Ecoregions of Alaska

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1567

Prepared in cooperation with Colorado State University 

and the Environmental Protection Agency

&i^^

•n. *
Ecoregions of Alaska

By Alisa L. Gallant, Emily F. Binnian, James M. Omernik, and Mark B. Shasby

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1567

Prepared in cooperation with 

Colorado State University and the 

Environmental Protection Agency

A spatial analysis of regional 

ecological patterns in Alaska 

using analog and digital maps 

and descriptive information

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1995
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY 

Gordon P. Eaton, Director

For sale by U.S. Geological Survey, Information Services

Box 25286, Federal Center

Denver, CO 80225

Any use of trade, product, or firm names in this publication is for descriptive purposes only and 

does not imply endorsement by the U.S. Government
CONTENTS

Abstract......................................................................................................................... 1

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

Background................................................................................................................... 1

Methods......................................................................................................................... 3

Materials........................................................................................................................ 5

Ecoregion Descriptions................................................................................................. 7

Arctic Coastal Plain................................................................................................ 8

Arctic Foothills....................................................................................................... 11

Brooks Range.......................................................................................................... 15

Interior Forested Lowlands and Uplands................................................................ 17

Interior Highlands................................................................................................... 20

Interior Bottomlands............................................................................................... 23

Yukon Flats............................................................................................................. 25

Ogilvie Mountains .................................................................................................. 28

Subarctic Coastal Plains.......................................................................................... 30

Seward Peninsula.................................................................................................... 32

Ahklun and Kilbuck Mountains.............................................................................. 34

Bristol Bay-Nushagak Lowlands ........................................................................... 38

Alaska Peninsula Mountains................................................................................... 41

Aleutian Islands...................................................................................................... 43

Cook Inlet................................................................................................................ 45

Alaska Range.......................................................................................................... 48

Copper Plateau........................................................................................................ 51

Wrangell Mountains................................................................................................ 53

Pacific Coastal Mountains...................................................................................... 55

Coastal Western Hemlock-Sitka Spruce Forests.................................................... 56

Summary....................................................................................................................... 59

Acknowledgments......................................................................................................... 59

References..................................................................................................................... 60

Appendix 1.................................................................................................................... 64

Appendix 2.................................................................................................................... 70

Appendix 3.................................................................................................................... 71

PLATES

1. Ecoregions of Alaska........................................................................................................................................... In pocket

ffl
IV CONTENTS

ILLUSTRATIONS

1. Map of Alaska................................................................_ 9

2. Arctic Coastal Plain thaw lakes.................................................................................................................................... 9

3. Arctic Coastal Plain vegetation .................................................................................................................................... 10

4. Arctic Coastal Plain vegetation .................................................................................................................................... 10

5. Arctic Foothills physiography and drainage pattern..................................................................................................... 13

6. Arctic Foothills beaded stream drainage ...................................................................................................................... 13

7. Arctic Foothills vegetation............................................................................................................................................ 14

8. Brooks Range physiography......................................................................................................................................... 14

9. Brooks Range unstable slopes...................................................................................................................................... 16

10. Brooks Range vegetation.............................................................................................................................................. 16

11. Interior Forested Lowlands and Uplands forest vegetation ......................................................................................... 18

12. Interior Forested Lowlands and Uplands burned area ................................................................................................. 18

13. Interior Highlands physiography.................................................................................................................................. 22

14. Interior Bottomlands physiography, surface water, and vegetation............................................................................. 22

15. Yukon Flats physiography and surface water............................................................................................................... 25

16. Yukon Flats physiography and vegetation.................................................................................................................... 26

17. Yukon Flats vegetation ................................................................................................................................................. 26

18. Ogilvie Mountains physiography and vegetation......................................................................................................... 29

19. Subarctic Coastal Plains physiography, surface water, and vegetation........................................................................ 29

20. Subarctic Coastal Plains forest vegetation ................................................................................................................... 31

21. Seward Peninsula physiography and vegetation .......................................................................................................... 33

22. Seward Peninsula gelifluction lobes............................................................................................................................. 33

23. Seward Peninsula low scrub and dwarf scrub-graminoid communities...................................................................... 35

24. Ahklun and Kilbuck Mountains physiography............................................................................................................. 35

25. Ahklun and Kilbuck Mountains vegetation.................................................................................................................. 36

26. Ahklun and Kilbuck Mountains vegetation.................................................................................................................. 37

27. Bristol Bay-Nushagak Lowlands physiography ......................................................................................................... 37

28. Bristol Bay-Nushagak Lowlands vegetation ............................................................................................................... 40

29. Alaska Peninsula Mountains physiography, soils, and vegetation............................................................................... 40

30. Alaska Peninsula Mountains vegetation....................................................................................................................... 42

31. Aleutian Islands physiography and vegetation............................................................................................................. 42

32. Cook Inlet vegetation.................................................................................................................................................... 44

33. Cook Inlet vegetation.................................................................................................................................................... 44

34. Cook Inlet vegetation.................................................................................................................................................... 47

35. Alaska Range physiography and glaciation.................................................................................................................. 48

36. Alaska Range vegetation .............................................................................................................................................. 50

37. Alaska Range vegetation .............................................................................................................................................. 50

38. Copper Plateau surface water and vegetation............................................................................................................... 52

39. Wrangell Mountains physiography and glaciation....................................................................................................... 53

40. Wrangell Mountains glacial till.................................................................................................................................... 54

41. Pacific Coastal Mountains physiography..................................................................................................................... 55

42. Coastal Western Hemlock-Sitka Spruce Forests physiography and vegetation.......................................................... 57
ECOREGIONS OF ALASKA

By Alisa L. Gallant1 , Emily F. Binnian2 , James M. Omernik3 , and Mark B. Shasby4

ABSTRACT

A map of ecoregions of Alaska has been produced as a 

framework for organizing and interpreting environmental data 

for State, national, and international inventory, monitoring, 

and research efforts. The map and descriptions of 20 ecological regions were derived by synthesizing information on the 

geographic distribution of environmental factors such as climate, terrain (including information on physiography, geology, glaciation, permafrost, and hydrologic features), soils, and 

vegetation. A qualitative assessment was used to interpret the 

distributional patterns and relative importance of these factors 

for influencing the character of the landscape from place to 

place. The specific procedures and materials used to delineate 

the ecoregion boundaries are documented, and the environmental characteristics in each ecoregion are described. An 

accompanying map shows the distribution of the ecoregions 

and the transitional areas along their boundaries.

INTRODUCTION

A map and descriptions of ecological regions (ecoregions) of Alaska have been produced as a framework for 

organizing and interpreting environmental data for State, 

national, and international inventory, monitoring, and 

research efforts. Ecoregions have been defined by Wiken 

(1986) as ecologically distinct areas resulting from "... the 

mesh and interplay of the geologic, landform, soil, vegetative, climatic, wildlife, water and human factors which may 

be present. The dominance of any one or a number of these 

factors varies with the given ecological land unit." The map 

of Alaskan ecoregions was derived by synthesizing information on the geographic distribution of environmental factors 

such as climate, terrain (including information on physiography, geology, glaciation, permafrost, and hydrologic fea-

'Forest Sciences Department, Colorado State University, Fort Collins. 

Work performed under U.S. Geological Survey Cooperative Agreement 

#1434-93-A-00760

2Hughes STX Corporation, U.S. Geological Survey, EROS Alaska Field 

Office, Anchorage. Work performed under U.S. Geological Survey 

Contract #1434-92-C^004

Environmental Protection Agency, Environmental Research 

Laboratory, Corvallis.

4U.S. Geological Survey, EROS Alaska Field Office, Anchorage.

5The term "framework" will be used throughout this report to represent the 

ecoregion map and accompanying descriptions as a package. The descriptions 

are an important component because they allow the user to assess the characteristics that are representative of each ecoregion and the relative amounts of 

within-region environmental variability. Use of the map without the descriptions restricts the selection of representative field sites for regional analyses.

tures), soils, and vegetation. This synthesis was a qualitative 

assessment of the distributional patterns and relative importance of these factors for influencing the character of the 

landscape from place to place.

