 

Bald eagle (Haliaeetus leucocephalus)) 

California State Rare Species

Plants 

Thompkins’ sedge (Carex tompkinsii) 

Congdon’s woolly-sunflower (Eriophyllum congdonii)

Congdon’s lewisia (Lewisia congdonii)

California State Species of Special Concern 

Birds 

Northern goshawk (Accipiter gentilis) 

Long-eared owl (Asio otus)

Vaux’s swift (Chaetura vauxi) 

Northern harrier (Circus cyaneus) 

Olive-sided flycatcher (Contopus cooperi) 

Black swift (Cypseloides niger) 

Yellow warbler (Setophaga petechia) 

Harlequin duck (Histrionicus histrionicus)

Great gray owl (Strix nebulosa)

California spotted owl (Strix occidentalis occidentalis) 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-4 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

TABLE N-1: SPECIES CONSIDERED IN THIS BIOLOGICAL ASSESSMENT (CONTINUED) 

California State Species of Special Concern (cont.) 

Fish 

Hardhead (Mylopharodon conocephalus)

Mammals 

Pallid bat (Antrozous pallidus) 

Sierra Nevada mountain beaver (Aplodontia rufa californica) 

Townsend’s big-eared bat (Corynorhinus townsendii townsendii) 

Spotted bat (Euderma maculatum) 

Greater western mastiff bat (Eumops perotis californicus) 

Western red bat (Lasiurus blossevillii) 

Sierra Nevada snowshoe hare (Lepus americanus tahoensis) 

Western white-tailed jackrabbit (Lepus townsendii townsendii) 

Pacific fisher (Martes pennanti pacifica) 

Mount Lyell shrew (Sorex lyellii) 

American badger (Taxidea taxus)

Reptiles and Amphibians 

Yosemite toad (Bufo canorus) 

Western pond turtle (Emys marmorata*) 

Mount Lyell salamander (Hydromantes platycephalus)

Foothill yellow-legged frog (Rana boylii)

Sierra Nevada yellow-legged frog (Rana sierrae) 

Park Rare Species 

Plants

Spurred snapdragon (Antirrhinum leptaleum) 

Lemmon’s wild ginger (Asarum lemmonii) 

California bolandra (Bolandra californica) 

Threadleaf beakseed (Bulbostylis capillaris) 

Mono Hot Spring evening primrose (Camissonia sierrae ssp. alticola) 

Sierra suncup (Camissonia sierrae ssp. sierrae) 

Buxbaum’s sedge (Carex buxbaumii) 

Silvery sedge (Carex canescens) 

Cleft sedge (Carex fissuricola) 

Yosemite sedge (Carex sartwelliana) 

Thompkins’ sedge (Carex tompkinsii)

Bolander’s woodreed (Cinna bolanderi) 

Narrow leaf collinsia (Collinsia linearis) 

Short-bracted bird’s beak (Cordylanthus rigidus ssp. brevibracteus) 

Mountain lady’s slipper (Cypripedium montanum) 

Stream orchid (Epipactis gigantea) 

Congdon’s wooly sunflower (Eriophyllum congdonii)

Purple fawn-lily (Erythronium purpurascens) 

Northern mannagrass (Glyceria borealis) 

California sunflower (Helianthus californicus) 

Common mare’s tail (Hippuris vulgaris) 

Redray alpinegold (Hulsea heterochroma) 

Western quillwort (Isoetes occidentalis) 

Sierra laurel (Leucothoe davisiae) 

Congdon’s lewisia (Lewisia congdonii) 

False pimpernel (Lindernia dubia var. anagallidea) 

Tanoak (Lithocarpus densiflorus var. echinoides) 

Northern bugleweed (Lycopus uniflorus) 

Yellow and white monkeyflower (Mimulus bicolor) 

Inconspicuous monkeyflower (Mimulus inconspicuus) 

Cutleaf monkeyflower (Mimulus laciniatus) 
I. Introduction 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-5 

TABLE N-1: SPECIES CONSIDERED IN THIS BIOLOGICAL ASSESSMENT (CONTINUED) 

Park Rare Species (cont.) 

Pansy monkeyflower (Mimulus pulchellus)

Sierra sweet-bay (Myrica hartwegii) 

California bog asphodel (Narthecium californicum)

Azure penstemon (Penstemon azureus ssp. angustissimus) 

Purdy’s foothill penstemon (Penstemon heterophyllus var. purdyi) 

Tansy leafed phacelia (Phacelia tanacetifolia) 

Coleman’s piperia (Piperia colemanii)

Torrey’s popcornflower (Plagiobothrys torreyi var. torreyi) 

Nuttall’s pondweed (Potamogeton epihydrus ssp. nuttallii) 

Valley oak (Quercus lobata) 

Wood saxifrage (Saxifraga mertensiana) 

Oregon saxifrage (Saxifraga oregana) 

Bolander’s skullcap (Scutellaria bolanderi) 

Clark’s ragwort (Senecio clarkianus) 

Small bur reed (Sparganium natans) 

Sierra bladdernut (Staphylea bolanderi) 

Narrowleaf wakerobin (Trillium angustipetalum) 

California red huckleberry (Vaccinium parvifolium) 

Hall’s wyethia (Wyethia elata)

*Believed to be extirpated from the Merced River corridor. 

The Sierra Nevada bighorn sheep formerly ranged throughout the high elevations of the Sierra 

Nevada. By the beginning to the 20th century, however, their numbers had been decimated by 

overhunting, competition for forage with domestic sheep, and especially by diseases contracted from 

domestic sheep. By 1999, fewer than 200 Sierra Nevada bighorn sheep were left in the entire range, 

prompting its listing that year as endangered. Currently, the Sierra Nevada bighorn sheep occurs 

primarily along the Sierra Crest in the northeast portion of Yosemite Park. Most of the herd inhabits 

Forest Service land adjacent to the park. 

The Valley elderberry longhorn beetle was listed by the USFWS as threatened on August 8, 1980. This 

listing was primarily a result of destruction of riparian habitat in the San Joaquin Valley that removed the 

beetle’s host plant, the elderberry (Sambucus sp.). Critical habitat has been designated for the beetle in 

two areas: along the American River near the Sacramento metropolitan area and along Putah Creek in 

Solano County. However, the beetle also occurs up to 3,000 feet in elevation in the Sierra Nevada. 

Special-Status Species 

Special-status species that could be affected by this plan are listed in table N-1. There are 50 special 

status plant species and 33 special status wildlife species known to occur or having the potential to 

occur within Yosemite National Park’s Merced River corridor. The species on this list include the 

federally listed species in the ten U.S. Geological Survey quadrangles that encompass the project area for 

the plan (see USFWS Consultation), species listed in the California Natural Diversity Data Base, and 

“park rare” plants identified by National Park Service. Park rare plants include those that are: 

 locally rare natives 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-6 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

 listed by the California Native Plant Society 

 endemic to the park or local vicinity 

 at the furthest extent of their range 

 of special importance to the park (identified in legislation or park management objectives) 

 the subject of political concern or unusual public interest 

 vulnerable to local population declines 

 subject to human disturbance during critical portions of their life cycle 

There is no classification of “park rare” for any wildlife species. 

Species Removed from Further Analysis 

The following species are on the list of “Endangered and Threatened Species that may occur or be 

Affected by Projects in the USFWS 7 1⁄2 Minute Quads” that was provided by the USFWS. However, 

the National Park Service has determined that they would not be affected by the Merced River 

Plan/DEIS because they do not occur in the project area nor were they historically found in the project 

area. Therefore, there is no effect on these species from the Preferred Alternative in the Yosemite 

Valley Plan/DEIS, nor are they potentially indirectly or cumulatively affected by the Preferred 

Alternative. These species will not be evaluated further in this Biological Assessment. 

 Delta smelt, Hypomesus transpacificus (Federal Threatened) 

 Lahontan cutthroat trout, Oncorhynchus (=Salmo) clarki henshawi (Federal Threatened) 

 Paiute cutthroat trout, Oncorhynchus (=Salmo) clarki seleniris (Federal Threatened) 

 Central Valley steelhead, Oncorhynchus mykiss (Federal Threatened) 

 California red-legged frog, Rana draytonii (Federal Threatened) 

Critical Habitat 

Critical habitat is a specific area or type of area that is considered to be essential for the survival of a 

species, as designated by the USFWS under the Endangered Species Act. No critical habitat occurs in 

Yosemite National Park or the El Portal Administrative Site. 
II. Current Management Direction 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-7 

CHAPTER II. CURRENT MANAGEMENT DIRECTION 

Authorities 

The following legislation and policies address the management of special-status species in the park: the 

National Park Service Organic Act, the Endangered Species Act, the National Environmental Quality 

Act, the California Endangered Species Act, the Migratory Bird Conservation Act, the Fish and 

Wildlife Coordination Act, the Wild and Scenic Rivers Act, and the Wilderness Act. 

The USFWS normally takes the lead departmental responsibility of coordinating and implementing 

provisions of the Federal Endangered Species Act for all listed endangered, threatened, and candidate 

species. This Biological Assessment is prepared in accordance with Section 7 of the Federal 

Endangered Species Act of 1973, as amended, as part of the consultation process with the USFWS. 

Policy and Program Objectives 

The following National Park Service policies and program objectives prescribe the management of 

special-status species: 

 The Natural Resources Management Guideline NPS-77 (1991) states: 

“Management affects the distribution, abundance, and ecological relationships of and among 

species. Whereas preservation can be accomplished by a zoo, botanical garden, or other 

non-natural refugium, the National Park Service’s goal is the long-term preservation of species 

and their ecological role and function as part of a “natural ecosystem.” It is, therefore, critical 

that ecological aspects of management prevail in dealing with threatened and endangered 

species. An understanding of factors limiting the distribution and abundance of the species of 

concern must be well understood and incorporated into any management action.” 

 National Park Service Management Policies (1988) states: 

“Consistent with the purposes of the Endangered Species Act (16 USC 1531 et seq.), the 

National Park Service will identify and promote the conservation of all federally listed 

threatened, endangered, or candidate species within park boundaries and their critical 

habitats.” 

“The National Park Service also will identify all state and locally listed threatened, 

endangered, rare, declining, sensitive, or candidate species that are native to and present in the 

parks, and their critical habitats. These species and their critical habitats will be considered in 

National Park Service planning activities.” 

 The 1980 General Management Plan for Yosemite states: 

“Protect threatened and endangered plant and animal species and reintroduce, where 

practical, those species eliminated from the natural ecosystems.” 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-8 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

CHAPTER III. THE MERCED RIVER PLAN/DEIS 

The Preferred Alternative – Enhanced Visitor Experiences and Essential 

Riverbank Restoration 

The Preferred Alternative of the Merced River Plan/DEIS would include significant restoration within 

100 feet of the river and in meadow and riparian areas, maintaining daily visitation in Yosemite Valley 

to accommodate the same peak levels observed in recent years, reducing unnecessary facilities and 

services, and converting facilities from administrative use to public use where feasible. This alternative 

would restore approximately 203 acres of currently disturbed or developed habitats throughout the 

Merced River corridor to natural conditions by removing infrastructure and development from 

sensitive areas such as meadows, riparian habitat, and riverbanks. Much of the development within 

100 feet from the ordinary high water mark of the Merced River would be removed under this 

alternative. 6,135 linear feet of riprap would be removed from the banks of the Merced River. Targeted 

infrastructure within the bed and banks of the river would be removed. Sugar Pine Bridge would be 

removed to promote free-flowing conditions of the river and channel complexity would be enhanced 

below other bridges. Restoration actions also include filling ditches and removing informal trails from 

meadows to improve hydrology and reduce meadow fragmentation. Collectively, these actions would 

enhance meadow and floodplain connectivity and the free-flowing condition of the river. 

Actions to manage visitor use and facilities under Alternative 5, specifically those concerning vehicle 

access and overnight accommodations, would result in a 2% increase in lodging accommodations. The 

campsite inventory would increase by 29% in the Merced River corridor and 37% in Yosemite Valley. 

All campsites within 100 feet of the river would be removed. Campsite losses would be offset with the 

addition of new camping adjacent to Upper Pines Campground and east of the Camp 4 Campground, 

as well as new sites west of Backpackers Campground, in the former Upper Rivers Campground area, 

and east of El Capitan Picnic Area at Eagle Creek. Under Alternative 5, there would be a net increase of 

13% in Yosemite Valley overnight use. This would largely result from the increase in units at Curry 

Village. Management actions related to lodging would focus on removing lodging from the ordinary 

high water mark and Housekeeping Camp, and slightly reducing lodging in wilderness. Tent cabins in 

the Boys Town area would be replaced with hard-sided lodging in Curry Village to increase the 

availability of year-round accommodations. 

Alternative 5 would restore approximately 203 acres of vegetation, including 40.52 acres of wetlands, 

as a result of actions common to Alternatives 2-6 in conjunction with actions specific to Alternative 5. 

Actions to manage visitor use and facilities would result in the loss of approximately 36.89 acres of 

vegetation and 2.67 acres of wetlands as a result of actions specific to Alternative 5. 

For a detailed description of the Preferred Alternative, refer to Vol. I, Chapter 9 of the Merced River 

Plan/DEIS (NPS 2012). 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-9 

CHAPTER IV. EXISTING ENVIRONMENT 

Habitat Descriptions 

The Merced River and Yosemite National Park 

The Merced River is one of 23 wild and scenic rivers in California and one of six wild and scenic rivers 

on the western slope of the Sierra Nevada. It is one of 15 major river systems in the Sierra Nevada 

mountain range of California. Originating in the alpine peaks of the central Sierra Nevada, the river 

flows west for 145 miles to its confluence with the San Joaquin River in the Central Valley of 

California, encompassing a drainage basin of about 1,700 square miles. The first 122 miles of the 

Merced River, beginning at its Sierran headwaters, are designated as wild and scenic; the National Park 

Service manages 81 miles of the river through Yosemite National Park and the El Portal Administrative 

Site, including both the main stem and the South Fork Merced River (together referred to as the 

Merced River). In Yosemite National Park, the main stem of the Merced River flows freely through a 

wilderness landscape of alpine peaks, glacially carved valleys, and high-elevation meadows. As the 

gradient lessens into Yosemite Valley, the Merced River meanders through the rich meadow and 

riparian habitat. These wetlands and riparian areas are distinct and important types of vegetation 

communities that contribute to the outstandingly remarkable biological river values as well as values to 

biological communities. 

Yosemite National Park, one of the largest and least-fragmented habitat blocks in the Sierra Nevada 

range, supports a diverse and abundant assemblage of wildlife. It plays an important role in protecting 

the long-term survival of certain species and the overall biodiversityof wildlife in the Sierra Nevada 

region. The Merced River corridor also serves an essential ecological role in linking wildlife habitats 

across the park’s landscape and gradients of elevation. 

Yosemite Valley is a glacier-carved valley with sheer granite cliffs rising over 2,000 feet above the valley 

floor. Alluvial deposits are found to a depth of about 2,000 feet below the soil surface, creating a huge 

underground aquifer. Habitats in Yosemite Valley can be loosely grouped into meadow, riparian, and 

upland. Mammals resident or transient in Yosemite Valley include deer mouse, California ground 

squirrel, western gray squirrel, broad-footed mole, Botta’s pocket gopher, mink, ringtail, raccoon, 

coyote, bobcat, mule deer, mountain lion, and black bear. 

Regional Vegetation and Habitats 

The major vegetation zones of the Sierra Nevada region form readily apparent, large-scale, northsouth elevational bands along the axis of the Sierra Nevada range. In the Yosemite region, these 

vegetation zones include foothill-woodland, lower montane forest, upper montane forest, subalpine 

forest, and alpine zones; they are distributed from the lowest elevations on the western boundary of 

the park to the highest elevations from 9,500 feet along the crest of the Sierra Nevada range. Major 

east-west watersheds that dissect the Sierra Nevada range into steep canyons form a secondary pattern 

of vegetation. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-10 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Merced River Habitats 

All eight major vegetation types supported by Yosemite National Park occur within the Merced River 

corridor and are presented in table N-2, below. It is estimated that half of all plant species in the park 

occur within the Merced River corridor. The Special Status Plant Species Report (NPS, 2011b) 

concluded that the characteristic pattern of special status species occurrence along the Merced River 

corridor within Yosemite National Park was found to be within unique habitat types that are often 

restricted in size. These habitat types are typically associated with specific kinds of water availability, 

such as waterfall spray zones, braided river channel oxbow cutoffs, gravel bars resulting from periodic 

flooding, water seepage on rock walls, vernal pools resulting from snowmelt flooding, and the average 

high water margin of streams and rivers. Although riparian and wetland habitats are not classified 

independently under the eight broad-scale vegetation types used in the parkwide vegetation map of 

the Merced River Plan/DEIS, their value as biological communities warrants a thorough discussion. 

Therefore, they are discussed in-depth below. Additionally, because meadow habitats are integral in 

connecting upland and aquatic habitats, they are also discussed in-depth in this assessment. 

TABLE N-2: VEGETATION TYPES WITHIN THE MERCED RIVER CORRIDOR

Vegetation Type 

Area per Segment (acres) 

1 2 3 4 5 6 7 8 Total 

Alpine (9,500 to 

11,800 feet)* 87.8 0 0 0 6.5 0 0 0 94.3 

Meadow (2,000 to 

11,000) 1,801.3 324.1 67.6 28.8 389.0 0 140.6 0.9 2,752.3 

Chaparral (2,000 to 

10,000 feet) 1,669.1 991.4 2,270.6 74.9 694.0 0 166.4 66.6 5,933.0 

Subalpine Coniferous 

Forest (8,000 to 

9,500 feet) 

9,610.4 45.8 0 0 3,108.9 0 0 0 12765.1 

Upper Montane 

Coniferous Forest 

(6,000 to 8,000 feet) 

16,525.7 3,697.0 1,572.0 0 11,611.8 23.3 990.5 28.4 34,448.7 

Lower Montane 

Coniferous Forest 

(3,000 to 6,000 feet) 

3,505.6 7,248.5 4,785.3 151.4 6,010.4 72.0 4,969.0 1,980.8 28,723.0 

Lower Montane 

Broadleaf Forest 

(3,000 to 6,000 feet) 

461.6 3,331.4 2,982.7 569.7 816.7 3.4 761.1 397.0 9,323.6 

Foothill Woodland 

(1,800 to 3,000 feet) 0 0 9.8 324.8 0 0 0 0 334.6 

Barren 

(1,800 to 11,800 feet) 14,143.4 2,319.5 455.7 27.6 2586.4 2.9 170.2 2.6 19,708.3 

Developed 0.3 150.0 59.3 54.5 8.1 0.2 82.2 10.3 364.9 

*Elevation ranges are approximated 

SOURCE: NPS 1997; NPS 2007x 

Meadows. Meadow habitats within the Merced River corridor include alpine, subalpine, and montane 

meadows and seeps. The meadows in Yosemite National Park play a particularly critical role in the 

Merced River ecosystem. There are approximately 2,752.3 acres of meadow habitat within the Merced 

River corridor. Meadows serve as a transition zone, linking aquatic and riparian habitats along the 

Merced River to drier upland habitats such as California black oak. High spring flows create wet areas 

in side channels, low-lying wetlands, meadows, and cutoff channels. These areas support the 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-11 

concentration of organic matter, nutrients, microorganisms, and aquatic invertebrates throughout the 

relatively dry summer. When the flush of winter or spring flooding occurs, this stored aquatic biomass 

is washed into the main river channel, forming the base of the aquatic food chain. 

Meadows in Yosemite Valley were maintained in the past by natural flooding and by frequent, lowintensity broadcast fires set by Native American residents of the Valley. Today, prescribed fire is used 

as a tool to clear the meadows of encroaching conifers and release nutrients into the soil. 

Special-status species that use meadows, seeps, and other wetlands in Yosemite Valley for foraging 

and/or reproduction include the Yosemite toad, Mount Lyell salamander, western pond turtle, 

northern harrier, olive-sided flycatcher, peregrine falcon, great gray owl, special-status bats, California 

wolverine, Mount Lyell shrew, Sierra Nevada red fox, special-status sedges and grasses, stream orchid, 

purple fawnlily, California sunflower, false pimpernel, among others (see table N-3 for a complete 

listing of special-status species that have been found or could occur in Yosemite Valley). 

Riparian Habitats. There are approximately 180.7 acres of riparian habitat within the Merced River 

corridor. Riparian zones extend outward from the banks of the Merced River and its tributaries 

toward adjacent meadow and forest communities. Broadleaf deciduous trees such as white alder, black 

cottonwood, and willow characterize riparian zones in Yosemite Valley. Riparian vegetation along 

moving water is frequently disturbed and constantly responds to the deposition and removal of soil. 

Riparian vegetation actively colonizes new areas and is made up of a wide range of ages and types of 

vegetation. This in turn provides a wide range of foraging, nesting, and resting opportunities for 

wildlife. 

Special-status species that are representative of riparian habitats in Yosemite Valley include 

amphibians (foothill yellow-legged frog, Sierra Nevada yellow-legged frog), reptiles (western pond 

turtle), birds (yellow warbler, willow flycatcher, harlequin duck), and mammals (special-status bats, 

Mount Lyell shrew), among others. Special-status plants occurring in riparian habitats include the 

Sierra sweet bay, stream orchid, purple fawnlily, and Sierra laurel, among others (see Table N-3 for a 

complete listing of special-status species that have been found or could occur in Yosemite Valley). 

Upland Habitats. Upland plant communities are found where soil moisture conditions are average to 

dry and where soils are not periodically flooded or saturated. Upland habitats within the Merced River 

corridor are comprised of Chaparral, Foothill Woodland, Lower Montane Broadleaf Forest, Lower 

Montane Coniferous Forest, Subalpine Coniferous Forest, Alpine, and Barren (table N-2, above). 

In-depth descriptions of each habitat type within each segment of the Merced River are described in 

Chapter 9 of the Merced River Plan/DEIS (NPS, 2012). 

Segment 1 

At its headwaters, the Merced River begins in the lower alpine/subalpine forest zone. The river then 

descends through the upper montane forest zone and concludes in Little Yosemite Valley within the 

lower montane forest zone. Vegetation in the upper main stem river corridor is classified into seven 

broad vegetation types: meadow, chaparral, lower montane broadleaf forest, lower montane 

coniferous forest, upper montane coniferous forest subalpine coniferous forest, and alpine plant 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-12 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

communities. Special-status species that are representative in upland habitat within the Merced River 

corridor above Nevada Falls include northern goshawk, golden eagle, northern harrier, yellow 

warbler, California spotted owl, special-status bat species, California wolverine, western white-tailed 

jackrabbit, Mount Lyell shrew, Sierra Nevada red fox, and Pacific fisher. Special-status plants 

occurring in upland habitat within this segment includes California bolandra, redray alpinegold, and 

Coleman’s piperia (see table N-3 for a complete listing of special-status species that have been found 

or could occur in Segment 1). 

Segment 2 

Yosemite Valley is a broad, flat-bottomed valley formed by glaciation and subsequent alluvial 

deposition. The river corridor includes the Merced River in addition to portions of Illilouette Creek, 

Tenaya Creek, Yosemite Creek, Sentinel Creek, Ribbon Creek, and Bridalveil Creek. Upland habitats 

cover about 75% of Yosemite Valley and are dominated by mixed conifer, canyon live oak, California 

black oak, and microhabitats on steep granite walls (Acree 1994). 

Mixed conifer communities in Yosemite Valley are typically dominated by ponderosa pine, but may 

have significant numbers of incense-cedar, Douglas-fir, white fir, California black oak, and an 

occasional sugar pine. The mixed conifer community is naturally adapted to low-intensity, frequent 

fires. Nearly 100 years of fire suppression has resulted in a change from open forest to dense thickets 

of shade-tolerant tree species such as incense-cedar and white fir. Under natural conditions, the return 

interval for fire is estimated at 8 to 12 years (NPS 1990). Most undeveloped, mixed conifer areas of 

Yosemite Valley are now managed through a combination of mechanical removal of hazardous fuel 

and prescribed burning. These treatments simulate the natural and Native American – maintained fire 

regimes of the Valley and help decrease forest densities to more natural levels. 

Canyon live oak communities grow on both north- and south-facing talus slopes. They often form 

pure or almost pure stands. Fires in this community are infrequent but intense, with a fire return 

interval of 20 to 50 years on south-facing slopes. Most trees and shrubs in this community resprout 

after fires. 

In addition to being a component of the mixed conifer community, California black oaks in Yosemite 

Valley form pure, open stands of large trees with a herbaceous understory. These pure stands are 

found between the upland forest communities and lower-lying meadow and riparian communities. 

These stands are unique to the Valley due to thousands of years of Native American activities, 

including annual burning and removal of young conifers. California black oaks also grow in dense 

stands on talus slopes near drainages. 

Special-status species that are representative of upland habitats in Yosemite Valley include Specialstatus species that are representative in upland habitat within Yosemite Valley include long-eared owl, 

Vaux’s swift, northern harrier, olive-sided flycatcher, yellow warbler, bald eagle, great gray owl, 

California spotted owl, special-status bat species, Sierra Nevada mountain beaver, western white-tailed 

jackrabbit, and American badger. Special-status plants occurring in upland habitat within this segment 

includes Sierra suncup, Buxbaum’s sedge, short-bracted bird’s beak, purple fawnlily, tanoak, 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-13 

monkeyflowers, penstemons, redray alpinegold, and wood saxifrage, among others (see table N-3 for a 

complete listing of special-status species that have been found or could occur in Yosemite Valley). 

Segment 3 and 4 

The Merced River gorge travels through the lower montane forest zone and into the foothillwoodland zone, where it enters the El Portal area. Vegetation in the Merced River gorge and El Portal 

river corridor is classified into four broad vegetation types: chaparral, foothill woodland, lower 

montane broadleaf forest, and lower montane coniferous forest. Valley oak woodland (foothill 

woodland) occurs in the El Portal area. 

El Portal lies in the Merced River canyon at 2,000 feet in elevation. The Merced River in this segment is 

lined with a narrow band of riparian vegetation with occasional wider floodplains. A dense mosaic of 

chaparral and foothill woodland communities lines the steep canyon walls. Many factors shape this 

unique biological environment, including natural floods and lightning-ignited fire. Soils derived in the 

contact zone between metamorphic and granitic rock form a unique substrate for vegetation. Many 

special-status plants are concentrated in this unique area. Steep canyon walls that are almost 

inaccessible to human passage create secluded refuges for wildlife. Extremely hot and dry summer 

weather places a critical importance on riparian habitat for many wildlife species. 

Special-status species that have been found or could occur in El Portal include the long-eared owl, 

bald eagle, and Townsend’s bigeared bat. Special-status plants with the potential to occur in this 

segment include Thompkin’s sedge, mountain lady’s slipper, narrowleaf collinsia, Congdon’s woollysunflower, tanoak, Congdon’s lewisia, northern bugleweed, small flowered monkeyflower, valley oak, 

and Sierra bladdernut (see table N-3 for a complete listing of special-status species that have been 

found or could occur in El Portal). 

Segments 5 and 8 

These segments include nearly a full range of environments typical to the Sierra Nevada. Vegetation 

zones along the upper South Fork (Segment 5) include the alpine, subalpine, upper montane forest, 

and lower montane forest zones. Vegetation in the upper South Fork is classified into six broad 

vegetation types: meadow, chaparral, lower montane broadleaf forest, lower montane coniferous 

forest, upper montane coniferous forest and subalpine coniferous forest. 

Vegetation zones along the lower South Fork (Segment 8) include the lower montane forest and 

foothill-woodland zones. Vegetation in the lower South Fork is classified into three broad vegetation 

types: chaparral, lower montane broadleaf forest, and lower montane coniferous forest. These 

segments of the river are designated as wilderness. 

Special-status species with the potential to occur within these segments include the northern goshawk, 

golden eagle, long-eared owl, olive-sided flycatcher, yellow warbler, California spotted owl, specialstatus bats, Sierra Nevada mountain beaver, California wolverine, Sierra Nevada snowshoe hare, western 

white-tailed jackrabbit, Pacific fisher, and Sierra Nevada red fox. Special-status upland plants with the 

potential to occur along the upper and lower South Forks include the small flowered monkeyflower. 

ia 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-14 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Segments 6 and 7 

Major vegetation zones in the central South Fork (Wawona) include the upper montane forest and 

lower montane forest zones. Vegetation in the central South Fork is classified into four broad 

categories: meadow, chaparral, lower montane broadleaf forest, and lower montane coniferous forest.

Special-status species that are representative of these areas include the golden eagle, long-eared owl, 

Vaux’s swift, northern harrier, olive-sided flycatcher, bald eagle, great gray owl, California spotted 

owl, special-status bats, Sierra Nevada mountain beaver, western white-tailed jackrabbit, pacific fisher, 

and American badger. Special-status plants representative of these areas include spurred snapdragon, 

mountain lady’s slipper, narrow leaf collinsia, small flowered monkeyflower, Sierra sweet-bay, 

California red huckleberry, and Hall’s mule ears (see table N-3 for a complete listing of special-status 

species that have been found or could occur in the Wawona area). 

Species Accounts 

TABLE N-3: PRESENTS A SUMMARY OF SPECIAL-STATUS WILDLIFE AND PLANT SPECIES ADDRESSED IN THIS 

ANALYSIS

Scientific Name 

Common Name 

Listing Status:

Federal/State/

CNPS General Habitat 

Potential to 

Occur in 

Project Area 

Segment 

Invertebrates 

Desmocerus californicus 

dimorphus 

Valley elderberry 

longhorn beetle 

FT Breeds and forages exclusively on elderberry 

shrubs (Sambucus spp.) typically associated with 

riparian forests, riparian woodlands, elderberry 

savannas, and other Central Valley and foothill 

habitats below 3,000 feet in elevation. 

3,4, 

Fish 

Mylopharodon conocephalus 

Hardhead 

CSC Inhabits larger middle- and low elevation streams and 

rivers, from sea level to 4,750 feet. Typically found in 

undisturbed streams with clear, deep pools that have 

sand-gravel-boulder substrates and slow water 

velocities. 

4,6,7 

Amphibians 

Hydromantes platycephalus 

Mount Lyell salamander 

CSC Occurs in massive rock areas between 4,000 and 

12,139 feet in elevations, in rock fissures, seeps, 

shade, and low-growing plants. Commonly found 

in talus slopes of granite where water is flowing. 

Also found near streams and within the spray 

zones of waterfalls, under rocks and moss. 

1,2,5 

Anaxyrus canorus 

Yosemite toad 

FC/CSC Restricted to wet mountain meadows, lakes, ponds, 

and shallow spring channels in the central high 

Sierra Nevada, between 4,790 - 11910 feet. Wet 

meadow habitat is the focal habitat for this species 

1,5 

Rana boylii* 

Foothill yellow-legged 

frog

CSC Primarily found in streams with riffles, rocky 

substrates and open banks from sea level to 

6,390 feet. 

2,3,4,6,7,8 

Rana sierrae 

Sierra Nevada yellowlegged frog

FC/CCE/CSC High mountain lakes, ponds, tarns and streams at 

elevations ranging from 5,500 to 12, 000 feet; 

rarely found more than 3 feet from water. 

1,5 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-15 

TABLE N-3: PRESENTS A SUMMARY OF SPECIAL-STATUS WILDLIFE AND PLANT SPECIES ADDRESSED IN THIS 

ANALYSIS (CONTINUED) 

Scientific Name 

Common Name 

Listing Status:

Federal/State/

CNPS General Habitat 

Potential to 

Occur in 

Project Area 

Segment 

Reptiles 

Emys marmorata* 

Western pond turtle 

CSC Inhabit a wide range of permanent and ephemeral 

aquatic habitats including ponds, marshes, rivers, 

streams, and ditches to about 6,700 feet, but are 

uncommon anywhere above 5,000 feet. Prefers 

open, grassy south-facing slopes for nest sites. 

2,3,4,6,7,8 

Birds 

Histrionicus histrionicus 

Harlequin duck 

CSC Breeds along large, swift-moving mountain rivers 

with vegetated banks for cover. At the conclusion of 

the breeding season, they move back to the coast 

where they forage in intertidal areas. 

1-8 

Accipiter gentilis 

Northern goshawk 

CSC Favors moderately dense coniferous forests broken 

by meadows, and other openings, between 5,000 

and 9,000 feet in elevation. Typically nest in mature 

conifer stands near streams. Forage in mature and 

old-growth forests that have relatively dense 

canopies and open understories, but also hunt 

among a variety of vegetative cover, including 

meadow edges. 

1,5 

Aquila chrysaetos 

Golden eagle 

CFP Forages in open terrain such as grasslands, deserts, 

savannahs, and early successional stages of forest 

and shrub habitats; nests in canyons and large trees 

in open habitats. In the Sierra Nevada, golden eagles 

favor grasslands and areas of shrubs or saplings, and 

open-canopied woodlands of young blue oaks. 

1-8 

Circus cyaneus 

Northern harrier 

CSC Favors open areas such as grasslands, meadows, 

wetlands, and agricultural clearings. Rarely seen 

migrant that passes through Yosemite. 

2,7 

Haliaeetus leucocephalus 

Bald eagle 

FD/CE/CFP Nests in tall trees, usually over 100 feet in height, or 

on cliffs, usually near water. Favor lakes and rivers 

with abundance prey (mostly fish). 

2,3,4,7 

Falco peregrinus 

Peregrine falcon 

CFP Nests on vertical cliff habitat, with large potholes or 

ledges, that is inaccessible to land predators. Hunts in 

a wide variety of habitats including meadows, 

woodlands, marshes, and mudflats. 

1,2,3,5,7 

Asio otus 

Long-eared owl 

CSC In the Sierra Nevada, this species is found from 

blue oak savannah up to ponderosa pine and 

black oak habitats, usually in association with 

riparian habitats. 

2,3,4,5,6,7,8 

Strix nebulosa 

Great gray owl 

CE Entire California population of this species is 

restricted to the Yosemite region. Breeds in mixed 

conifer/red fir forests bordering meadows. Winters in 

mixed conifer down to blue oak woodlands. 

2,7 

Strix occidentalis occidentalis 

California spotted owl 

CSC Strongly associated with areas of mature and old 

forest with thick dense canopy closure that contains 

many dense, old, live trees and snags and fallen logs. 

1,2,3,5,7 

Chaetura vauxi 

Vaux’s swift 

CSC Inhabits redwood and Douglas-fir habitats. Utilizes 

large hollow trees and snags, especially tall, burnedout stubs for nest sites. Breeding occurs in Yosemite 

Valley, usually in forested habitat near meadows. 

2,3,7,8 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-16 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

TABLE N-3: PRESENTS A SUMMARY OF SPECIAL-STATUS WILDLIFE AND PLANT SPECIES ADDRESSED IN THIS 

ANALYSIS (CONTINUED) 

Scientific Name 

Common Name 

Listing Status:

Federal/State/

CNPS General Habitat 

Potential to 

Occur in 

Project Area 

Segment 

Birds (cont.) 

Cypseloides niger borealis 

Black swift 

CSC In Yosemite, black swifts only nest near or behind 

waterfalls, through elsewhere in their range nests are 

found on sea cliffs or other sheer rock faces. 

2 

Contopus cooperi 

Olive-sided flycatcher 

CSC Breeds in montane and northern coniferous forests, 

at forest edges and openings, such as meadows and 

ponds. Winters at forest edges and clearings where 

tall trees or snags are present. 

1,2,5,7 

Empidonax traillii 

Willow flycatcher 

CE Breeds in moist, shrubby areas, often with standing 

or running water. Winters in shrubby clearings and 

early successional growth. Deciduous trees and 

shrubs interspersed with open areas enhances the 

quality of foraging habitat 

2,6,7 

Setophaga petechia 

Yellow warbler 

CSC Prefers riparian woodlands, but also breeds in 

chaparral, ponderosa pine, and mixed conifer 

habitats with substantial amounts of brush. 

1-8 

Mammals 

Sorex lyelli 

Mount Lyell shrew 

CSC Found primarily in wetland communities, near 

streams, in grassy areas, under willows, and in 

sagebrush steppe communities. Requires moist soil 

and uses logs, stumps, and other surface objects for 

cover. 

1,5 

Antrozous pallidus 

Pallid bat 

CSC Common species of low elevations in California. 

Occupies grasslands, desert, shrublands, woodlands, 

and forests from sea level up through mixed conifer 

forests. This species is quite versatile in its choice of 

roosting sites, and has been documented using tree 

hollows, rock crevices, caves, abandoned mines, and 

structures. 

1-8 

Corynorhinus townsendii 

Townsend’s big-eared bat 

CSC Found in all habitat types from low to moderate 

elevations. Not found in high elevation subalpine and 

alpine habitats. Requires caves, mines, or buildings 

for roosting. Prefers mesic habitats where it gleans 

from brush or trees along habitat edges. 

2,3,4,7,8 

Euderma maculatum 

Spotted bat 

CSC Occupies a wide variety of habitats from arid deserts 

and grasslands through mixed conifer forests. In 

montane habitats, the spotted bat forages over 

meadows, along forest edges, or in open coniferous 

woodland. Feeds almost entirely on moths. Needs 

rock crevices in cliffs or caves for roosting. 

1,2,5,7 

Lasiurus blossevillii 

Western red bat 

CSC Typically found in trees, hedgerows, and forest 

edges. Roosts in foliage in summer. 

1-8 

Eumops perotis 

Western mastiff bat 

CSC Found in a variety of habitats, from desert scrub and 

chaparral to montane coniferous forest. Typically 

found in rocky cliff and canyon areas. Its presence is 

determined by the availability of significant rock 

features offering suitable roosting habitat. 

1,2,5,7 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-17 

TABLE N-3: PRESENTS A SUMMARY OF SPECIAL-STATUS WILDLIFE AND PLANT SPECIES ADDRESSED IN THIS 

ANALYSIS (CONTINUED) 

Scientific Name 

Common Name 

Listing Status:

Federal/State/

CNPS General Habitat 

Potential to 

Occur in 

Project Area 

Segment 

Mammals (cont.) 

Lepus americanus tahoensis 

Sierra Nevada snowshoe 

hare 

CSC Boreal riparian areas in the Sierra Nevada. Thickets of 

deciduous trees in riparian areas and thickets of 

young conifers. 

1,5 

Lepus townsendii 

townsendii 

Western white-tailed 

jackrabbit

CSC Inhabits a variety of habitats, including sagebrush, 

perennial grasslands, alpine dwarf-shrub, early 

successional conifer habitats, and wet meadows to 

timberline and above. 

1,5 

Aplodontia rufa californica 

Sierra Nevada mountain 

beaver

CSC Dense growth of small deciduous trees and shrubs, 

wet soil, and abundance of forbs in the Sierra 

Nevada and east slope. Needs dense understory for 

food and cover. Burrows into soft soil. Needs 

abundant supply of water. 

1,5 

Vulpes vulpes necator 

Sierra Nevada red fox

CT Occupied habitats are typical of the high Sierra 

Nevada: high elevation barren, conifer and shrub 

habitats, montane meadows, talus slopes, subalpine 

woodlands, and fell-fields. Found mostly above 

7,000 feet and rarely below elevations of 5,000 feet. 

1,5 

Gulo gulo 

California wolverine

FC/CT/CSC Habitats used in the southern Sierra Nevada include 

red fir, mixed conifer, lodgepole, subalpine conifer, 

alpine dwarf-shrub, barren, wet meadows, montane 

chaparral, and Jeffrey pine, from 6,400 to 

10,800 feet. Uses caves, hollows in cliffs, logs, rock 

outcrops, and burrows for cover and denning. 

1,5 

Martes pennanti pacifica 

Pacific fisher

FC/CSC Dens and bears young in the cavities of large trees or 

snags and strongly associated with mid-elevation 

mature and late successional coniferous or mixed 

forests. Generally found in stands with high canopy 

closure, large trees and snags, large woody debris, 

large hardwoods, and multiple canopy layers. 

1,2,5,7 

Taxidea taxus 

American badger

CSC Drier open stages of most shrub, forest, and 

herbaceous habitats, with friable soils. 

7 

Ovis canadensis sierrae 

Sierra Nevada bighorn 

sheep

FE/CE/CFP Occurs primarily along the Sierra Crest in the 

northeast portion of the park. Most of the herd 

inhabits Forest Service land adjacent to the park. 

5 

STATUS: 

FE – Federal Endangered 

FT – Federal Threatened 

FC – Federal Candidate 

FD – Federal Delisted 

CE – California Endangered 

CT – California Threatened 

CCE – California Candidate Endangered 

CFP – California Fully Protected Species 

CSC – California Species of Concern 

*Believed to be extirpated from the Merced River Corridor 

SOURCE: Special Status Wildlife Species Report for the Merced River Corridor in Yosemite National Park (NPS 2011a) 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-18 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

TABLE N-3: PRESENTS A SUMMARY OF SPECIAL-STATUS WILDLIFE AND PLANT SPECIES ADDRESSED IN THIS 

ANALYSIS (CONTINUED) 

Scientific Name 

Common Name 

Listing 

Status: 

Park/CNPS/ 

State General Habitat 

Potential to 

Occur in 

Project Area 

Segment 

Plants and Fungi 

Antirrhinum leptaleum 

Spurred snapdragon 

SSP Small washes, shallow ditches, disturbed areas, in 

foothill woodland, yellow pine forest; historic 

collection from Wawona; elevations between 300-

2100 meters. 

7 

Asarum lemmonii 

Lemmon’s wild ginger 

SSP Shady wet places along creeks, north-facing river 

banks; Yosemite Valley, Wawona; elevations 

between 1100-1900 meters. 

2,7 

Bolandra californica 

California bolandra 

SSP/4.3 Lower and upper montane coniferous forest, mesic, 

rocky shaded places; Lyell Fork Merced River; 

elevations between 2000-3000 meters. 

1 

Bulbostylis capillaris 

Threadleaf beakseed 

SSP/4.2 Meadows and seeps, meadow habitats, vernally 

moist gravel pans; Yosemite Valley; elevations 

between 1000-2000 meters. 

2 

Camissonia sierrae ssp. alticola 

Mono Hot Spring evening 

primrose 

SSP/1B.2 On vernally moist gravel and sand pans; Merced 

Lake; elevations between 2000 - 2350 meters. 1 

Camissonia sierrae ssp. sierrae 

Sierra suncup 

SSP/4.3 Granite gravel seepage areas; Yosemite Valley; 

elevations between 500-1300 meters. 2 

Carex buxbaumii 

Buxbaum’s sedge 

SSP/4.2 Montane and subalpine fens; Coastal Prairie, Yellow 

Pine Forest, Red Fir Forest, Lodgepole Forest, 

Subalpine Forest, Meadows and seeps, wet 

conditions in meadow habitats. Yosemite Valley; 

elevations between 1200-3300 meters. 

2 

Carex canescens 

Silvery sedge 

SSP Lake margins, drainages in wet meadows; historic 

collection from Clark’s Wawona; elevations 

between 1000-3200 meters. 

7 

Carex fissuricola 

Cleft sedge 

SSP Meadow slopes and flats, among rocks, wet areas, 

spray zones; Nevada Falls; elevations between 

1500-3500 meters. 

1 

Carex sartwelliana 

Yosemite sedge 

SSP Moist forest openings and meadow borders; 

Wildcat Creek; elevations between 1200-2600 

meters.

1,2,5,7 

Carex tompkinsii 

Thompkins’ sedge 

SSP/4.3/ 

Rare 

Canyon slopes and river bottomlands under coniferoak woodland canopy; El Portal area; elevations 

between 1200-1800 meters.

4 

Cinna bolanderi 

Bolander’s woodreed 

SSP/1B.2 Montane stringer meadows and fens; Wawona & 

Little Yosemite Valley; elevations between 1670-

2440 meters. 

1,7 

Collinsia linearis 

Narrow leaf collinsia 

SSP Rocky, metamorphic substrates of broad-leaved 

upland forest, chaparral, cismontane woodland; El 

Portal & Wawona; elevations between 200-2000 

meters. 

4,7 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-19 

TABLE N-3: PRESENTS A SUMMARY OF SPECIAL-STATUS WILDLIFE AND PLANT SPECIES ADDRESSED IN THIS 

ANALYSIS (CONTINUED) 

Scientific Name 

Common Name 

Listing 

Status: 

Park/CNPS/ 

State General Habitat 

Potential to 

Occur in 

Project Area 

Segment 

Plants and Fungi (cont.) 

Cordylanthus rigidus ssp. 

brevibracteatus 

Short-bracted bird’s beak 

SSP/4.3 North side Yosemite Valley, dry sandy roadside full 

sun, 1 mi E Cascade Creek; elevations between 

1100-2500 meters. 

2 

Cypripedium montanum 

Mountain lady’s slipper 

SSP/4.2 Deep humus and shade of canyon bottoms; 

Wawona & below Yosemite Valley; elevations 

between 200-2200 meters. 

3,7 

Epipactis gigantea 

Stream orchid 

SSP Moist conditions in meadows, streambank habitats 

& cliff basins; Yosemite Valley; elevations between 

1500-2600 meters. 

2 

Eriophyllum congdonii 

Congdon’s woolly sunflower 

SSP/1B.2/Ra

re 

Sunny rockys slopes on metamorphic talus; next to 

river in El Portal; elevations between 500-1900 

meters. 

4 

Erythronium purpurascens 

Purple fawnlily 

SSP Open forests, meadows, rocky places; Yosemite 

Valley - possibly extinct; elevations between 1500-

2700 meters. 

2 

Glyceria borealis 

Northern mannagrass 

SSP Marshes and shallow lake borders; Yosemite Valley; 

elevations between 800-1250 meters. 2 

Helianthus californicus 

California sunflower 

SSP Meadows, seeps, streambanks, seasonally 

inundated areas; Wawona; elevations between 

1600-2000 meters. 

7 

Hippuris vulgaris 

Common mare’s tail 

SSP Lakes, ponds, springs, rivers. Little Yosemite Valley; 

elevations between 0-2600 meters. 1 

Hulsea heterochroma 

Redray alpinegold 

SSP Chaparral, openings in yellow pine forest, Yosemite 

Valley, 5 miles above Nevada Fall; elevations 

between 300-2500 meters. 

1,2 

Isoetes occidentalis 

Western quillwort 

SSP Mountain lakes and rivers; In Merced River Little 

Yosemite Valley; elevations between 1500-2500 

meters. 

1 

Leucothoe davisiae 

Sierra laurel 

SSP Moist, shaded drainage bottoms along creeks and 

rivers; Yosemite Valley; elevations between 1300-

2600 meters. 

2 

Lewisia congdonii 

Congdon’s lewisia 

SSP/1B.3/Ra

re 

Lower montane coniferous forest, metamorphic 

cliffs; El Portal; elevations between 500-2800 

meters. 

3,4 

Lindernia dubia var. anagallidea 

False pimpernel 

SSP Exposed margins of lakes and ponds, mudflats; 

Yosemite Valley; elevations between 500-1600 

meters. 

2 

Lithocarpus densiflorus var. 

echinoides 

Tanoak

SSP Dry shady forest conditions in slope habitats; 

Merced River below Yosemite Valley; elevations 

between 600-2000 meters. 

2,3 

Lycopus uniflorus 

Northern bugleweed 

SSP/4.3 Moist areas, marshes, near springs; Merced River 

banks from El Portal up; elevations between 1600-

2000 meters. 

3,4 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-20 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

TABLE N-3: PRESENTS A SUMMARY OF SPECIAL-STATUS WILDLIFE AND PLANT SPECIES ADDRESSED IN THIS 

ANALYSIS (CONTINUED) 

Scientific Name 

Common Name 

Listing 

Status: 

Park/CNPS/ 

State General Habitat 

Potential to 

Occur in 

Project Area 

Segment 

Plants and Fungi (cont.) 

Mimulus bicolor 

Yellow and white 

monkeyflower 

SSP Occurs under vernally moist conditions; usually in 

non-wetlands, but occasionally found on wetlands 

& river bottomlands; Wawona; elevations between 

360-2100 meters. 

7 

Mimulus inconspicuus 

Small flowered 

monkeyflower 

SSP/4.3 Chaparral, cismontane woodland, lower montane 

coniferous forest, mesic, shady areas; mouth of 

Moss Creek; elevations between 160-2000 meters. 

2,3,7,8 

Mimulus laciniatus 

Cutleaf monkeyflower 

SSP/4.3 Chaparral, lower and upper montane coniferous 

forest, mesic areas of granitic substrate, vernally 

moist seepage areas; Yosemite Valley; elevations 

between 900-2000 meters. 

2 

Mimulus pulchellus 

Yellowlip pansy 

monkeyflower

SSP/1B.2 Lower montane coniferous forest, vernally mesic 

meadows; Yosemite Valley; elevations between 

600-2000 meters. 

2 

Myrica hartwegii 

Sierra sweet bay 

SSP Stream and riverbanks; Along Merced below 

Wawona; elevations between 300-1500 meters. 7,8 

Narthecium californicum 

California bog asphodel 

SSP Fens, seeps; occurs under wet conditions by streams 

and waterfalls; Bridalveil Falls; elevations between 

700-2600 meters. 

2 

Penstemon azureus ssp. 

angustissimus 

Azure penstemon 

SSP Chaparral, Yellow Pine Forest, Sagebrush Scrub, 

Foothill Woodland; occurs under dry conditions in 

slope habitats. Yosemite Valley; elevations between 

300-700 meters. 

2 

Penstemon heterophyllus var. 

purdyi 

Purdy’s foothill penstemon 

SSP Chaparral, Foothill Woodland, Yellow Pine Forest; 

occurs under dry conditions in slope habitats. 

Yosemite Valley; elevations between 50-1600 

meters. 

2 

Phacelia tanacetifolia 

Tansy leafed phacelia 

SSP Habitat variable, occurs in slope habitats; Bridalveil 

Falls, Yosemite Valley; elevations between 1000-

2000 meters. 

2 

Pinus albicaulis 

Whitebark pine 

FC Cold, windy high elevation sites between 3,000 

meeters-3,750 meters 1,2,5 

Piperia colemanii 

Coleman’s piperia 

G3/4.3 Chaparral, lower montane coniferous forest. Little 

Yosemite Valley; elevations between 1200-2300 

meters. 

1 

Plagiobothrys torreyi var. torreyi 

Torrey’s popcornflower 

SSP/1B.2 Moist meadows and flats, forest edges; Yosemite 

Valley; elevations between 1200-3400 meters. 2 

Potamogeton epihydrus ssp. 

nuttallii 

Nuttall’s pondweed 

SSP/2.2 Freshwater marshes, tanks; Yosemite Valley; 

elevations between 400-1900 meters. 2 

Quercus lobata 

Valley oak 

SSP Deep soil on slopes and in valleys. Known from a 

few majestic specimens in El Portal; elevation 720 

meters. 

4 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-21 

TABLE N-3: PRESENTS A SUMMARY OF SPECIAL-STATUS WILDLIFE AND PLANT SPECIES ADDRESSED IN THIS 

ANALYSIS (CONTINUED) 

Scientific Name 

Common Name 

Listing 

Status: 

Park/CNPS/ 

State General Habitat 

Potential to 

Occur in 

Project Area 

Segment 

Plants and Fungi (cont.) 

Saxifraga mertensiana 

Wood saxifrage 

SSP Mossy rocks, cliffs; Yosemite Valley; elevations 

between 1000-2500 meters. 2 

Saxifraga oregana 

Oregon saxifrage 

SSP Meadows and seeps; occurs under wet conditions 

in meadow habitats; Yosemite Valley & Little 

Yosemite Valley; elevations between 150-2500 

meters. 

1,2 

Scutellaria bolanderi ssp. 

bolanderi 

Sierra skullcap 

SSP Gravelly soils, stream & riverbanks, meadows in oak 

or pine woodland; Wawona; elevations between 

300-2000 meters. 

7 

Senecio clarkianus 

Clark’s ragwort 

SSP Damp montane meadows; Wawona; elevations 

between 1400-2700 meters. 7 

Sparganium natans 

Small bur reed 

SSP/4.3 Freshwater wetlands, in lake margin and edge 

habitats, tanks in meadows; tributaries of Merced 

River; elevations between 2000-2500 meters. 

2,7 

Staphylea bolanderi 

Sierra bladdernut 

SSP Chaparral, Foothill Woodland, Yellow Pine Forest; 

occurs in shaded canyon habitats; Merced River 

Canyon in El Portal; elevations between 240-1720 

meters. 

3,4 

Trillium angustipetalum 

Narrowpetal wakerobin 

SSP Shaded bottomlands; Wawona, Yosemite Valley; 

elevations between 100-2000 meters. 2,7 

Vaccinium parvifolium 

California red huckleberry 

SSP Moist, shaded drainage bottoms along creeks and 

rivers; Merced River Wawona area; elevations 

between 1400-2500 meters. 

7 

Wyethia elata 

Hall’s mule ears 

SSP/4.3 Open woodland, forest; Wawona; elevations 

between 1000-1400 meters. 7 

STATUS: 

FC – Federal Candidate 

Rare: Designated as rare by the State of California 

SSP: Park Designated Special Status Species 

CNPS RANKINGS:

List 1A: Plants presumed extinct in California 

List 1B: Plants Rare, Threatened, or Endangered in California and Elsewhere 

List 2: Plants Rare, Threatened, or Endangered in California, But More Common Elsewhere 

List 3: Need more information 

List 4: Plants of Limited Distribution 

 Threat Ranks: 

 .1: Seriously endangered in California 

 .2: Fairly endangered in California 

 .3: Not very endangered in California 

SOURCE: Special Status Plant Species in the Merced River Corridor within Yosemite National Park (NPS 2011b) 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-22 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Federal Endangered Species

Mammals 

Sierra Nevada bighorn sheep 

Ovis canadensis sierrae

Status. Federal Endangered, California Endangered, California Fully Protected 

General Distribution. Sierra Nevada bighorn sheep use habitats ranging from the highest elevations 

along the crest of the Sierra Nevada (4,000 meters [13,120 feet]) to winter ranges at the eastern base of 

the range as low as 1,450 meters (4,760 feet) (USFWS 2007). The Sierra Nevada bighorn sheep 

population has increased from a low of 100 individuals in 1995 to more than 400 animals since the 

species was listed as endangered under the federal ESA in 1999. The Yosemite Recovery Unit consists 

of approximately 40 individuals at high elevations along the northeastern section of Yosemite. 

Habitat Requirements. Habitats used by Sierra Nevada bighorn sheep include alpine dwarf-shrub, 

low sage, sagebrush, bitterbrush, pinyon-juniper, palm oasis, desert riparian, desert succulent shrub, 

desert scrub, subalpine conifer, perennial grassland, montane chaparral, and montane riparian 

(DeForge 1980, Monson and Sumner 1980, Wehausen 1980). Bighorn sheep use rocky, steep terrain 

for escape and bedding and remain near rugged terrain while feeding in open habitat (Zeiner et al. 

1990). Low-elevation winter ranges provide this species an important source of high quality forage 

early in the growing season (USFWS 2007). They use steep, rugged slopes and canyons for lambing 

areas (Wehausen 1980). 

Status in Merced River Corridor. Historically, bighorn sheep occupied alpine and subalpine areas 

along the Sierra Crest and in the Cathedral Range. It is generally believed that they seasonally migrated 

from the crest to winter on the eastern escarpment. Given that they occupied the Cathedral Range, it is 

very likely that bighorn sheep historically occupied the upper reaches of the Merced River drainage. A 

Museum of Vertebrate Zoology specimen was taken from the east lobe of Lyell Glacier within 1 

kilometer (0.62 mile) of the Merced River corridor in October 1933. Another specimen was taken 

within 3 kilometers of the river corridor east of Crescent Lake near Wawona in 1921 (Museum of 

Vertebrate Zoology Database 2011). In 1976, a bighorn sheep was sighted near Donohue Pass, 

approximately 3.5 kilometers northeast of the Merced River corridor (Yosemite Wildlife Observation 

Database 2011). Although rams might occasionally (rarely) wander into the upper (along the crest) 

Merced River drainage, it is highly unlikely that bighorn sheep currently occupy the Merced River 

drainage (Chow, pers. comm.). In addition, bighorn sheep critical habitat (designated in 2008 by 

USFWS) does not occur within the Merced River corridor. 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-23 

Federal Threatened Species 

Invertebrates 

Valley elderberry longhorn beetle 

Desmoscerus californicus dimorphus

Status. Federally threatened 

General Distribution. The valley elderberry longhorn beetle is found in areas below 915 meters 

(3,000 feet) in elevations that support species of elderberry (Sambucus sp.). At the time of listing in 

1980, the beetle was known from fewer than 10 locations on the American River, Putah Creek, and 

Merced River. Current distribution ranges from southern Shasta County to Fresno County. 

Habitat Requirements. The valley elderberry longhorn beetle is an invertebrate species that is 

completely dependent on its host plant, elderberry, throughout its one-year to two-year life cycle. The 

beetle spends most of its life in the larval stage, living in the stems of elderberry shrubs. Adults emerge 

from late March through June, when feeding and mating occurs, about the same time the elderberry 

flowers. The adult stage is short-lived; females lay their eggs on the bark, larvae hatch and burrow into the 

stems, and the cycle is repeated. Although elderberry shrubs are relatively common in riparian habitat, it 

appears that to serve as suitable habitat, shrubs must have stems that are 1 inch or greater in diameter at 

ground level (Barr 1991). Use of elderberry by the beetle is rarely apparent. Frequently, the only exterior 

evidence of the use by the beetle is a distinct exit hole created by the larva just before the pupal stage. 

Status in Merced River Corridor. The El Portal Administrative Site is the only area in Yosemite 

National Park that lies below 915 meters (3,000 feet) in elevation. In El Portal, elderberry plants 

represent a subdominant species within live oak forests, interior live oak forests, interior live oak 

woodlands, blue oak woodlands, canyon live oak forests, mixed north slope forests, foothill pine/live 

oak/chaparral woodlands, northern mixed chaparral, interior live oak chaparral, and westside 

ponderosa pine forests. Elderberry shrubs are scattered throughout the El Portal Administrative Site. 

Federal Candidate Species 

Amphibians 

Yosemite toad 

Bufo canorus

Status. Federal candidate, California species of special concern 

General Distribution. The historic range of Yosemite toads in the Sierra Nevada occurs from the Blue 

Lakes region north of Ebbetts Pass (Alpine County) to 5 kilometers (3.1 miles) south of Kaiser Pass in 

the Evolution Lake/Darwin Canyon area (Fresno County) (Jennings and Hayes 1994). Historically, the 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-24 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

toad ranged from 1,460 meters to 3,630 meters (4,790 feet to 11,910 feet) in elevation (Stebbins 1985) 

throughout its range and from 1,950 meters to 3,444 meters (6,400 feet to 11,300 feet) in elevation in 

Yosemite (Karlstrom 1962). The toad is currently known from 179 sites in Yosemite between the 

elevations of 2,134 meters to 3,505 meters (7,000 feet to 11,500 feet) (Knapp 2003). Estimates suggest 

that the toad has disappeared from between 47% and 79% of the sites that it previously occupied 

(Jennings and Hayes 1994, Drost and Fellers 1996). Remaining populations appear more scattered 

across the landscape and consist of a small number of breeding adults (Kagarise Sherman and Morton 

1993). 

The NPS surveyed 446 meadows for Yosemite toads during the summer of 2010, 166 of which had 

been surveyed at least once between 1992 and 2009. The remaining 280 meadows had never been 

surveyed. The surveys documented 44 new breeding populations of toads, and increased the number 

of documented breeding populations from 135 to 179. Toads were not found in approximately 50% of 

the sites where toads had been previously documented, while 9% of meadows where toads had not 

been documented previously had breeding during the 2010 survey. 

Habitat Requirements. The Yosemite toad has been recorded in a broad range of high montane, 

subalpine, and alpine habitats, including wet meadows, lakes, ponds, and shallow spring channels. The 

Yosemite toad is most commonly found, however, in shallow, warm water areas, including standing 

and flowing water in wet meadows, small permanent and ephemeral ponds, and flooded shallow 

grassy areas and meadows adjacent to lakes (Karlstrom 1962). Wet meadow habitat is the focal habitat 

for this species. 

Status in the Merced River Corridor. Yosemite toad observations have been recorded on 2,142 

occasions in Yosemite. Of these observations, 11 records are from the Merced River corridor. There 

are no records of Yosemite toads within the Merced River corridor prior to 1999, which is likely due 

to a lack of survey efforts targeting the toad. Between 1999 and 2010, there were a multiple sightings at 

higher elevation sites around Triple Divide, Isberg, and Rodgers peaks. 

Sierra Nevada yellow-legged frog 

Rana sierrae

Status. Federal candidate, California candidate 

General Distribution. Sierra Nevada yellow-legged frogs currently range from north of the Feather 

River in northern Plumas County, California, south, including all of Yosemite, to the divide between 

the South and Middle Forks of the Kings Rivers in Kings Canyon National Park. The majority of their 

range is in federally designated wilderness. Despite the fact that most of their habitat is fully protected, 

the Sierra Nevada yellow-legged frog has disappeared from >93% of their historic range. The declines 

have escalated since the late1970s, and most of the remaining populations are much smaller than those 

that would have occurred historically (Knapp 2005). Consequently, the Sierra Nevada yellow-legged 

frog has gone from being one of the most abundant species in the Sierra Nevada (Grinnell and Storer 

1924) to one that is considered critically endangered. This species is currently known to occur at 

approximately 166 sites in Yosemite at elevations ranging from 1,676 meters to 3,536 meters (5,500 feet 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-25 

to 11,600 feet). The Sierra Nevada yellow-legged frog is a candidate species for listing under the federal 

ESA, and the USFWS plans to initiate a proposed rule to list this species in 2013. A listing decision 

would occur within 12 months of proposed ruling. 

Habitat Requirements. The Sierra Nevada yellow-legged frog occupies aquatic habitats for almost all 

of their seasonal life history; they breed, tadpoles develop, and they overwinter in lakes and ponds or 

low-flowing streams and use flowing water to move between sites. This species is rarely found more 

than a few feet from water. Because it overwinters in water and has a multi-year tadpole phase, it 

requires waters that are deep enough that they don’t freeze solid in the winter and they don’t dry out 

during the summer. 

Status in the Merced River Corridor. Sierra Nevada yellow-legged frog observations have been 

recorded on 4,581 occasions in Yosemite. Of these observations, 20 records are from the Merced River 

corridor. Most of the sites where Sierra Nevada yellow-legged frogs are known to exist fall outside of 

the Merced River corridor. Concerted efforts to survey amphibians in the park have been conducted 

between 1992 and 2010. Before 1992, there were five records of Sierra Nevada yellow-legged frogs 

within the river corridor at Wawona (1922), Yosemite Valley (1922, 1958), Triple Peak (1940), and 

Horsethief Canyon (1991). One of the historic records from Yosemite Valley may have been from 

farther up Tamarack Creek rather than from the Valley. During a comprehensive survey of all mapped 

and unmapped lakes and ponds in Yosemite conducted in 2000–2002, Knapp (2005) observed Sierra 

Nevada yellow-legged frogs at 13 sites around Red and Rodgers peaks. A total of 30 adults or subadults 

and about 1400 tadpoles were recorded at these sites. Between 1992 and 2010, there were two 

additional observations in the upper reaches of the Merced River. 

Mammals 

California Wolverine 

Gulo gulo luteus

Status. Federal candidate, California threatened 

General Distribution. The California wolverine is an uncommon resident of north Coast Range 

mountains and the Sierra Nevada. Sightings range from Del Norte and Trinity counties east through 

Siskiyou and Shasta counties, and south through Tulare County (Zeiner et al. 1990). Wolverines have 

not been scientifically confirmed in California since the 1920s, but a remote camera sighting detected 

an individual wolverine in Tahoe National Forest in March 2008. 

Habitat Requirements. Habitats used by the California wolverine in the southern Sierra Nevada 

include red fir, mixed conifer, lodgepole, subalpine conifer, alpine dwarf-shrub, barren, wet meadows, 

montane chaparral, and Jeffrey pine, while their elevation range in the southern Sierra Nevada is 

2,000 meters to 3,400 meters (6,400 feet to 10,800 feet) (Zeiner et al. 1990). The wolverine uses caves, 

hollows in cliffs, logs, rock outcrops, and burrows for cover and denning, generally in denser forest 

stages (Zeiner et al. 1990). The wolverine may dig dens in the snow. Wolverines are hunters and 

scavengers and feed primarily on small mammals and carrion but might kill large snowbound prey 

(Grinnell et al. 1937, Ingles 1965). Wolverines have extremely large home ranges; in Montana, their 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-26 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

yearly home range was 422 km2 (156 mi2) for males and 388 km2 (144 mi2) for females (Hornocker and 

Hash 1981). 

Status in Merced River Corridor. Two California wolverine specimens were collected at the head of 

Lyell Canyon in 1915, just 2 kilometers from the Merced River corridor (Museum of Vertebrate 

Zoology Database 2011). There have been three unconfirmed sightings within the corridor; along the 

south fork of the Merced River in 1959, near Pohono Bridge in 1990, and near the junction of Iron 

Creek and the Merced River in 1959 (Yosemite Wildlife Observation Database 2011). The likelihood 

of these latter three sightings being legitimate is highly unlikely, however. 

Pacific fisher 

Martes pennanti pacifica

Status. Federal candidate, California species of special concern 

General Distribution. Although the historic distribution of Pacific fisher was once contiguous across 

California and the Pacific Northwest, including the northern Coast range, Klamath Mountains, 

southern Cascades, and western slope of the Sierra Nevada, the fisher has declined during the past 

century. Remaining populations are geographically and, in some cases, genetically isolated from one 

another (Grinnell et al.1937, Zielinski et al. 1995). Pacific fisher currently occur in only two regions of 

the state, which are separated by over 430 kilometers: the northwest, including the northern Coast 

Range and Klamath Province; and the southern Sierra Nevada, including Yosemite National Park 

(Zielinski et al. 1995). Yosemite lies at the northern tip of the fisher’s southern range. The fisher’s 

elevation range is approximately 1,219 meters to 2,134 meters (4,000 feet to 7,000 feet). 

Habitat Requirements. The Pacific fisher is one of the most habitat-specific mammals in North 

America (Buskirk and Powell 1994). Fishers den and bear young in the cavities of large trees or snags 

and are strongly associated with mid-elevation, mature and late successional coniferous or mixed 

forests (Powell and Zielinski 1994, Zielinski et al. 2004a, 2004b). In particular, fisher are generally 

found in stands with high canopy closure, large trees and snags, large wood, large hardwoods, and 

multiple canopy layers. Fisher generally avoid entering open areas that have no overstory or shrub 

cover (Buskirk and Powell 1994), while Chow (2009) found that fisher in Yosemite prefer habitat near 

permanent streams. The fisher has a varied diet consisting primarily of small mammals, such as 

squirrels, but they also consume porcupines, birds, invertebrates, vegetation, and fruit (Powell and 

Zielinski 1994). 

Status in Merced River Corridor. Fisher are elusive and more challenging to detect compared with 

other carnivores, but recent fisher surveys (2009–2011) conducted in collaboration with U.C. Berkeley 

have confirmed the presence of 5– 8 individual fisher south of the Merced River near Chinquapin, 

Wawona, Mariposa Grove, and along the South Fork Merced River. Previous fisher surveys in the park 

conducted by Chow (2009) during 1992–1994 detected relatively few fisher despite the availability of 

suitable habitat and use of a combination of survey methods, including remote cameras and track 

plates. Chow (2009) concluded that Pacific fisher inhabit Yosemite at very low population densities. 

The Merced River may be one of multiple barriers currently preventing northward expansion of their 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-27 

range. Two fisher specimens were collected within the Merced River corridor in Yosemite Valley in 

1919 and 1920 (Museum of Vertebrate Zoology Database 2011). 

Plants 

Whitebark pine 

Pinus albicaulis

General Ecology and Distribution. Whitebark pine, a tree from the pine family, is native to 

California. It occurs in subalpine and upper montane forests at elevations ranging between 2,300 and 

4,000 meters. It is considered a keystone species and a major food source for many species of birds and 

mammals. Whitebark pine is rapidly declining throughout most of its range, primarily due to a 

combination of white pine blister rust, periodic mountain pine beetle outbreaks, fire suppression, and 

climate change (Natural Resources Defense Council [NRDC], 2008 and Fryer, 2002). 