The ecoregion map has been designed to accommodate 

a wide range of regional concerns, basically any that affect, 

or are affected by, the environmental factors analyzed to 

develop the map. Examples of applications for the map 

include the assessment of natural resources (regional chemical, physical, and biological characteristics of surface 

waters, soil erosion potential, wildlife habitat diversity, and 

ecological risk assessment) and effects research (potential 

regional ecological effects from environmental contaminants 

or climate change). The map can also be used to evaluate 

how well research sites are distributed across ecoregions or 

along regional environmental gradients, and the regional 

descriptions can be used to infer the relative density of sample sites needed to represent the ecological variability occurring within each ecoregion so that site-level information can 

be extrapolated to larger areas. Given national trends toward 

more holistic monitoring and management of ecosystems, 

the ecoregion map and descriptions provide an ecological 

framework5 to help integrate efforts among different environmental disciplines and agencies.

Sections in this report describe the origin of the need and 

philosophy for delineating ecoregions of Alaska 

(Background), general procedures (Methods) and references 

(Materials) used, and environmental characteristics occurring 

in each ecoregion (Ecoregion Descriptions). The accompanying map (pi. 1) shows the distribution of Alaskan ecoregions. 

Environmental characteristics that typify each ecoregion are 

tabulated in appendix 1 and also appear on the reverse side of 

the map. Specific methods used to delineate each ecoregion 

are discussed in the descriptions of the individual regions.

BACKGROUND

Interest in developing the map of Alaskan ecoregions 

evolved from the need to have an ecological framework that 

is based on a variety of environmental characteristics of 

interest to different State, Federal, and international agencies. Single-theme frameworks have traditionally been popular because they are customized for specific concerns, such 

as forest resources, soil characteristics, or agricultural potential. However, use of different frameworks by different 

administrative agencies results in duplication of effort and 

inability to integrate and co-reference data across agencies 

and disciplines (Rubec, 1979). An ecological framework

l
ECOREGIONS OF ALASKA

that can integrate many environmental characteristics diminishes these problems and assists in the exchange of information (Bailey and others, 1985). The utility of multipurpose 

ecoregion frameworks, such as those developed for the conterminous United States (Omernik, 1987, 1995) and Canada 

(Wiken, 1986), has been successfully demonstrated in various projects (for example, Hughes and others, 1986; Rubec, 

1979; Whittier and others, 1988; Whittier and others, 1987). 

Work is under way to combine the frameworks for Canada 

and the conterminous United States into one covering all of 

North America (James Omernik and Ed Wiken, oral commun., 

1993, 1994). Delineation of Alaskan ecoregions is a step to 

furthering this work. Additionally, a growing interest in the 

effects of potential global environmental change on ecosystems, particularly on arctic systems,6 has promoted an effort to 

expand the ecoregional frameworks developed for Alaska and 

Northern Canada to all the northern circumpolar area.

The ecological frameworks developed for Alaska, the 

conterminous United States, and Canada reflect a common 

philosophy and methodology, making it possible to combine 

these frameworks across international borders. The 

approach and objectives of these frameworks differ from 

those used to develop other, multipurpose7 , regional schemes 

covering Alaska, such as the "Land Resource Regions and 

Major Land Resource Areas of the United States" (commonly referred to as MLRAs; U.S. Soil Conservation Service, 

1981), the "Major Ecosystems of Alaska" (Joint FederalState Land Use Planning Commission for Alaska, 1973), and 

the "Ecoregions and Subregions of the United States" 

(Bailey and others, 1994).

The map of MLRA's depicts two levels of classification 

hierarchy that were developed by considering a number of 

environmental characteristics similar to those used to delineate the ecoregions of Alaska. However, the main focus of 

the Soil Conservation Service in developing MLRA's was 

land management concerns; the identification of regions was 

based on their land use potential. In addition, the Soil

6This interest is evidenced in the escalating number of international 

meetings and symposia on arctic ecological concerns, such as those included in this list of recent meetings: (1) The Panarctic Biota Project (Moscow, 

Russia, February 1991), (2) the Arctic Monitoring and Assessment 

Program (Troms0, Norway, December 1991), (3) the Classification of 

Circumpolar Arctic Vegetation (Boulder, Colorado, USA, March 1992), 

(4) the Second Circumpolar Symposium on Remote Sensing (Troms0, 

Norway, May 1992), (5) Global Change and Arctic Terrestrial Ecosystems 

Conference (Oppdal, Norway, August 1993), (6) the Arctic Environmental 

Reference Database Workshop (Arendal, Norway, September 1993), (7) 

the International Symposium on the Ecological Effects of Arctic Airborne 

Contaminants (Reykjavik, Iceland, October 1993), and (8) the Third 

Circumpolar Symposium on Remote Sensing of Arctic Environments 

(Fairbanks, Alaska, USA, May 1994).

7The term "multipurpose" refers to regions that reflect general patterns 

of many ecosystem characteristics, therefore providing an ecological 

framework that should be generally useful for many environmental purposes.

8The ecoregional maps delineated for the conterminous United States 

(Omernik, 1987) and Canada (Wiken, 1986) were developed using this 

approach.

Conservation Service did not have access to several 

statewide references that have since become available. 

These references improve the data base for interpreting 

ecoregion patterns.

The map of "Major Ecosystems of Alaska" (Joint 

Federal-State Land Use Planning Commission for Alaska, 

1973) shows the distribution of nine classes of ecosystems 

within a single hierarchic level. The focus of the ecosystems 

map is on the regional distribution of vegetation community 

type and structure. Information relating to other landscape 

characteristics, such as topography, hydrology, and climate, 

is considered only so far as it influences ecosystem type. 

The resultant classes contain much variability in environmental characteristics that are not reflected in the ecosystem 

type. For example, the "Alpine Tundra" ecosystem class 

encompasses mountain formations of different geologic origin and climatic regime. Therefore, the map may not be useful for addressing concerns related to soil or surface water 

characteristics.

The map "Ecoregions and Subregions of the United 

States" (Bailey and others, 1994) depicts four hierarchic levels of terrestrial ecological units. The authors explain that, 

"At each successive level [of the hierarchy] a different 

ecosystem component is assigned prime importance in the 

placing of map boundaries." Climatic characteristics are 

used to delineate regions at the broadest level; vegetative 

features are used at the second level; the distinction between 

montane and nonmontane areas distinguishes the third level; 

and physiographic units define the finest level.

The "Ecoregions of Alaska" map depicts a single level 

of resolution (although the ecoregions are being aggregated 

to conform with the coarser level of resolution planned for 

the map of North American ecoregions that was discussed 

earlier). Unlike the method used by Bailey and others (1994) 

in defining the ecoregions for Alaska, our approach is to consider a suite of environmental characteristics, regardless of 

the level of hierarchic resolution, rather than assigning 

importance to a single environmental characteristic per level 

of classification hierarchy. 8 There are at least three reasons 

for this approach. First, the degree of influence of any one 

environmental characteristic changes from region to region, 

and even within regions (Omernik, 1987, 1995; Wiken, 

1986); that is, there is no single, consistently reliable predictor of where boundaries should be drawn for multipurpose 

regions. An example is the popular use of "climate" at global, regional, and finer scales to predict the distribution of 

ecosystems. The predictions have been disappointing in 

light of the actual distribution of ecosystems. The reason for 

this poor performance is that vegetation is also strongly 

affected by other characteristics, such as interspecific competition, factors affecting soil temperature and moisture, rate 

of seed dispersal and establishment of propagules, and land 

management practices (Barbour and others, 1987; Davis and 

others, 1986 in Prentice, 1992; Prentice, 1992;), so consideration of interrelationships among several environmental
METHODS

variables is necessary to understand distributional patterns.

Second, if emphasis is placed on a single factor at a particular hierarchic level, the resultant regions may not reflect 

the distribution of other important features that have only a 

weak association with that factor. Recall that in the example 

described for the map of "Major Ecosystems of Alaska," 

regional patterns related to soil type or surface water characteristics were not adequately recognized when the single factor of vegetation community type was emphasized for delineating the regions.

Third, the data set representing the distribution of the 

single factor includes varying degrees of informational resolution and accuracy. For example, weather stations are not 

distributed in a systematic network. The quality of interpolation of data among stations is affected by the methods of 

measurement at each station, the distance between stations, 

and the intervening orographic (or other) effects. Similar 

problems arise with soil or geology references, where continuous map surfaces have been generated from differentially distributed observations. Therefore, weaknesses in a single information source can have a heavy impact when that 

source is emphasized in delineating regions. Incorporating a 

suite of independently derived references into the delineation 

process helps to counter the influence of weak information 

from a single data source.