Habitat and Status in the Project Area. This species occurs on cold and windy, high-elevation sites 

in isolated stands in the subalpine zone. However, it also co-occurs with a diversity of confiers that 

vary by location and elevation (NRDC, 2008 and Fryer, 2002). In the Project Area, it is found in 

Segments 1, 2, and 5 (Merced River above Nevada Fall, Yosemite Valley, and South Fork above 

Wawona, respectively). 

California State Endangered Species 

Sierra Nevada bighorn sheep (see Federal Endangered Species section) 

Birds 

Willow flycatcher 

Empidonax trailii

Status. California endangered 

General Distribution. The willow flycatcher is a neotropical migrant that breeds in riparian and moist 

meadow willow thickets in the United States and southern Canada (American Ornithologists’ Union 

1983). The willow flycatcher winters from Mexico to northern South America. Currently, about half of 

the willow flycatcher breeding population in California occurs in the Sierra Nevada (Zeiner et al. 1990, 

Kus et al. 2000). Most willow flycatchers in the Sierra Nevada are found at elevations from 366 meters 

to 2,900 meters (1,200 feet to 9,500 feet), although most of the known willow flycatcher sites (88%) 

occur at elevations between 1,200 meters and 2,400 meters (3,900 feet to 7,900 feet) (Serena 1982, 

Harris et al. 1988, Stafford and Valentine 1985). Willow flycatchers are a rare former breeder in 

Yosemite. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-28 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Habitat Requirements. As their name suggests, willow flycatchers frequent the willows found along 

languid streams and, to a lesser degree, within moist meadows (Gaines 1992). Deciduous trees and 

shrubs interspersed with open areas enhance the quality of foraging habitat. Willow flycatchers forage 

by either gleaning insects from vegetation while flying, or by waiting on an exposed perch and 

capturing insects in flight (Ettinger and King 1980, Sanders and Flett 1989). 

Status in Merced River Corridor. Once a commonly observed bird in Yosemite Valley, willow 

flycatchers are now exceedingly rare in the park as a whole. Willow flycatcher observations have been 

recorded on 50 occasions in Yosemite. Of these observations, 26 records are from the Merced River 

corridor. The first documented observation of a willow flycatcher in Yosemite was made by the 

Grinnell survey in 1915. Almost all of the river corridor’s willow flycatcher observations fall between 

1915 and 1931 (Yosemite Wildlife Observation Database 2011). Gaines (1992) indicates that they had 

stopped breeding in the Valley by 1966. Two observations from the 1970s (Yosemite Valley 1974, 

Wawona 1977) are the most recent sightings of willow flycatchers in the river corridor, although they 

are still seen on rare occasions elsewhere in the park. A recent study found that willow flycatchers no 

longer breed in Yosemite National Park (Siegel et al. 2008). 

Bald eagle

Haliaeetus leucocephalus

Status. California State endangered, California fully protected 

General Distribution. Bald eagles are found throughout North America, and there are breeding 

populations in almost all U.S. states and Canadian provinces. Once far more numerous than they are 

today, bald eagle populations suffered tremendously during the 20th century due to state-enacted 

bounties (Robards and King 1966) and poisoning from pesticides like DDT (Buehler 2000). Stricter 

protection measures and a reduced exposure to environmental toxins has led to the large-scale 

recovery of bald eagles, a feat widely regarded as one of the most successful modern conservation 

efforts. Bald eagles are uncommon but occasional breeders in Yosemite. 

Habitat Requirements. Bald eagles favor lakes and rivers with abundant prey (mostly fish) and large 

trees in which to nest. The relative paucity of bald eagle observations in Yosemite indicates that there 

may be insufficient fish in Yosemite rivers to support a robust eagle population. Bald eagles also 

compete directly with ospreys, occasionally stealing food from them. Bald eagles are regularly 

observed in Sierra foothill reservoirs and at lakes east of Tioga Pass; in both locations the eagles are 

feeding on stocked fish populations that are higher in elevation than what would naturally be present. 

Status in Merced River Corridor. Bald eagle observations have been recorded on 123 occasions in 

Yosemite. Of those observations, 25 records are from the Merced River corridor (Yosemite Wildlife 

Observation Database 2011). Roughly half of the bald eagle observations in the river corridor are from 

areas downstream of Yosemite Valley. The first records of bald eagles in Yosemite are from Wawona 

(November 1957). From the late 1970s to 1992, bald eagles were documented in the river corridor at a 

rate of one every few years. 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-29 

California State Threatened Species 

California wolverine (see Federal Candidate Species section) 

Mammals 

Sierra Nevada red fox 

Vulpes vulpes necator

Status. California threatened 

General Distribution. The Sierra Nevada red fox is one of 10 currently recognized red fox subspecies 

in North America (Hall 1981). Vulpes vulpes necator is one of three subspecies of mountain red fox, 

along with the foxes of the Cascade Mountains (V. v. cascadensis) and the Rocky Mountains (V. v. 

macroura) (Perrine et al. 2010). The Sierra Nevada red fox has historically been found throughout 

high elevations of the Sierra Nevada from Tulare County northward to Sierra County, and from 

Mount Shasta and Lassen Peak westward to the Trinity Mountains (Trinity County) (Grinnell et al. 

1937). The Sierra Nevada red fox elevation range is approximately 1,200 meters to 3,600 meters 

(4,000 feet to 11,800 feet); it is seldom observed below 1,500 meters (4,900 feet) and most often is seen 

above 2,100 meters (6,900 feet) (Grinnell et al. 1937, Perrine et al. 2010). This fox occurs at low 

densities, even in areas of high relative abundance (Perrine et al. 2010). Current Sierra Nevada red fox 

distribution and range are uncertain (CDFG 1996); until recently, the Lassen Peak region accounted 

for the only verified contemporary detections of mountain red fox (Kucera 1993 and 1995, Perrine and 

Arnold 2001, Perrine 2005). In August 2010, biologists on the Humboldt-Toiyabe National Forest 

detected a Sierra Nevada red fox at an automatic camera station near Sonora Pass at an elevation of 

3,048 meters (10,000 feet) along the border of Tuolumne and Mono counties. Since this detection, 

three (and possibly five) individual Sierra Nevada red foxes have been detected within 80 miles of this 

area, with the lowest detection at 1,828 meters (6,000 feet). 

Habitat Requirements. The Sierra Nevada red fox occupied habitats are typical of the high Sierra 

Nevada: high-elevation barren, conifer, and shrub habitats, montane meadows, talus slopes, subalpine 

woodlands, and fell-fields (Perrine et al. 2010, Grinnell et al. 1937, Ingles 1965). Possible den sites 

include natural cavities in talus slopes or rockslides, earthen dens, boulder piles, or even the space 

beneath vacant cabins (Grinnell et al. 1937, Aubry 1983). In the winter, Sierra Nevada red foxes may 

follow the forested edge of openings, possibly avoiding areas where they would be exposed to attack 

by other carnivores, while ski tracks and other packed snow may also facilitate travel (Perrine et al. 

2010). Red foxes are opportunistic predators and scavengers that eat a wide variety of foods, 

depending on their seasonal availability, including small and medium-sized mammals, birds, insects, 

invertebrates, fruit, carrion, and garbage (Perrine et al. 2010). 

Status in Merced River Corridor. Until recently, the last verified Sierra Nevada red fox sighting 

(confirmed by photograph) near Yosemite National Park occurred during the winter of 1990-1991 at 

the Tioga Pass Resort 2,940 m (9,645 ft) on the Inyo National Forest, just outside the park (Les Chow, 

NPS Inventory and Monitoring Network, pers. comm.). However, in the last few years there have been 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-30 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

several more detections. In 2009, the CDFG began surveying high-elevation habitats in the southern 

Cascade and Sierra Nevada ranges for Sierra Nevada red fox with the goal of determining current red 

fox distribution as well as genetic make-up of existing individuals or populations. Using baited remote, 

motion-sensing camera stations and passive hair-snaring devices, a total of nine individual Sierra 

Nevada red foxes have been detected in high elevation wilderness areas in the Sierra (C. Stermer, Pers. 

Comm.). In April 2012, a Sierra Nevada red fox was detected on the northern border of Yosemite 

National Park near Dorothy Lake in Toiyabe National Forest. Surveys targeting other carnivores, such 

as Martes, are not adequate for detecting Sierra Nevada red fox (Perrine et al. 2010). Surveys in the 

park targeting red fox are being proposed; however, based on previous survey and sighting data, it is 

unlikely that a significant red fox population exists in Yosemite National Park. 

California State Fully Protected Species 

Birds 

Bald eagle (see California State Endangered Species section) 

Golden eagle 

Aquila chrysaetos

Status. California fully protected 

General Distribution. Golden eagles occur across most of North America, ranging from high alpine 

habitats to low deserts. Nearly all nesting in the United States occurs west of the Great Plains, with the 

rest of the range used primarily by migrants (Palmer 1988). In California, they inhabit foothills, 

mountainous areas, sage‐juniper flats, and desert habitats (Zeiner et al. 1990). In the Sierra Nevada, 

golden eagles favor grasslands and areas of shrubs or saplings, and open-canopied woodlands of 

young blue oaks. In late summer, they often range to above timberline (Zeiner et al. 1990). The golden 

eagle is a locally uncommon breeder at Yosemite. 

Habitat Requirements. Golden eagles feed mostly on rabbits and rodents but may also take other 

mammals, birds, reptiles, and carrion. They hunt in meadows, clearings, rock outcroppings, granite 

shelves, fell-fields, talus, and other open or openly wooded habitats, but they avoid dense forests 

(Gaines 1992). They employ three main strategies to search for prey: soaring, still‐hunting from a 

perch, and low contouring flight (Edwards 1969, Dunstan et al. 1978, Dekker 1985, Palmer 1988). 

Status in Merced River Corridor. Golden eagle observations have been recorded on 273 occasions in 

Yosemite. Of these observations, there are 74 records from the Merced River corridor. These records 

span the years from 1915–2008. The majority of these observations are from locations in Yosemite 

Valley. Golden eagles have also been observed near Wawona Dome (1983) and at Washburn Lake 

(1940), as well as in the Merced Gorge between the Valley and El Portal (Yosemite Wildlife 

Observation Database 2011). Nevada Fall is a representative nesting location (Gaines 1992). 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-31 

Peregrine falcon 

Falco peregrinus

Status. California fully protected 

General Distribution. Peregrine falcons can be found on nearly every ice-free landmass on earth. 

They will frequently migrate enormous distances; individuals from northern populations might travel 

25,000 kilometers (15,530 miles) annually (White et al. 2002). In California, they breed along the coast 

as well as in most northern mountain ranges, including the Sierra Nevada (Polite and Pratt 1990). 

Peregrine falcon nests are often scrapes on ledges or cliffs, a habit they practice in the Valley on 

features like El Capitan and Glacier Point. The use of dichlorodiphenyltrichloroethane (DDT) as a 

pesticide in the mid-to-late 1900s decimated peregrine falcon populations, and as recently as 1981 

there may have been as few as 39 breeding pairs in California (Monk 1981). Intensive management of 

peregrines falcons, including captive rearing, led to a resurgence of their populations in the last three 

decades. The peregrine falcon is a rare but regular breeder in Yosemite. 

Habitat Requirements. Peregrine falcons will hunt in a wide variety of habitats, including meadows, 

woodlands, marshes, and mudflats, but typically nest on cliff ledges with expansive views (Gaines 

1992). Peregrine falcons feed almost exclusively on birds, which are taken in flight. They require cliffs 

and ledges for cover and usually breed and hunt near water (Polite and Pratt 1990). 

Status in Merced River Corridor. Peregrine falcon observations have been recorded on 118 

occasions in Yosemite. Of those observations, 65 records are from the Merced River corridor 

(Yosemite Wildlife Observation Database 2011). The first documented peregrine sighting in Yosemite 

Valley was in 1940. Following this record are three observations from the summer of 1949, one of 

which involved two peregrines. In the 1950s and 1960s, DDT sent peregrine falcon populations 

plummeting all over the world. In 1972, the use of DDT was essentially banned; and in 1973, the 

peregrine was one of the first species to be listed under the federal ESA. By the early 1970s, peregrine 

falcons had all but disappeared in Yosemite. In 1978, rock climbers scaling the face of El Capitan in 

Yosemite Valley discovered nesting peregrine falcons; the first time in over 35 years that this species 

had been confirmed as breeding in the park. Since 1978, over 30 years ago, peregrine falcons have 

continued to recover in the park. Breeding surveys conducted in 2010 revealed eight active nests in 

Yosemite, the most ever documented in one season. Yosemite has a policy of temporarily closing rock 

climbing routes between March and August that pass through active peregrine falcon nesting sites. 

California State Rare Species 

Plants 

Thompkins’ sedge 

Carex tompkinsii

General Ecology and Distribution. This perennial herb in the sedge family is endemic to California 

and occurs in chaparral, foothill woodland, red fir forest, and yellow pine forest habitats at elevations 

of 1,200 to 1,800 meters. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-32 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Habitat and Status in the Project Area. It is found in canyon slopes and river bottomlands under 

conifer-oak woodland canopy. This species occurs in the El Portal area (Segment 4). 

Congdon’s woolly-sunflower 

Eriophyllum congdonii

General Ecology and Distribution. This species, a native annual herb in the aster family, is endemic 

to California and restricted to Mariposa County. It is found on dry, mostly south-facing metamorphic 

and metasedimentary outcrops in chaparral and oak woodlands. It is endemic to the main stem of the 

Merced River canyon near El Portal and the South Fork of the Merced River downstream of Wawona. 

Habitat and Status in the Project Area. Habitat for this species occurs on sunny rocky slopes next to 

the river in El Portal (Segment 4). 

Congdon’s lewisia 

Lewisia congdonii

General Ecology and Distribution. This perennial herb in the montia family is endemic to California 

and occurs in chaparral, foothill woodland, red fir forest, and yellow pine forest. It is only found 

within Mariposa and Fresno Counties at elevations between 500 and 2,800 meters. 

Habitat and Status in the Project Area. This species is known from approximately ten occurrences 

in the canyons of the Kings and Merced Rivers. In the Project Area, it occurs on metamorphic cliffs 

within lower montane coniferous forests in El Portal (Segment 3). 

California State Species of Special Concern 

California wolverine (see Federal Candidate Species section) 

Pacific fisher (see Federal Candidate Species section) 

Yosemite toad (see Federal Candidate Species section) 

Sierra Nevada yellow-legged frog (see Federal Candidate Species section) 

Fish 

Hardhead 

Mylopharodon conocephalus

Status. California species of special concern 

General Distribution. Hardhead are endemic to California and native to the Sacramento and San 

Joaquin River basins and the Russian River watershed. Hardhead are typically found in undisturbed 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-33 

areas of larger middle- and low-elevation streams and rivers. This species ranges from sea level to 

1,450 meters (4,750 feet) in elevation. Historically, hardhead were regarded as a widespread and locally 

abundant species. Hardhead still appear to be widespread in foothill streams, but their specialized 

habitat requirements combined with widespread alteration of downstream habitats has resulted in 

isolated populations making them more susceptible to local extinction (Moyle et al. 1995). 

Habitat Requirements. Hardhead are typically found in undisturbed streams with clear, deep pools 

that have sand-gravel-boulder substrates and slow water velocities (Moyle et al. 1995). This species 

distribution might be limited to well-oxygenated streams because they are relatively intolerant of low 

oxygen levels, especially at higher temperatures (Cech et al. 1990). Most streams in which they occur 

have summer temperatures in excess of 20 °Celsius (C) (68 °Fahrenheit [F]); optimal temperatures for 

hardhead appear to 24–28 °C (75–82 °F). 

Status in the Merced River Corridor. Hardhead observations have been recorded on two occasions 

in Yosemite, both from the Merced River. It is unlikely that hardheads occurred above El Portal on the 

Merced River. The Merced River gorge likely prevented them from migrating any farther up the river. 

The only documented observations of hardheads in the Merced River corridor were in 1987 and 2006 

in El Portal (Stillwater Sciences 2008). Electrofishing surveys conducted by CDFG in 2008 at two sites 

in El Portal did not detect any hardhead. 

Amphibians 

Foothill yellow-legged frog 

Rana boylei

Status. California species of special concern 

General Distribution. Historically, foothill yellow-legged frogs occurred from the Santiam River 

(Marion County), Oregon, in the north to the San Gabriel Mountains (Los Angeles County), California 

(Hayes and Jennings 1988) in the south. They occupied the western slopes of the Cascade Mountains, 

the western foothills of the Sierra Nevada and Coast Ranges, and the Tehachapi and San Gabriel 

Mountains. An isolated population also occurred in the Sierra San Pedro Martir, Baja California, 

Mexico (Loomis 1965). Today, foothill yellow-legged frogs continue to occur across their historical 

range in Oregon and California but in greatly reduced numbers (Lannoo 2005). In California, they 

inhabit elevations from sea level to 1,939 meters (6,360 feet) (Hemphill 1952). The species is believed 

to have disappeared from 51% of its historic localities throughout its range and is estimated to have 

disappeared from approximately two-thirds of its historic localities within the Sierra Nevada (Hayes 

and Jennings 1996). 

Habitat Requirements. Foothill yellow-legged frogs are primarily found in streams with riffles, rocky 

substrates, and open banks (Lannoo 2005). Adults have also been found in deep, isolated pools and 

vegetated backwaters (Hayes and Jennings 1988). Breeding and rearing habitat is located in gently 

flowing water where there is a reduced risk to egg masses and tadpoles from high water events and 

scouring (Kupferberg 1996a). 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-34 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Status in the Merced River Corridor. There are only four recorded observations of foothill yellowlegged frogs in Yosemite. All four of those sightings were in Yosemite Valley and near Cascade Creek. 

The first specimen was collected near Cascade Creek in July 1948 (University of Michigan Museum of 

Zoology). Three additional observations were reported for Yosemite Valley in 1974 (Yosemite 

Wildlife Observation Database 2011). No individuals have been reported in the park since the mid1970s, and the species is believed to be extirpated from the park. The low number of historic records is 

likely a reflection of the limited habitat for foothill yellow-legged frogs in the park. 

Birds 

Northern goshawk 

Accipter gentilis

Status. California species of special concern 

General Distribution. Northern goshawks occupy temperate and boreal forests throughout the 

Holarctic (Brown and Amadon 1968, Squires and Reynolds 1997). They are year‐round residents 

throughout all or most of the California range, although in winter some individuals remain on or near 

breeding territories while others migrate short distances to winter elsewhere (Keane 1999). 

Throughout their range, they inhabit moderately dense coniferous forests broken by meadows and 

other openings, at elevations between 1,500 meters and 2,700 meters (4,920 feet and 8,860 feet). 

Northern goshawk is an uncommon year‐round resident in Yosemite. 

Habitat Requirements. Northern goshawks forage in mature and old‐growth forests that have 

relatively dense canopies and open understories (Beier and Drennan 1997) but also hunt among a 

variety of vegetative cover, including meadow edges (Younk and Bechard 1994). Goshawks hunt from 

tree perches, scanning the ground and lower canopy for prey. As such, an open understory improves 

the chances of detection and capture of prey (Reynolds et al. 1992). 

Status in Merced River Corridor. Northern goshawk observations have been recorded on 160 

occasions in Yosemite. Of these records, 54 observations were in the Merced River corridor, mostly in 

Yosemite Valley. Besides in the Valley, one bird was seen in flight near Wawona Dome (1982), three 

were recorded from Little Yosemite Valley (1990, 1994), and two were recorded from Merced Lake 

(1982, 1990) (Yosemite Wildlife Observation Database 2011). Gaines (1992) indicates Little Yosemite 

Valley as a “representative nesting locality.” 

Long-eared owl 

Asio otus

Status. California species of special concern 

General Distribution. The long-eared owl inhabits open and sparsely forested habitats across North 

America and Eurasia between 30° and 65°North latitude (Marks et al. 1994). Long-eared owls are 

found across most of the United States but are uncommon throughout their range. In the Sierra 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-35 

Nevada, this species is found from blue oak savannah up to ponderosa pine and black oak habitats, 

usually in association with riparian habitats. In Yosemite, they are known to nest in riparian forests 

and oak-conifer woodlands (Gaines 1992). Long-eared owls will also use live oak thickets and other 

dense stands of trees for roosting and nesting (Zeiner et al. 1990). Long-eared owl is a rare summer 

resident and breeder at Yosemite. 

Habitat Requirements. Long-eared owls nest in riparian, oak-conifer, and eastside pine and juniper 

forests in the Sierra Nevada, and are associated with edges between forests and grasslands or 

shrublands (Gaines 1992, Marks et al. 1994, Hunting 2008). These owls might be more numerous than 

is known; little is known of their population status, habitat requirements, and prey in the park (Gaines 

1992). 

Status in Merced River Corridor. In Yosemite, little is known about the status of the long-eared owl. 

During one year of meadow surveys for great gray owls, long-eared owls were detected at 5 out of 15 

meadows (Keane et al. 2011); none of these meadows were within the Merced River corridor. The 

species has been recorded on 22 different occasions in Yosemite, of which only three records are from 

Yosemite Valley (Yosemite Wildlife Observation Database 2011). Long-eared owls are only known to 

have nested in the Valley on one occasion, and that bird was shot and collected by the Grinnell/MVZ 

survey in 1915. Two records are from the same date and general location (Yosemite School and Leidig 

Meadow, October 1, 1987). 

Vaux’s swift 

Chaetura vauxi

Status. California species of special concern 

General Distribution. Vaux’s swifts breed from southwestern Canada through the western United 

States to Mexico, Central America, and northern Venezuela. In winter, northern migrant populations 

of this species overlap southern residents (Bull and Collins 2007). Vaux’s swifts are an uncommon 

breeder in Yosemite. 

Habitat Requirements. Vaux’s swifts require older trees and hollow snags for nesting and roosting 

habitat. To maintain nest and roost trees over time, both live and dead large-diameter hollow trees 

should be maintained, as well as green trees with some indication of decay to replace those that fall or 

become unsuitable (Bull and Collins 2007). 

Status in Merced River Corridor. Vaux’s swift observations have been recorded on 24 different 

occasions in Yosemite. Of these observations, five records are from the Merced River corridor 

(Yosemite Wildlife Observation Database 2011). They are a rare summer resident in the Merced River 

corridor, although Gaines (1992) suspects that Wawona Meadow is a regular nesting site for them. 

Furthermore, Gaines (1992) suspects that Vaux’s swifts are “thinly but widely distributed” through 

old-growth forests with suitable nesting sites, and that the many documentations of them near 

meadows may not reflect the true nature of their habitat preferences. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-36 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Northern harrier 

Circus cyaneus

Status. California species of special concern 

General Distribution. The northern harrier is found as a breeding species throughout North America 

and Eurasia (where it is called the hen harrier). It is a long-distance migrant, and its range extends from 

northern South America to breeding grounds north of the Arctic Circle (Macwhirter and Bildstein 

1996). Throughout its range, the northern harrier favors open areas such as grasslands, meadows, 

wetlands, and agricultural clearings. Northern harrier is a rarely seen migrant that passes through 

Yosemite. 

Habitat Requirements. Northern harriers nest on the ground and in winter will roost communally on 

the ground. Their densest populations on the breeding grounds are typically associated with large 

tracts of undisturbed habitats dominated by thick vegetation growth (Apfelbaum and Seelbach 1983, 

Toland 1986, Kantrud and Higgins 1992). Northern harriers winter in a variety of open habitats 

dominated by herbaceous cover, including upland grasslands, open-habitat floodplains, and 

freshwater marshes (Temeles 1986, Collopy and Bildstein 1987). They typically hunt by flying low over 

habitats while searching for mammals and small birds (Macwhirter and Bildstein 1996). 

Status in Merced River Corridor. Northern harriers observations have been recorded on 47 

occasions in Yosemite. Of these observations, 19 records are from the Merced River corridor 

(Yosemite Wildlife Observation Database 2011). The majority of the records are from meadows in 

Yosemite Valley during the fall. Three records are from Wawona; two of those observations were in 

the same location on the same day (Wawona Meadow, August 1, 1977), and one was from 2006. The 

earliest documentations of northern harriers in the Valley are two records from 1926 and 1928 (Gaines 

1992). Following these records is an observation of two birds from 1954. Beginning in 1977, there are 

records of several northern harriers per decade in the Valley through 2006 (Yosemite Wildlife 

Observation Database 2011). 

Olive-sided flycatcher 

Contopus cooperi

Status. California species of special concern 

General Distribution. The olive-sided flycatcher breeding range extends from Alaska across Canada 

south into the United States, where it occupies forested areas. In California, the general outline of its 

current breeding range is largely unchanged from historic range. However, local extirpations have 

been reported for a few areas (Marshall 1988, Raphael et al. 1988). The olive-sided flycatcher is well 

sampled by Breeding Bird Surveys, which show that while the species is still abundant in the state, 

populations declined steadily from 1968 to 2004 (Sauer et al. 2005). Likewise, migration data from 

Southeast Farallon Island also show significant declines over a 25-year period (1968–1992) (Pyle et al. 

1994). Olive-sided flycatchers are a fairly common summer resident in Yosemite. 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-37 

Habitat Requirements. Olive-sided flycatchers forage in unobstructed canopies with high perches 

(Altman and Sallabanks 2000). Grinnell and Miller (1944) described their foraging and singing-post 

perches as apical tips of snags that protrude above the surrounding canopy. Altman (1999) observed 

that most foraging took place from the upper third of trees or snags. 

Status in Merced River Corridor. Olive-sided flycatcher observations have been recorded on 81 

occasions in Yosemite. Of these observations, 15 records are from the Merced River corridor. The first 

recorded observations of olive-sided flycatchers in Yosemite Valley were in the 1920s. Between 1923 

and 1939, there were nine observations of this species in the Valley. Four records are from the 1970s, 

with one of these being the sole Wawona observation. An observation at Washburn Lake from 1990 is 

the highest-elevation observation from the Merced River corridor (Yosemite Wildlife Observation 

Database 2011). 

Black swift 

Cypseloides niger borealis

Status. California species of special concern 

General Distribution. Black swifts are found throughout the western United States and Canada, and as 

far south as Costa Rica. Despite their large range, black swift populations are poorly understood and 

probably small; fewer than 100 of their breeding sites have been documented (Lowther and Collins 

2002). In California, their populations are focused in the central coast, the central and southern Sierra 

Nevada, and in the San Bernardino and San Jacinto mountains (Roberson and Collins 2008). 

Habitat Requirements. In Yosemite, black swifts only nest near or behind waterfalls, although 

elsewhere in their range nests are found on sea cliffs or other sheer rock faces (Lowther and Collins 

2002). Their primary food source during the breeding season are events of emergent winged ants, 

which in southern California accounts for as much as 90% of what adults feed a fledgling (Foerster 

1987, Marin 1999, Rudalevige et al. 2003). 

Status in Merced River Corridor. Black swifts have been observed on 32 occasions in Yosemite 

National Park. Of these observations, 21 records are from the Merced River corridor. Despite suitable 

habitat elsewhere in Yosemite, the vast majority of black swift observations in the park are in or near the 

main stem of the Merced River (Yosemite Wildlife Observation Database 2011). There is only one 

documented observation of a black swift in the Tuolumne River drainage (Hetch Hetchy Reservoir, 

2001). In the 1920s, local naturalists located black swift nests near Yosemite Valley (Gaines 1992), and 

Grinnell and Miller (1944) indicate the Valley and other locations in Mariposa County as nesting sites. 

Bridalveil Fall is suspected to be one of only three sites in California where nesting populations of black 

swifts exceed 10 pairs (Roberson and Collins 2008). Gaines also indicates Nevada Fall as a nesting site. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-38 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Yellow warbler 

Setophaga petechia

Status. California species of special concern 

General Distribution. Breeding range of the yellow warbler extends over most of North America, and 

wintering range extends to northern South America. In California, yellow warblers breed over much of 

the state where suitable breeding habitat occurs. Some yellow warblers winter in extreme southern 

California. Yellow warbler is a locally common summer resident and regular breeder in Yosemite. 

Habitat Requirements. Yellow warblers breed primarily in riparian woodlands from coastal, valley, 

and desert lowlands, up to 2,400 meters in elevation in the Sierra Nevada. Other breeding habitat types 

includes montane chaparral, ponderosa pine, and mixed conifer where substantial amounts of brush 

occur (Zeiner et al. 1990). In the Merced River corridor, they generally inhabit areas of willow and 

cottonwood. 

Status in Merced River Corridor. Yellow warbler observations have been recorded on 53 occasions 

in Yosemite (Yosemite Wildlife Observation Database 2011). Of these observations, 24 records are 

from the Merced River corridor. The first documented observation of yellow warblers in Yosemite 

Valley was in 1926 (Gaines 1992). Gaines (1992) characterized the Valley and Little Yosemite Valley as 

representative nesting localities. In 2010, bird surveys detected 49 individual yellow warblers in 

Yosemite Valley and confirmed breeding based on two specific observations: (1) an adult carrying 

food for young and (2) recently fledged young. 

Harlequin duck 

Histrionicus histrionicus

Status. California species of concern 

General Distribution. Harlequin ducks are found on both the western and eastern seaboards of 

North America. In western North America, their breeding range extends from western Alaska and the 

northern Yukon south to the Sierra Nevada. From April to September, they migrate inland to breed 

along turbulent mountain rivers with vegetated banks for cover (Beedy 2008). At the conclusion of the 

breeding season, they move back to the coast where they forage in intertidal areas. Harlequin duck 

population decline has been noted across much of their range (Robertson and Goudie 1999). 

Harlequin duck is a rare breeder in Yosemite. 

Habitat Requirements. Yosemite features the clear, fast-flowing river and stream conditions 

associated with the breeding grounds of harlequin ducks. These conditions include low acidity, steep 

banks, and substantial streamside vegetation (Beedy 2008). They feed primarily by diving into the 

water and searching among rocks for aquatic insects, although they will occasionally take fish 

(Robertson and Goudie 1999). 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-39 

Status in Merced River Corridor. As of 2011, there are 43 records of harlequin ducks in Yosemite’s 

Wildlife Observation Database. Of these records, 39 observations are from the Merced River corridor. 

According to Gaines (1992), harlequin ducks were found in every major Yosemite watershed from 

1,200 meters in elevation to timberline until the 1920s. After an absence of nearly 20 years, a female 

harlequin was observed in Wawona in 1940 (Gaines 1992). It wasn’t until 1977 that harlequins were 

again observed in the Merced River, and they were seen with some regularity until 1985. After a 15-

year absence, harlequin ducks were documented repeatedly in the Merced River between 2000–2007 

(Yosemite Wildlife Observation Database 2011). 

Great gray owl 

Strix nebulosa

Status. California Endangered 

General Distribution. The great gray owl is a large forest owl that ranges across northern boreal and 

temperate forests in both North America and Eurasia. Throughout its circumpolar range, the species is 

considered rare. In California, great gray owls are restricted to the Sierra Nevada and southern 

Cascades. The core breeding distribution is centered on Yosemite and the immediately adjacent and 

surrounding Stanislaus, Sierra, and Sequoia National Forests (Winter 1986, Rich 2000, Keane et al. 

2011). The Sierra Nevada population is the southernmost population in the world, with the closest 

known breeding population occurring in southern Oregon. An estimated 100 to 200 pairs of great gray 

owls occur in California, with a limited geographic distribution centered in Yosemite and adjacent 

National Forest lands in the central Sierra Nevada (Keane et al. 2011). Recent genetic work by Hull et 

al. (2010a) has revealed that the Yosemite population of great gray owls has been demographically 

isolated from other S. nebulosa populations for an extensive period of time, and the authors 

recommend designating a separate subspecies S. n. yosemitensis for the Sierra Nevada lineage. Genetic 

diversity also was extremely low for this subspecies, which is typical of recent population bottlenecks 

and likely attributable to habitat loss and fragmentation (Hull et al. 2010a). Given that S. n. yosemitensis 

is essentially restricted to Yosemite and immediate environs, this park is unequivocally imperative for 

the conservation of this subspecies (Hull et al. 2010a). The great gray owl is a rare year-round resident 

and regular breeder in Yosemite. 

Habitat Requirements. In the Sierra Nevada, the owls require extensive, densely vegetated wet or 

moist meadows margined by old-growth coniferous forest from the mixed conifer through the red fir 

to the lower lodgepole pine zones (Siegel and DeSante 1999) between 750 meters to 2,700 meters 

elevation (Greene 1995). Great gray owls breed in conifer stands with large snags and high canopy 

closure in the immediate vicinity of a montane meadow. The vast majority of known nesting sites have 

been within 250 meters of a meadow, with most averaging 150 meters from the meadow’s edge 

(Maurer 2006, Siegel 2006). In the greater Yosemite area, great gray owls tend to nest in large, brokentopped conifer snags, particularly red fir (Abies magnifica) or white fir (Abies concolor), and in lower 

elevations have also been found in black oak (Quercus kellogi) (Greene 1995, Keane et al. 2011). 

Status in Merced River Corridor. Great gray owl observations have been recorded on 204 occasions 

in Yosemite. Of these observations, 21 records are from the Merced River corridor. The majority of 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-40 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

these observations were in or around Wawona Meadow, with just five observations in Yosemite Valley 

(Yosemite Wildlife Observation Database 2011). 

California spotted owl 

Strix occidentalis occidentalis

Status. California species of concern 

General Distribution. The California spotted owl ranges from the southern Cascades south 

throughout the entire Sierra Nevada and in the central Coast Ranges. Population density in Yosemite 

is higher than elsewhere in the Sierra Nevada. In Yosemite, owl density was estimated from 0.25 to 

0.46 owls per square kilometer (km2) (1,000 square miles [m2]), whereas the mean density in 

surrounding areas in the Sierra Nevada was estimated from 0.10 to 0.21 km2 (1,000 m2) (Roberts 2008). 

Although Roberts (2008) did not calculate home ranges, California spotted owl pairs in Yosemite 

[1 pair per 5.6 km2 (3.48 m2)] exceeded the mean home range estimate throughout California [10.5 

km2 (6.52 m2)] (Zabel et al. 1992). Roberts (2008) estimated 315 spotted owl pairs in Yosemite, with 

154 pairs in burned mixed-conifer forest and 161 pairs in unburned forest. Spotted owl is an 

uncommon year-round resident and regular breeder in Yosemite. 

Habitat Requirements. The California spotted owl is strongly associated with areas of mature and old 

forest with thick canopy that contains many dense, old, live, and dead trees and fallen logs (Blakesley 

et al. 2005, Seamans 2005). Spotted owls prey mainly on small to medium-sized mammals, primarily 

rodents in the Sierra Nevada. It mostly consumes northern flying squirrels (Glaucomys sabrinus) in the 

higher elevations (conifer forests) and woodrats (Neotoma spp.) at lower elevations (burned mixedconifer, oak woodlands, and riparian forests) and throughout southern California (Verner et al. 1992a, 

Roberts 2008). Downed woody debris in higher-elevation forests of the Sierra Nevada is strongly 

associated with underground fungi, which are important food for spotted owl prey species, such as 

northern flying squirrels (Davis and Gould 2008). 

Status in Merced River Corridor. The Sierra Nevada offers the only extensive, nearly continuous 

habitat for the California spotted owl and is of critical importance for protecting this subspecies 

(Siegel and DeSante 1999). California spotted owl observations have been recorded on 72 occasions in 

Yosemite. Of these observations, 14 records are from the Merced River corridor. The first 

documented observation of a California spotted owl in Yosemite Valley was in 1940. Sightings of 

California spotted owls are sporadic in the Valley. Yosemite’s wildlife observation database only 

contains one reference to a California spotted owl in Wawona in 1972 and one high-elevation 

observation at Merced Lake in 2004 (Yosemite Wildlife Observation Database 2011). 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-41 

Mammals 

Pallid bat 

Antrozous pallidus

Status. California species of special concern 

General Distribution. The pallid bat is found from southern British Columbia and Montana to central 

Mexico and Cuba, and east to Texas, Oklahoma, and Kansas. Throughout California, the species inhabits 

primarily low to mid elevations, although it has been found up to 3,400 meters (11,000 feet) in the Sierra 

Nevada (Barbour and Davis 1969). Habitats range from desert to coniferous forest and nonconiferous 

woodlands. The pallid bat occurs in Yosemite, but its status is not well known. There are eight museum 

specimens for pallid bats for Yosemite, all from Yosemite Valley (Museum of Vertebrate Zoology 

Database 2011) collected between 1934 and 1940 (Pierson et al. 2006). 

Habitat Requirements. This species is quite versatile in its choice of roosting sites and has been 

documented using tree hollows (both oak and ponderosa pine), rock crevices, caves, abandoned 

mines, and other anthropogenic structures such as buildings and bridges (Barbour and Davis 1969, 

Hermanson and O’Shea 1983, Lewis 1996, Orr 1954, Pierson et al. 1996, Pierson et al. 2001). This 

species is gregarious and roosts in nursery colonies of typically between 30 and several hundred 

individuals. The pallid bat feeds primarily on large, flightless arthropods such as scorpions, Jerusalem 

crickets, cicadas, wolf spiders, and centipedes (Pierson et al. 2006). Large cerambycid beetles, 

particularly Prionus californicus, and ten-lined June beetles (Polyphylla decemlineata) are also major 

prey items (Orr 1954, Pierson et al. 2004). 

Status in Merced River Corridor. The pallid bat has been detected within the Merced River corridor 

in Yosemite Valley and in Little Yosemite Valley, and recent acoustic surveys by park biologists in 2010 

have detected the pallid bat in El Portal, Little Yosemite Valley, and along the South Fork Merced 

River. In Yosemite, the species shows an association with oak habitat (Rainey and Pierson 1996), 

mixed deciduous forest (for example, in Yosemite Valley and Wawona), and giant sequoia habitat 

(Pierson and Heady 1996, Rainey et al. 1992, Pierson et al. 2006). This species occurs at elevations of at 

least 1,890 meters (6,200 feet) in Yosemite (Pierson and Rainey 1993, 1995, Pierson et al. 2001). 

Sierra Nevada mountain beaver 

Aplodontia rufa californica

Status. California species of special concern 

General Distribution. The Sierra Nevada mountain beaver is endemic and restricted to western 

North America. Currently seven subspecies are recognized (Dalquest and Scheffer 1945, Hall 1981), 

including the isolated population A.r. californica that extends through much of the Sierra Nevada in 

eastern California into the western extreme portion of Nevada (Arjo 2007). Sierra Nevada mountain 

beavers can be found up to 3,000 meters (9,800 feet) in elevation in portions of the Sierra Nevada; 

however, they are more commonly found at lower elevations in humid, densely vegetated understory 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-42 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

areas (Feldhamer et al. 2003). Sierra Nevada mountain beavers are confined to well-vegetated, moist, 

cool environments and require a large daily intake of water due to their poor ability to concentrate 

urine and low tolerance for temperature extremes (Nungesser and Pfeiffer 1965). 

Habitat Requirements. Sierra Nevada mountain beavers require abundant riparian plants for 

harvesting, but the species composition is relatively unimportant (Todd 1990). Good forage cover (e.g., 

ferns, forbs, and shrubs) as well as large amounts of small-diameter woody debris or uprooted stumps 

are usually found in areas selected by Sierra Nevada mountain beaver (Todd 1992, Hacker and 

Coblenz 1993). Willow (Salix sp.), alder (Alnus sp.), and fir (Abies sp.) dominate areas preferred by 

mountain beavers in the higher elevations of the Sierra Nevada (Arjo 2007). 

Status in Merced River Corridor. Todd (1990) estimated that Sierra Nevada mountain beavers 

occupy approximately 200 to 550 sites in Yosemite. By extrapolating the number of Sierra Nevada 

mountain beaver sites to the numbers of animals, Todd (1990) estimated from 400 to 6,600 adults 

living in the park. Of the 41 sites Todd (1990) found occupied by mountain beaver, none fell within the 

Merced River corridor. Unverified sightings of Sierra Nevada mountain beaver within the corridor 

include the Civilian Conservation Corps (CCC) camp near El Capitan Meadow in 1993 and along the 

south fork of the Merced River in Wawona in 1960 (Yosemite Wildlife Observation Database 2011). 

Although no Museum of Vertebrate Zoology specimens have been taken from within the corridor, 

several were taken just outside the corridor at the head of Lyell Canyon in 1915 (Museum of 

Vertebrate Zoology Database 2011). More recently during the Grinnell Resurvey Project, a mountain 

beaver specimen was recorded from Indian Creek at Chinquapin (Moritz 2007). Mountain beaver sign 

was also observed along both Lyell Fork and Maclure Creek (at elevations of 2,987 meters to 

3,200 meters or 9,800 feet to 10,500 feet) during the Grinnell Resurvey Project (Moritz 2007). 

Townsend’s big-eared bat 

Corynorhinus townsendii townsendii

Status. California species of special concern 

General Distribution. The Townsend’s big-eared bat occurs throughout the west and is distributed 

from the southern portion of British Columbia south along the Pacific coast to central Mexico and east 

into the Great Plains, with isolated populations occurring in the central and eastern United States. In 

California, the majority of records are from low-to-moderate elevations, although the species has been 

found to almost 3,000 meters (9,800 feet) in elevation. In the Sierra Nevada, maternity colonies have 

been found to up over 1,500 meters (5,000 feet) in elevation. The Townsend’s big-eared bat is 

concentrated in areas with mines (particularly in the desert regions to the east and southeast of the 

Sierra Nevada) or caves (in the northeast portion of California and karstic regions in the Sierra Nevada 

and Trinity Alps) as roosting habitat (Pierson and Fellers 1998). 

Habitat Requirements. The Townsend’s big-eared bat feeds primarily on small moths, with over 90% 

of its diet composed of lepidopterans. Foraging associations include edge habitats along streams, 

adjacent to and within a variety of wooded habitats (Fellers and Pierson 2002, Sherwin 2005). All 

known nursery sites in the Sierra Nevada occur at relatively low elevations (the highest being at 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-43 

1,650 meters (5,400 feet) along the Yuba River), although males have been detected much higher 

(Pierson et al. 2001). Szewczak et al. (1998) reported two nursery roosts in the White Mountains at 

elevations higher than 1,700 meters (5,500 feet). 

Status in Merced River Corridor. In Yosemite, Townsend’s big-eared bats have been detected at 

Mirror Lake (Pierson and Rainey 1993), Wawona (Pierson and Rainey 1995), and at the barium mine 

on U.S. Forest Service (USFS) land in El Portal. This mine is fenced and protected from disturbance. 

This species was detected within the Merced River corridor at two sites in Yosemite Valley in 1996 and 

2004. Acoustic surveys conducted by park biologists in summer of 2010 did not detect this species 

within the Merced River corridor. 

Spotted bat 

Euderma maculatum

Status. California species of special concern 

General Distribution. Although considered one of North America’s rarest mammals (Zeiner et al. 

1990), the spotted bat is widely distributed throughout much of the western United States, with its 

range extending as far north as southern British Columbia and as far south as Durango, Mexico 

(Pierson et al. 2006). In the Sierra Nevada, spotted bats are widely distributed in habitats ranging from 

desert scrub to montane coniferous forest, with acoustic detections at elevations up to 3,000 meters 

(9,800 feet) (Pierson et al. 2006). 

Habitat Requirements. Limited information suggests that spotted bats do not roost in colonies, 

predominantly in crevices in high cliff faces (Wai-Ping and Fenton 1989). Surveys in the Sierra Nevada 

suggest that they are most abundant in areas with fractured rock (Pierson and Rainey 1996, 1998a, b). 

The spotted bat is capable of long distance and rapid flight, thus foraging ranges can be large. Radiotracking studies in Arizona documented this species traveling up to 40 kilometers each night 

(Chambers et al. 2005). In montane habitats, the spotted bat forages over meadows, along forest edges, 

or in open coniferous woodland. Spotted bats feed primarily on large [(5–12 millimeter (0.20 inch–

0.47 inch)] moths, particularly noctuids (Chambers and Herder 2005). 

Status in Merced River Corridor. Studies conducted in Yosemite have shown that spotted bats are 

relatively abundant in many areas where suitable cliff-roosting habitat is prevalent. The majority of 

detections are from relatively open foraging settings (such as wet meadows) at lower elevations (for 

example, Yosemite Valley and Wawona) and from a number of sites with elevations up to 3,000 meters 

(9,800 feet) (Pierson and Rainey 1993, 1995, 1996, Pierson et al. 2001). Yosemite Valley had the highest 

population of spotted bats of any location surveyed in California (Pierson and Rainey 1995, 1996). 

Surveys have revealed spotted bats foraging on the north side of El Capitan Meadow, just below 

El Capitan, Bridalveil Meadow, Leidig Meadow, and Ahwahnee Meadow (Pierson and Rainey 1993). 

Pierson and Rainey (1993) suggest that spotted bats roost on or near Half Dome and El Capitan. 

Acoustic surveys conducted in 2010 detected this species in Yosemite Valley, Little Yosemite Valley, 

Merced Lake, and along the South Fork Merced River. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-44 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Western mastiff bat 

Eumops perotis 

Status. California species of special concern 

General Distribution. The subspecies of western mastiff bat that occurs in North America ranges 

from central Mexico across the southwestern United States (parts of California, southern Nevada, 

Arizona, southern New Mexico and western Texas) (Eger 1977, Bradley and O’Farrell 1967). The 

western mastiff bat is found along the west side of the Sierra Nevada, primarily at low to midelevations but has been detected up to 3,000 meters (9,800 feet) in the summer (Pierson et al. 2006). 

Habitat Requirements. Western mastiff bats are found in a variety of habitats, from desert scrub and 

chaparral to montane coniferous forest. Its presence is determined by the availability of significant 

rock features offering suitable roosting habitat (Pierson et al. 2006). This species may forage in flocks, 

regularly 30 inches to 60 meters over the substrate and can forage considerable distances from their 

roosting sites (Siders 2005). Foraging habitats include dry desert washes, floodplains, chaparral, oak 

woodland, open ponderosa pine forest, grassland, agricultural areas, and high-elevation meadows 

surrounded by mixed-conifer forests (Siders 2005). The diet of western mastiff bats consists primarily 

of moths (Lepidoptera) but also includes beetles, crickets, and katydids (Siders 2005). 

Status in Merced River Corridor. In Yosemite, western mastiff bats have been detected in Yosemite 

Valley in Bridalveil Meadow, El Capitan Meadow, Leidig Meadow, Cook’s Meadow, Ahwahnee 

Meadow, Stoneman Meadow, Wosky Pond, and wetlands near Happy Isles. They were also detected 

in a few upland habitats east of El Capitan Meadow and Sentinel Beach Picnic Area (Pierson and 

Rainey 1995). A radio-telemetry study in 1996 detected a large colony in the cliffs west of Cascade 

Creek (Pierson 1997). Yosemite Valley has the highest population of the western mastiff bat of any 

locality surveyed in California (Pierson and Rainey 1995). In addition, the species has been captured in 

Wawona (Pierson and Rainey 1995). Acoustic surveys conducted in 2010 detected this species in 

El Portal, Yosemite Valley, Little Yosemite Valley, and Merced Lake. 

Western red bat 

Lasiurus blossevillii

Status. California species of special concern 

General Distribution. The western red bat is broadly distributed from southern British Columbia in 

Canada, through much of the western United States, through Mexico and Central America, to 

Argentina and Chile in South America (Bolster 2005). In California, the majority of records are from 

the coastal areas from the San Francisco Bay Area south, plus the Central Valley and bordering 

foothills, with a limited number of records from southern California extending as far east as western 

Riverside and central San Diego Counties (Pierson et al. 2006). There are a few records from higher 

elevations and the east side of the Sierra Nevada (Constantine 1998, Pierson et al. 2000). Winter 

populations of both sexes are concentrated along the central and southern coast (Pierson et al. 1999). 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-45 

Grinnell (1918) suggested that western red bats in California were sexually segregated in summer, with 

males moving to higher elevations, a pattern more recently noted in other species (e.g., Cryan et al. 

2000). Western red bats (most likely males or nonreproductive females) have been documented at 

elevations up to 2,500 meters (8,200 feet) in the Sierra Nevada (Pierson et al. 2000 and 2001). 

Habitat Requirements. Western red bats roost on the underside of overhanging leaves. Recent 

studies in the Central Valley found that summering populations (and breeding females) are 

substantially more abundant in remnant stands of cottonwood/sycamore riparian that extend greater 

than 50 meters (164 feet) back from the river than they are in younger, less extensive stands (Pierson et 

al. 1999). Red bats forage on a number of insect taxa and fly at both canopy height and low over the 

ground (Shump and Shump 1982). Studies have reported diets consisting of primarily small moths, in 

addition to a variety of other insects, primarily Orthoptera (Ross 1961) but also Homoptera, Coleoptera, 

Hymenoptera, and Diptera (Shump and Shump 1982). 

Status in Merced River Corridor. The first record of a western red bat in Yosemite was the capture of 

three individuals (two adult males and one nulliparous female) over the South Fork Merced River on 

September 16, 1998. Since then, the species has been documented acoustically at multiple localities up as 

high as Siesta Lake at 2,422 meters (8,000 feet) (Pierson et al. 2001). Previous acoustic detections have 

been obtained in association with black cottonwood in both Yosemite and Sequoia National Parks; 

however, acoustic surveys conducted in 2010 did not detect this species within the Merced River corridor. 

Sierra Nevada snowshoe hare 

Lepus americanus

Status. California species of special concern 

General Distribution. Sierra Nevada snowshoe hares inhabit the mid-elevations (914 meters to 

2,133 meters [3,000 feet to 7,000 feet) of the northern and central Sierra Nevada from approximately 

Mount Lassen in southeastern Shasta County south through Yosemite National Park to Mono and 

Mariposa counties (Bolster 1998). They have also been recorded from Nevada in the general vicinity of 

Lake Tahoe (Hall 1946, Richardson 1954). The southern locality is north of Mammoth in Mono 

County (Bolster 1998). The population status of the Sierra Nevada snowshoe hare is poorly known. 

Habitat Requirements. In California, the Sierra Nevada snowshoe hare is primarily found in montane 

riparian habitats with thickets of alders and willows, and in stands of young conifers interspersed with 

chaparral. The early seral stages of mixed conifer, subalpine conifer, red fir, Jeffrey pine, lodgepole pine, 

and aspen are likely snowshoe hare habitats, primarily along edges and especially near meadows (Orr 

1940, Ingles 1965). This species’ abundance is highly cyclic in parts of its range, and may be in California 

as well, but there is little evidence. They prefer dense cover, either in understory thickets of montane 

riparian habitats or in shrubby understories of young conifer habitats. The snowshoe hares’ summer 

food primarily consists of grasses, forbs, sedges, and low shrubs (Zeiner et al. 1990). They eat needles and 

the bark of conifers, and leaves and green twigs of willow and alder in the winter (Wolff 1980). 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-46 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Status in Merced River Corridor. Sierra Nevada snowshoe hare favor dense streamside vegetation. 

This species typically occurs at elevations below 2,438 meters (8,000 feet); however, its upper elevation 

limits are unknown. There are a number of apparent sightings from Yosemite above 2,438 meters, 

although these have not been verified (Yosemite Wildlife Observation Database 2011). Other 

unconfirmed snowshoe hare sightings within the Merced River corridor include the Merced Lake 

Ranger Station in 1991 and at the junction of the Merced River and Echo Creek in 1990 (Yosemite 

Wildlife Observation Database 2011). 

Western white-tailed jackrabbit 

Lepus townsendii townsendii

Status. California species of special concern 

General Distribution. The western white-tailed jackrabbit ranges from the high Sierra crest and 

upper east slope from the Mount Whitney region at elevations up to 3,657 meters (12,000 feet) in 

sagebrush, subalpine conifers, alpine dwarf-shrub, and grasslands; it is also found on flat areas east of 

the mountains, especially in winter. 

Habitat Requirements. This species inhabits a variety of habitats, including sagebrush, perennial 

grasslands, alpine dwarf-shrub, and wet meadows to timberline and above, and early successional 

stages of a variety of conifer habitats, including lodgepole pine, yellow pine, western juniper, dwarf 

juniper, red fir, and mixed conifers (Verner and Boss 1980, Williams 1986, Zeiner et al. 1990). In most 

of these habitats, western white-tailed jackrabbits prefer open or sparsely wooded areas with young or 

stunted conifers, or scattered shrubs which they use for protective cover during the day (Grinnell and 

Storer 1924, Verner and Boss 1980, Harris 1982). During the spring through fall, they eat grasses and a 

variety of herbaceous plants, including cultivated crops (as encountered) (Zeiner et al. 1990). In 

winter, they prefer buds, bark, and twigs of shrubs, particularly sagebrush, creambush, and small trees 

(Bailey 1931, Orr 1937). 

Status in Merced River Corridor. Unverified sightings of western white-tailed jackrabbit within the 

Merced River corridor include two sightings in Little Yosemite Valley in 1974 and1975 and a sighting 

near Merced Lake in 1951 (Yosemite Wildlife Observation Database 2011). 

Mount Lyell shrew 

Sorex lyelli

Status. California species of special concern 

General Distribution. The known range of this species spans a small area of the east-central Sierra 

Nevada, California, including areas in and around Yosemite in Tuolumne, Mariposa, and Mono 

counties, at elevations of 2,100 meters–3,150 meters (6,900 feet–10,350 feet) (Grinnell 1933, Williams 

1984). This shrew might possibly occur in similar habitat from Mono County to Modoc County, but the 

area outside its known range has not been adequately surveyed. Recent surveys by the Grinnell Resurvey 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-47 

Project in 2007 documented this species at the two original localities where it was recorded in the 

Grinnell era (upper Lyell Basin and Vogelsang Lake) (Moritz 2007). The Mount Lyell shrew was also 

found to have expanded its known range to the north, and to lower elevations, at Glen Aulin 

(2,408 meters [7,900 feet]), Kerrick Meadow (2,926 meters [9,600 feet]) and upper Return Creek in 

Virginia Canyon (3,018 meters [9,900 feet]). This species was found to be uncommon at each locality 

(Moritz 2007). 

Habitat Requirements. Mount Lyell shrew specimens have been found primarily in wetland 

communities, near streams, in grassy areas, under willows, and in sagebrush steppe communities 

(Grinnell 1933, Williams 1984, Museum of Vertebrate Zoology Database 2011). This shrew requires 

moist soil (Ingles 1965) and uses logs, stumps, and other surface objects for cover (Grinnell and Storer 

1924). This species eats insects and other invertebrates found while foraging on the ground, in stumps, 

and in logs (Grinnell and Storer 1924, Ingles 1965). 

Status in Merced River Corridor. Surveys for the Mount Lyell shrew in and near Yosemite in 2003–

2007 yielded specimens from several locations, one of which was within the Merced River corridor at 

Cathedral Pass in July 2007 (Museum of Vertebrate Zoology Database 2011). In addition, one male 

specimen was collected in July 1915 1.5 kilometer from the river corridor at the head of Lyell Canyon 

(Museum of Vertebrate Zoology Database 2011). 

American badger 

Taxidea taxus

Status. California species of special concern 

General Distribution. American badgers are uncommon but found throughout most of California, 

irrespective of elevation, from the Central Valley over the Sierra Nevada east into the Great Basin. The 

badger is most abundant in drier open stages of most shrub, forest, and herbaceous habitats, with 

friable soils (Zeiner et al. 1990). 

Habitat Requirements. The American badger prefers open areas and may also frequent brushlands 

with little groundcover. During periods of inactivity, badgers occupy underground burrows. They 

frequently reuse old burrows, although some may dig a new den each night, especially in summer 

(Messick and Hornocker 1981). They are usually found in relatively dry grasslands and open forests 

(Rahme et al. 1995) and may be active at any hour but are mainly nocturnal. Badgers feed primarily on 

small rodents usually captured by digging out their burrows. Their main prey species includes ground 

squirrels, pocket gophers, kangaroo rats, prairie dogs, and mice. Badgers also eat reptiles, insects, 

earthworms, eggs, birds, and carrion, especially when ground squirrel populations are low (Messick 

and Hornocker 1981, Zeiner et al. 1990). The American badger is active all year, but it may sleep in its 

den for several days or weeks during severe winter weather (Nowak 2005). 

Status in Merced River Corridor. Unverified American badger sightings within the Merced River 

corridor include the CCC Camp in El Capitan Meadow in 1993, at the Yosemite Valley Visitor Center 

in 1954 (Yosemite Wildlife Observation Database 2011), and in Wawona in 2004 (California Natural 

Diversity Database 2012). 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-48 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Western pond turtle 

Emys marmorata

Status. California Species of Special Concern 

General Distribution. The historic range of western pond turtles included the Pacific slope from 

Puget Sound to Sierra San Pedro Martir in Baja California Norte and isolated inland populations in 

Washington, Oregon, California, Nevada, and Idaho. Some of these isolated populations may 

represent introductions (Holland 1994). Western pond turtles have an elevation range from sea level 

to about 2,042 meters (6,700 feet) but are uncommon anywhere above about 1,524 meters (5,000 feet) 

(Holland 1994). The species is believed to be declining throughout 75%–80% of its range primarily due 

to habitat loss, nonnative predators (bullfrogs, large‐mouth bass, and possums), and overharvesting for 

food. According to Jennings and Hayes (1994), the western pond turtle still occurs in 90% of its 

historic range in the Central Valley and west of the Sierra Nevada, but in greatly reduced numbers. 

Habitat Requirements. Western pond turtles inhabit a wide range of permanent and ephemeral aquatic 

habitats, including ponds, marshes, rivers, streams, and ditches (Stebbins 1985, Behler 2002). In rivers 

and streams, they usually occupy slow‐moving, deep pools with rocky or muddy bottoms and abundant 

vegetation (Stebbins 1985, Behler 2002). There is also a high correlation between turtle abundance and 

availability of logs, boulders, vegetation mats, and mud banks to use as basking sites (Bury and Germano 

2008). Emergent basking sites such as logs are preferred because they offer some protection from 

terrestrial predators and offer quick escapes into deep water. This species may also spend a substantial 

amount of time in upland terrestrial habitats. Terrestrial habitat includes basking sites and nesting 

habitat. Western pond turtles deposit their eggs on land, usually above the floodplain, up to several 

hundred feet from water. For nesting, gravid (with eggs) females tend to seek out open areas with sparse, 

low vegetation (annual grasses and herbs), low slope angle, and dry hard soil. 

Status in the Merced River Corridor. Western pond turtle observations have been recorded on 

16 occasions in Yosemite. Of these observations, there have only been two sightings of western pond 

turtles in the Merced River corridor; both sightings were in Yosemite Valley in the 1950s. In 1950, 

there was a sighting in Sentinel Meadow and, in 1958, another turtle was observed in Stoneman 

Meadow (CNDDB 2012). There have been no sightings since the 1950s in the Merced River corridor, 

and the species is believed to be extirpated from the Merced River within Yosemite. 

Mount Lyell salamander 

Hydromantes platycephalus

Status. California species of special concern 

General Distribution. The Mount Lyell salamander, endemic to the Sierra Nevada, ranges from the 

Sonora Pass (Sonora County) to Silliman Gap, Sequoia National Park (Tulare County). Isolated 

populations have also been documented in the Desolation Wilderness (El Dorado County) and on the 

Sierra Buttes (Sierra County). They inhabit high elevation (2,100 meters to 3,700 meters [6,890 feet to 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-49 

12,139 feet]) snowmelt seep and waterfall habitat throughout the Sierra Nevada. There are also several 

populations of Mount Lyell salamander at lower elevations in the spray zones of waterfalls in Yosemite 

Valley (1,200 meters to 1,300 meters [3,937 feet to 4,265 feet]) and in riparian areas at lower elevation 

(1,400 meters to 2,000 [4,593 feet to 6,562 feet]) on the arid eastern slope of the Sierra Nevada, near the 

floor of the Owens Valley. The Owens Valley population was treated by CDFG as a separate species 

(Jennings and Hayes 1994), but recent genetics analysis does not support treating this as a separate 

species (Rovito 2009). Although the species has the broadest geographic range of any members of its 

genus Hydromantes, within that range, Mount Lyell salamanders may be very patchily distributed with 

small local populations that might be especially susceptible to local extirpation (Jennings and Hayes 

1994). Consequently, they are a California species of special concern. According to Wake and 

Papenfuss in Lannoo 2005, there is no indication that either the size of the range or the density of this 

species has changed recently. In fact, new populations are continuing to be discovered. In Yosemite, 

the species has been observed at a number of sites in recent years. 

Habitat Requirements. Juveniles and adults are commonly found in talus slopes of granite where 

water is flowing. They appear to favor habitats that are downslope of melting snowfields that persist 

long into or through the entire summer. Mount Lyell salamander may also be found near streams and 

within the spray zones of waterfalls, under rocks and moss. They are nocturnal and take refuge under 

rocks during the daytime. 

Status in the Merced River Corridor. Mount Lyell salamander observations have been recorded on 

140 occasions in Yosemite National Park. Of these observations, 24 records are from the Merced River 

corridor. Between 1950 and 1954, there were 12 observations at a site along the John Muir Trail 

between Yosemite Valley and Little Yosemite Valley, and at two sites in Yosemite Valley. In 1969 and 

again in 1995, there were single observations in Yosemite Valley. One individual was observed along 

the John Muir Trail between Yosemite Valley and Little Yosemite Valley in 1995. From 2000–2006, 

there were four sightings along the John Muir Trail between Yosemite Valley and Little Yosemite 

Valley and five sightings in Yosemite Valley (CNDDB 2012). In 2006, there were also two individuals 

observed in Yosemite Valley immediately outside of the river corridor buffer. 

Park Rare Species 

Plants 

Spurred snapdragon (Antirrhinum leptaleum) 

General Ecology and Distribution. Spurred snapdragon, an annual herb, is endemic to California and 

limited to the seasonally moist areas in the foothill and Sierra Nevada counties between 300 and 1,200 

meters. 

Habitat and Status in the Project Area. The snapdragon is restricted to small washes and shallow ditches 

in disturbed areas in Foresta and Wawona. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-50 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Lemmon’s wild ginger (Asarum lemmonii) 

General Ecology and Distribution. This perennial herb in the birthwort family is endemic to California 

and is found in yellow pine forests, red fir forests, and wetland-riparian habitats within the park 

between 1,100 and 1,900 meters. It occurs almost always under natural conditions in wetlands. 

Habitat and Status in the Project Area. Lemmon’s wild ginger occurs in shady wet places along creeks 

and north-facing river banks; it is found in Yosemite Valley and Wawona. 

California bolandra (Bolandra californica) 

General Ecology and Distribution. This perennial herb in the saxifrage family is endemic to California 

and is restricted to lower and upper montane coniferous forests within the park, in mesic areas and 

rocky soils. It is restricted to elevations between 2,000-3,000 meters. 

Habitat and Status in the Project Area. The California bolandra occurs at Lyell Fork of the Merced 

River in Segment 1 of the Merced River corridor. 

Threadleaf beakseed (Bulbostylis capillaris) 

General Ecology and Distribution. Threadleaf beakseed is a monocot annual herb in the sedge family; it 

is native to California and occurs in yellow pine forests and wetland-riparian habitats at elevations 

between 1,000-2,000 meters. 

Habitat and Status in the Project Area. The threadleaf beakseed occurs in meadows and seeps, meadow 

habitats, and vernally moist areas. It is found in Yosemite Valley (Segment 2). 

Mono Hot Spring evening primrose (Camissonia sierrae ssp. alticola) 

General Ecology and Distribution. This annual herb in the evening primrose family is endemic to 

California and is found in lodgepole and red fir forests (lower and upper montane coniferous forests) 

in granitic, gravel and sand pans. The Mono Hot Spring evening primrose is found at elevations of 

2,000-2,350 meters. 

Habitat and Status in the Project Area. This evening primrose is found on vernally moist gravel and sand 

pans and at Merced Lake in Segment 1. 

Sierra suncup (Camissonia sierrae ssp. sierrae) 

General Ecology and Distribution. This annual herb in the evening primrose family is endemic to 

California and is restricted to cismontane woodlands and lower montane coniferous forests at 

elevations between 500 and 1,300 meters. 

Habitat and Status in the Project Area. The milkvetch occurs on granite gravel seepage areas within 

Yosemite Valley. 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-51 

Buxbaum’s sedge (Carex buxbaumii) 

General Ecology and Distribution. Buxbaum’s sedge is a monocot and perennial herb in the sedge 

family. It occurs in montane and subalpine fens. It favors wet conditions in meadow habitats at 

elevations between 1,200-3,300 meters. 

Habitat and Status in the Project Area. Buxbaum’s sedge occurs in Yosemite Valley. 

Silvery sedge (Carex canescens) 

General Ecology and Distribution. This monocot, perennial herb belongs to the sedge family and is 

found throughout the Sierra Nevada as well as other mid- to high-elevation sites in North America. It 

occurs in meadow and perennially moist areas in subalpine and alpine forests at elevations between 

1,000-3,200 meters. 

Habitat and Status in the Project Area. The silvery sedge is found in lake margins and drainages in wet 

meadows. Historic collections were taken from Wawona, where this species is commonly found 

(Segment 7). 

Cleft sedge (Carex fissuricola)

General Ecology and Distribution. This perennial herb in the sedge family is native to California, but is 

confined to western North America. It is found in red fir and subalpine forests and wetland-riparian 

habitats at elevations between 1,500 and 3,500 meters. 

Habitat and Status in the Project Area. This sedge occurs in meadow slopes and flats, among rocks, wet 

areas, and spray zones. It is found at Nevada Falls within Segment 1. 

Yosemite sedge (Carex sartwelliana) 

General Ecology and Distribution. This perennial herb in the sedge family is endemic to California and 

occurs in yellow pine and red fir forests, as well as wetland-riparian habitats at elevations of 1,200 to 

2,600 meters. 

Habitat and Status in the Project Area. This sedge is found in meadow borders and moist forest 

openings. It can be found at Wildcat Creek and in Segments 1, 2, 5, and 7. 

Bolander’s woodreed (Cinna bolanderi) 

General Ecology and Distribution. This perennial herb in the grass family is endemic to California and 

occurs in wetland-riparian habitat, but occasionally is found in non wetlands. It is found in elevations 

ranging between 1,670 to 2,440 meters. 

Habitat and Status in the Project Area. Bolander’s woodreed is found in montane stringer meadows and 

fens in Wawona and Little Yosemite Valley (Segments 7 and 1, respectively). 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-52 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Narrow leaf Collinsia (Collinsia linearis) 

General Ecology and Distribution. This annual herb in the plantain family is primarily limited to 

California, with some extensions into adjacent states. It is found in lower- to mid-elevation (200 to 

2,000 meters) coniferous forests on rock outcrops and dry slopes. It reaches the southern extent of its 

range in Mariposa County. 

Habitat and Status in the Project Area. Narrow leaf collinsia is found in El Portal and Wawona 

(Segments 4 and 7, respectively), where it is restricted to dry, metamorphic rock outcrops along the 

metamorphic-granitic contact zone. 

Short-bracted bird’s beak (Cordylanthus rigidus ssp. brevibracteus) 

General Ecology and Distribution. Short-bracted bird’s beak is an annual herb in the broomrape family 

and is endemic to California. It is widely distributed in the Sierra Nevada from Mariposa County 

southward to Kern County at elevations ranging between 1,100 to 2,500 meters. 

Habitat and Status in the Project Area. This plant occurs on the north side of Yosemite Valley, where it 

receives full sun on dry sandy roadside habitats. Known populations occur one mile east of Cascade 

Creek in Segment 2 (Yosemite Valley). 

Mountain lady’s slipper (Cypripedium montanum) 

General Ecology and Distribution. Mountain lady’s slipper is a perennial herb in the orchid family; it is 

native to California and is confined to western North America in yellow pine forests, mixed evergreen 

forests, and wetland-riparian habitats at elevations between 200 to 2,200 meters. In the Sierra Nevada, 

it occurs in Tuolumne, Mariposa, and Madera Counties. It also occurs in northwestern California, the 

Cascade Range, southwest San Francisco Bay Area, and Modoc Plateau. 

Habitat and Status in the Project Area. This herb occurs on deep humus and shade of canyon bottoms. 

It is found in Wawona and below Yosemite Valley. 