The multihierarchic maps so far discussed (the MLRA's 

and "Ecoregions and Subregions of the United States") primarily represent a "top down" approach toward delineating 

ecological units. Information is first analyzed to delineate 

the coarsest level of classification in a hierarchy (on the 

order of 104 km2 for our purposes). Successively more 

detailed information is then analyzed to subdivide the classes into more detailed subunits. An alternate approach is 

described by Walker and Walker (1991) in their work on 

Alaska's North Slope. Data are gathered and patterns analyzed beginning at the microscale level (10°-106 m2). A hierarchy of units is then constructed upward ("bottom up") 

through mesoscale (ICP-IO4 km2) and macroscale (lOMO6 km2) 

levels of information. The objectives of the approach taken by 

Walker and Walker (1991) were to define the types of ecological processes, questions, data, and linkages appropriate 

to different hierarchic scales of regional analysis. Such an 

approach requires a very long-term, intensive effort for mapping regions. Since our objective was to develop an ecoregion framework for the state of Alaska, a "top down" 

approach was more appropriate because it directly addressed 

the landscape scale of interest, with little dependence on 

intensive, detailed ecosystem studies. This top-down 

approach not only resulted in a product within a relatively 

short time, but also provided an overall ecological context 

for further subdivision of regions as interest and availability 

of more specific data emerge.

When ecoregions are being mapped, errors can be introduced into the process in several ways. Boundaries and 

other map components may be inaccurately located; classes

can be incorrectly assigned or may not be informationally 

discrete; the spatial or informational resolution of classes 

may be misrepresented; data may not be available for some 

areas; and data accuracy may change because of temporal 

aspects in the landscape (for example, water level changes). 

These factors pertain to the reference maps used to derive the 

ecoregion map, as well as to the process used to delineate the 

ecoregions. This makes it difficult to determine the accuracy of the map.

Other problems with determining the accuracy of an 

ecoregion map relate to field sampling logistics, 

within-region heterogeneity, and field and map differences 

in informational resolution.

Field Sampling Logistics. - Because each ecoregion has 

been defined on the basis of a number of ecological characteristics, field verification of the ecoregion map would entail 

collecting information on climate, physiography, geology, 

soils, permafrost, glaciation, hydrology, and vegetation for 

each sample site. Some of these variables are readily evaluated in the field, but others are not. The difficulty of collecting information for all of these variables at each site, plus 

the problem of site accessibility (most sites are not accessible by ground transportation, and many are not accessible by 

air), makes accuracy assessment from the field infeasible.

Within-Region Heterogeneity. - The array of combinations of environmental characteristics that could be expected 

within each ecoregion would have to be represented in the 

field verification data set. This requires a more detailed level 

of within-region analysis than that used to delineate the 

ecoregions because of the top-down approach that was used.

Field and Map Informational Resolution. - The ecoregions have been delineated at a very general level of informational resolution. It would be necessary to design the collection of field data so that the same level of generalization is represented. This is difficult because the surrounding environmental context for an ecoregion may be lost at the site level.

Because of the multipurpose nature of the ecoregion 

map, it may be inappropriate to attempt to assess its accuracy. Boundaries between regions are expected to be "generally" correct for a number of purposes, but are not expected 

to precisely fit the distribution of any singular variable. 

Therefore, there is not even a conceptual set of boundaries 

that will be perfect for all uses of the map. It is more pertinent to assess whether stratification of sample data by ecoregion helps to explain spatial variation of particular variables 

of interest (an assessment of the utility of the map).

METHODS

A number of environmental references were examined for 

this analysis, including statewide information on climate (seasonal and annual temperatures, rain, and snow), physiography 

(landsurface forms, topography, elevation, amount of local 

relief, and local surface irregularity), surficial and bedrock
ECOREGIONS OF ALASKA

geology, soils, permafrost, glaciation, hydrology, and current 

and potential vegetation. Previous work (Gallant and others, 

1989; Omernik, 1987; Oswald and Senyk, 1977; U.S. Soil 

Conservation Service, 1981; Wiken, 1979, 1986) has shown 

that these factors are of primary importance for delineating 

ecoregional patterns. The steps for mapping ecoregions have 

been described in Gallant and others (1989) and involve delineating areas where unique combinations of different environmental factors coincide. In Alaska, for example, topographic 

data and physiographic maps show several extensive flat 

coastal plain areas that coincide with areas depicted as wet tundra on a map of major ecosystems. Among these coincidental 

areas, one occurs where arctic climate prevails, while several 

occur where subarctic climate prevails. Different climatic 

regimes result in different growing season lengths, different 

hydrologic cycles, and some variation in occurrence of plant 

species. Such differences led us to distinguish the Arctic 

Coastal Plain Ecoregion from the Subarctic Coastal Plains 

Ecoregion. Another example includes the montane areas in 

Alaska. All of these areas are mapped as having steep, high, 

rugged mountains and alpine tundra ecosystems. Within these 

areas of coinciding terrain and vegetation components are 

areas subject to arctic, continental, transitional, or coastal climatic influences that affect hydrologic characteristics and plant 

species distributions. Additionally, there are different geologic 

formations and soil parent materials that affect soil chemistry 

and moisture holding capacity and the physical and chemical 

characteristics of surface waters. These variations in conditions resulted in our recognition of several different montane 

ecoregions.

We used a predominantly qualitative approach for evaluating and delineating ecoregions. It would have been 

quicker and easier to duplicate a product derived from a 

strictly quantitative approach; however, we thought that the 

product would have been less accurate in its representation 

of ecoregions. It is difficult to apply strict quantitative 

weightings to represent the importance of different environmental factors for delineating ecoregions because the importance of these factors, and the accuracy with which they are 

mapped, vary within and among ecoregions. An example 

occurs within the Yukon-Kuskokwim lowland portion of the 

Subarctic Coastal Plains Ecoregion. The importance of a 

particular vegetation type for defining the extent of the 

ecoregion varies across the region. Areas north of the Yukon 

River include both wet and moist tundra communities and 

exclude forests, while areas south of the Yukon River include 

only wet tundra because moist tundra is more indicative of 

the adjacent region to the south. A qualitative, interactive 

approach allows the human interpreter to recognize the need 

for changing the delineation criteria along the border of adjacent ecoregions. A more mechanical approach would simply 

delineate the ecoregions using prescribed factor weightings. 

The question of whether a factor's importance varied 

throughout a region would most likely be overlooked.

The decision of when to delineate an area as an ecoregion is a judgment call that depends on (1) the combination 

and pattern of environmental characteristics occurring in that 

area versus those in the surrounding areas, (2) the size of the 

area, (3) the informational resolution and accuracy of the reference material used in delineating regions, and (4) the informational resolution and scale intended for the final framework. These four aspects are further described below.

1. There is more variation in the combination of environmental characteristics within some regions than between 

others. The size and distribution of the components that 

make up a landscape pattern are important for deciding 

whether areas should be classified as separate regions or 

consolidated within a single region at a given level of regional resolution. For example, the Ahklun and Kilbuck 

Mountains Ecoregion consists of clusters of steep, jagged 

peaks separated by broad valleys. At the informational resolution depicted on our map, it is more appropriate to aggregate these mountains and valleys into a single ecoregion. 

However, the ecoregion could then be subdivided to separate 

the mountains from the valleys at a finer level of resolution.

2. There are no hard and fast rules for designating a minimum-area criterion for ecoregions. Generally, 10,000 km2 

or larger is a good size for regions of State-level frameworks 

because the area is large enough both to be distinctive on 

statewide maps of environmental variables and to be recognized as a management unit for State resources. However, in 

some circumstances this "rule" is not suitable. For instance, 

an extensive ecoregion might have many small outliers that 

are easily distinguishable on the reference materials, as in 

the Interior Highlands and the Interior Bottomlands 

Ecoregions in Alaska. The outliers, alone, are too small to 

be considered as a separate ecoregion; but in the context of 

mapping the larger, more extensive part of the ecoregion, it 

makes sense to delineate associated outliers that are still discernible at the statewide scale. Another exception to a size 

criterion arises when an ecoregion is broken up by a waterbody, as in the Aleutian Island Ecoregion. All of the individual islands may be smaller than the minimum-size criterion, but they are distinctive enough to be recognized as a 

region in the context of their grouping and their location, and 

their total area exceeds the minimum-size criterion.