Stream orchid (Epipactis gigantea) 

General Ecology and Distribution. This species, a perennial herb in the orchid family, is widely 

distributed throughout California and North America. In Yosemite, it is restricted to moist granitic 

ledges and planted in landscaped areas at elevations between 1,500 to 2,600 meters. 

Habitat and Status in the Project Area. This species occurs in Yosemite Valley within a number of 

landscaped areas. Former populations above Happy Isles were obliterated by the rockfall in 1996. 

Natural habitat for this species exists throughout the Valley in perennially moist, shaded areas. 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-53 

Purple fawn-lily (Erythronium purpurascens) 

General Ecology and Distribution. This perennial herb is endemic to California and the Sierra Nevada. 

It grows along shaded streams and river corridors in montane coniferous forests at elevations of 1,500 

to 2,700 meters. 

Habitat and Status in the Project Area. This species is known from riparian corridors in the eastern end 

of Yosemite Valley. It was collected in the past for its showy flowers and is possibly extinct. 

Northern mannagrass (Glyceria borealis) 

General Ecology and Distribution. This perennial herb in the grass family is native to California and is 

also found elsewhere in North America and beyond. It occurs in yellow pine and red fir forests, as well 

as wetland-riparian habitats. In Yosemite, it is found in elevations ranging between 800-1,250 meters. 

Habitat and Status in the Project Area. Northern managrass grows in marshes and shallow lake borders 

in Yosemite Valley (Segment 2). 

California sunflower (Helianthus californicus) 

General Ecology and Distribution. This perennial herb in the aster family is native to California and is 

confined to western North America. It occurs in foothill woodland, valley grassland, freshwater 

wetlands, and wetland-riparian habitats at elevations ranging between 1,600 and 2,000 meters. 

Habitat and Status in the Project Area. California sunflower grows along streambanks, within meadows 

and freshwater marshes, seeps, and seasonally inundated areas. It occurs in Wawona (Segment 7). 

Common mare’s tail (Hippuris vulgaris) 

General Ecology and Distribution. This perennial aquatic herb in the plantain family is native to 

California but is also found elsewhere in North America and beyond. It occurs in a variety of habitats, 

including yellow pine, red fir, lodgepole, and subalpine forests; foothill woodland, chaparral, valley 

grassland, and wetland-riparian habitats at elevations ranging between 0 to 2,600 meters. It occurs 

almost always under natural conditions in wetlands. 

Habitat and Status in the Project Area. This species occurs within lakes, ponds, springs, rivers in Little 

Yosemite Valley (Segment 1). 

Redray alpinegold (Hulsea heterochroma) 

General Ecology and Distribution. This perennial herb in the aster family is native to California and 

elsewhere outside of California, but is confined to western North America. It occurs in chaparral and 

openings in yellow pine forests between 300 and 2,500 meters in elevation. 

Habitat and Status in the Project Area. This species occurs in Yosemite Valley and 5 miles above 

Nevada Fall (Segments 2 and 1, respectively). 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-54 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Western quillwort (Isoetes occidentalis) 

General Ecology and Distribution. This fern is native to California and belongs to the quillworts family. 

It occurs in wetland-riparian habitats in the high Sierra Nevada, Klamath Ranges within California at 

elevations between 1,500 and 2,500 meters. Outside of California, it can be found in British Columbia 

and Colorado. 

Habitat and Status in the Project Area. Western quillwort occurs in mountain lakes and rivers. In the 

Project Area, it is found in Segment 1 (Little Yosemite Valley). 

Sierra laurel (Leucothoe davisiae) 

General Ecology and Distribution. This shrub, a perennial in the heath family, is found slightly beyond 

California’s boundaries and is restricted to wetland, bog, and moist habitats at elevations between 

1,300 and 2,600 meters. 

Habitat and Status in the Project Area. Within the Merced River corridor, Sierra laurel is found in 

moist, shaded drainage bottoms along creeks and rivers within Yosemite Valley (Segment 2). 

False pimpernel (Lindernia dubia var. anagallidea) 

General Ecology and Distribution. This annual herb in the plantain family is found in freshwater 

wetlands and meadows at low to mid elevations (500 to 1,600 meters) in California and North 

America. 

Habitat and Status in the Project Area. False pimpernel is found in meadow soils throughout Yosemite 

Valley (Segment 2) that remain moist for the duration of the plant’s seasonal life span. 

Tanoak (Lithocarpus densiflorus var. echinoides) 

General Ecology and Distribution. Tanoak is a tree or shrub in the oak family and is native to California. 

It occurs on dry shady forest conditions in slope habitats at elevations ranging between 600 and 

2,000 meters. 

Habitat and Status in the Project Area. Tanoak occurs along the Merced River below Yosemite Valley 

(Segment 2) and in the El Portal area (Segment 3). 

Northern bugleweed (Lycopus uniflorus) 

General Ecology and Distribution. This perennial herb in the mint family is native to California and is 

also found elsewhere in North America and beyond. It occurs in freshwater wetlands and wetlandriparian habitat at elevations ranging between 1,600 and 2,000 meters. 

Habitat and Status in the Project Area. Northern bugleweed occurs in moist areas, marshes, adjacent to 

springs, and along the Merced River banks from El Portal up to the Merced Gorge (Segments 4 and 3, 

respectively). 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-55 

Yellow and white monkeyflower (Mimulus bicolor) 

General Ecology and Distribution. Yellow and white monkeyflower, an annual herb from the lopseed 

family, is endemic to California. It occurs in foothill woodland, yellow pine forest, and chaparral 

habitats at elevations ranging between 360 and 2,100 meters. 

Habitat and Status in the Project Area. This species occurs under vernally moist conditions, usually in 

non-wetlands, but occasionally found in wetlands and river bottomlands. In the Project Area, it is 

found in Wawona (Segment 7). 

Small flowered monkeyflower (Mimulus inconspicuus) 

General Ecology and Distribution. This annual herb in the lopseed family is endemic to California. It is 

restricted to wetlands and seasonally moist sites in lower montane forests and foothill woodlands in 

partial shade at elevations between 160 and 2,000 meters. 

Habitat and Status in the Project Area. Small flowered monkeyflower occurs at the mouth of Moss 

Creek and also in Segments 2, 3, 7, and 8. 

Cutleaf monkeyflower (Mimulus laciniatus) 

General Ecology and Distribution. This annual herb in the lopseed family is endemic to California. It 

typically occurs in red fir and yellow pine forests and wetland-riparian habitats at elevations ranging 

between 900 and 2,000 meters. 

Habitat and Status in the Project Area. Cutleaf monkeyflower occurs in chaparral, lower and upper 

montane coniferous forests, vernally moist seepage areas, and mesic areas with granitic substrate in 

Yosemite Valley (Segment 2). 

Yellow-lip pansy monkeyflower (Mimulus pulchellus) 

General Ecology and Distribution. This annual herb in the lopseed family is endemic to California and 

limited to Mariposa, Tuolumne, and Calaveras Counties. It is restricted to wetlands and seasonally 

moist sites at elevations ranging between 600 and 2,000 meters. 

Habitat and Status in the Project Area. This species occurs in vernally mesic meadows and lower 

montane coniferous forests within Yosemite Valley (Segment 2). 

Sierra sweet-bay (Myrica hartwegii) 

General Ecology and Distribution. This perennial shrub in the wax-myrtle family is endemic to 

California. It is limited in occurrence to streambanks and riparian communities at low to moderate 

elevations (300 to 1,500 meters) in the Sierra Nevada, where it forms small thickets along the river. 

Habitat and Status in the Project Area. Patchy distribution of Sierra sweet-bay occurs along the South 

Fork of the Merced River through Wawona as well as along tributaries to the South Fork and Big 

Creek near the South Entrance Station. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-56 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

California bog asphodel (Narthecium californicum) 

General Ecology and Distribution. This perennial shrub in the Nartheciaceae family and is endemic to 

California. It occurs along streambanks and in meadows within yellow pine, red fir, and douglas-fir 

forests, as well as wetland-riparian habitat. Elevation range for this species is between 700 to 

2,600 meters. 

Habitat and Status in the Project Area. This species occurs in fens, seeps, and adjacent to streams and 

waterfalls. In the Project Area, it can be found at Bridalveil Falls in Yosemite Valley (Segment 2). 

Azure penstemon (Penstemon azureus ssp. angustissimus) 

General Ecology and Distribution. This perennial herb in the plantain family is endemic to California 

and is near its southern extent in Yosemite. It is generally found in moist woodlands and open forests 

at lower to moderate elevations in the Sierra Nevada at elevations of 300 to 700 meters. 

Habitat and Status in the Project Area. This herb is found in scattered locations in Yosemite Valley 

(Segment 2). It was first described from collections taken in Yosemite Valley, although that original 

population appears to have disappeared. 

Purdy’s foothill penstemon (Penstemon heterophyllus var. purdyi) 

General Ecology and Distribution. This perennial herb in the plantain family is endemic to California. It 

is generally found under dry conditions in slope habitats of chaparral, foothill woodland, and yellow 

pine forest habitats. It occurs at elevations of 50 to 1,600 meters. 

Habitat and Status in the Project Area. This penstemon occurs in Yosemite Valley (Segment 2). 

Tansy Leafed Phacelia (Phacelia tanacetifolia) 

General Ecology and Distribution. This annual herb in the borage family is found throughout California 

and is confined to western North America. It grows in seasonally moist, sandy and gravelly open areas. 

Habitat and Status in the Project Area. This species occurs at scattered locations throughout Yosemite 

Valley at elevations of 1,000 to 2,000 meters, where it blooms and sets seed early each spring. 

Coleman’s piperia (Piperia colemanii) 

General Ecology and Distribution. This perennial native herb is endemic to California and limited to the 

high North Coast Ranges, high Cascade Range, and the Sierra Nevada. It grows on sandy substrates in 

lower montane coniferous forests and are also found in chaparral habitat at 1,200-2,300 meters in 

elevation. 

Habitat and Status in the Project Area. This species occurs in Little Yosemite Valley (Segment 1). 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-57 

Torrey’s popcornflower (Plagiobothrys torreyi var. torreyi) 

General Ecology and Distribution. This annual herb in the borage family is endemic to California and 

occurs in Mariposa, Fresno, and Kern Counties. Suitable habitat include meadows within yellow pine, 

red fir, and lodgepole pine forests, as well as subalpine forests at elevations ranging between 1,200 and 

3,400 meters. 

Habitat and Status in the Project Area. This herb is found within moist meadows and flats, as well as 

forest edges within Yosemite Valley (Segment 2). 

Nuttall’s pondweed (Potamogeton epihydrus (previously P. ephydrus ssp. nuttallii)) 

General Ecology and Distribution. This perennial herb in the pondweed family is native to California at 

elevations ranging between 400 and 1,900 meters; it occurs in the outer North Coast Ranges, high 

Sierra Nevada, Modoc Plateau, and elsewhere in North America. 

Habitat and Status in the Project Area. Nuttall’s pondweed is restricted to freshwater wetlands and 

wetland-riparian habitats. In Yosemite Valley (Segment 2), it can be found in freshwater marshes and 

tanks. 

Valley oak (Quercus lobata) 

General Ecology and Distribution. This tree is endemic to California and occurs throughout California, 

with the exception of eastern California and desert areas. 

Habitat and Status in the Project Area. Valley oak occurs on deep soil on slopes and in valleys. It is 

known from a few majestic specimens in El Portal (Segment 4) at elevations of approximately 

720 meters. 

Wood saxifrage (Saxifraga mertensiana) 

General Ecology and Distribution. This perennial herb in the saxifrage family is endemic to California 

and limited to the northern and central Sierra Nevada at elevations of 1,000 to 2,500 meters. It reaches 

its southern extent in Mariposa County, where it grows on mossy rocks and moist cliffs in lower to 

montane coniferous forests. 

Habitat and Status in the Project Area. This species occurs at scattered locations in moist, shaded sites 

throughout Yosemite Valley (Segment 2). 

Oregon saxifrage (Micranthes oregana (previously Saxifraga oregana)) 

General Ecology and Distribution. This perennial herb in the saxifrage family is native to California but 

is also found in other areas of western North America. It occurs in meadows within yellow pine, red 

fir, lodgepole pine, and subalpine forests, as well as wetland-riparian communities at elevations of 

150 to 2,500 meters. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-58 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Habitat and Status in the Project Area. This species occurs in meadows and seeps, almost always under 

wet conditions, in Yosemite Valley and Little Yosemite Valley (Segments 2 and 1, respectively). 

Bolander’s skullcap (Scutellaria bolanderi) 

General Ecology and Distribution. This perennial herb in the mint family is endemic to California. It is 

primarily found in lower montane forests in the Sierra Nevada, where it occurs in gravelly soils along 

streambanks and in California black oak woodlands and ponderosa pine forests at elevations between 

300-2,000 meters. 

Habitat and Status in the Project Area. This species is known from isolated populations scattered 

throughout the Wawona basin (Segment 7). 

Clark’s ragwort (Senecio clarkianus) 

General Ecology and Distribution. This perennial herb in the aster family is endemic to California and 

occurs in red fir and lodgepole forests, as well as wetland-riparian habitats at elevations ranging 

between 1,400 and 2,700 meters. 

Habitat and Status in the Project Area. It occurs in damp montane meadows within Wawona 

(Segment 7). 

Small bur reed (Sparganium natans) 

General Ecology and Distribution. This perennial herb in the Typhaceae family is native to California, 

but is also found elsewhere in North America and beyond. It occurs at lake margins and edges of 

freshwater wetlands and wetland-riparian habitats at elevations ranging between 2,000 and 

2,500 meters. 

Habitat and Status in the Project Area. This species is found in tributaries of the Merced River in 

Segments 2 and 7 (Yosemite Valley and Wawona, respectively). 

Sierra bladdernut (Staphylea bolanderi) 

General Ecology and Distribution. This tree or shrub belongs to the Staphyleaceae and is endemic to 

California; it occurs in canyons within chaparral, foothill woodland, and yellow pine forest 

communities at elevations between 240 and 1,720 meters. 

Habitat and Status in the Project Area. This species occurs in shaded canyon habitats along the Merced 

River Canyon in El Portal and the Merced Gorge Area (Segments 4 and 3, respectively). 

Narrowleaf trillium (Trillium angustipetalum) 

General Ecology and Distribution. This perennial herb in the Melanthiaceae family is almost entirely 

restricted to California. It is most common in the coastal ranges of the state, but occurs in limited, 
IV. Existing Environment 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-59 

small populations in the Sierra Nevada where it is found in shady areas within mature montane 

coniferous forests with well-developed duff and litter layers. Elevations range from 100 to 2,000 

meters. This species may be at risk due to the lack of natural fire patterns, which allows an unnatural 

buildup of duff and litter to the exclusion of the plant, as well as overly intense fire behavior resulting 

in loss of root and plant materials through overheating. 

Habitat and Status in the Project Area. This species is scattered over a 10-acre area along the south side 

of the South Fork of the Merced River in Wawona (Segment 7), near the eastern end of River Road. It 

also occurs in Yosemite Valley (Segment 2). 

California red huckleberry (Vaccinium parvifolium) 

General Ecology and Distribution. This shrub belongs to the heath family and is endemic to California. 

It occurs in canyons within redwood forest, red fir forest, and mixed evergreen forest communities at 

elevations between 1,400 and 2,500 meters. 

Habitat and Status in the Project Area. This species prefers moist, shaded drainage bottoms along 

creeks and rivers. It occurs in Wawona (Segment 7). 

Hall’s wyethia (Wyethia elata) 

General Ecology and Distribution. This species, a perennial herb in the aster family, is endemic to 

California. It is restricted to the southern Sierra Nevada foothills and lower montane forests at 

elevations between 1,000 and 1,400 meters and reaches the northern extent of its range in Yosemite. 

Habitat and Status in the Project Area. It is found in open woodlands and forests in the Wawona basin 

(Segment 7). 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-60 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

CHAPTER V. ENVIRONMENTAL EFFECTS 

Methods Used to Assess Effects 

Assumptions 

The following assumptions were used as a basis in the analysis of effects on special-status species: 

 The greater the size of a biotic community and the stronger its links to neighboring 

communities, the more valuable it is to the integrity and maintenance of biotic processes that 

sustain special-status species. Development limits the size of a community and fragments and 

disassociates communities from each other. 

 The more developed areas become, the less valuable they are as habitat for special-status 

species. New development would increase human presence and increase the potential for soil, 

wildlife, and vegetation disturbance. The potential for negative wildlife interactions (such as 

human injury from wildlife and the introduction of unnatural food sources) also would 

increase. If development were removed from an area, the value of the habitat for special-status 

species would increase. In some cases, the dispersal of visitors over a wider area that may 

follow removal of developed facilities may well have a greater impact than focused visitor use 

within the well-defined area of development. Human effects can also improve habitat quality 

for non-native species and unnaturally increase the abundance of some native species, both of 

which can have an adverse effect on special-status species. 

 The presence of humans and the effects of human food on the behavior, distribution, and 

abundance of wildlife species would continue in existing developments. 

 Roads can change water inflow and outflow patterns and may dewater sections of meadow or 

wetland habitat (USFS 1996). Roads can also cause mortality of wildlife and may form barriers 

and fragment wildlife habitat. 

 Development and effects in riparian zones may influence critical water quality elements such 

as temperature, suspended sediments, and nutrients. These elements interact in complex ways 

in aquatic systems and directly and indirectly influence patterns of growth, reproduction, and 

migration of aquatic organisms. 

 Development that has an adverse effect on habitat features that are important to certain 

special-status species (e.g., particular plant species upon which a species relies, or habitat 

features that define suitable habitat for a species) can have an acute, negative effect on those 

species. 

 Radiating effects of human use can affect use of habitats adjacent to developed areas by 

special-status species, even though such habitats are not directly affected by the development. 

 Implementation of threatened or endangered species recovery plans and other formal 

agreements between the U.S. Fish and Wildlife Service and the National Park Service would 

not be affected by the management direction resulting from the Merced River Plan/DEIS. The 

current management direction for special-status species would continue to remain in effect. 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-61 

Special-Status Plants 

The assessment of effects on special-status plants was based on the following: 

 The sensitivity of the individual species to effects (based on the rarity, resilience, size of 

population, and extent of the species throughout the park) 

 The location of the species in relation to the Preferred Alternative 

Special-Status Wildlife 

The assessment of effects on special-status wildlife was based on the following: 

 The possibility of a species or its preferred habitat occurring in those areas expected to be 

affected 

 The direct loss of habitat 

 The partial loss of habitat from its modification 

 The species’ sensitivity to disturbance from human activities that may alter use of habitats in 

areas adjacent to development 

Habitat fragmentation was also a critical component of the analysis. Restored blocks of habitat should 

be large enough to support viable populations, and intact habitat must not be reduced or affected to 

the point that it will no longer support viable populations. 

Impact Analysis 

Impacts on special status species from actions proposed in the Merced River Plan/DEIS were evaluated 

in terms of the context, intensity, duration, and type of impact, as defined below. Generally, the 

methodology for natural resource impact assessment follows direction provided in the Council of 

Environmental Quality Regulations for Implementing the National Environmental Policy Act, 

Section 1508.27. 

 Context. The context of the impact considers whether the impact would be local, 

segmentwide, parkwide, or regional. For the purposes of this analysis, local impacts would be 

those that occur in a specific area within a segment of the Merced River. This analysis will 

further identify if there would be local impacts in multiple segments. Segmentwide impacts 

would consist of a number of local impacts within a single segment or larger-scale impacts 

that would affect the segment as a whole. Parkwide impacts would extend beyond the river 

corridor and the study area within Yosemite National Park. Regional impacts would have an 

influence in a Sierra-wide context. Context suggests that certain impacts depend on the 

setting of the proposed action. For instance, impacts that would reduce the connectivity 

between habitat types could be minor if such connections are abundant in a given region, 

moderate or major if they are not. 

 Intensity. Impacts can be adverse or beneficial. A negligible impact means that special status 

species would not be affected, or effects would not be measurable. A minor impact would be 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-62 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

detectable; both short-term and long-term impacts could potentially affect breeding success 

and habitat availability. Mitigation measures would be sufficient to offset minor adverse 

effects. A moderate impact would be readily apparent and would result in the reduction or 

expansion of potential habitat required to meet life requisite needs of one or more species. 

Mitigation would be required to offset moderate adverse impacts. A major impact would be 

readily apparent and would result in the direct or indirect gain or loss of occupied breeding 

sites, take of individuals, or changes to habitat affecting potential for occupancy or 

reproductive potential. Extensive mitigation would be necessary to offset adverse effects and 

its success could not be guaranteed. Impacts to rare, threatened, and endangered species 

would be quantified where possible by determining the acreage of habitat for each species 

altered. The amount of each habitat type that would be directly affected would be determined 

by a comparative analysis of suitable habitat spatial data representing existing conditions and 

conditions under proposed management actions. Effects associated with habitat distribution 

and patch size will also be addressed quantitatively where baseline data are available to 

support such an analysis. Other potential direct and indirect effects to rare, threatened, and 

endangered species habitats, such as effects associated with invasive species or the potential 

for disturbance to populations due to increases in human activity, will be analyzed 

qualitatively. 

 Duration. A short-term impact would have an immediate effect on native habitat, diversity, 

and native populations but would not cause long-term declines in populations or diversity. 

Short-term impacts are normally associated with transitional types of activities, such as facility 

construction. Long-term impacts would lead to a loss of native habitat, diversity, and species 

populations as exhibited by a decline in species abundance, viability, and/or survival. 

 Type. The type of impact considers whether the impact would be beneficial or adverse. 

Adverse impacts are those that alter the range, location, number, or population of a species or 

its habitat. Beneficial impacts would improve one or more of these characteristics. 

Cumulative Analysis 

Cumulative effects on rare, threatened, and endangered species discussed herein are based on analysis 

of past, present, and reasonably foreseeable actions in the Yosemite region. The intensity of impact 

depends on whether the impacts are anticipated to interact cumulatively. For example, factors 

external to the park, such as broad regional habitat loss and pesticide use, can combine with existing, 

in-park impacts, such as from nonnative species, to cause declines in rare, threatened, or endangered 

amphibians (such as Sierra Nevada yellow-legged frog and Yosemite toad), which would be an 

adverse, cumulative impact. The projects identified below are those that have the potential to affect 

populations of rare, threatened, or endangered species (i.e., within the Merced River corridor) as well 

as large-scale or regional populations of the same species. 

Past Actions 

Natural habitats in Yosemite have been manipulated almost since the beginning of the park. Regional 

wildlife and vegetation patterns have been historically affected by logging, fire suppression, rangeland 

clearing, grazing, mining, draining, damming, diversions, and the introduction of nonnative species. 

Mammal species that survive but are extremely rare are the Pacific fisher and Sierra Nevada red fox. 

Several bird species have probably been reduced in Yosemite Valley by visitor activity but are present 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-63 

in less disturbed areas of the park. Willow flycatchers no longer nest in the Valley—probably due as 

much to parasitism by brown-headed cowbirds as to destruction of riparian and meadow habitat. 

Amphibians in Yosemite have suffered population declines similar to those seen in the rest of the 

Sierra Nevada (Drost and Fellers 1996). Red-legged frogs likely were found in the Valley in the past 

but are now are presumed extirpated. Significant factors in their disappearance probably include 

reduction in perennial ponds and wetlands, and predation by bullfrogs. At higher elevations, Sierra 

Nevada yellow-legged frogs and Yosemite toads are still present in a number of areas but are severely 

reduced in population and range. Foothill yellow-legged frogs have disappeared completely from the 

park, if not the entire Sierra Nevada. Research continues to identify the causes of Sierra Nevada-wide 

amphibian declines; known and possible causes include habitat destruction, nonnative fish, pesticides, 

and diseases. Past and ongoing activities that affect rare, threatened, or endangered species include 

construction of dams, diversion walls, bridges, roads, pipelines, riprap, recreational use, buildings, 

campgrounds, and other recreational features. 

In 1991, the USFS and the Bureau of Land Management developed a joint South Fork and Merced Wild 

and Scenic River Implementation Plan for the main stem Merced River and South Fork Merced River 

that are under their jurisdiction; this plan is also a general management plan with many prescriptive 

goals and few actions. The plan endeavors to limit or end consumptive uses such as grazing within the 

river corridor and calls for the formalization of camping and launch facilities for nonmotorized 

watercraft. Implementation of these actions has a beneficial effect by eliminating impacts where 

feasible (grazing does not currently occur within the river corridor), concentrating impacts in areas 

able to withstand visitor use, and providing facilities that mitigate adverse effects associated with 

visitor use (e.g., restrooms). 

Past projects and plans that could have a cumulative effect on special status species in the Merced River 

Wild and Scenic corridor include the following: 

Management and Restoration – South Fork and Merced Wild and Scenic River Implementation 

Plan, Cascades Diversion Dam Removal, Cook’s Meadow Ecological Restoration, Fern Springs 

Restoration, Happy Isles Dam Removal, Happy Isles Fen Habitat Restoration Project, Happy Isles 

Gauging Station Bridge Removal, Merced River Ecological Restoration at Eagle Creek Project 

Present Actions 

Current facility-related projects and plans that could have a cumulative effect on special status species 

include the following: 

Facility Development – Crane Flat Utilities, East Yosemite Valley Utilities Improvement 

Plan/Environmental Assessment, Wahhoga Indian Cultural Center, Parkwide Communication 

Data Network, South Entrance Station Kiosk Replacement, Tioga Road Rehabilitation 

Beneficial impacts of present management and restoration actions are similar to those discussed for 

past actions. Specific examples of present projects and plans with beneficial effects include the 

following: 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-64 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Management and Restoration – Yosemite Vegetation Management Plan, General Ecological 

Restoration, 2004 Fire Management Plan/EIS, Fuels reductions/forest rehabilitation projects 

(USFS), Tuolumne Wild and Scenic River Comprehensive Management Plan

Reasonably Foreseeable Future Actions 

Reasonably foreseeable future actions proposed in the region that could have a cumulative effect on 

regional special status species include: 

 changing demographics of visitors in Yosemite 

 climate change 

 concessioner parking lot restoration 

 Restoration of the Mariposa Grove Ecosystem 

 Yosemite Wilderness Stewardship Plan/EIS 

Federal Endangered Species 

Wildlife 

Sierra Nevada bighorn sheep (Ovis canadensis sierrae) 

Direct and Indirect Effects. There would be no direct or indirect effects on the Sierra Nevada 

bighorn sheep or its preferred habitat. Habitat for the Sierra Nevada bighorn sheep is located in steep 

terrain in the northeastern portion of Yosemite Park, outside of the Merced River corridor. 

Additionally, most of the herd inhabits lands outside of the Park. No development would occur within 

suitable habitat for this species. Therefore, there would be no direct or indirect effects on the Sierra 

Nevada bighorn sheep. 

Cumulative Effects. Regional and parkwide planning efforts such as the Vegetation Management 

Plan, General Ecological Restoration, Grazing Allotment Permit Renewals (U.S. Forest Service) and 

2009 Fire Management Plan could provide benefits to the size, integrity, and connectivity of suitable 

habitat for the Sierra Nevada bighorn sheep. These regional plans would have a long-term, moderate, 

beneficial effect on the Sierra Nevada bighorn sheep. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on Sierra 

Nevada bighorn sheep. 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-65 

Federal Threatened Species 

Valley elderberry longhorn beetle (Desmocerus californicus dimorphus) 

Direct and Indirect Effects. Potential Valley elderberry longhorn beetle habitat is defined by the 

presence or absence of elderberry plants in areas below 3,000 feet in elevation. Potential habitat for 

this species occurs in Segments 3 and 4 (Merced Gorge and El Portal, respectively), generally in 

riparian areas; however, activities that have the potential to affect Valley elderberry longhorn beetle 

would only occur in Segment 4 (El Portal, see figure N-1). 

Approximately 124 elderberry plants of a size sufficient to support the Valley elderberry longhorn 

beetle occur in areas of potential development or management activities in El Portal. Valley elderberry 

longhorn beetle exit holes that verify beetle activity were found in 11 of these elderberry plants, 

though beetle larvae could still be present in elderberry plants without exit holes. Actions in 

Segment 4, including moving temporary housing units to El Portal and development at the Abbieville 

and Trailer Village, would result in potential indirect or direct impacts on elderberry shrubs, including 

removal of shrubs. Approximately 37 elderberry plants were documented within potential areas of 

ground disturbance, seven with exit holes. Complete impact avoidance would not be possible for these 

plants. The infill in El Portal would affect up to nine elderberry shrubs with stems greater than one inch 

in diameter. The development at Abbieville would affect up to 16 shrubs, while the development at 

Trailer Village would affect up to 12 shrubs as proposed in the Merced River Plan/DEIS. However, 

planning and implementation would strive to minimize effects to riparian vegetation and shrubs that 

are retained in the area. For example, new employee housing would be constructed outside of the 100-

year floodplain to avoid impacts to riparian vegetation. Nevertheless, shrubs retained adjacent to 

proposed developed areas could be subject to future damage from human activities, such as 

unauthorized pruning and vehicles. 

Direct or indirect impacts on valley elderberry longhorn beetle habitat would result in adverse effects to 

this species. To minimize and avoid potential effects where possible, NPS will implement avoidance and 

mitigation measures outlined in the 1999 USFWS Conservation Guidelines for the Valley Elderberry 

Longhorn Beetle (Conservation Guidelines) (mitigation measure MM-WL-4, as applicable; see 

Appendix C). The Conservation Guidelines prescribe conservation measures to avoid and minimize 

adverse effects on the valley elderberry longhorn beetle, including specific procedures for transplanting, 

requirements to plant additional seedlings or cuttings and associated native species, protective measures, 

maintenance, and reporting. 

Using the measures outlined in the Conservation Guidelines, the NPS estimates that 37 elderberry plants 

would need transplanting, 174 additional seedlings or cuttings would need to be planted, along with 101 

associated native plants. In addition, a 1.53 acre Habitat Conservation Area would be required to protect 

transplants and establish required associated native plants. The NPS proposes to establish a 1.53 acre 

Habitat Conservation Area at the Greenemeyer Sand Pit, pending confirmation from the USFWS (see 

Appendix C for details). 
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V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-67 

Ecological restoration actions occurring in El Portal include riparian revegetation and removal of 

abandoned utilities and facilities. Additionally, no new development would occur within 150 feet of 

the river. These actions combined would result in long-term beneficial effects to the Valley elderberry 

longhorn beetle, as this species’ primary habitat occurs within riparian habitat. 

Cumulative Effects. Foreseeable projects that could have adverse effects on the Valley elderberry 

longhorn beetle and its habitat include the Utilities Master Plan/East Yosemite Valley Utilities 

Improvement Plan and Parkwide Communication Data Network. These projects would have the 

potential to damage or destroy elderberry plants and directly affect local Valley elderberry longhorn 

beetle populations. 

Long-term, beneficial effects would be expected from the Vegetation Management Plan, General 

Ecological Restoration, Grazing Allotment Permit Renewals (U.S. Forest Service), 2009 Fire 

Management Plan, Invasive Plant Management Plan Update, Fuels reductions/forest rehabilitation 

projects (U.S. Forest Service) because these planning efforts could lead to greater protection of 

elderberry plants. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on valley 

elderberry longhorn beetle. 

Federal Candidate Species 

Wildlife 

Yosemite toad (Bufo canorus) 

Direct and Indirect Effects. The areas of likely occurrence of Yosemite toads in the study area, based 

upon previous observations and collections, are in high-elevation meadows and lakes in Segment 1 

(Merced River above Nevada Fall) and Segment 5 (South Fork Merced River above Wawona). The 

Yosemite toad is regarded as a high-elevation species. There is a single historic record of this species 

in Yosemite Valley that places it approximately 2,500 feet below its usual range. It is unlikely that this 

record reflects the sustainable range of Yosemite toads. The proposed actions within Segments 1 and 

5 are primarily ecological restoration actions, and thus would result in direct and indirect negligible 

effects to the Yosemite toad. Meadow restoration, cessation of pack stock grazing, and re-routing 

trails outside of sensitive meadow habitat would result in long-term, beneficial effect to the Yosemite 

toad. Meadow restoration at the Merced Lake High Sierra Camp area would also have long-term 

beneficial impacts on Yosemite toads. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-68 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Overall, effect of the Preferred Alternative on Yosemite toads is expected to be long-term, local and 

beneficial. 

Cumulative Effects. Projects that have an appreciable effect on high-elevation meadow habitats are 

most likely to affect the Yosemite toad. Regional and parkwide planning efforts such as the Vegetation 

Management Plan, General Ecological Restoration, Grazing Allotment Permit Renewals (U.S. Forest 

Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, Fuels 

reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic Resources 

Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, and 

Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

habitat for the Yosemite toad. These actions could have long-term, moderate to major, beneficial 

effects on suitable habitat, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the Yosemite toad include the Parkwide 

Communication Data Network, Tioga Road Rehabilitation, and Tuolumne Meadows Water 

Treatment System Improvements. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on Yosemite 

toad. 

Sierra Nevada yellow-legged frog (Rana sierrae) 

Suitable habitat for this species occurs in Segments 1 (Merced River above Nevada Fall) and 5 (South 

Fork Merced River above Wawona) in high elevation lakes, ponds, and streams near the South Fork 

above Wawona. The proposed actions within these segments are primarily ecological restoration 

actions, and thus would result in direct and indirect negligible effects to the Sierra Nevada yellowlegged frog. Meadow restoration, cease of pack stock grazing, and re-routing trails outside of sensitive 

meadow habitat would result in beneficial effect to the Sierra Nevada yellow-legged frog as these 

habitats often form direct connections to other aquatic habitats (e.g., lakes and streams). Meadow 

restoration at the Merced Lake High Sierra Camp area would result in beneficial effect to Sierra 

Nevada yellow-legged frog. 

Overall, effect of the Preferred Alternative on Sierra Nevada yellow-legged frog is expected to be longterm, local and beneficial. 

Cumulative Effects. Projects that have an appreciable effect on high-elevation aquatic habitats are 

most likely to affect the Sierra Nevada yellow-legged frog. Regional and park-wide planning efforts 

such as the Vegetation Management Plan, General Ecological Restoration, Grazing Allotment Permit 

Renewals (U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, 

Fuels reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-69 

Resources Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, 

and Tuolumne Meadows Concept Plan could improve water quality and habitat for the Sierra Nevada 

yellow-legged frog. These actions could have long-term, moderate to major, beneficial effects on 

suitable habitat, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the Sierra Nevada yellow-legged frog include 

the Parkwide Communication Data Network, Tioga Road Rehabilitation, and Tuolumne Meadows 

Water Treatment System Improvements. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on Sierra 

Nevada yellow legged frog. 

California wolverine (Gulo gulo luteus) 

Direct and Indirect Effects. Wolverines typically inhabit semi-open terrain at or above the 

timberline from spring through fall, and then move to lower-elevation forests in winter. They have 

been seen in a variety of habitats, including treeless barrens, alpine meadows, and mixed coniferous 

forests (Thelander et al. 1994). The most important habitat characteristic appears to be a low level of 

human disturbance (Thelander et al. 1994). 

The Merced River corridor supports wolverine habitat in Segments 1 and 5 (Merced River above 

Nevada Fall and South Fork Merced River above Wawona, respectively). Proposed actions within 

these two segments primarily involve ecological restoration of meadow habitat. Additionally, given 

existing low level of development and apparent scarcity of wolverines in the Sierra Nevada, ecological 

restoration activities at these two segments would be expected to result in negligible effects to the 

species during restoration activities. Overall, impacts on wolverines under the Preferred Alternative 

would be beneficial following habitat restoration. 

Cumulative Effects. Regional and parkwide planning efforts such as the Vegetation Management 

Plan, General Ecological Restoration, Grazing Allotment Permit Renewals (U.S. Forest Service) and 

2009 Fire Management Plan could provide benefits to the size, integrity, and connectivity of suitable 

habitat for the California wolverine. These regional plans would have a long-term, moderate, 

beneficial effect on suitable habitat, depending upon the extent of their implementation over time. 

Given the high-elevation occurrence of wolverines and their aversion to human contact, no 

foreseeable projects would have an effect on this species. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-70 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on California 

wolverine. 

Pacific fisher (Martes pennanti) 

Direct and Indirect Effects. Fisher habitat in the Merced River Corridor is primarily conifer and 

mixed conifer forests in Segments 1, 2, 5, and 7 (Merced River above Nevada Fall, Yosemite Valley, 

South Fork Merced River above Wawona, and Wawona, respectively). Although some suitable habitat 

for Pacific fisher occurs in Segment 2, this species is highly sensitive to human presence and would not 

likely utilize habitats in Yosemite Valley. Proposed actions in Segments 1 and 5 are primarily 

ecological restoration actions, and thus would have a negligible effect on Pacific fishers during 

implementation and beneficial effect following restoration. Proposed actions in Wawona include 

removing select campsites and retaining current facilities and services, which would continue to affect 

wildlife in general. However, there are no proposed actions which would remove suitable fisher 

habitat (large trees and snags within coniferous or mixed forests). 

Proposed actions to manage visitor use and facilities in Segment 2 would occur at Curry Village, 

Yosemite Village, Housekeeping Camp, Yosemite Lodge, and Camp 4. Potential foraging habitat for 

Pacific fisher may be affected by proposed construction and reorganization activities in the near-term 

in these areas, including direct loss of ponderosa pine (34.04 acres) habitat. Near-term actions in 

Segments 1 at the Merced Lake High Sierra Camp would retain the camp, reduce capacity of beds, and 

replace flush toilets with composting toilets. In Segment 7, near-term actions would remove campsites 

that are within the 100-year floodplain or in culturally sensitive areas at the Wawona Campground 

area. All of these actions would occur near currently developed areas that receive relatively high levels 

of human disturbance. Because, this species is sensitive to human presence, it is therefore not likely to 

occur in potentially affected areas Thus, these actions would not likely result in any direct or indirect 

effects to the Pacific fisher. 

Cumulative Effects. Regional and parkwide planning efforts such as the Vegetation Management 

Plan, General Ecological Restoration, Grazing Allotment Permit Renewals (U.S. Forest Service), 2009 

Fire Management Plan, Invasive Plant Management Plan Update, Fuels reductions/forest 

rehabilitation projects (U.S. Forest Service) could provide benefits to the fisher. 

The Utilities Master Plan/East Yosemite Valley Utilities Improvement Plan and Parkwide 

Communication Data Network, projects may have an adverse effect on fisher habitat. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on Pacific 

fisher. 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-71 

Whitebark pine (Pinus albicaulis) 

Direct and Indirect Effects. Whitebark pine is generally found in high-elevation upper montane and 

subalpine forests in Segments 1 (Merced River above Nevada Fall) and 5 (South Fork Merced River 

above Wawona). The proposed actions in Segments 1 and 5 are primarily ecological restoration 

actions in meadows and wetlands that generally do not require the removal of conifers, and thus 

would result in no adverse effects to the whitebark pine. Meadow and wetland restoration, cessation 

of pack stock grazing, and re-routing trails outside of sensitive meadow and wetland habitat in 

Segments 1 and 5 would result in no beneficial or adverse effects to the whitebark pine as these 

activities generally occur outside of whitebark pine habitat (forests). 

Overall, no adverse or beneficial effect on whitebark pine is expected as a result of the implementation 

of the Preferred Alternative. 

Actions at the Merced Lake High Sierra Camp in Segment 1 would retain the camp, reduce capacity of 

beds, and replace flush toilets with composting toilets. It is unlikely that proposed actions in Segment 

1 would affect whitebark pine because the actions would occur outside the elevation range for 

whitebark pine. 

Cumulative Effects. Whitebark pine is rapidly declining throughout most of its range, and recent 

monitoring and research results suggest that whitebark pine mortality may be increasing in California 

due to mountain pine beetle outbreaks (Gibson et al. 2008). Other factors that contribute to whitebark 

pine decline include white pine blister rust from a fungal pathogen, fire suppression, and climate 

change (by predisposing trees to insect and pathogen attacks and enabling white pine blister rust to 

expand to higher elevations) (Millar et al. 2012) 

Projects that have an appreciable effect on high-elevation forest habitats are most likely to affect the 

whitebark pine. Regional and parkwide planning efforts such as the Vegetation Management Plan, 

General Ecological Restoration, 2009 Fire Management Plan, Invasive Plant Management Plan 

Update, Fuels reductions/forest rehabilitation projects (U.S. Forest Service), and Tuolumne Wild and 

Scenic River Comprehensive Management Plan could improve habitat conditions for whitebark pine. 

Particularly, fire management designed to remove late-successional trees and favor whitebark pine 

may reduce competition from other conifer species for suitable openings for seed germination. These 

actions could have long-term, beneficial effects on whitebark pine, depending upon the extent of their 

implementation over time. 

Projects that could have a potentially adverse effect on the whitebark pine include the Parkwide 

Communication Data Network and Tioga Road Rehabilitation. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on whitebark 

pine. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-72 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

California State Endangered Species 

Wildlife 

Bald eagle (Haliaeetus leucocephalus) 

Direct and Indirect Effects. Bald eagles are rarely seen within Yosemite and are not known to nest in 

the park. However, riparian and meadow areas of Yosemite Valley, El Portal, and Wawona may 

provide foraging habitat for transient eagles. Actions proposed in this plan, such as the restoration of 

meadow and riparian habitat, would increase the size, integrity, and connectivity of potential habitat 

for this species. This would have a beneficial impact on potential foraging habitat for the bald eagle. 

Upland habitats are not the primary habitats used by the bald eagle, and the size of the proposed new 

developments in Yosemite Valley, El Portal, and Wawona, are relatively small in relation to the range 

of the bald eagle. Therefore, development and fragmentation in upland habitats would have negligible 

effects on this species. There would be a relatively large amount of restoration of meadow and riparian 

habitat in relation to development in upland habitats; therefore, the Preferred Alternative would have 

an overall long-term, beneficial effect on the bald eagle. 

Proposed actions to manage visitor use and facilities in Segment 2 would occur at Curry Village, 

Yosemite Village, Housekeeping Camp, Yosemite Lodge, and Camp 4. In Segment 7, actions would 

remove campsites that are within the 100-year floodplain or in culturally sensitive areas at the 

Wawona Campground area. The facility actions in Segments 2 and 7 would not likely directly or 

indirectly affect the bald eagle because this species is a rare visitor to the park. Preconstruction surveys 

would be conducted to ensure no active raptor nest sites are affected by the proposed actions. 

Cumulative Effects. Regional and parkwide planning efforts such as the Yosemite Vegetation 

Management Plan, Invasive Plant Management Plan, Tuolumne Wild and Scenic River 

Comprehensive Management Plan, Fire Management Plan could improve the size, integrity, and 

connectivity of suitable habitat for the bald eagle. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on bald eagle. 

Great gray owl (Strix nebulosa) 

Direct and Indirect Effects. In the Sierra Nevada, great gray owls nest in mature red fir, mixed 

conifer, or lodgepole pine forests near wet meadows or other vegetated openings. Suitable great gray 

owl habitat occurs in forested areas near meadows within Yosemite Valley and Wawona (Segments 2 

and 7, respectively). Although some suitable habitat for great gray owl occurs in Segment 2, this 

species is highly sensitive to human presence and would not likely utilize habitats in Yosemite Valley. 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-73 

Overall, the Preferred Alternative would result in beneficial effects to great gray owl and their habitat 

as a result of a substantial amount of restored high-quality habitat in Yosemite Valley and Wawona. 

Cumulative Effects. Projects that have an appreciable effect on mid-elevation forest and meadow 

habitats are most likely to affect the great gray owl. Regional and parkwide planning efforts such as the 

Vegetation Management Plan, General Ecological Restoration, Grazing Allotment Permit Renewals 

(U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, Fuels 

reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic Resources 

Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, and 

Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

foraging and nesting habitat for the great gray owl. These actions could have long-term, beneficial 

effects on suitable habitat, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the great gray owl include those that affect 

forest and meadow habitats, such as the Parkwide Communication Data Network, Tioga Road 

Rehabilitation, and Tuolumne Meadows Water Treatment System Improvements. The 2009 Fire 

Management Plan and Fuels reductions/forest rehabilitation projects (U.S. Forest Service) may affect 

great gray owls during plan implementation. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on great gray 

owl. 

Willow flycatcher (Empidonax traillii) 

Direct and Indirect Effects. Habitat loss and alteration is likely the greatest cause of willow 

flycatcher’s decline in the west (NatureServe 2009). Within the Sierra Nevada, habitat degradation due 

to historic and/or ongoing grazing of riparian and meadow habitats appears to be associated with 

population declines (Siegel et al. 2008). Other threats such as climate change, altered fire regimes, and 

invasive species can also lead to habitat degradation indirectly. Willow flycatchers are particularly 

vulnerable to brood parasitism by brown‐headed cowbirds (Molothrus ater). Willow flycatchers are at 

greater risk of cowbird brood parasitism where pack stations, corrals, supplemental feed, livestock 

holding facilities, livestock herds, campgrounds, picnic areas, rural communities or other 

brown‐headed cowbird‐associated locations occur within at least 8 km of occupied willow flycatcher 

sites (Rothstein et al. 1980, Verner and Rothstein 1988). Brownheaded cowbirds are frequently 

observed in Yosemite taking advantage of unnatural food sources at pack stations, stables, 

campgrounds, and in park residential areas. 

Willow flycatchers have not been observed in Yosemite Valley for over 30 years, and are seen on rare 

occasions elsewhere in the park. The species is typically found in meadows with a lush growth of 

willow shrubs. Riparian and meadow restoration within Yosemite Valley and Wawona would increase 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-74 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

the size, integrity, and connectivity of potential habitat for this species and increase the chances for its 

recolonization. 

Proposed actions to manage visitor use and facilities in Segment 2 would occur at Curry Village, 

Yosemite Village, Housekeeping Camp, Yosemite Lodge, and Camp 4. In Segment 7, actions would 

remove campsites that are within the 100-year floodplain or in culturally sensitive areas at the 

Wawona Campground area. The facility actions in Segments 2 and 7 would not likely directly or 

indirectly affect the willow flycatcher because this species rarely occurs in Yosemite Valley and 

elsewhere in the park. 

Overall, these actions would result in a beneficial effect on the willow flycatcher due to the large 

amount of suitable habitat that would be restored in Yosemite Valley and Wawona. 

Cumulative Effects. Projects that would cause degradation of meadow habitat or increased 

abundance of brown-headed cowbirds would adversely affect willow flycatchers through respective 

habitat loss and nest parasitism. 

Regional and parkwide planning efforts such as the Yosemite Vegetation Management Plan, Invasive 

Plant Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, Fire 

Management Plan could improve the size, integrity, and connectivity of suitable habitat for the willow 

flycatcher. Implementation of these plans could help restore habitats, control the effects of grazing, 

and reduce cowbird abundance by reducing fragmentation of forest communities. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on willow 

flycatcher. 

Sierra Nevada bighorn sheep (Ovis Canadensis sierra) 

Refer to the Federal Endangered Species section, above. 

California State Threatened Species 

Wildlife 

California wolverine (Gulo gulo luteus) 

Refer to the Federal Candidate Species section, above. 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-75 

Sierra Nevada red fox (Vulpes vulpes necator) 

Direct and Indirect Effects. Expansion of non‐native lowland red foxes or coyotes into high 

elevation areas may result in increased competition and potential transmission of harmful diseases and 

parasites to Sierra Nevada red foxes (Perrine et al. 2010). Interbreeding with non‐native red foxes may 

reduce genetic adaptation to local conditions (Perrine et al. 2010) and damage genetic integrity of the 

native subspecies. Development and recreation, resulting in increased exposure to humans, vehicles 

and pets, and possibly facilitating dispersal of non‐native red foxes, coyotes and other competitors are 

additional threats (Perrine et al. 2010). Habituation and begging habits may increase risk of mortality 

at roads and campgrounds, while fish poisoning disease may result from stocking infected fish for 

recreational fisheries (Perrine et al. 2010). Diseases from domestic animals, including rabies and 

distemper, and parasites, such as trematodes, can also cause significant mortality in red fox 

populations (Perrine et al. 2010). Rodenticides used for vegetation or livestock management purposes 

may result in secondary poisoning (Perrine et al. 2010). Climate change may reduce or change 

important habitat features in their boreal environment, such as reduced snowfall (Perrine et al. 2010). 

The Merced River corridor supports Sierra Nevada red fox habitat in Segments 1 and 5 (Merced River 

above Nevada Fall and South Fork Merced River above Wawona). Proposed actions in Segments 1 

and 5 are primarily ecological restoration actions, and thus would have negligible, direct and indirect 

effects on Sierra Nevada red fox during construction and beneficial effect following restoration. 

Facility-related actions at the Merced Lake High Sierra Camp in Segment 1 would include reducing 

capacity of beds and replacing flush toilets with composting toilets. These actions would result in 

negligible effects on the Sierra Nevada red fox. 

Cumulative Effects. Regional and parkwide planning efforts such as the Yosemite Vegetation 

Management Plan, Invasive Plant Management Plan, Tuolumne Wild and Scenic River 

Comprehensive Management Plan, Fire Management Plan could improve the size, integrity, and 

connectivity of suitable habitat for red foxes. These actions could have long-term, beneficial effects on 

suitable habitat, depending upon the alternatives chosen for implementation and the extent of their 

implementation over time. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on Sierra 

Nevada red fox. 

Golden eagle (Aquila chrysaetos) 

Direct and Indirect Effects. The greatest outside threat to golden eagle populations stems from 

interactions with humans and human‐built structures (Steel et al. 2011). In particular, collisions with 

structures and electrocution by power lines cause the majority of non‐natural Golden Eagle deaths 

(Steel et al. 2011). Such interactions could have detrimental effects to golden eagle populations in 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-76 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Yosemite. Overall, the relatively intact habitats in Yosemite are beneficial to golden eagles, and recent 

large fires in the park have likely expanded the area of suitable foraging habitat by providing more 

open terrain. 

Although golden eagles have been seen over most of the park, the areas of potential development 

under the Preferred Alternative that contain the most suitable habitat include Yosemite Valley and 

El Portal. The following are assessments of potential effects to golden eagles in these locations: 

Yosemite Valley – Restoration of meadow and riparian habitats would improve habitat quality for 

golden eagles under the Preferred Alternative. Even with this restoration, however, the terrain of 

Yosemite Valley would be marginal habitat for golden eagles, compared to other areas in the park 

(e.g., Merced River canyon). Effects in Yosemite Valley would be beneficial. 

El Portal – Development of housing, parking, and operations in this location would primarily 

affect wooded areas near the bottom of the Merced River canyon, which is not preferred golden 

eagle habitat. Most development would occur in or adjacent to areas with existing or previous 

development. These factors, coupled with the abundance of golden eagle habitat at higher 

elevations in the canyon, indicate that the impact on golden eagles under this alternative would be 

negligible. 

Proposed actions to manage visitor use and facilities in Segment 2 would occur at Curry Village, 

Yosemite Village, Housekeeping Camp, Yosemite Lodge, and Camp 4. Proposed actions would not 

occur in golden eagle preferred habitat (open terrain and early successional forest and shrub habitats; 

large trees in open habitats or canyons) and thus would not likely affect golden eagles. Additionally, 

trees that would potentially serve as suitable golden eagle nesting habitat are generally located near 

developed sites. Thus, it is not anticipated that golden eagle nest sites would occur in proximity to 

areas with near-term actions. Preconstruction surveys would be conducted to ensure no active nest 

sites are affected by the proposed actions. Overall, effects of the Preferred Alternative on golden 

eagles would be beneficial, due primarily to restoration of habitats in Yosemite Valley. 

Cumulative Effects. Regional and parkwide planning efforts such as the Yosemite Vegetation 

Management Plan, Invasive Plant Management Plan, Tuolumne Wild and Scenic River 

Comprehensive Management Plan, Fire Management Plan could improve the size, integrity, and 

connectivity of suitable habitat for golden eagles. These regional plans would have a long-term 

beneficial effect on golden eagles. 

Foreseeable facility development projects that could have an adverse effect on golden eagles include 

the Crane Flat Utilities, East Yosemite Valley Utilities Improvement Plan, and Wahhoga Indian 

Cultural Center. These projects, in total, would have a minor, adverse effect on golden eagles, because 

of the limited area they would affect. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on golden eagle. 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-77 

American peregrine falcon (Falco peregrinus anatum) 

Direct and Indirect Effects. Enough high‐quality habitat exists in the river corridor to sustain a 

healthy population of peregrine falcons; primary threats to them include predation on young by 

golden eagles and great horned owls and competition with ravens for nest sites. Other threats include 

disturbances posed by helicopters during search and rescue flights or medical evacuations and 

conflicts between nesting falcons and rock climbers. 

The Merced River corridor supports peregrine falcon habitat in Segments 1, 2, 3, 5, and 7. Proposed 

actions in Segments 1, 3 and 5 are primarily ecological restoration actions, and thus would have a 

negligible, direct and indirect effect on peregrine falcon during implementation and a beneficial effect 

following restoration. 

Restoration of meadow and riparian habitats in Yosemite Valley would have a beneficial impact on 

potential foraging habitat for the peregrine falcon. Development in Yosemite Valley associated with 

the preferred alternative could have a short-term adverse impact during periods of construction. 

Construction would not take place when the peregrine falcon is nesting or foraging in the vicinity of 

Cathedral Rocks. Development in forested habitats in Yosemite Valley and Wawona would have a 

negligible effect on peregrine falcons because this habitat type is abundant in these locations, and the 

falcon prefers to hunt in open areas such as along cliff faces and over meadows and water. 

Proposed actions at the Merced Lake High Sierra Camp in Segment 1 would retain the camp, reduce 

capacity of beds, and replace flush toilets with composting toilets. Proposed actions in to manage 

visitor use and facilities in Segment 2 would occur at Curry Village, Yosemite Village, Housekeeping 

Camp, Yosemite Lodge, and Camp 4. In Segment 7, actions would remove campsites that are within 

the 100-year floodplain or in culturally sensitive areas at the Wawona Campground area. All of these 

actions would occur near currently developed areas that receive relatively high levels of human 

disturbance. 

The proposed actions in Segment 2 and 7 would not occur in suitable nesting habitat for peregrine 

falcons. However, construction-related noise and human presence may cause peregrine falcons to 

temporarily avoid certain areas for foraging, such as wet meadow and woodland habitats. Actions in 

Segment 1 are not likely to affect peregrine falcon as these actions would occur outside of peregrine 

falcon nesting and foraging habitat. Overall, effects of the Preferred Alternative on peregrine falcons 

would be beneficial, due primarily to restoration of habitats in Yosemite Valley. 

Cumulative Effects. Regional and parkwide planning efforts such as the Yosemite Vegetation 

Management Plan, Invasive Plant Management Plan, Tuolumne Wild and Scenic River 

Comprehensive Management Plan, Fire Management Plan could improve the size, integrity, and 

connectivity of suitable habitat for peregrine falcons. These actions could have long-term, beneficial 

effects on suitable habitat, depending upon the alternatives chosen for implementation and the extent 

of their implementation over time. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-78 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on peregrine 

falcon. 

Bald eagle (Haliaeetus leucocephalus) 

Refer to the California State Endangered Species section, above. 

California State Rare Species 

Plants 

Thompkins’ sedge (Carex tompkinsii) 

Direct and Indirect Effects. Habitat for Thompkins’ sedge occurs in Segment 4 (El Portal). There 

would be no direct effects on Thompkins’ sedge as a result of the Preferred Alternative. Continued 

and increased use of the El Portal area could result in indirect adverse effects to this species as a result 

of increased population and associated foot traffic. Non-native species could be introduced and 

become established in newly developed areas and spread into Thompkins’ sedge habitat. These 

indirect effects would have a long-term adverse impact on the species. 

Cumulative Effects. The actions under the Preferred Alternative would have long-term, beneficial 

effects on special-status species in the Merced River corridor. However, in relation to past, present, 

and reasonably foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., 

introduction and spread of nonnative species, direct displacement of habitat) the actions under 

Alternative 5 would have a minimal beneficial effect. Overall, in conjunction with actions proposed in 

Alternative 5, cumulative actions on special status species would result in long-term, adverse effects 

on Thompkins’ sedge. 

Congdon’s woolly-sunflower (Eriophyllum congdonii) 

Direct and Indirect Effects. Habitat for Congdon’s woolly-sunflower occurs in Segment 4 

(El Portal). There would be no direct effects on Congdon’s woolly-sunflower as a result of the 

Preferred Alternative. Continued and increased use of the El Portal area could result in indirect 

adverse effects to this species as a result of increased population and associated foot traffic. Nonnative species could be introduced and become established in newly developed areas and spread into 

Congdon’s woolly-sunflower habitat. These indirect effects would have a long-term adverse impact 

on the species. 

Cumulative Effects. The actions under the Preferred Alternative would have long-term, beneficial 

effects on special-status species in the Merced River corridor. However, in relation to past, present, 

and reasonably foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., 

introduction and spread of nonnative species, direct displacement of habitat) the actions under 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-79 

Alternative 5 would have a minimal beneficial effect. Overall, in conjunction with actions proposed in 

Alternative 5, cumulative actions on special status species would result in long-term, adverse effects 

on Congdon’s woolly sunflower. 

Congdon’s lewisia (Lewisia congdonii) 

Direct and Indirect Effects. This species is known from the lower portion of the South Fork of the 

Merced River, El Portal, and through the lower portions of the Merced River gorge. Continued and 

increased use of the El Portal and Wawona areas could result in indirect adverse effects to this species 

through introduction and establishment of non-native species that could out-compete Congdon’s 

lewisia, and through additional foot traffic that could result from an increased residential population. 

Most Congdon’s lewisia plants are found in relatively inaccessible areas that have steep slopes and 

poison oak. These indirect effects would have a long-term adverse impact on the species. 

Cumulative Effects. The actions under the Preferred Alternative would have long-term, beneficial 

effects on special-status species in the Merced River corridor. However, in relation to past, present, 

and reasonably foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., 

introduction and spread of nonnative species, direct displacement of habitat) the actions under 

Alternative 5 would have a minimal beneficial effect. Overall, in conjunction with actions proposed in 

Alternative 5, cumulative actions on special status species would result in long-term, adverse effects 

on Congdon’s lewisia. 

California State Species of Special Concern 

Wildlife 

Hardhead (Mylopharodon conocephalus) 

Direct and Indirect Effects. In the Sierra Nevada, hardhead is a native fish that inhabit the lower 

reaches of the Merced River up to the vicinity of El Portal. It requires undisturbed areas of larger 

middle- and low-elevation streams that support clear, deep pools with sand-gravel-boulder substrates 

and slow water velocities. Suitable habitat for the hardhead is found in Segments 4, 6, and 7 of the 

Merced River corridor (El Portal, South Fork Merced River Impoundment, and Wawona, 

respectively). 

The Preferred Alternative in the Merced River Plan/DEIS does not propose any actions that would 

result in adverse or beneficial effects to the hardhead in Segment 6 (the Impoundment area). 

Actions that would potentially result in adverse effects to the hardhead and its habitat include 

construction of new park facilities and infrastructure (e.g., parking lots and high density employee 

housing) in Segments 4 and 7. These actions would have a negligible adverse impact because of the 

limited area that would be involved, the existing human disturbance in the area, and construction 

outside of suitable habitat for the hardhead (i.e., the Merced River and adjacent riparian habitat within 

the 100-year floodplain). Additionally, the Preferred Alternative would also restore significant 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-80 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

amounts of riparian habitat in Segments 4 and 7. These restorative actions would have long-term 

beneficial effects on hardhead due to increased productivity of the river ecosystem and enhanced 

water quality of the Merced River. 

Cumulative Effects. Projects that have an appreciable effect on montane riparian and riverine 

habitats are most likely to affect the hardhead. Regional and park-wide planning efforts such as the 

Vegetation Management Plan, General Ecological Restoration, Grazing Allotment Permit Renewals 

(U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, Fuels 

reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic Resources 

Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, and 

Tuolumne Meadows Concept Plan could increase the productivity of the Merced River, enhance river 

complexity, and maintain good water quality. These actions could have long-term beneficial effects on 

suitable habitat for the hardhead, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the hardhead include the Parkwide 

Communication Data Network, Tioga Road Rehabilitation, and Tuolumne Meadows Water 

Treatment System Improvements. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on hardhead. 

Northern goshawk (Accipiter gentilis) 

Direct and Indirect Effects. The northern goshawk breeds in most mountain areas, where they 

generally remain through the winter. Their preferred habitat is moderately dense coniferous forests 

broken by meadows and other openings, between 5,000 and 9,000 feet elevation. Segments 1 and 5 

(Merced River above Nevada Fall and South Fork Merced River above Wawona, respectively) 

support this species. 

The Preferred Alternative would restore meadows within Segments 1 and 5 and would result in 

negligible adverse effects to the northern goshawk during restoration. Meadow restoration, cessation 

of pack stock grazing, and re-routing trails outside of sensitive meadow habitat would result in longterm beneficial effects on the northern goshawk as foraging habitat within meadows would improve 

over time. 

Proposed actions at the Merced Lake High Sierra Camp in Segment 1 would retain the camp, reduce 

capacity of beds, and replace flush toilets with composting toilets. These actions would result in a 

negligible beneficial impact on northern goshawk in Segment 1by reducing stresses from visitor use. 

Cumulative Effects. Projects that have an appreciable effect on high-elevation forest and meadow 

habitats are most likely to affect the northern goshawk. Regional and parkwide planning efforts such 

as the Vegetation Management Plan, General Ecological Restoration, Grazing Allotment Permit 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-81 

Renewals (U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, 

Fuels reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic 

Resources Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, 

and Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

habitat for the northern goshawk. These actions could have long-term, beneficial effects on suitable 

habitat, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the northern goshawk include those that affect 

forest and meadow habitats, such as the Parkwide Communication Data Network, Tioga Road 

Rehabilitation, and Tuolumne Meadows Water Treatment System Improvements. The 2009 Fire 

Management Plan and Fuels reductions/forest rehabilitation projects (U.S. Forest Service) could 

temporarily affect northern goshawks during plan implementation. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on northern 

goshawk. 

Long-eared owl (Asio otus) 

Direct and Indirect Effects. Given the rarity of observations in Yosemite Valley, and the age of the 

last confirmed nesting there, it is possible that increasing human disturbance has affected use of Valley 

habitats by long-eared owls, especially in meadow and riparian habitats. Long-eared owl habitat is 

largely intact in the park, except for localized habitat destruction from roads and development. 

Suitable habitat for the long-eared owl is found in most segments of the Merced River corridor 

(Segments 2, 3, 4, 6, 7, and 8) west of Nevada Fall and the impoundment area. 

The proposed actions within segments 3, 6, and 8 under the Preferred Alternative primarily involve 

ecological restoration or maintaining current types of uses. Thus, impacts to the long-eared owl as a 

result of these actions would be long-term, local, and beneficial. Additionally, the Preferred 

Alternative would also restore montane riparian, wet meadow, oak woodland, and aquatic habitats in 

Segments 2, 4, and 7. These restorative actions would have long-term, beneficial effects on long-eared 

owls. 

Under the Preferred Alternative in the Merced River Plan/DEIS, actions that would have adverse 

effects on potential long-eared owl habitat include construction of new park facilities and 

infrastructure (e.g., campgrounds, roundabouts, pedestrian under-crossing, parking lots, and high 

density employee housing) in Segments 2, 4 and 7. Long-eared owl habitat would be affected by 

proposed actions to manage visitor use and facilities in Segment 2 at Curry Village, Camp 6 Yosemite 

Village, and Yosemite Lodge and Camp 4; and by removal of campsites that are within the 100-year 

floodplain or in culturally sensitive areas at the Wawona Campground in Segment 7. Construction 

activities in Segment 2 could indirectly affect long-eared owl due to disturbance associated with 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-82 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

removal, restoration, and construction of new facilities. Potential foraging habitat for long-eared owl 

in Segment 2 would be affected, including direct loss of ponderosa pine (34.04 acres), montane 

riparian (0.81 acres), and montane hardwood (1.73 acres) habitat. Tree removal associated with the 

construction of new facilities in Segment 2 would remove potential suitable roosts or perches for owls. 

However, the location of trees planned for removal are in proximity to existing developed sites, and 

thus would not likely serve as nest sites for long-eared owls. Heavy construction equipment and an 

increase in human presence in Segments 2 and 7 would temporarily cause long-eared owls to relocate 

or avoid the area for foraging. Pre-construction surveys for long-eared owl nests would be conducted 

prior to the implementation of proposed actions in Segments 2 and 7 to ensure that no active owl nest 

sites could be affected. Additionally, older trees and snags would be retained in Segment 2 for longeared owl habitat where possible. In summary, proposed actions related to managing visitor use and 

facilities in Segments 2, 4 and 7 would have adverse effects on long-eared owls as a result of 

construction-related disturbances to foraging habitat. 

Overall, there would be a long-term beneficial impact on the long-eared owl as a result of a substantial 

amount of restored high-quality habitat in Yosemite Valley, El Portal, and Wawona areas. 

Cumulative Effects. Regional and park-wide planning efforts such as the Vegetation Management 

Plan, General Ecological Restoration, Grazing Allotment Permit Renewals (U.S. Forest Service), 2009 

Fire Management Plan, Invasive Plant Management Plan Update, Fuels reductions/forest 

rehabilitation projects (U.S. Forest Service) could provide benefits to the long-eared owl. 

The Utilities Master Plan/East Yosemite Valley Utilities Improvement Plan and Parkwide 

Communication Data Network projects may have an adverse effect on long-eared owl habitat. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably foreseeable 

future actions throughout the Sierra Nevada and larger region, (e.g., introduction and spread of 

nonnative species, direct displacement of habitat) the actions under Alternative 5 would have a minimal 

beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, cumulative actions on 

special status species would result in long-term, adverse effects on long eared owl. 

Vaux’s swift (Chaetura vauxi) 

Direct and Indirect Effects. Vaux’s swift habitat occurs in forested areas near meadows within 

Yosemite Valley and Wawona (Segments 2 and 7, respectively). It inhabits redwood and Douglas-fir 

habitats and utilizes large hollow trees and snags, and prefers tall, burned-out stubs as nest sites. 

Vaux’s swifts forage in a variety of habitats, especially over water, including riparian habitats. The 

Preferred Alternative would restore a variety of habitats, including those used by Vaux’s swift such as 

montane riparian and coniferous forest, in Segments 2 and 7. These restorative actions would have 

long-term, beneficial effects on Vaux’s swift. 

Under the Preferred Alternative in the Merced River Plan/DEIS, actions that would have adverse 

effects on potential Vaux’s swift habitat include construction of new park facilities and infrastructure 

(e.g., campgrounds, roundabouts, pedestrian under-crossing, and parking lots) in Segment 2 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-83 

(Yosemite Valley). Vaux’s swift habitat would be affected by proposed actions to manage visitor use 

and facilities in Segment 2 at Camp 6Yosemite Village, including construction and restoration 

activities associated with formalizing parking lots, moving parking lots away from riparian areas, 

construction of new parking spaces, and construction of a pedestrian underpass and a roundabout. 

Indirect effects to Vaux’s swift would result from disturbance associated with construction activities. 

Potential foraging habitat for Vaux’s swift would be affected, including direct loss of montane riparian 

habitat (0.81 acres). Habitat and tree removal associated with the construction of new facilities would 

remove potential suitable perches for swifts. However, the location of trees planned for removal is 

typically located in proximity to existing developed sites that receive relatively high levels of human 

disturbance. Heavy construction equipment and an increase in human presence would temporarily 

cause Vaux’s swifts to relocate or avoid the area for foraging. Pre-construction surveys for Vaux’s 

swift nests would be conducted prior to the implementation of proposed actions in Segment 2 to 

ensure that no active nest sites could be affected. In summary, proposed actions related to managing 

visitor use and facilities in Segment 2 would have long-term, adverse effects on Vaux’s swifts as a 

result of construction-related disturbances to foraging habitat. Overall, there would be a long-term 

beneficial impact on the Vaux’s swift as a result of a substantial amount of restored high-quality 

habitat in Yosemite Valley and Wawona. 