3. The informational resolution and accuracy of the reference materials used for delineating ecoregions impose 

implicit limits on the level of detail that can be depicted in 

the resultant ecoregion map. It is misleading to delineate 

regions that are more detailed than the bulk of the reference 

material from which they were defined; rather, regions 

should be less detailed than the components that were used 

to define them.

4. The intended use of the final framework affects the 

size and level of detail that is delineated for the regions. A 

very general framework will have relatively large regions 

separated by smooth boundaries. Accompanying regional 

descriptions will also be fairly general, listing only the major 

characteristics that typify each region. A very refined frame-
MATERIALS

work will have small regions (or one or more levels of 

regional hierarchy) with more intricate boundaries and 

detailed descriptions of regional characteristics. The purpose for creating the framework governs the level of detail 

that should be shown on the final product.

The general procedures used to produce the map of 

ecoregions of Alaska involved an iterative cycle of steps. The 

initial delineation of ecoregions was based on analysis of 

hardcopy maps and descriptive text. Maps representing the 

environmental variables listed earlier were examined to 

locate concurrent spatial patterns of the different variables. 

Also considered were the ecological processes associated 

with these factors. An early draft map of ecoregions was prepared by outlining areas (that met the minimum size criterion) of unique combinations of factors. This initial draft map 

was used to plan an itinerary for summer field reconnaissance. The purpose of the reconnaissance was to compare 

ecosystems on the ground with the variables that represented 

them on the reference maps. Prospective ecoregions were 

visited by means of low-altitude flyovers and, where accessible, by ground. The draft map of ecoregions was then modified on the basis of field reconnaissance, and a second version was prepared and circulated to a number of regional 

experts for review. Reviewers were asked to comment, based 

on their field experience, on whether the set of ecoregions 

depicted on the map corresponded with their understanding 

and general knowledge of ecological patterns in Alaska. 

Review comments provided guidance toward modifications 

for a third draft map. This third map was circulated to the 

reviewers, and their comments were incorporated. Final 

boundary placement involved manipulating of digital files in 

a geographic information system (GIS) to reduce errors introduced by estimating the location of landscape patterns from 

the variety of scales and projections used in the reference 

maps. The GIS also was helpful for creating new maps 

derived by combining information from different reference 

maps (for example, mapping the coincidence of the distribution of major ecosystem types with different terrain features 

or with patterns on images developed from satellite data).

The final map of ecoregions was further augmented to 

show the approximate transitional zones between regions. 

The zones are depicted as cross-hatched areas overprinted on 

the ecoregions. A transitional zone represents an area that 

shares the characteristics of adjacent regions. For example, a 

transitional zone between a mountainous region and a plains 

region might consist of widely scattered mountains separated 

by broad plains. Within each ecoregion are areas that are not 

indicative of the environmental characteristics that typify the 

region. These areas are not shown as transitional zones. 

Transitional zones distinguish land that is adjacent to, and 

shares the characteristics of, two or more ecoregions. 

Because of the relatively small scales of the ecoregion map 

and the references used to develop the map, it is not possible 

to depict transitional zones along all of the ecoregion boundaries. It is important to remember that a line on the ecoregion

map already represents an area (swath) on the ground, even 

when no additional transitional zones are indicated.

When selecting names for ecoregions, we generally 

tried to include information on the location of the region, as 

well as a dominant distinguishing feature. Some examples 

of names are: (1) Arctic Coastal Plain Ecoregion, which 

confers climatic, physiographic, and location information, 

(2) Interior Forested Lowlands and Uplands Ecoregion, 

which confers information on physiography, vegetation community structure, and location, and (3) Coastal Western 

Hemlock-Sitka Spruce Forests Ecoregion, which indicates 

maritime climate, forest type, and coastal location attributes. 

Most of the mountainous regions simply bear the name of 

their respective physiographic units, because this information 

conveys both location and terrain characteristics. Regions 

encompassing a large variety of ecological characteristics, 

such as the Seward Peninsula and Cook Inlet Ecoregions, 

have names that denote only location. Attempts to make the 

names more descriptive would have made them long and 

unwieldy. We also avoided locational adjectives that are 

Alaska-centered, such as northern or southeastern, because 

eventually Alaskan regions will be included in North 

American and Northern Circumpolar regional frameworks.

MATERIALS

Statewide and regional data sets and reports were 

acquired for climate, physiography, elevation, geology and 

geomorphology, soils, permafrost, glaciation, vegetation, 

hydrology, wildfire occurrence, land use, and wildlife characteristics. These references are itemized below by topic.

Climate. - Weather station data were obtained primarily 

from two sources: (1) the World WeatherDisc (WeatherDisc 

Associates, Inc., 1990, U.S. Monthly Normals and 

Worldwide Airfield Summaries data sets), a data base containing data acquired from the archives of the National 

Climatic Data Center and the National Center for 

Atmospheric Research and (2) a six-volume set of Regional 

Profiles of Alaska (Selkregg, 1974). Climatic information 

was also compiled from regional descriptions in several publications (Black, 1955; Hopkins, 1959; Kimmins and Wein, 

1986; Oswald and Senyk, 1977; Reiger and others, 1979; 

Slaughter and Viereck, 1986).

Terrain. -A number of references provided information 

on physiographic characteristics (Black, 1955; Drury, 1956; 

Oswald and Senyk, 1977; Reiger and others, 1979; 

Spetzman, 1959; U.S. Geological Survey, 1964; Wahrhaftig, 

1965). The U.S. Geological Survey (USGS) Map E shaded-relief map (1987a) was also useful. USGS digital elevation data at a 1-km2 resolution were used to determine elevation, slope gradient, and terrain roughness. Terrain roughness is an evaluation of the variability of local (within 5 km)
ECOREGIONS OF ALASKA

topographic relief. A terrain roughness map was derived 

using the steps identified in appendix 2. Classes of local terrain roughness include very low, low, moderate, high, and 

very high (see appendix 2 for a definition of these classes).

Information on geology was obtained from maps and 

reports by Beikman (1980), Black (1951, 1955, 1969), Drew 

and Tedrow (1962), Karlstrom and others (1964), Oswald 

and Senyk (1977), Reiger and others (1979), Selkregg 

(1974), Spetzman (1959), U.S. Geological Survey (1964, 

1987a), and Wahrhaftig (1965).

A map showing the extent of Pleistocene glaciation in 

Alaska (Coulter and others, 1962) was the main source of 

information on glaciation. Several reports (Oswald and 

Senyk, 1977; Reiger and others, 1979; U.S. Geological 

Survey, 1964; Wahrhaftig, 1965) were also helpful.

Information on permafrost came from a map classifying 

the distribution of permafrost in Alaska (Ferrians, 1965). Other 

publications (Black, 1955; Ferrians and Hobson, 1973; Reiger 

and others, 1979) were used to augment this information.

Several publications were helpful for characterizing surface waters and other hydrologic features (Drury, 1956; 

Reiger and others, 1979; Selkregg, 1974; Wahrhaftig, 1965; 

U.S. Geological Survey, 1987a). A map showing the distribution of wetlands in Alaska (Hall, 1991) was helpful in 

depicting general areas of wetlands, but it included no further classification of wetland types.

Soils. - A series of draft maps of various soil components, 

derived from information published in the Exploratory Soil 

Survey of Alaska (Reiger and others, 1979), was provided by 

the USGS (Larson and Bliss, written cornmun., 1992). Several 

published references were also used (Drew and Tedrow, 1962; 

Reiger and others, 1979; Selkregg, 1974). More recent soil 

information (since the publication of the Exploratory Soil 

Survey) was provided by soil scientists (Moore, written commun., 1993 and Ping, written cornmun., 1993).

Vegetation. - No statewide vegetation map has been 

completed for Alaska, although parts of the State have been 

mapped by different agencies. A subset of these maps 

(Fitzpatrick-Lins and others, 1989; Markon, 1992; Powell 

and others, 1993; Talbot and Markon, 1986, 1988; Talbot 

and others, 1986; U.S. Geological Survey, 1987b), along 

with other descriptive information and species lists (Drury,

"The AVHRR, mounted on National Oceanic and Atmospheric 

Administration (NOAA) satellites, has a polar, sun-synchronous orbit. The 

AVHRR sensor offers spatial resolution of approximately 1 km2 (after geographic correction) and collects data in the red-visible, near-infrared, 

mid-infrared, and thermal-infrared wavelengths.