Cumulative Effects. Projects that have an appreciable effect on mid-elevation forest and meadow 

habitats are most likely to affect the Vaux’s swift. Regional and parkwide planning efforts such as the 

Vegetation Management Plan, General Ecological Restoration, Grazing Allotment Permit Renewals 

(U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, Fuels 

reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic Resources 

Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, and 

Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

foraging habitat for the Vaux’s swift. These actions could have long-term, beneficial effects on suitable 

habitat, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the Vaux’s swift include those that affect 

forest, meadow, and aquatic habitats, such as the Parkwide Communication Data Network, Tioga 

Road Rehabilitation, and Tuolumne Meadows Water Treatment System Improvements. The 2009 Fire 

Management Plan and Fuels reductions/forest rehabilitation projects (U.S. Forest Service) may affect 

Vaux’s swift during plan implementation. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on Vaux’s swift. 

Northern harrier (Circus cyaneus) 

Direct and Indirect Effects. Northern harrier habitat occurs in open grassland, meadows, and 

wetlands within segments 2 and 7 (Yosemite Valley and Wawona, respectively). The Preferred 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-84 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Alternative would restore large areas of habitat suitable for northern harrier, including wet meadows 

in Yosemite Valley and Wawona. These restorative actions would have beneficial effects on northern 

harrier as foraging and nesting habitat for this species would improve (in size, integrity, and 

continuity) over time. 

Under the Preferred Alternative in the Merced River Plan/DEIS, actions that would have adverse 

effects on potential northern harrier habitat include construction of new park facilities and 

infrastructure (e.g., campgrounds, roundabouts, pedestrian under-crossing, and parking lots) in 

Segments 2 and 7 (Yosemite Valley and Wawona, respectively). The proposed actions in Segment 2 

and 7 would not occur in suitable nesting habitat for northern harrier. However, construction-related 

noise and human presence may cause northern harriers to temporarily avoid certain areas for 

foraging, causing negligible adverse impacts on this species. 

Overall, there would be a long-term beneficial impact on the northern harrier as a result of a 

substantial amount of restored high-quality habitat in Yosemite Valley and Wawona. 

Cumulative Effects. Projects that have an appreciable effect on meadow and grassland habitats are 

most likely to affect the northern harrier. Regional and parkwide planning efforts such as the 

Vegetation Management Plan, General Ecological Restoration, Grazing Allotment Permit Renewals 

(U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, Fuels 

reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic Resources 

Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, and 

Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

foraging habitat for the northern harrier. These actions could have long-term, beneficial effects on 

suitable habitat, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the northern harrier include those that affect 

meadows, wetlands, and grassland habitats, such as the Parkwide Communication Data Network, 

Tioga Road Rehabilitation, and Tuolumne Meadows Water Treatment System Improvements. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably foreseeable 

future actions throughout the Sierra Nevada and larger region, (e.g., introduction and spread of 

nonnative species, direct displacement of habitat) the actions under Alternative 5 would have a minimal 

beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, cumulative actions on 

special status species would result in long-term, adverse effects on northern harrier. 

Olive-sided flycatcher (Contopus cooperi) 

Direct and Indirect Effects. Olive-sided flycatcher habitat occurs in forest and woodland habitats 

below 9,000 feet. It prefers mixed conifer, montane hardwood-conifer, Douglas-fir, redwood, red fir, 

and lodgepole pine habitats for nesting. Olive-sided flycatchers prefer unobstructed airspace within 

openings and over forest canopies with exposed perches for foraging. Suitable habitat for this species 

occurs in Segments 1, 2, 5, and 7 (Merced River above Nevada Fall, Yosemite Valley, South Fork 

Merced River above Wawona, and Wawona, respectively). 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-85 

The proposed actions in Segments 1 and 5 are primarily ecological restoration actions in meadows 

and wetlands that would result in negligible adverse effects to the olive-sided flycatcher during 

construction as these restoration activities occur outside of preferred flycatcher nesting habitat. 

Meadow and wetland restoration, cessation of pack stock grazing, and re-routing trails outside of 

sensitive meadow habitat would result in long-term beneficial impacts to foraging habitat for the 

olive-sided flycatcher. 

The Preferred Alternative would restore large areas of suitable foraging habitat for the olive-sided 

flycatcher in Segments 2 (Yosemite Valley) and 7 (Wawona), including meadows within forest 

openings. These restorative actions would have beneficial effects on olive-sided flycatcher as foraging 

habitat for this species would improve (in size, integrity, and continuity) over time. 

Under the Preferred Alternative in the Merced River Plan/DEIS, actions that would have adverse 

effects on potential olive-sided flycatcher habitat include construction of new park facilities and 

infrastructure (e.g., campgrounds, roundabouts, pedestrian under-crossing, and parking lots) in 

Segments 2 and 7 (Yosemite Valley and Wawona, respectively).Olive-sided flycatcher foraging habitat 

would be affected by proposed actions to manage visitor use and facilities in Segment 2 at Yosemite 

Village Day-use Parking Area, including construction and restoration activities associated with 

formalizing parking lots, moving parking lots away from riparian areas, construction of new parking 

spaces, and construction of a pedestrian underpass and a roundabout. Indirect effects to olive-sided 

flycatcher would result from disturbance associated with construction activities. Potential foraging 

habitat for olive-sided flycatcher would be affected, including direct loss of montane riparian habitat 

(0.81 acres). Habitat and tree removal associated with the construction of new facilities would remove 

potential suitable perches for flycatchers. However, the location of trees planned for removal is 

typically located in proximity to existing developed sites that receive relatively high levels of human 

disturbance. Heavy construction equipment and an increase in human presence would temporarily 

cause olive-sided flycatchers to relocate or avoid the area for foraging. Pre-construction surveys for 

olive-sided flycatcher nests would be conducted prior to the implementation of proposed actions in 

Segment 2 to ensure that no active nest sites could be affected. In summary, proposed actions related 

to managing visitor use and facilities in Segment 2 would have adverse effects on olive-sided flycatcher 

as a result of construction-related disturbances to foraging habitat. 

Overall, the Preferred Alternative would result in long-term beneficial effects on olive-sided flycatcher 

as a result of a substantial amount of restored high-quality habitat in Yosemite Valley and Wawona. 

Cumulative Effects. Projects that have an appreciable effect on forest, woodland, and meadow 

habitats are most likely to affect the olive-sided flycatcher. Regional and parkwide planning efforts 

such as the Vegetation Management Plan, General Ecological Restoration, Grazing Allotment Permit 

Renewals (U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, 

Fuels reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic 

Resources Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, 

and Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

foraging habitat for the olive-sided flycatcher. These actions could have long-term, beneficial effects 

on suitable habitat, depending upon the extent of their implementation over time. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-86 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Projects that could have a potentially adverse effect on the olive-sided flycatcher include those that 

affect forest, woodland, and open meadow habitats, such as the Parkwide Communication Data 

Network, Tioga Road Rehabilitation, and Tuolumne Meadows Water Treatment System 

Improvements. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably foreseeable 

future actions throughout the Sierra Nevada and larger region, (e.g., introduction and spread of 

nonnative species, direct displacement of habitat) the actions under Alternative 5 would have a minimal 

beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, cumulative actions on 

special status species would result in long-term, adverse effects on olive-sided flycatcher. 

Black swift (Cypseloides niger) 

Direct and Indirect Effects. Black swift nest sites are located in moist crevices, caves or on cliffs 

behind or adjacent to waterfalls in deep canyons. The Preferred Alternative would not result in direct 

or indirect adverse effects on nesting habitat for the black swift. It forages in various habitats. Suitable 

foraging habitat for this species occurs in Segment 2 (Yosemite Valley). 

The Preferred Alternative would restore large areas of suitable foraging habitat for the black swift in 

Segment 2 (Yosemite Valley), including meadows and riparian habitats. These restorative actions 

would have beneficial effects on black swift as foraging habitat for this species improves over time (in 

size, integrity, and continuity). 

Under the Preferred Alternative in the Merced River Plan/DEIS, actions that would have potential 

adverse effects on foraging habitat for black swift include construction of new park facilities and 

infrastructure (e.g., campgrounds, roundabouts, pedestrian under-crossing, and parking lots) in 

Yosemite Valley. These actions would have a negligible adverse impact because of the limited area that 

would be involved, the existing human disturbance in the area, and the large area of suitable, 

unaffected habitat that would continue to exist in surrounding areas. Additionally, all actions occur 

outside of black swift preferred nesting habitat (behind waterfalls). 

Overall, the Preferred Alternative would result in long-term beneficial effects on black swift as a result 

of a substantial amount of restored high-quality habitat in Yosemite Valley. 

Cumulative Effects. Projects that have an appreciable effect to meadow, wetlands, and riparian habitats 

are most likely to affect the black swift as they forage in a variety of habitats. However, most actions 

would not affect black swift nesting habitat due to their specialized requirements. Regional and 

parkwide planning efforts such as the Vegetation Management Plan, General Ecological Restoration, 

Grazing Allotment Permit Renewals (U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant 

Management Plan Update, Fuels reductions/forest rehabilitation projects (U.S. Forest Service), High 

Elevation Aquatic Resources Management Plan, Tuolumne Wild and Scenic River Comprehensive 

Management Plan, and Tuolumne Meadows Concept Plan could improve the size, integrity, and 

connectivity of suitable foraging habitat for the black swift. These actions could have long-term, 

beneficial effects on suitable habitat, depending upon the extent of their implementation over time. 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-87 

Projects that could have a potentially adverse effect on the black swift include those that affect 

meadow, wetlands, and riparian/woodland habitats, such as the Parkwide Communication Data 

Network, Tioga Road Rehabilitation, and Tuolumne Meadows Water Treatment System 

Improvements. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on black swift. 

Yellow warbler (Setophaga petechia) 

Direct and Indirect Effects. The yellow warbler prefers riparian woodlands, but also breeds in 

chaparral, ponderosa pine, and mixed conifer habitats with substantial amounts of brush. Suitable 

habitat for the yellow warbler occurs in all segments (Segments 1-8) within the Merced River corridor. 

The Preferred Alternative would restore large tracts of previously disturbed meadow, riparian, 

coniferous and broadleaf forest, and Valley oak woodland habitats, primarily in Yosemite Valley, 

El Portal, and Wawona, totaling approximately 203 acres of habitat. Removal of campgrounds and 

park facilities located within 100 feet of the river and restoring these areas would increase the amount, 

integrity, and contiguity of habitat for this species. This would improve suitable habitat for the yellow 

warbler. These restorative actions would have beneficial effects on yellow warbler as foraging habitat 

for this species improves over time (in size, integrity, and continuity). 

Under the Preferred Alternative in the Merced River Plan/DEIS, actions that would have potential 

adverse effects to yellow warbler include construction of new park facilities and infrastructure (e.g., 

campgrounds, roundabouts, pedestrian under-crossing, employee housing, and parking lots) in 

Yosemite Valley, El Portal, and Wawona. 

Yellow warbler habitat would be affected by proposed actions to manage visitor use and facilities in 

Segment 2 at Yosemite Village Day-use Parking Area, including construction and restoration activities 

associated with formalizing parking lots, moving parking lots away from riparian areas, construction 

of new parking spaces, and construction of a pedestrian underpass and a roundabout. Indirect effects 

to yellow warbler would result from disturbance associated with construction activities. Potential 

foraging habitat for yellow warbler would be affected, including direct loss of montane riparian 

habitat (0.81 acres). Habitat and tree removal associated with the construction of new facilities would 

remove potential suitable perches for warblers. However, the location of trees planned for removal is 

typically located in proximity to existing developed sites that receive relatively high levels of human 

disturbance. Heavy construction equipment and an increase in human presence would temporarily 

cause yellow warblers to relocate or avoid the area for foraging. Pre-construction surveys for yellow 

warbler nests would be conducted prior to the implementation of proposed actions in Segment 2 to 

ensure that no active nest sites could be affected. In summary, proposed actions related to managing 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-88 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

visitor use and facilities in Segment 2 would have adverse effects on yellow warbler as a result of 

construction-related disturbances to foraging habitat. 

The overall, long-term effect on yellow warblers under the Preferred Alternative in the Merced River 

Plan/DEIS would be beneficial, primarily due to the restoration of highly suitable riparian habitat and 

the prohibition of new development within the 100-year floodplain of the Merced River. 

Cumulative Effects. Projects that substantially affect riparian woodland, chaparral, ponderosa pine, 

and mixed conifer habitats would likely affect the yellow warbler. Regional and parkwide planning 

efforts such as the Vegetation Management Plan, General Ecological Restoration, Grazing Allotment 

Permit Renewals (U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan 

Update, Fuels reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic 

Resources Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, 

and Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

foraging and nesting habitat for the yellow warbler. These actions could have long-term, beneficial 

effects on suitable habitat, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the yellow warbler include those that affect 

riparian/woodland and forest habitats, such as the Parkwide Communication Data Network and 

Tioga Road Rehabilitation Project. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably foreseeable 

future actions throughout the Sierra Nevada and larger region, (e.g., introduction and spread of 

nonnative species, direct displacement of habitat) the actions under Alternative 5 would have a minimal 

beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, cumulative actions on 

special status species would result in long-term, adverse effects on yellow warbler. 

Harlequin duck (Histrionicus histrionicus) 

Direct and Indirect Effects. Harlequin ducks are very rarely seen in Yosemite, possibly due to 

human disturbance in riparian areas that provide cover for nest sites and broods. Nests are established 

near swift rivers or streams in recesses sheltered overhead by stream banks, rocks, woody debris, or 

low shrubs. Nests are usually within 7 feet of the water, but can be up to 90 feet away. Although they 

are rare within Yosemite, potential suitable habitat for the harlequin duck occurs in all segments 

(Segments 1-8) within the Merced River corridor. 

The Preferred Alternative would restore large tracts of previously disturbed meadow, riparian, 

coniferous and broadleaf forest, and Valley oak woodland habitats, primarily in Yosemite Valley, 

El Portal, and Wawona, totaling approximately 203 acres of habitat. Restoration of riparian habitat 

would improve and increase the amount of suitable habitat for the harlequin duck. Removal of 

campgrounds and park facilities located within 100 feet of the river and restoring these areas would 

increase the amount, integrity, and contiguity of habitat for this species. These restorative actions 

would have beneficial effects on the harlequin duck as nesting and foraging habitat for this species 

improves over time (in size, integrity, and continuity). 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-89 

Under the Preferred Alternative in the Merced River Plan/DEIS, actions that would have potential 

adverse effects to the harlequin duck include construction of new park facilities and infrastructure 

(e.g., campgrounds, roundabouts, pedestrian under-crossing, employee housing, and parking lots) in 

Yosemite Valley, El Portal, and Wawona. These actions would have a negligible adverse impact 

because of the limited area that would be involved, the existing human disturbance in the area, and the 

large area of suitable, unaffected habitat that would continue to exist in surrounding areas. 

Additionally, proposed new campgrounds and park facilities would be constructed outside of the 

100-year floodplain to further avoid impacts to intact riparian habitat. 

The overall, long-term effect on the harlequin duck under the Preferred Alternative in the Merced 

River Plan/DEIS would be beneficial, primarily due to the restoration of highly suitable riparian 

habitat and the prohibition of new development within the 100-year floodplain of the Merced River. 

Cumulative Effects. Foreseeable projects that could have beneficial effects on the harlequin duck and 

its habitat include regional and parkwide planning efforts such as the Vegetation Management Plan, 

General Ecological Restoration, Grazing Allotment Permit Renewals (U.S. Forest Service), 2009 Fire 

Management Plan, Invasive Plant Management Plan Update, Fuels reductions/forest rehabilitation 

projects (U.S. Forest Service), High Elevation Aquatic Resources Management Plan, Tuolumne Wild 

and Scenic River Comprehensive Management Plan, and Tuolumne Meadows Concept Plan. These 

actions could have long-term, beneficial effects on suitable habitat for harlequin duck, depending 

upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the harlequin duck include those that affect 

riparian woodland habitat, such as the Parkwide Communication Data Network and Tioga Road 

Rehabilitation Projects. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on harlequin 

duck. 

California spotted owl (Strix occidentalis occidentalis) 

Direct and Indirect Effects. California spotted owl occurs in oak and ponderosa pine forests to 

lower elevation red fir forests up to 7,600 feet in elevation; preferred elevation is ranges between 

3,000 and 7,000 feet. Tree cavities, broken-off trees and snags, abandoned nests of other species, or 

mistletoe clumps are used as nesting sites. California spotted owl requires dense forest, with a canopy 

closure of greater than 70%. The presence of black oak in the canopy also enhances habitat quality. In 

the Merced River corridor, suitable spotted owl habitat occurs in mature and old forests with dense 

canopies in segments 1, 2, 5, and 7 (Merced River above Nevada Fall, Yosemite Valley, South Fork 

Merced River above Wawona, and Wawona, respectively). 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-90 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

The Preferred Alternative in the Merced River Plan/DEIS would restore meadows within Segments 1 

and 5, which would result in no effects to the spotted owl as these activities are not conducted within 

preferred spotted owl habitat. The Preferred Alternative would restore large areas of habitat in 

Segments 2 (Yosemite Valley) and 7 (Wawona). These restorative actions would have beneficial 

effects on the spotted owl by potentially increasing the quality and extent of suitable foraging habitat. 

Under the Preferred Alternative in the Merced River Plan/DEIS, actions that may result in adverse 

effects to spotted owl habitat include construction of new park facilities and infrastructure (e.g., 

campgrounds, roundabouts, pedestrian under-crossing, and parking lots) in forest habitats within 

Segments 2 and 7 (Yosemite Valley and Wawona). California spotted owl habitat would be affected by 

proposed actions to manage visitor use and facilities in Segment 2 at Curry Village, Yosemite Village, 

Housekeeping Camp, Yosemite Lodge, and Camp 4. Construction and reorganization activities at 

these locations could indirectly affect long-eared owl due to disturbance associated with construction 

activities. Potential habitat for spotted owl would be affected, including direct loss of ponderosa pine 

(34.04 acres) and montane hardwood (1.73 acres) habitat. Tree removal associated with the 

construction of new facilities would remove potential suitable roosts or perches for owls. However, 

the location of trees planned for removal are in proximity to existing developed sites that receive 

relatively high levels of human disturbance, and thus would not likely serve as nest sites for spotted 

owls. Heavy construction equipment and an increase in human presence would temporarily cause 

spotted owls to relocate or avoid the area for foraging. Pre-construction surveys for spotted owl nests 

would be conducted prior to the implementation of proposed actions in Segment 2 to ensure that no 

active owl nest sites could be affected. Additionally, older trees and snags would be retained for 

spotted owl habitat where possible. In summary, proposed actions related to managing visitor use and 

facilities in Segment 2 would have long-term, adverse effects on spotted owls as a result of 

construction-related disturbances to foraging and nesting habitat. 

Overall, the Preferred Alternative would result in long-term beneficial effects to California spotted 

owl and their habitat as a result of a substantial amount of restored high-quality habitat in Yosemite 

Valley and Wawona. 

Cumulative Effects. Projects that have an appreciable effect on intermediate to late successional 

forests with dense canopy closure are most likely to affect the California spotted owl. Regional and 

parkwide planning efforts such as the Vegetation Management Plan, General Ecological Restoration, 

2009 Fire Management Plan, Invasive Plant Management Plan Update, Fuels reductions/forest 

rehabilitation projects (U.S. Forest Service), and Tuolumne Wild and Scenic River Comprehensive 

Management Plan, could improve the size, integrity, and connectivity of suitable foraging and nesting 

habitat for the spotted owl. These actions could have long-term, beneficial effects on suitable habitat, 

depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the California spotted owl include those that 

affect forest habitats, such as the Parkwide Communication Data Network and Tioga Road 

Rehabilitation Projects. The 2009 Fire Management Plan and Fuels reductions/forest rehabilitation 

projects (U.S. Forest Service) may affect spotted owls during plan implementation. 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-91 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on California 

spotted owl. 

Pallid bat (Antrozous pallidus) 

Direct and Indirect Effects. Pallid bats occurs in a variety of habitats including oak woodlands, 

coniferous forests, riparian woodland, and meadows. This species is quite versatile in its choice of 

roosting sites and has been documented using tree hollows, rock crevices, caves, abandoned mines, 

and structures. Suitable habitat for this species occurs in all segments (Segments 1-8) within the 

Merced River corridor. 

The Preferred Alternative would restore approximately 203 acres of previously disturbed meadow, 

riparian, wetland, coniferous and broadleaf forest, and Valley oak woodland habitat, primarily in 

Segments 2, 4, and 7. Minor restoration actions would also occur in Segments 1 and 5. These 

restorative actions would have long-term, beneficial effects on the pallid bat by improving foraging 

habitat for this species. 

Under the Preferred Alternative in the Merced River Plan/DEIS, actions that would have potential 

adverse effects to the pallid bat include construction of new park facilities and infrastructure (e.g., 

campgrounds, roundabouts, pedestrian under-crossing, employee housing, and parking lots) in 

Yosemite Valley, El Portal, and Wawona. Pallid bat habitat would be affected by proposed actions to 

manage visitor use and facilities in Segment 2 at Curry Village, Yosemite Village, Housekeeping Camp, 

Yosemite Lodge, and Camp 4. Construction and reorganization activities at these locations could 

indirectly affect pallid bat due to disturbance associated with construction activities. Potential 

foraging and roosting habitat for pallid bat would be affected, including direct loss of ponderosa pine 

(34.04 acres), montane hardwood (1.73 acres), montane riparian (0.81 acres), and wet meadow 

(0.31 acres) habitat. Removal of mature trees with cavities or structures associated with the 

construction of new facilities would remove potential suitable roosting habitat for pallid bats. Heavy 

construction equipment and an increase in human presence would temporarily cause pallid bats to 

relocate or avoid the area for foraging. Pre-construction surveys for pallid bat roosting colonies would 

be conducted prior to the implementation of proposed actions in Segment 2 to ensure that no colony 

sites could be affected. Additionally, older trees and snags would be retained for pallid bat habitat 

where possible. In summary, proposed actions related to managing visitor use and facilities in 

Segment 2 would have adverse effects on pallid bats as a result of construction-related disturbances to 

foraging and roosting habitat. 

Overall, the Preferred Alternative would result in long-term beneficial impacts on the pallid bat from 

actions to restore large areas of potential bat foraging habitat in Segments 2, 4, and 7, and to protect 

bat roosting habitat (trees) within the Merced River floodplain by restricting new development. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-92 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Cumulative Effects. Projects that substantially affect riparian woodland, ponderosa pine, and mixed 

conifer habitats would likely affect the pallid bat. Regional and parkwide planning efforts such as the 

Vegetation Management Plan, General Ecological Restoration, Grazing Allotment Permit Renewals 

(U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, Fuels 

reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic Resources 

Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, and 

Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

foraging and roosting habitat for the pallid bat. These actions could have long-term, beneficial effects 

on suitable habitat, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the pallid bat include those that affect 

riparian/woodland and forest habitats, such as the Parkwide Communication Data Network and 

Tioga Road Rehabilitation Project. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on pallid bat. 

Sierra Nevada mountain beaver (Aplodontia rufa californica) 

Direct and Indirect Effects. Mountain beavers occur in moist meadows and riparian zones near 

small perennial streams and creeks within the montane zone and require abundant riparian plants for 

harvesting. Potential suitable habitat for this species occurs in segments 1 and 5 (Merced River above 

Nevada Fall and South Fork Merced River above Wawona). Proposed actions in Segments 1 and 5 are 

primarily ecological restoration actions, and thus would have negligible, direct and indirect effects on 

Sierra Nevada red fox during construction and beneficial effect following restoration. 

Cumulative Effects. Projects that substantially affect high elevation riparian woodland and meadow 

habitats would likely affect the mountain beaver. Regional and parkwide planning efforts such as the 

Vegetation Management Plan, General Ecological Restoration, Grazing Allotment Permit Renewals 

(U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, Fuels 

reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic Resources 

Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, and 

Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

foraging and breeding habitat for the mountain beaver. These actions could have long-term, beneficial 

effects on suitable habitat, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the mountain beaver include those that affect 

riparian/woodland and wet meadow habitats, such as the Parkwide Communication Data Network, 

Tioga Road Rehabilitation, and Tuolumne Meadows Water Treatment System Improvements 

Projects. 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-93 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on Sierra 

Nevada mountain beaver. 

Townsend’s big-eared bat (Corynorhinus townsendii townsendii) 

Direct and Indirect Effects. Previous mist-net surveys indicate that the Townsend’s big-eared bat 

occurred in several locations within and adjacent to the Merced River corridor, namely in Yosemite 

Valley (Mirror Lake), Wawona (near the South Fork of the Merced River), and El Portal (in a barium 

mine on U.S. Forest Service land). It requires caves, mines, or buildings for roosting and mesic habitats 

with brush or trees along habitat edges for foraging. Potential suitable habitat for this species occurs in 

Segments 2, 3, 4, 7, and 8. 

The Preferred Alternative would restore approximately 203 acres of previously disturbed meadow, 

riparian, wetland, coniferous and broadleaf forest, and Valley oak woodland habitats, primarily within 

Segments 2, 4, and 7. These restorative actions would have long-term, beneficial effects on 

Townsend’s big-eared bat by improving foraging habitat for this species. The proposed actions within 

segments 3 and 8 under the Preferred Alternative primarily involve ecological restoration or 

maintaining current types of uses. Thus, impacts to the Townsend’s big-eared bat as a result of these 

actions would be negligible, long-term, local, and beneficial. 

Under the Preferred Alternative, actions that would potentially result in adverse effects to the 

Townsend’s big-eared bat and its habitat include removal of select park facilities and construction of 

new park facilities and infrastructure (e.g., roundabouts, pedestrian under-crossing, parking lots and 

high density employee housing) in Segments 2, 4 and 7. Townsend’s big-eared bat habitat would be 

affected by proposed actions to manage visitor use and facilities in Segment 2 at Curry Village, 

Yosemite Village, Housekeeping Camp, Yosemite Lodge, and Camp 4. Construction and 

reorganization activities at these locations could indirectly affect Townsend’s big-eared bat due to 

disturbance associated with construction activities (removal, restoration, and construction of new 

facilities). Potential foraging and roosting habitat for Townsend’s big-eared bat would be affected, 

including direct loss of ponderosa pine (34.04 acres), montane hardwood (1.73 acres), montane 

riparian (0.81 acres), and wet meadow (0.31 acres) habitat. Removal of mature trees with cavities or 

structures associated with the construction of new facilities would remove potential suitable roosting 

habitat for Townsend’s big-eared bats. Heavy construction equipment and an increase in human 

presence would temporarily cause bats to relocate or avoid the area for foraging. Pre-construction 

surveys for Townsend’s big-eared bat roosting colonies would be conducted prior to the 

implementation of proposed actions in Segment 2 to ensure that no colony sites could be affected. 

Additionally, older trees and snags would be retained for Townsend’s big-eared bat habitat where 

possible. In summary, proposed actions related to managing visitor use and facilities in Segment 2 

would have adverse effects on Townsend’s big-eared bats as a result of construction-related 

disturbances to foraging and roosting habitat. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-94 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Overall, the Preferred Alternative would result in long-term beneficial impacts on Townsend’s bigeared bat from actions to restore large areas of potential bat foraging habitat in Segments 2, 4, and 7, 

and to protect bat roosting habitat (trees) within the Merced River floodplain by restricting new 

development. 

Cumulative Effects. Regional and park-wide planning efforts such as the Vegetation Management 

Plan, General Ecological Restoration, Grazing Allotment Permit Renewals (U.S. Forest Service), 2009 

Fire Management Plan, Invasive Plant Management Plan Update, Fuels reductions/forest 

rehabilitation projects (U.S. Forest Service) could provide benefits to the Townsend’s big-eared bat. 

Foreseeable projects that could have adverse effects on suitable habitat for Townsend’s big-eared bats 

include the Utilities Master Plan/East Yosemite Valley Utilities Improvement Plan and Parkwide 

Communication Data Network Project. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on Townsend’s 

big-eared bat. 

Spotted Bat (Euderma maculatum) 

Direct and Indirect Effects. There is a significant population of spotted bats in Yosemite Valley that 

uses meadow and wetland habitats exclusively (as indicated by acoustic data/auditory surveys). It is 

also present in Wawona. Preferred roosting habitat include high cliff faces, likely on Half Dome and 

El Capitan. Foraging habitat is primarily meadows and forest edges, or in open coniferous woodland. 

Suitable habitat for this species occurs in segments 1, 2, 5, and 7 (Merced River above Nevada Fall, 

Yosemite Valley, South Fork Merced River above Wawona, and Wawona, respectively). 

The Preferred Alternative would restore significant amounts of meadow, wetland, coniferous and 

broadleaf forest, and riparian habitats in Segments 1, 2, 5 and 7. These restorative actions would have 

long-term, beneficial effects on the spotted bat by improving foraging habitat and enhancing habitat 

complexity for this species. 

Under the Preferred Alternative in the Merced River Plan/DEIS, actions that would have potential 

adverse effects to the spotted bat include construction of new park facilities and infrastructure (e.g., 

campgrounds, roundabouts, pedestrian under-crossing, and parking lots) primarily in Yosemite 

Valley and retaining certain services in Wawona. Spotted bat habitat would be affected by proposed 

actions to manage visitor use and facilities in Segment 2 at Curry Village, Yosemite Village, 

Housekeeping Camp, Yosemite Lodge, and Camp 4. Construction and reorganization activities at 

these locations could indirectly affect spotted bat due to disturbance associated with construction 

activities. Potential foraging habitat for spotted bat would be affected, including direct loss of 

ponderosa pine (34.04 acres), montane riparian (1.73 acres), and wet meadow (0.31 acres) habitat. 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-95 

Roosting habitat (cliffs and caves) for spotted bat would not be impacted. Heavy construction 

equipment and an increase in human presence would temporarily cause bats to avoid the area for 

foraging. In summary, proposed actions related to managing visitor use and facilities in Segment 2 

would have adverse effects on spotted bats as a result of construction-related disturbances to foraging 

and roosting habitat. 

Overall, the Preferred Alternative would result in long-term beneficial impacts on the spotted bat from 

actions to restore large areas of potential bat foraging habitat in Segments 1, 2, 5, and 7, and to protect 

bat roosting habitat (trees) within the Merced River floodplain by restricting new development. 

Cumulative Effects. Projects that substantially affect coniferous woodland and meadow habitats 

would likely affect the spotted bat. Regional and parkwide planning efforts such as the Vegetation 

Management Plan, General Ecological Restoration, Grazing Allotment Permit Renewals (U.S. Forest 

Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, Fuels 

reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic Resources 

Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, and 

Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

foraging habitat for the spotted bat. These actions could have long-term, beneficial effects on suitable 

habitat, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the spotted bat include those that affect 

coniferous woodland and wet meadow habitats, such as the Parkwide Communication Data Network, 

Tioga Road Rehabilitation, and Tuolumne Meadows Water Treatment System Improvements Projects. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on spotted bat. 

Western mastiff bat (Eumops perotis) 

Direct and Indirect Effects. There is a significant population of western mastiff bats in Yosemite 

Valley, representing the highest population of the western mastiff bat in any localities surveyed in 

California. It is also present in Wawona. It roosts in rocky cliffs and canyons and forages in a variety of 

habitats, primarily meadows and coniferous forests. Suitable foraging habitat for the greater western 

mastiff bat occurs in Segments 1, 2, 5, and 7. 

The Preferred Alternative would restore significant amounts of meadow, wetland, coniferous and 

broadleaf forest, and riparian habitats in Segments 1, 2, 5 and 7. These restorative actions would have 

long-term, beneficial effects to the western mastiff bat by improving foraging habitat and enhancing 

habitat complexity for this species. 

Under the Preferred Alternative in the Merced River Plan/DEIS, actions that would have potential 

adverse effects to the western mastiff bat include construction of new park facilities and infrastructure 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-96 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

(e.g., campgrounds, roundabouts, pedestrian under-crossing, and parking lots) primarily in Yosemite 

Valley and retaining certain services in Wawona. Western mastiff bat habitat would be affected by 

proposed actions to manage visitor use and facilities in Segment 2 at Curry Village, Yosemite Village, 

Housekeeping Camp, Yosemite Lodge, and Camp 4. Construction and reorganization activities at 

these locations could indirectly affect western mastiff bat due to disturbance associated with 

construction activities. Potential foraging and roosting habitat for western mastiff bat would be 

affected, including direct loss of ponderosa pine (34.04 acres) and montane hardwood (1.73 acres) 

habitat. Roosting habitat (rock features) for western mastiff bat would not be impacted. Heavy 

construction equipment and an increase in human presence would temporarily cause bats to avoid 

areas for foraging. In summary, proposed actions related to managing visitor use and facilities in 

Segment 2 would have adverse effects on western mastiff bats as a result of construction-related 

disturbances to foraging habitat. 

Overall, the Preferred Alternative would result in long-term beneficial impacts on the western mastiff 

bat from actions to restore large areas of potential bat foraging habitat in Segments 1, 2, 5, and 7. 

Cumulative Effects. Projects that substantially affect coniferous woodland and meadow habitats 

would likely affect the greater western mastiff bat. Regional and parkwide planning efforts such as the 

Vegetation Management Plan, General Ecological Restoration, Grazing Allotment Permit Renewals 

(U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, Fuels 

reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic Resources 

Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, and 

Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

foraging habitat for the greater western mastiff bat. These actions could have long-term, beneficial 

effects on suitable habitat, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the greater western mastiff bat include those 

that affect coniferous woodland and wet meadow habitats, such as the Parkwide Communication 

Data Network, Tioga Road Rehabilitation, and Tuolumne Meadows Water Treatment System 

Improvements Projects. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on western 

mastiff bat. 

Western Red Bat (Lasiurus blossevillii) 

Direct and Indirect Effects. Western red bats are strongly associated with riparian habitats, but they 

also occur over a wide variety of habitats including grasslands, shrublands, open woodlands and 

forests. They roost in trees and less often in shrubs often located in edge habitats adjacent to streams, 

fields, or urban areas. Potential suitable habitat for the western red bat occurs in all segments of the 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-97 

Merced River corridor, in trees, hedgerows, and forest edges. However, their occurrence is rare 

within the Sierra Nevada because the majority of western red bats are concentrated at lower 

elevations. 