10An NDVI value is calculated for each pixel by using the following 

equation: (Near IR - Visible)/(Near IR + Visible). This ratio relates to a 

measure of relative photosynthetic activity; that is, the higher the NDVI 

value, the greater the level of photosynthetic activity (Eidenshink, 1992). 

However, NDVI values can be misleading because of the effects that 

clouds, background soil color, and surface texture have on the original visible and near-IR reflectance values (Huete and Jackson, 1988; Huete and 

others, 1985).

1956; Fleming, written communication, 1993; Reiger and 

others, 1979; Selkregg, 1974; Shasby, unpub. mapping, 

1985; Spetzman, 1959; U.S. Fish and Wildlife Service, 

1987a, 1987b; U.S. Forest Service, 1992; Viereck, 1989; 

Viereck and Little, 1972; Viereck and others, 1986, 1992; 

Wibbenmeyer and others, 1982) were used for this project. 

Descriptive information on vegetation for Alaskan ecoregions that border Canada was augmented using a publication 

by Oswald and Senyk (1977).

We also used surrogate information regarding the distribution of vegetation, such as statewide maps of major ecosystem types (Joint Federal-State Land Use Planning 

Commission for Alaska, 1973; Viereck and Little, 1972) and 

maps of characteristics related to photosynthetic activity 

(Markon and others, 1995). The latter refers to a collection 

of data sets derived from twice-monthly composites of 

advanced very high resolution radiometer (AVHRR)9 sensor 

data that were available for the 1991 (Binnian and Ohlen, 

1992) growing season. Each twice-monthly composite represents the five-band sensor data for the acquisition date having the highest Normalized Difference Vegetation Index10 

(NDVI) value for each pixel. The conceptual basis for the 

composite is that the highest NDVI value represents conditions of least atmospheric interference during data acquisition 

(Loveland and others, 1991). The products derived from 

these composites (hereafter referred to as the "derivative 

products") include maps of the (1) temporal classification of 

composite NDVI values over a growing season (resulting in 

80 "greenness" classes; methodology for deriving this type of 

classification has been described in Loveland and others, 

1991), (2) duration of greenness (number of days, per greenness class, that the NDVI value exceeded a threshold value of 

0.10), (3) yearly maximum NDVI (maximum NDVI per pixel 

for a growing season), (4) mean NDVI (the average 

twice-monthly composite value per pixel), (5) onset of greenness (the composite period during which the NDVI value for 

a given pixel rose above 0.10), and (6) period of peak greenness (the composite period during which the maximum NDVI 

value occurred for each pixel). Another derivative product 

that proved particularly useful for capturing spatial trends in 

vegetative characteristics is a relative color-infrared representation (hereafter referred to as the "relative CIR image") 

of the 80 greenness classes (Fleming, 1994).

The AVHRR data products were not used to delineate the 

actual boundaries of ecoregions because these data represent 

characteristics detected over a single growing season. The 

annual variation in these characteristics has not been analyzed, so it is difficult to determine how well a single growing season represents long-term landscape patterns. We used 

the AVHRR data products to aid in the interpretation of the 

spatial patterns shown on the rest of the reference maps.

Wildfire. - Although not used to delineate ecoregions, 

information on wildfire has been included in the descriptions. Wildfire information in this report is limited to fires
ECOREGION DESCRIPTIONS

started by natural causes. Human-caused fires are not discussed because they are concentrated primarily along highways and in settled areas and are not necessarily indicative 

of natural regional ecological processes. Information on the 

occurrence of lightning fires was obtained from Gabriel and 

Tande (1983), and somewhat augmented from Selkregg 

(1974). The report by Gabriel and Tande summarized data 

from a 23-year span (1957-1979). Information in the current report, therefore, does not represent wildfires outside of 

this interval.

Land use. - Although not used to delineate ecoregions, 

information on extractable resources and subsistence land 

use has been included in the descriptions. Extractable 

resource information was compiled from the U.S. Bureau of 

Mines (1992a; 1992b), Selkregg (1974), and Pittman (1992). 

Information on subsistence land use came from Langdon 

(1993), Morgan (1979), and Selkregg (1974).

Wildlife. - Information on wildlife was not used to 

delineate ecoregions. Wildlife is an important component of 

the Alaskan landscape; however, it was beyond the scope of 

this report to describe the distribution and density of important species across individual ecoregions.

ECOREGION DESCRIPTIONS

Ecoregion descriptions have been compiled from the 

references listed in the Materials Section. An attempt has 

been made to provide consistent types of information for 

each ecoregion, but variations in the quality and quantity of 

information available have sometimes hindered this objective. A State map of selected features (fig. 1) precedes these 

descriptions to assist readers unfamiliar with locations that 

are mentioned.

The description of each ecoregion has been divided into 

the following topics: Distinctive Features, Climate, Terrain, 

Soils, Vegetation, Wildfire, Land Use and Settlement, 

Delineation Methods, and References. The general contents 

of each topic are described below.

Distinctive Features. - Approximate location and size 

of the ecoregion are described. Information on the primary 

factors that distinguish it from the rest of the ecoregions has 

been extracted from the subsequent paragraphs describing 

that ecoregion.

Climate. - Overall climatic regime is described in terms 

of major influencing factors (coastal, continental, transitional, arctic), winter and summer temperatures, and annual pre-

"Wildfire information was obtained from Gabriel and Tande (1983). 

Because their reporting units did not coincide completely with ecoregion 

boundaries, data were summarized (using the actual frequency values provided in the original report) to a coarser class of information.

cipitation. Annual precipitation refers to the water equivalent (for both rain and snow) per year, and annual snowfall 

refers to cumulative depth. Weather stations are poorly distributed across most ecoregions. Because the available data 

provide an imprecise representation of regional climate in 

most ecoregions, we have rounded the figures to the nearest 

10 mm for total annual precipitation and 5 cm for total annual snowfall.

Terrain. - Information about physiography, geology, 

extent of glaciation and permafrost, and hydrologic features 

is provided. Elevation information is based on height 

(meters) above mean sea level.

Soils. - Principal soils are listed and parent materials are 

described.

Vegetation. - Major community types are described and 

common or typifying species are listed. Names of community types and species closely follow those described by 

Viereck and others (1992). For the purposes of this report, 

Equisetum (horsetail) species are considered herbaceous vegetation in the sense that they are nonwoody. Appendix 3 is a 

list of Latin and common names for plant species mentioned 

in this report.

Wildfire. - Frequency of lightning fires for each ecoregion has been classified based on the following categories 11 : very low (<1 fire/yr.), low (1-5 fires/yr.), common 

(6-10 fires/yr.), very common (11-20 fires/yr.), and frequent (>20 fires/yr.; the only region in this last category 

averages more than 80 fires per year). The range and the average area burned are also provided. Other descriptive information is included where available.

Land Use and Settlement. - Information is provided 

regarding native human subsistence and selected commodities, such as resource extraction, agriculture, and timber harvest. Listings of extractable resources for an individual 

region generally follow the frequency of occurrence (from 

high to low) in the Bureau of Mines data base .

Delineation Methods. - Specific materials used to 

decide boundary placement on the basis of synthesized characteristics typifying each ecoregion are discussed. Although 

nearly all information described above (except land use) was 

assessed to evaluate regional patterns, only a small subset of 

the material was used to delineate the boundaries. This subset represents maps that best integrate the spatial patterns of 

the full set of characteristics defining each ecoregion. 

Scientists from Environment Canada and Agriculture 

Canada assisted in the delineation of regional boundaries 

that cross the international border into Canada.

References. - A list of specific references used to com-
ECOREGIONS OF ALASKA

pile each ecoregion description is included.

101.12 ARCTIC COASTAL PLAIN

Distinctive Features. - As the northernmost ecoregion 

in Alaska, the 50,000-km2 Arctic Coastal Plain Ecoregion is 

bounded on the north and the west by the Arctic Ocean and 

stretches eastward nearly to the international boundary 

between Alaska and the Yukon Territory, Canada. The poorly drained, treeless coastal plain rises very gradually from 

sea level to the adjacent foothills. The region has an arctic 

climate, and the entire area is underlain by thick permafrost. 

Because of poor soil drainage, wet graminoid herbaceous 

communities are the predominant vegetation cover, and 

numerous thaw lakes dot the region (fig. 2).

Climate. - The coastal plain has arctic climatic conditions, with very low mean annual temperatures and very low 

annual precipitation. Although July and August are generally frost-free, freezing temperatures can occur in any month 

of the year. Winds are persistent and strong. The few weather stations in this region are primarily located along the 

coast, but the data are fairly consistent from station to station. Average daily minimum winter temperatures are about 

-30°C, and average daily maximum winter temperatures are 

about -21°C. Daily minimum summer temperatures average 

just above freezing, and daily maximum summer temperatures average 8°C. Continuous sunlight during the summer 

months yields diurnal temperature fluctuations of only about 

5°C. Cloud cover or fog prevails during the summer months, 

although fog decreases (and temperature rises) with increasing distance from the coast. The ecoregion receives approximately 140 mm of precipitation13 annually. Average annual 

snowfall varies among weather stations, ranging from 30 cm 

to 75 cm.

Terrain. - The ecoregion is mainly a smooth plain rising very gradually (slope gradients <1°) from the Arctic 

Ocean to the foothills of the Brooks Range, 180 m above sea 

level. Locally, permafrost-related features mark the terrain 

surface. Pingos rise 6 m to 70 m above the surrounding area, 

and other ice-related features, such as extensive networks of 

ice-wedge polygons, oriented lakes (ranging from a few 

meters to 15 km in length), peat ridges, and frost boils are 

common. Northeast-trending sand dunes, 3 m to 6 m high, 

occur between the Kuk and Colville Rivers.

The coastal plain is mantled with Quaternary deposits of 

alluvial, glacial, and aeolian origin. Siltstone and sandstone 

lie beneath the unconsolidated materials at depths of several

12Numbers in front of ecoregion headings correspond with those used 

on the map "Ecoregions of Alaska."

13The average annual precipitation figure for all ecoregion descriptions 

includes the snow water equivalent.

meters to tens of meters. The ecoregion was not glaciated 

during the Pleistocene epoch, but the arctic climate is 

responsible for permafrost to depths of more than 300 m. 

The permafrost table is at or near the ground surface, with an 

active layer of less than 0.50 m (except beneath the larger 

rivers, where thawing may be deeper).

The Arctic Coastal Plain is very poorly drained. Thaw 

lakes cover 20 percent to 50 percent of the land surface 

across the region. In many areas, for example, near 

Teshekpuk Lake, lakes are rectangular and oriented 

north-northwest. This orientation is related to the effects of 

predominant winds on the permafrost shorelines of thaw 

lakes. Thaw lakes expand approximately 1 m per year in 

places and range from less than 1 m to 7 m in depth. Lake 

bottoms are usually covered by organic muck. Streams originate in the highlands of ecoregions to the south. Streams 

west of the Colville River tend to be sluggish and meandering; those east of the Colville River are more braided and 

distributary, building deltas into the Arctic Ocean. Most of 

the smaller streams dry up or freeze during the winter and 

have clean sand or gravel beds.

Soils. - The principal soils of the Arctic Coastal Plain 

are Histic Pergelic Cryaquepts and Pergelic Cryaquepts. 

Soils are poorly drained and have developed under thick 

vegetation cover. Very poorly drained fibrous peat soils 

occupy broad depressions, shallow drainages, and lake borders, commonly under a thick cover of sedges. Pergelic 

Cryopsamments have developed on low, stabilized sand 

dunes. Very gravelly soils form from stream deposits in 

braided and distributary channels of streams west of, and 

including, the Sagavanirktok River. Lower parts of the terrain are subject to annual flooding from runoff of spring 

snowmelt and heavy summer rainstorms in the upper, 

mountainous reaches of their watersheds. East of the 

Colville River are extensive areas of loamy and poorly 

drained soils that have formed beneath a cover of sedge tussocks, mosses, and low shrubs in nonacid and calcareous 

sediments.

Vegetation. - The distribution of vegetation communities is strongly related to microtopographic features that 

affect soil drainage. Wet soil conditions are most typical of 

this ecoregion, supporting wet graminoid herbaceous communities dominated by sedges or grasses (fig. 3). Dryer soil 

conditions occur where slight rises in microtopographic 

relief provide a rooting zone above the standing water table, 

such as along the rims of old lake basins, on river, lake, and 

coastal bluffs, and on pingos. Dwarf scrub communities 

grow in these better drained areas (fig. 4).

Sedge communities are generally dominated by Carex 

aquatilis and Eriophorum angustifolium. Various herbaceous species may share dominance with sedges in some 

areas. Mosses (usually Scorpidium spp. or Drepanocladus 

spp.) may be common.
ARCTIC COASTAL PLAIN

Base adapted from U.S. Geological Survey Map C

Figure 1. Locational map of Alaskan features.

Figure 2. Thaw lakes scattered over the treeless Arctic Coastal Plain Ecoregion. Many are oriented north-northwest, as in 

this area east of the Kuparuk River.
10 ECOREGIONS OF ALASKA

Figure 3. Wet graminoid herbaceous community dominated by sedge (Carex and Eriophorum species) in the Arctic Coastal 

Plain Ecoregion. (Photo taken by Carl Markon. Hughes STX Corporation, U.S. Geological Survey, EROS Alaska Field 

Office, Anchorage.)

Figure 4. Dwarf scrub community indicative of dryer soil conditions occurring on raised topographic features (approximately 10 cm or more above the surrounding plain) in the Arctic Coastal Plain Ecoregion. (Photo taken by Carl Markon, 

Hughes STX Corporation, U.S. Geological Survey, EROS Alaska Field Office, Anchorage.)
ARCTIC FOOTHILLS 11

Grass communities are generally dominated by Dupontia 

fischeri andAlopecurus alpinus, butArctophilafulva dominates 

where surface water is 15 to 200 cm deep. Various herbaceous 

species may share dominance with grasses in some areas.

Dwarf scrub communities commonly include entire-leaf 

mountain-avens (Dryas integrifolia), mountain-cranberry 

(Vaccinium vitis-idaea), four-angled cassiope (Cassiope 

tetragona), bearberry (Arctostaphylos alpina and A. rubra), 

and willows (Salix reticulata and S. phlebophylld).

Wildfire. - Occurrence of wildfires in the Arctic Coastal 

Plain Ecoregion is very low. Fire records show a range in size 

from 1 ha to 3,400 ha, with an average size of 1,135 ha.

Land Use and Settlement. - Native inhabitants of this 

region are Inuit (Taremiut) who have traditionally depended 

heavily on large marine mammals (for example, bowhead 

whales, beluga whales, and walrus) for food and materials. 

Winter ice fishing and seal hunting supplement these food 

supplies. Caribou are hunted during late spring, following 

the conclusion of the major whale hunts. Edible plant roots 

and summer waterfowl and their eggs add variety to the diet.

The ecoregion is rich in energy related commodities, 

including oil, gas, and coal. The Prudhoe Bay area has 

played a major role in providing these commodities. A number of sand and gravel operations support construction and 

road maintenance.

Delineation Methods. - The reference that best depicted the integration of important regional characteristics was 

the terrain roughness map. The ecoregion boundary corresponds with the pattern of continuous, very low terrain roughness. This boundary encompasses the full extent of "Wet 

Tundra" ecosystems shown on the arctic portion of the 

"Major Ecosystems of Alaska" map, as well as the thaw lakes 

shown on the USGS Map E base map. Some inclusions of 

"Moist Tundra" from the map "Major Ecosystems of Alaska" 

also occur, and are depicted as transitional gray tones on the 

ecoregion map. Patterns on the relative CIR image reflect a 

combination of those shown on the surface roughness map 

and those shown on the ecosystems map; so the image is generally in agreement with the ecoregion boundary.

References. - The information provided in this regional 

description has been compiled from: Beikman (1980), Black 

(1951, 1955, 1969), Coulter and others (1962), Ferrians 

(1965), Gabriel and Tande (1983), Joint Federal-State Land 

Use Planning Commission for Alaska (1973), Karlstrom and 

others (1964), Langdon (1993), Larson and Bliss (written 

commun., 1992), Moore (written commun., 1993), Morgan 

(1979), Ping (written commun., 1993), Reiger and others 

(1979), Selkregg (1974), Spetzman (1959), U.S. Bureau of 

Mines (1992a, 1992b), U.S. Geological Survey (1964, 

1987a),Viereck and Little (1972), Viereck and others (1992), 

Wahrhaftig (1965), and WeatherDisc Associates, Inc. (1990).