The Preferred Alternative would restore approximately 203 acres of previously disturbed meadow, 

riparian, wetland, coniferous and broadleaf forest, and Valley oak woodland habitat, primarily in 

Segments 2, 4, and 7. Minor restoration actions would also occur in Segments 1 and 5. This would 

improve suitable habitat for the western red bat. Removal of campgrounds and park facilities located 

within 100 feet of the river and restoring these areas would increase the amount, integrity, and 

contiguity of habitat for the western red bat. These restorative actions would have long-term, 

beneficial effects on western red bat as foraging habitat for this species improves over time (in size, 

integrity, and continuity). 

Under the Preferred Alternative in the Merced River Plan/DEIS, actions that would have potential 

adverse effects to western red bat include construction of new park facilities and infrastructure (e.g., 

campgrounds, roundabouts, pedestrian under-crossing, employee housing, and parking lots) in 

Yosemite Valley, El Portal, and Wawona. Western red bat habitat would be affected by proposed 

actions to manage visitor use and facilities in Segment 2 at Curry Village, Yosemite Village, 

Housekeeping Camp, Yosemite Lodge, and Camp 4. Construction and reorganization activities at 

these locations could indirectly affect western red bat due to disturbance associated with construction 

activities. Potential foraging and roosting habitat for western red bat would be affected, including 

direct loss of ponderosa pine (34.04 acres) and montane riparian (0.81 acres) habitat. Removal of 

mature trees with cavities associated with the construction of new facilities would remove potential 

suitable roosting habitat for western red bats. Heavy construction equipment and an increase in 

human presence would temporarily cause western red bats to relocate or avoid the area for foraging. 

Pre-construction surveys for Western red bat active roosting sites would be conducted prior to the 

implementation of proposed actions in Segment 2 to ensure that no active roosting sites could be 

affected. Additionally, older trees and snags would be retained for western red bat habitat where 

possible. In summary, proposed actions related to managing visitor use and facilities in Segment 2 

would have adverse effects on western red bats as a result of construction-related disturbances to 

foraging and roosting habitat. 

Overall, the Preferred Alternative would result in long-term beneficial impacts on the western red bat 

from actions to restore large areas of potential bat foraging habitat, primarily in Segments 2, 4, and 7, 

and to protect bat roosting habitat (trees) within the Merced River floodplain by restricting new 

development. Cumulative Effects. Projects that substantially affect riparian woodland habitat would 

likely affect the western red bat. Regional and park-wide planning efforts such as the Vegetation 

Management Plan, General Ecological Restoration, Grazing Allotment Permit Renewals (U.S. Forest 

Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, Fuels 

reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic Resources 

Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, and 

Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

foraging and roosting habitat for the western red bat. These actions could have long-term, beneficial 

effects on suitable habitat, depending upon the extent of their implementation over time. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-98 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Projects that could have a potentially adverse effect on the western red bat include those that affect 

riparian/woodland and forest habitats, such as the Parkwide Communication Data Network and 

Tioga Road Rehabilitation Project. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on western red 

bat. 

Sierra Nevada snowshoe hare (Lepus americanus tahoensis) 

Direct and Indirect Effects. Sierra Nevada snowshoe hares are relatively scarce in Yosemite, since 

this area is apparently at the southern extreme of their range. It occurs in boreal riparian habitats, 

within thickets of deciduous trees in riparian and conifer forests. Segments 1 and 5 (Merced River 

above Nevada Fall and South Fork Merced River, respectively) provide suitable habitat for the Sierra 

Nevada snowshoe hare at high elevations. 

The Preferred Alternative would restore meadows and wetlands within Segments 1 and 5, which 

would result in no adverse or beneficial effects to the Sierra Nevada snowshoe hare as these activities 

are conducted outside of the preferred foraging and breeding habitat. However, meadow habitats are 

ecologically linked to adjacent habitats, such as riparian woodland, a suitable habitat for the snowshoe 

hare. Restoration activities to enhance meadow habitat and improve habitat connectivity would 

enhance foraging habitat for the snowshoe hare and other wildlife in general. 

Overall, effect of the Preferred Alternative on Sierra Nevada snowshoe hare is expected to be 

negligible, long-term, local and beneficial. 

Cumulative Effects. Projects that have an appreciable effect on high-elevation riparian woodland and 

coniferous forests are most likely to affect the Sierra Nevada snowshoe hare. Regional and park-wide 

planning efforts such as the Vegetation Management Plan, General Ecological Restoration, Grazing 

Allotment Permit Renewals (U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant 

Management Plan Update, Fuels reductions/forest rehabilitation projects (U.S. Forest Service), High 

Elevation Aquatic Resources Management Plan, Tuolumne Wild and Scenic River Comprehensive 

Management Plan, and Tuolumne Meadows Concept Plan could improve the size, integrity, and 

connectivity of suitable habitat for the snowshoe hare. These actions could have long-term, beneficial 

effects on suitable habitat, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the snowshoe hare include those that affect 

riparian and coniferous forest habitats, such as the Parkwide Communication Data Network, Tioga 

Road Rehabilitation, and Tuolumne Meadows Water Treatment System Improvements. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-99 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on Sierra 

Nevada snowshoe hare. 

Western white-tailed jackrabbit (Lepus townsendii townsendii) 

Direct and Indirect Effects. Although habitats for the western white-tailed jackrabbit are relatively 

intact in Yosemite, reported observations of white-tailed jackrabbits are rare. Important foraging 

habitat for this species includes open alpine and mountain meadows, and open stands of trees with 

some brush and an herbaceous understory. Segments 1 and 5 (Merced River above Nevada Fall and 

South Fork Merced River above Wawona) likely provide suitable habitat for the western white-tailed 

jackrabbit. 

The Preferred Alternative would restore meadows and wetlands within Segments 1 and 5 and would 

result in negligible adverse effects to the white-tailed jackrabbit during restoration. Overgrazing by 

livestock has been identified as a principal factor in the decline of jackrabbits. Meadow restoration, 

cessation of pack stock grazing, and re-routing trails outside of sensitive meadow habitat would result 

in long-term beneficial impacts to the jackrabbit as foraging habitat within meadows would improve 

over time. 

Cumulative Effects. Projects that have an appreciable effect on mid-elevation forest and meadow 

habitats are most likely to affect the white-tailed jackrabbit. Regional and park-wide planning efforts 

such as the Vegetation Management Plan, General Ecological Restoration, Grazing Allotment Permit 

Renewals (U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, 

Fuels reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic 

Resources Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, 

and Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

foraging habitat for the jackrabbit. These actions could have long-term, beneficial effects on suitable 

habitat, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the jackrabbit include those that affect forest 

and meadow habitats, such as the Parkwide Communication Data Network, Tioga Road 

Rehabilitation, and Tuolumne Meadows Water Treatment System Improvements. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on western 

white-tailed jackrabbit. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-100 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Mount Lyell shrew (Sorex lyellii) 

Direct and Indirect Effects. The Mount Lyell shrew occurs in wetland and riparian communities and 

moist habitats near streams, in grass, or under willows. Its limited distribution makes it vulnerable to 

extirpation. Suitable habitat occurs in wetland communities within segments 1 and 5 (Merced River 

above Nevada Fall and South Fork Merced River above Wawona, respectively). 

The Preferred Alternative would restore meadows and wetlands within Segments 1 and 5 and would 

result in negligible adverse effects to the Mount Lyell shrew during restoration. However, meadow 

restoration, cessation of pack stock grazing, and re-routing trails outside of sensitive meadow habitat 

would result in long-term beneficial impacts to the Mount Lyell shrew as foraging habitat within 

meadows and wetlands would improve over time. 

Cumulative Effects. Projects that have an appreciable effect on high-elevation riparian and meadow 

habitats are most likely to affect the Mount Lyell shrew. Regional and park-wide planning efforts such 

as the Vegetation Management Plan, General Ecological Restoration, Grazing Allotment Permit 

Renewals (U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, 

Fuels reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic 

Resources Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, 

and Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

habitat for the shrew. These actions could have long-term, beneficial effects on suitable habitat, 

depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the Mount Lyell shrew include those that 

affect riparian, wetland, and meadow habitats, such as the Parkwide Communication Data Network, 

Tioga Road Rehabilitation, and Tuolumne Meadows Water Treatment System Improvements. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably foreseeable 

future actions throughout the Sierra Nevada and larger region, (e.g., introduction and spread of 

nonnative species, direct displacement of habitat) the actions under Alternative 5 would have a minimal 

beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, cumulative actions on 

special status species would result in long-term, adverse effects on Mount Lyell shrew. 

American Badger (Taxidea taxus) 

Direct and Indirect Effects. The American badger occurs in drier open stages of most shrub, forest, 

and herbaceous habitats, with friable soils. Suitable habitat for the badger occurs in Wawona 

(Segment 7). 

The Preferred Alternative would restore approximately two acres of riparian habitat in Segment 7. 

These restorative actions would have long-term, beneficial effects on the badger by improving 

foraging habitat for this species. 

Cumulative Effects. Projects that have significant effects on shrub, forest, and other herbaceous 

habitats are most likely to affect the American badger. Regional and park-wide planning efforts such 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-101 

as the Vegetation Management Plan, General Ecological Restoration, Grazing Allotment Permit 

Renewals (U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, 

Fuels reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic 

Resources Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, 

and Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

habitat for the American badger. These actions could have long-term, beneficial effects on suitable 

habitat, depending upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the American badger include those that affect 

forest and shrub habitats, such as the Park-wide Communication Data Network, Tioga Road 

Rehabilitation, and 2009 Fire Management Plan and Fuels reductions/forest rehabilitation projects 

(U.S. Forest Service). 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on American 

badger. 

Western pond turtle (Emys marmorata) 

Direct and Indirect Effects. The western pond turtle requires permanent ponds, rivers, streams, and 

irrigation ditches that typically have rocky or muddy bottoms and are overgrown with vegetation. 

Basking areas are required by this species and include partially submerged logs, rocks, mats of 

vegetation, or open mud banks. Park records show sightings of the western pond turtle in Yosemite 

Valley and El Portal. Suitable habitat for this species occurs in Yosemite Valley, El Portal, and 

Wawona (Segments 2, 4, and 7, respectively). However, this species is believed to be extirpated from 

the Merced River corridor in Yosemite National Park. 

Overall, the Preferred Alternative in the Merced River Plan/DEIS would have a beneficial impact to the 

western pond turtle from actions to restore large areas of meadow and riparian habitats in Segments 2, 

4, and 7, and to further protect riparian and meadow habitat within the Merced River floodplain by 

restricting new development. These habitats form direct ecological linkages to suitable western turtle 

habitat (ponds, rivers, streams, and ditches); thus, actions to restore meadow and riparian habitats 

would result in beneficial, long-term effects to the western pond turtle. 

Cumulative Effects. Projects that substantially affect riparian woodland, meadow, and other aquatic 

habitats would likely affect the western pond turtle. Regional and parkwide planning efforts such as 

the Vegetation Management Plan, General Ecological Restoration, High Elevation Aquatic Resources 

Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, and 

Tuolumne Meadows Concept Plan could improve the integrity and connectivity of suitable foraging 

and basking habitat for the western pond turtle. These actions could have long-term, beneficial effects 

on suitable habitat, depending upon the extent of their implementation over time. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-102 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Projects that could have a potentially adverse effect on the western pond turtle include those that 

affect riparian, wet meadow, and aquatic habitats, such as the Parkwide Communication Data 

Network, Tioga Road Rehabilitation, and Tuolumne Meadows Water Treatment System 

Improvements Projects. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on western 

pond-turtle. 

Mount Lyell salamander (Hydromantes platycephalus) 

Direct and Indirect Effects. Mount Lyell salamander occurs in wet habitats above 4,000 feet. It 

requires rock fissures or similar crevices for shelter, seeps from streams or melting snow, shade, and 

low-growing vegetation. Records indicate this species occur in Yosemite Valley in the vicinity of 

Vernal Fall and Curry Village, at the top of Vernal Fall, near the top of Half Dome, and various parts 

of Lyell Canyon. Suitable habitat for the Mount Lyell salamander occurs in Segments 1, 2, and 5. 

The Preferred Alternative would restore significant amounts of meadow, wetland, and riparian 

habitats throughout Yosemite Valley. Minor meadow and wetland restoration actions would also 

occur in Segments 1 and 5. These restorative actions may result in negligible, direct and indirect 

effects on o the Mount Lyell salamander during restoration; however, in the long-term, these actions 

would result in beneficial effects to the salamander by improving foraging and breeding habitat for 

this species. 

Under the Preferred Alternative in the Merced River Plan/DEIS, actions that would have potential 

adverse effects to the Mount Lyell salamander include construction of new park facilities and 

infrastructure (e.g., campgrounds, roundabouts, pedestrian under-crossing, and parking lots) in 

Yosemite Valley. These actions would have negligible adverse impacts because of the limited amount 

of habitat impacted, the existing human disturbance in the area, and the large area of suitable, 

unaffected habitat that would continue to exist in surrounding areas. Additionally, proposed new 

campgrounds and park facilities would be constructed outside wetlands, meadows, and riparian 

woodland habitat. 

Overall, the Preferred Alternative in the Merced River Plan/DEIS would have a beneficial impact to the 

Mount Lyell salamander from actions to restore large areas of suitable foraging and breeding habitat, 

and to further protect meadow, wetland, and riparian habitats within the Merced River floodplain by 

restricting new development. 

Cumulative Effects. Projects that substantially affect rocky slopes, seeps adjacent to streams, meadow 

and wetland habitats would likely affect the Mount Lyell salamander. Regional and parkwide planning 

efforts such as the Vegetation Management Plan, General Ecological Restoration, 2009 Fire 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-103 

Management Plan, Invasive Plant Management Plan Update, Fuels reductions/forest rehabilitation 

projects (U.S. Forest Service), High Elevation Aquatic Resources Management Plan, Tuolumne Wild 

and Scenic River Comprehensive Management Plan, and Tuolumne Meadows Concept Plan could 

improve the size, integrity, and connectivity of suitable foraging and breeding habitat for the 

salamander. These actions could have long-term, beneficial effects on suitable habitat, depending 

upon the extent of their implementation over time. 

Projects that could have a potentially adverse effect on the Mount Lyell salamander include those that 

affect rocky areas, seeps, talus slopes, and granitic areas adjacent to streams and waterfalls such as the 

Parkwide Communication Data Network and Tioga Road Rehabilitation Projects. However, due to 

the specialized habitat needs of this species, most projects would likely not affect the species. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on Mount Lyell 

salamander. 

Foothill yellow-legged frog (Rana boyllii) 

Direct and Indirect Effects. The few remaining populations of foothill yellow-legged frogs live in or 

near permanent freshwater rocky streams and rivers in a variety of habitats, including valley-foothill 

hardwood and conifer, chaparral, and wet meadow types. Recent surveys found no foothill yellowlegged frogs in Yosemite National Park (Fellers and Freel 1995; Fellers 1997) However, potential 

suitable habitat for this species occurs in Segments 2, 3, 4, 6, 7, and 8. This species is believed to be 

extirpated from the Merced River corridor in Yosemite National Park. 

Overall, the Preferred Alternative in the Merced River Plan/DEIS would have a beneficial impact to the 

foothill yellow-legged frog from actions to restore large areas of suitable foraging and breeding habitat 

in Segments 2, 4, and 7, and to further protect riparian and meadow habitat within the Merced River 

floodplain by restricting new development. 

Cumulative Effects. Projects that substantially affect riparian woodland and meadow habitats would 

likely affect the foothill yellow-legged frog. Regional and parkwide planning efforts such as the 

Vegetation Management Plan, General Ecological Restoration, Grazing Allotment Permit Renewals 

(U.S. Forest Service), 2009 Fire Management Plan, Invasive Plant Management Plan Update, Fuels 

reductions/forest rehabilitation projects (U.S. Forest Service), High Elevation Aquatic Resources 

Management Plan, Tuolumne Wild and Scenic River Comprehensive Management Plan, and 

Tuolumne Meadows Concept Plan could improve the size, integrity, and connectivity of suitable 

foraging and breeding habitat for the foothill yellow-legged frog. These actions could have long-term, 

beneficial effects on suitable habitat, depending upon the extent of their implementation over time. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-104 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Projects that could have a potentially adverse effect on the foothill yellow-legged frog include those 

that affect riparian/woodland and wet meadow habitats, such as the Parkwide Communication Data 

Network, Tioga Road Rehabilitation, and Tuolumne Meadows Water Treatment System 

Improvements Projects. 

The actions under the Preferred Alternative would have long-term, beneficial effects on special-status 

species in the Merced River corridor. However, in relation to past, present, and reasonably 

foreseeable future actions throughout the Sierra Nevada and larger region, (e.g., introduction and 

spread of nonnative species, direct displacement of habitat) the actions under Alternative 5 would 

have a minimal beneficial effect. Overall, in conjunction with actions proposed in Alternative 5, 

cumulative actions on special status species would result in long-term, adverse effects on foothill 

yellow-legged frog. 

Park Rare Species 

Plants 

Segment 1: Merced River Above Nevada Fall 

There are ten park rare plant species that are potentially found in Segment 1: California bolandra 

(Bolandra californica), Mono Hot Springs evening primrose (Camissonia sierrae ssp. alticola), cleft sedge 

(Carex fissuricola), Yosemite sedge (Carex sartwelliana), Bolander’s woodreed (Cinna bolanderi), 

common mare’s tail (Hippuris vulgaris), redray alpinegold (Hulsea heterochroma), western quillwort 

(Isoetes occidentalis), Coleman’s piperia (Piperia colemanii), and Oregon saxifrage (Saxifraga oregona). 

Special status plants may be adversely affected in the short term by construction/removal, restoration, 

and monitoring activities associated with management actions proposed in the Preferred Alternative 

in Segment 1. Proposed actions in the near-term at the Merced Lake High Sierra Camp in Segment 1 

would retain the Merced Lake High Sierra Camp, reduce the camp capacity, and replace flush toilets 

with composting toilets. Potential adverse impacts include temporary disturbance and loss of habitat, 

potential loss of individual plants or populations, and the potential introduction and spread of 

invasive nonnative species. Adhering to proposed mitigation measures presented in Appendix I and 

avoiding the removal of vegetation, where possible, would minimize these short-term impacts. 

Overall, the Preferred Alternative would result in long-term, beneficial impacts on special status plants 

in Segment 1 by reducing stresses from visitor use. 

Segment 2: Yosemite Valley 

There are 26 park rare plant species that are potentially found in Yosemite Valley: Lemmon’s wild 

ginger (Asarum lemmonii), threadleaf beakseed (Bulbostylis capillaris), Sierra suncup (Camissonia 

sierrae ssp. sierrae), Buxbaum’s sedge (Carex buxbaumii), Yosemite sedge (Carex sartwelliana), shortbracted bird’s beak (Cordylanthus rigidus ssp. brevibracteatus), stream orchid (Epipactis gigantea), 

purple fawnlily (Erythronium purpurascens), northern mannagrass (Glyceria borealis), redray 

alpinegold (Hulsea heterochroma), Sierra laurel (Leucothoe davisiae), false pimpernel (Linderia dubia 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-105 

var. anagallidea), tanoak (Lithocarpus densiflorus var. echinoides), small flowered monkeyflower 

(Mimulus inconspicuus), cutleaf monkeyflower (Mimulus lacinatus), yellowlip pansy monkeyflower 

(Mimulus pulchellus), California bog asphodel (Narthecium californicum), azure penstemon 

(Penstemon azureus ssp. angustissimus), Purdy’s foothill penstemon (Penstemon heterophyllus var. 

purdyi), tansy leafed phacelia (Phacelia tanacetifolia), Torrey’s popcornflower (Plagiobothrys torreyi 

var. torreyi), Nutall’s pondweed (Potamogeton epihydrus ssp. nuttallii), wood saxifrage (Saxifraga 

mertensiana), Oregon saxifrage (Saxifraga oregona), small bur reed (Sparganium natans), and 

narrowpetal wakerobin (Trillium angustipetalum). 

The Preferred Alternative would restore significant amounts of meadow, wetland, coniferous and 

broadleaf forest, and riparian habitats in Segment 2. Restoration of these habitats would have a beneficial 

impact on park rare plant species that occur in those communities. Special status plants may be adversely 

affected in the short term by construction/removal, restoration, and monitoring activities associated 

with management actions proposed in the Preferred Alternative in Segment 2. Potential adverse impacts 

include temporary disturbance and loss of habitat, potential loss of individual plants or populations, and 

the potential introduction and spread of invasive nonnative species. Adhering to proposed mitigation 

measures presented in Appendix I and avoiding the removal of vegetation, where possible, would 

minimize these short-term impacts. Proposed actions to manage visitor use and facilities in Segment 2 

would occur at Curry Village, Yosemite Village, Housekeeping Camp, Yosemite Lodge, and Camp 4. It is 

unlikely that any park rare plant species occur in these areas due to the high levels of visitation and 

human-related impacts such as vegetation trampling and soil compaction. In addition, no park rare 

plants were found during rare plant surveys conducted in 2010 in the areas listed above. Therefore, it is 

unlikely that park rare plant species will be affected by actions to manage visitor use and facilities in the 

Curry Village, Yosemite Village, Housekeeping Camp, Yosemite Lodge, and Camp 4 areas. 

Vegetation removed under the Preferred Alternative would not substantially fragment existing native 

vegetation communities, reduce species diversity, or substantially reduce the overall size or quality of 

native plant communities in Segment 2 because new construction would primarily occur in or adjacent 

to previously disturbed locations or in more resilient, upland habitat. Special status plant species would 

be avoided during construction activities. Adhering to proposed mitigation measures presented in 

Appendix I and avoiding the removal of vegetation, where possible, would minimize short-term impacts. 

Non-native plant species would continue to invade undeveloped areas in Yosemite Valley. New 

construction can promote non-native species because it creates conditions, such as disturbed soil, that 

are favored by many non-native plants. An increase in non-native plants could result in habitat loss and a 

competition for resources (i.e., light, water, and nutrients) for the rare plants in Segment 2. 

Overall, the Preferred Alternative would result in long-term beneficial impacts on special status plants 

in Segment 2. 

Segments 3 and 4: Merced Gorge and El Portal 

There are eight park rare plant species that are potentially found in the Merced Gorge and El Portal: 

Thompkins’ sedge (Carex tompkinsii), narrowleaf collinsia (Collinsia linearis), mountain lady’s slipper 

(Cypripedium montanum), tanoak (Lithocarpus densiflorus var. echinoides), northern bugleweed 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-106 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

(Lycopus uniflorus), small flowered monkeyflower (Mimulus inconspicuus), valley oak (Quercus 

lobata), and Sierra bladdernut (Staphylea bolanderi). 

The Preferred Alternative would restore nine acres of riparian and valley oak woodland habitats in 

Segment 4. Restoration of these habitats would have a beneficial impact on park rare plant species that 

occur in those communities. Special status plants may be adversely affected in the short term by 

construction/removal, restoration, and monitoring activities associated with management actions 

proposed in the Preferred Alternative in Segment 4. Potential adverse impacts include temporary 

disturbance and loss of habitat, potential loss of individual plants or populations, and the potential 

introduction and spread of invasive nonnative species. Adhering to proposed mitigation measures 

presented in Appendix I and avoiding the removal of vegetation, where possible, would minimize 

these short-term impacts. 

Vegetation removed under the Preferred Alternative would not substantially fragment existing native 

vegetation communities, reduce species diversity, or substantially reduce the overall size or quality of 

native plant communities in Segment 4 because new construction would primarily occur in or 

adjacent to previously disturbed locations or in more resilient, upland habitat. Special status plant 

species would be avoided during construction activities. Adhering to proposed mitigation measures 

presented in Appendix I and avoiding the removal of vegetation, where possible, would minimize 

short-term impacts. There could be indirect effects on these species as a result of the increased human 

population in El Portal, which could promote additional foot traffic and possible trampling of these 

species. Non-native plant species would continue to invade undeveloped areas in El Portal. New 

construction can promote non-native species because it creates conditions, such as disturbed soil, that 

are favored by many non-native plants. An increase in non-native plants could result in habitat loss 

and a competition for resources (i.e., light, water, and nutrients) for the rare plants in El Portal. 

Currently, vehicles park under the dripline of the 38 valley oak trees that are designated as a biological 

ORV. This practice compacts soil under the trees and impacts root health, water uptake, and soil 

aeration. Additionally, existing development and trampling in the vicinity of these trees limits the area 

where oak seedlings can be recruited. Under the Preferred Alternative, oak protection areas would be 

designated in the Odgers’ fuel transfer center as well as the adjacent parking lots. Parking within 

10 feet of the base of oak trees and parking and new building construction within the oak protection 

area would be prohibited. Nonnative fill would be removed and soils decompacted. Appropriate 

native understory plant species would be planted. Overall, these actions would result in long-term 

beneficial impacts on valley oaks in Segments 4. 

Overall, the Preferred Alternative would result in long-term beneficial impacts on special status plants 

in Segments 3 and 4. 

Segments 5-8: South Fork Merced River 

There are 18 park rare plant species that are potentially found in the South Fork Merced River corridor: 

spurred snapdragon (Antirrhinum leptaleum), Lemmon’s wild ginger (Asarum lemmonii), silvery sedge 

(Carex canescens), Yosemite sedge (Carex sartwelliana), Bolander’s woodreed (Cinna bolanderi), 

narrowleaf collinsia (Collinsia linearis), mountain lady’s slipper (Cypripedium montanum), California 

sunflower (Helianthus californicus), yellow and white monkeyflower (Mimulus bicolor), small flowered 
V. Environmental Effects 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-107 

monkeyflower (Mimulus inconspicuus), Sierra sweet-bay (Myrica hartwegii), Sierra skullcap (Scutellaria 

bolanderi ssp. bolanderi),Clark’s ragwort (Senecio clarkianus), small bur reed (Sparganium natans), Sierra 

bladdernut (Staphylea bolanderi), narrowpetal wakerobin (Trillium angustipetalum), California red 

huckleberry (Vaccinum parvifolium), and Hall’s mule ears (Wyethia elata). 

Proposed facilities actions in the near-term in the Wawona Campground area would involve removal 

of 13 sites that are either within the 100-year floodplain or in culturally sensitive areas. The Preferred 

Alternative would restore two acres of riparian habitat in Segment 7. Restoration of this habitat would 

have a beneficial impact on park rare plant species that occur in riparian areas. Special status plants 

may be adversely affected in the short term by construction/removal, restoration, and monitoring 

activities associated with management actions proposed in the Preferred Alternative in Segment 7. 

Potential adverse impacts include temporary disturbance and loss of habitat, potential loss of 

individual plants or populations, and the potential introduction and spread of invasive nonnative 

species. Adhering to proposed mitigation measures presented in Appendix I and avoiding the removal 

of vegetation, where possible, would minimize these short-term impacts. 

Vegetation removed under the Preferred Alternative would not substantially fragment existing native 

vegetation communities, reduce species diversity, or substantially reduce the overall size or quality of 

native plant communities in Segment 7 because new construction would primarily occur in or adjacent 

to previously disturbed locations or in more resilient, upland habitat. Special status plant species would 

be avoided during construction activities. Adhering to proposed mitigation measures presented in 

Appendix I and avoiding the removal of vegetation, where possible, would minimize short-term impacts. 

New construction can promote non-native species because it creates conditions, such as disturbed soil, 

that are favored by many non-native plants. An increase in non-native plants could result in habitat loss 

and a competition for resources (i.e., light, water, and nutrients) for the rare plants in Wawona. 

Overall, the Preferred Alternative would result in long-term beneficial impacts on special status plants 

in Segments 5 through 8. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-108 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

CHAPTER VI. DETERMINATION OF EFFECTS ON FEDERALLY LISTED OR 

CANDIDATE SPECIES 

The impact on listed or candidate species are analyzed in accordance with USFWS guidelines. Federal 

agencies must consult with the Fish and Wildlife Service to ensure their actions would not jeopardize 

the continued existence of any federally listed or proposed threatened or endangered species, or 

adversely modify designated or proposed critical habitat (Endangered Species Act, section 7(a)(2)). If 

listed species or their critical habitat are present, the federal agency must determine if the action would 

have “no effect,” “may effect, not likely to adversely affect,” or “may effect, likely to adversely affect” 

those species or their habitat. The National Park Service makes the determination of effect for the 

alternatives following guidance outlined in the Endangered Species Act Consultation Handbook:

Procedures for Conducting Section 7 Consultations and Conference Activities (USFWS and NMFS 1998). 

The following guidance is used to determine impacts whether the species is protected under the 

Endangered Species Act, listed or identified as sensitive by the state, or identified as sensitive by the 

park, another federal agency (e.g., BLM or USFS) or a local agency. 

This determination of effects is based solely on the Preferred Alternative in the Draft Merced River 

Plan as described in Chapter III of this document, and does not assume any potential mitigation 

measures. Mitigation measures are recommended in Chapter VII. The following criteria were used to 

develop determinations: 

 No Effect – The project (or action) is located outside suitable habitat and there would be no 

disturbance or other direct or indirect impacts on the species. The action would not affect the 

listed species or its designated critical habitat. 

 May Affect, Not Likely to Adversely Affect – The project (or action) occurs in suitable habitat 

or results in indirect impacts on the species, but the effect on the species is likely to be 

beneficial, discountable, or insignificant. The action may pose effects on listed species or 

designated critical habitat but given circumstances or mitigation conditions, the effects may be 

discounted, insignificant, or completely beneficial. 

a. Beneficial effects – contemporaneous positive effects without any adverse effects. 

b. Insignificant effects – relate to the size of the impact and should never reach the scale 

where take would occur. 

c. Discountable effects – those that are extremely unlikely to occur. Based on best 

judgment, a person would not (1) be able to meaningfully measure, detect, or evaluate 

insignificant effects or (2) expect discountable effects to occur. 

 May Affect, Likely to Adversely Affect – The project (or action) would have an adverse effect 

on a listed species as a result of direct, indirect, interrelated, or interdependent actions, and 

the effect is not discountable, insignificant, or beneficial.
VI. Determination of Effects on 

Federally Listed or candidate Species 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-109 

Determinations for Federally Listed Threatened or Endangered Species 

Sierra Nevada bighorn sheep (Ovis canadensis sierrae)

It is the determination of the National Park Service that actions that are proposed in the Merced River 

Plan/DEIS will have no effect on the Sierra Nevada bighorn sheep. The following conclusions have led 

to this determination: 

 There would be no direct or indirect effects on the Sierra Nevada bighorn sheep or its 

preferred habitat.

Valley elderberry longhorn beetle (Desmocerus californicus)

It is the determination of the National Park Service that the actions proposed in the Merced River 

Plan/DEIS may affect, and are likely to adversely affect, the Valley elderberry longhorn beetle. The 

following conclusions have led to this determination: 

 Elderberry plants grow within the project area. Based on the foregoing analysis, there is a 

likelihood that “take,” as defined in the Endangered Species Act, may occur. 

Elderberry plants, the sole foodplant and habitat for the Valley elderberry longhorn beetle, are 

abundant in the Merced River canyon in the elevation range of the beetle, especially in the El Portal 

area. Elderberry plants would be avoided during construction wherever practicable. 

Determinations for Federal Candidate Species 

Whitebark pine (Pinus albicaulis)

It is the determination of the National Park Service that actions that are proposed in the Merced River 

Plan/DEIS will have no effect on the whitebark pine. The following conclusions have led to this 

determination: 

 There would be no direct or indirect effects on the whitebark pine or its habitat.

Yosemite toad (Anaxyrus canorus)

It is the determination of the National Park Service that actions that are proposed in the Merced River 

Plan/DEIS may affect, but are not likely to adversely affect, the Yosemite toad. The following 

conclusions have led to this determination: 

 Yosemite toads utilize higher elevation wet meadows, small ponds, and flooded shallow grassy 

areas in Segments 1 and 5.

 Actions proposed in Segments 1 and 5 are generally habitat restoration projects that would 

ultimately benefit Yosemite toad.
APPENDIX N. BIOLOGICAL ASSESSMENT

N-110 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Sierra Nevada yellow-legged frog (Anaxyrus canorus)

It is the determination of the National Park Service that actions that are proposed in the Merced River 

Plan/DEIS may affect, but are not likely to adversely affect, the Sierra Nevada yellow-legged frog. The 

following conclusions have led to this determination: 

 Sierra Nevada yellow-legged frogs utilize aquatic habitats in Segments 1 and 5.

 Actions proposed in Segments 1 and 5 are generally habitat restoration projects that would 

ultimately benefit Sierra Nevada yellow-legged frog.

California wolverine (Gulo gulo)

It is the determination of the National Park Service that actions that are proposed in the Merced River 

Plan/DEIS may affect, but are not likely to adversely affect, the California wolverine. The following 

conclusions have led to this determination: 

 California wolverines have not been verified in Yosemite National Park since 1915; 

unconfirmed sightings have been reported in 1959 and 1990. However, California wolverine 

could utilize a variety of habitats in Segments 1 and 5, including wet meadows. 

 Actions proposed in Segments 1 and 5 are generally habitat restoration projects that would 

ultimately benefit California wolverine.

Pacific fisher (Martes pennant pacifica)

It is the determination of the National Park Service that actions that are proposed in the Merced River 

Plan/DEIS may affect, but are not likely to adversely affect, the Pacific fisher. The following 

conclusions have led to this determination: 

 Pacific fisher may utilize coniferous forests in Segments 1, 2, 5, and 7. 

 Actions proposed in Segments 1 and 5 are generally habitat restoration projects that would 

ultimately benefit Pacific fisher.

 Although suitable foraging habitat for this species would be impacted by proposed actions in 

Segments 2 and 7, this species is sensitive to human presence and is not likely to utilize habitats 

in these areas.
VII. References 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS N-111 

CHAPTER VII. REFERENCES 

Acree, Lisa Nemzer 

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Altman, B. 

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Altman, B., and Sallabanks, R. 

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American Ornithologists’ Union (AOU) 

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Bailey, V. 

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Beedy, E. C. 

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Bull, E. L., and C. T. Collins 

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Chambers, C. L., and M. J. Herder 

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Chow, Leslie Stephen 

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Collopy, M. W. and K. L. Bildstein 

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marshes. Auk 104:11‐16. 
APPENDIX N. BIOLOGICAL ASSESSMENT

N-114 Merced Wild and Scenic River Comprehensive Management Plan /DEIS

Constantine, D. G. 

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Cryan, P. M., M. A. Bogan, and J. S. Altenbach 

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VII. References 

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Greene, C. 

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Hall, E. R. 

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