102. ARCTIC FOOTHILLS

Distinctive Features. - The 124,000-km2 Arctic 

Foothills Ecoregion consists of a wide swath of rolling hills 

and plateaus that grades from the coastal plain on the north 

to the Brooks Range on the south. The east-west extent of 

the ecoregion stretches from the international boundary 

between Alaska and The Yukon Territory, Canada, to the 

Chukchi Sea. The hills and valleys of the region have better 

defined drainage patterns than those found in the coastal 

plain to the north and have fewer lakes (fig. 5). The Arctic 

Foothills Ecoregion is underlain by thick permafrost and has 

many ice-related surface features. The region is predominantly treeless and is vegetated primarily by mesic 

graminoid herbaceous communities.

Climate. - Arctic climate prevails in this ecoregion. 

The foothills are somewhat warmer in winter than the 

adjacent regions to the north and south, and gain some 

ameliorating effects from the Chukchi Sea to the west. 

Weather stations are rare in the Arctic Foothills Ecoregion, 

and information from the few data locations and anecdotal 

accounts may not be representative. Annual precipitation 

mirrors that of the Arctic Coastal Plain (=140 mm). As 

much as 50 mm of additional precipitation is intercepted 

near the boundary with the Brooks Range Ecoregion. The 

Noatak Valley, in the western portion of the Arctic 

Foothills Ecoregion, receives approximately twice as 

much annual precipitation as the rest of the region. 

Snowfall patterns are similar to overall annual precipitation patterns in that more snowfall occurs near the Brooks 

Range (up to 130 cm) and in the Noatak Valley (up to 150 cm) 

than throughout the rest of the region (75 cm to 100 cm). 

Average daily winter temperatures range from a minimum 

of -29°C to a maximum of -20°C. Average daily summer 

temperatures range from a minimum of 1°C to a maximum 

of 11°C to 15°C, although maximum temperatures of 24°C 

are not uncommon in some areas. Freezing can occur in 

any month of the year, but July and August are usually 

frost-free.

Terrain. - The Arctic Foothills Ecoregion can be topographically and geologically separated into northern and 

southern sections. The northern section consists of broad, 

rounded east-west ridges and mesa-like uplands built from 

unconsolidated Quaternary materials (glacial, alluvial, and 

aeolian in origin) over Lower Cretaceous continental 

deposits. Elevations are generally less than 600 m above sea 

level. The southern section has undifferentiated alluvial and 

colluvial deposits overlying Jurassic and early Cretaceous 

graywacke and chert formations. Elevations are higher than 

in the northern section (up to 800 m) and consist of irregular 

buttes, mesas, and long linear ridges with intervening undulating plains and plateaus.

The ecoregion was free from Pleistocene glaciation
12 ECOREGIONS OF ALASKA

(except for some areas directly north of the Brooks Range) 

but is currently underlain by thick permafrost. The active 

layer of the permafrost is generally less than 1 m, except 

beneath large rivers, where thawing may be deeper. Many 

ice-related features are present, such as pingos, gelifluction 

lobes, ice-wedge polygons, stone stripes, and beaded 

drainage (fig. 6). Although regional slope gradients generally vary from 0° to 5°, they may be steeper in some areas.

Drainage in the Arctic Foothills Ecoregion is integrated. 

Major streams originate from the Brooks Range and are 

structurally controlled by the bedrock. Most streams are 

swift, but portions may be braided across gravel flats. 

Smaller streams dry up or freeze to the bottom in winter; 

these streams typically have clean sand or gravel bottoms. 

Perennial streams have algae-covered rocky bottoms. 

During spring snowmelt and breakup of river ice, flooding 

and channel shifting are common. Oxbow lakes along major 

stream valleys are the predominant type of lake in this 

ecoregion. Most lake beds are organic muck, but some are 

sandy. Lake shores are surrounded by ice-push ridges (as 

much as 2 m high). Plant communities in lakes are generally arranged in concentric bands that correspond with water 

depth; aquatic vegetation is usually limited to water that is 

less than 1.5 m deep.

Soils. - Principal soils are Histic Pergelic Cryaquepts, 

Pergelic Cryaquepts, and Pergelic Ruptic-Histic Cryaquepts. 

Dominant soils in valleys and on long slopes formed in silty 

or loamy colluvial sediments. On hills and ridges, most of 

the soils are composed of very gravelly materials eroded 

from sedimentary rock. The dominant soils in the Noatak 

Valley are poorly drained and are derived from very gravelly glaciofluvial material from limestone rock in the surrounding mountains. Well drained soils occur on hilly 

moraines of the valley, formed from very gravelly, nonacid 

and calcareous drift. Shallow depressions on terraces 

accommodate fibrous peat soils.

Vegetation. - Vegetation over most of the region consists of mesic graminoid herbaceous (fig. 7) and dwarf scrub 

communities. Open low scrub occurs along drainages. 

Forest communities occur in the Noatak River Valley, a 

somewhat anomalous area of this ecoregion.

Mesic graminoid herbaceous communities dominated by 

tussock-forming sedges are widespread. Typical species are 

Eriophorum vaginatum and Carex bigelowii. Low shrubs, 

such as dwarf arctic birch (Betula nana), crowberry 

(Empetrum nigrum), narrow-leaf Labrador-tea (Ledum 

decumbens), and mountain-cranberry (Vaccinium vitis-idaea) 

often occur and may codominate with sedges. Mosses (for 

example, Hylocomium splendens and Sphagnum spp.) and 

lichens (for example, Cetraria cucullata, Cladonia spp., and 

Cladina rangiferina) are common between tussocks.

Dwarf scrub communities are dominated by mat-forming Dryas species accompanied by ericaceous species (for

example, Vaccinium spp., Cassiope tetragona, Arctostaphylos 

spp.) and prostrate willows (Salix reticulata and S. phlebophylld).

Open low scrub communities are codominated by alders 

(Alnus crispa) and willows (for example, Salix lanata, S. planifolia, and S. glauca). Mosses (for example, Tomenthypnum 

nitens and Drepanocladus spp.) are usually abundant.

Forest vegetation is common along river terraces of the 

lower Noatak Valley (as far inland as the Kugururok River). 

White spruce (Picea glauca) occurs in either pure stands or 

with balsam poplar (Populus balsamiferd). The spruce grows 

in open stands along the riverbanks, with an understory dominated by willows (for example, Salix alaxensis, S. planifolia, 

and S. lanata). Away from the river, forest canopies are 

closed and stands have few understory species (for example, 

ericads such as Ledum spp., Arctostaphylos spp., and 

Vaccinium spp.). A thick layer of feathermosses (for example, Hylocomium splendens) is common. Balsam poplar 

stands grow all along the river, occurring farther upriver than 

white spruce stands. Typical understory species are alpine 

bearberry (Arctostaphylos alpina), buffaloberry (Shepherdia 

canadensis), and bush cinquefoil (Potentillafruticosa).

Wildfire. - Occurrence of wildfires in the Arctic 

Foothills Ecoregion is very low. Fire records show a range in 

size from <1 ha to 1,600 ha, with an average size of 185 ha.

Land Use and Settlement. - The ecoregion has traditionally been home to the Inuit (Nunamiut). Caribou is the 

primary subsistence resource. Moose, bear, hare, ground 

squirrel, and ptarmigan are also hunted. Edible plant roots 

and berries supplement the diet.

Subsistence and recreational fishing and hunting remain 

the primary human activities in this ecoregion. A number of 

potential extractable resources have been investigated, 

including coal, barium, lead, chromium, zinc, and silver. 

Sand and gravel operations have supported construction of 

the trans-Alaska pipeline service road.

Delineation Methods. - Typical characteristics of the 

Arctic Foothills Ecoregion are integrated within the area of low 

terrain roughness on the arctic portion of the terrain roughness 

map. The ecoregion boundary shared with the Arctic Coastal 

Plain was delineated on the basis of a distinct boundary between 

very low terrain roughness and low terrain roughness. The 

ecoregion boundary shared with the Brooks Range was delineated along a generalized 600-m elevation contour, an elevation 

coinciding with the northern extent of "Alpine Tundra" in the 

Brooks Range, as depicted on the "Major Ecosystems of 

Alaska" map. This contour line corresponds well with regional 

patterns shown on the relative CIR image. The ecoregion 

boundary shared with Interior Forested Lowlands and Uplands 

was based on the interface of the forest ecosystems of the interior and the tundra (graminoid herbaceous) ecosystems of the 

Arctic. Transitional areas adjacent to the Brooks Range indicate
ARCTIC FOOTHILLS 13

Figure 5. Rolling hills of the Arctic Foothills Ecoregion showing better defined drainage patterns than those found in the 

coastal plain to the north. (Photo courtesy of Skip Walker, Institute of Arctic and Alpine Research, University of Colorado, 

Boulder.)

Figure 6. Beaded stream drainages controlled by the pattern of ice wedges formed in permafrost environments of the Arctic 

Foothills Ecoregion. (Photo courtesy of Skip Walker, Institute of Arctic and Alpine Research, University of Colorado, Boulder.)
14 ECOREGIONS OF ALASKA

Figure 7. Mesic graminoid herbaceous-dwarf scrub community near Umiat in the Arctic Foothills Ecoregion. (Photo courtesy of Skip Walker, Institute of Arctic and Alpine Research, University of Colorado, Boulder.)

Figure 8. The Brooks Range Ecoregion is composed of deeply dissected mountains formed from uplifted, stratified 

Paleozoic and Mesozoic sediments.
BROOKS RANGE 15

alpine tundra ecosystems, areas greater than 600 m in elevation, 

and areas of medium to high terrain roughness. Transitional 

areas adjacent to the Arctic Coastal Plain indicate inclusions of 

areas of very low terrain roughness.

References. - The information provided in this regional 

description has been compiled from Beikman (1980), Black 

(1951, 1955, 1969), Coulter and others (1962), D. Binkley 

(oral commun., 1994), Fenians (1965), Gabriel and Tande 

(1983), Joint Federal-State Land Use Planning Commission 

for Alaska (1973), Karlstrom and others (1964), Langdon 

(1993), Larson and Bliss (written commun., 1992), Moore 

(written commun., 1993), Morgan (1979), Ping (written 

commun., 1993), Reiger and others (1979), Selkregg (1974), 

Spetzman (1959), U.S. Bureau of Mines (1992a, 1992b), 

U.S. Geological Survey (1964, 1987a), Viereck and Little 

(1972), Viereck and others (1992), Wahrhaftig (1965), and 

WeatherDisc Associates, Inc. (1990).

103. BROOKS RANGE

Distinctive Features. - The 134,000-km2 Brooks 

Range Ecoregion consists of several groups of rugged, 

deeply dissected mountains carved from uplifted sedimentary rock (fig. 8). The ecoregion traverses much of the 

east-west extent of northern Alaska, from the Canadian border to within 100 km of the Chukchi Sea. Elevation of 

mountain peaks ranges from 800 m in the relatively low 

Baird Mountains in the west to 2,400 m in the central and 

eastern Brooks Range. Pleistocene glaciation was extensive, 

and small glaciers persist at elevations above 1,800 m. An 

arctic climatic regime and unstable hillslopes maintain a 

sparse cover of dwarf scrub vegetation throughout the mountains, though some valleys provide more mesic sites for 

graminoid herbaceous communities.

Climate. - The ecoregion is influenced by arctic climate. The only perennial weather station, located at 

Anaktuvuk Pass, sits at an elevation of 770 m, where winter 

temperatures average a daily minimum of -30°C and a daily 

maximum of -22°C, and summer temperatures average lows 

of 3°C and highs of 16°C. In most years, freezing temperatures occur each month. In general, temperatures decrease 

with elevation, but hillslope aspect, strong and persistent 

winds, and convective currents result in climate that is highly variable. Mean annual precipitation at Anaktuvuk Pass is 

280 mm, with 160 cm of annual snowfall. Precipitation is 

heaviest on south-facing slopes and near mountain summits.

Terrain. - The Brooks Range Ecoregion represents the 

Alaskan extension of the Rocky Mountains. The steep, 

rugged mountains consist of folded and faulted stratified 

Paleozoic and Mesozoic sedimentary deposits (including 

sandstone, shale, and limestone marine and nonmarine

deposits, and some metamorphic rocks) that were uplifted 

during the Cretaceous period. Elevations range from 500 m 

in the lower valleys to 2,400 m on the higher peaks. Slope 

gradients of 5° to 15° are common. The ecoregion was 

extensively glaciated during the Pleistocene epoch, but only 

small, scattered glaciers persist. Continuous thick permafrost underlies the region. The interplay between water 

(frozen and thawed) and sediments is evidenced by moraine 

and gravel outwash terraces in most valleys, by gelifluction 

lobes on hillslopes, by ice-push ridges around lakes, and by 

polygons, stripes, and circular frost scars on many surfaces. 

Rubble and exposed bedrock cover the mountain slopes.

Lakes are sparse for such a glacially influenced region, 

occurring primarily in rock basins at the mouths of large 

glaciated valleys, in areas of ground and end moraine, and on 

the floodplains of major streams. Streams often have a trellis drainage pattern, with major streams draining north or 

south and their tributaries draining east or west. Extensive 

alluvial fans of loose material carried down from mountain 

slopes have formed in broad valleys at the base of streams. 

Hot springs are known to occur in several areas.

Soils. - The principal soils of the Brooks Range 

Ecoregion are Pergelic Cryaquepts, Pergelic Cryumbrepts, 

and Lithic Cryorthents. Hillslope soils formed from local 

colluvium, while most valley soils generally developed from 

glacial till. Soils are often gravelly, but are covered in many 

places with silty colluvial and residual material from 

fine-grained sedimentary rocks. Because of glaciation, frost 

action, and rapid erosion of steep slopes, there is little soil 

accumulation on hillslopes. Soils throughout this ecoregion 

typically have poor drainage because of the shallow depth to 

permafrost.

Vegetation. - Because of highly credible hillslope sediments, shallow soils, high winds, and harsh climate in this 

ecoregion, vegetation cover is sparse (fig. 9) and generally 

limited to valleys and lower hillslopes. Drier sites support 

dwarf scrub communities. Wet to mesic sites support mesic 

graminoid herbaceous communities.

Dwarf scrub communities are dominated by ericaceous 

species (for example, Arctostaphylos alpina, A. rubra, 

Vaccinium spp., Ledum decumbens, Empetrum nigrum, and 

Cassiope tetragona), mountain-avens (Dryas octopetala and 

D. integrifolia), and willow (Salix rotundifolia, S. arctica, and 

S. polaris). Herbaceous species (for example, Carex spp.) and 

fruticose lichens (for example, Cladina spp. and Cetraria 

spp.) may codominate with shrubs in some areas (fig. 10).

Graminoid herbaceous communities are dominated by 

sedges (Carex aquatilis and C. bigelowii) and willows (Salix 

planifolia and S. lanata). Mosses (for example, Tomenthypnum 

nitens, Distichium capillaceum, Drepanocladus spp., and 

Campylium stellatum) are often abundant.

Wildfire. - Occurrence of wildfires in the Brooks Range
16 ECOREGIONS OF ALASKA

Figure 9. Steep, unstable slopes of the Brooks Range Ecoregion. Physiography and an arctic climate restrict vegetation.

Figure 10. Dwarf scrub community dominated by mountain-avens and lichen growing on a windswept site of the Brooks 

Range Ecoregion. (Photo courtesy of Skip Walker, Institute of Arctic and Alpine Research, University of Colorado, Boulder.)
INTERIOR FORESTED LOWLANDS AND UPLANDS 17

Ecoregion is common. Fire records show a range in size from 

<1 ha to 109,265 ha, with an average size of 1,790 ha.

Land Use and Settlement. - The Brooks Range has 

historically been used by nomadic groups of the Interior 

North Alaska Coast Inuit (Nunamiut) and by the Kutchin and 

Koyukon Athabascans. Salmon fishing and hunting for caribou and moose are the major means of subsistence. Small 

fur-bearing mammals are hunted secondarily. Edible plants 

are also gathered.

The fact that Anaktuvuk Pass is the only year-round settlement in this ecoregion underscores the harsh environment 

and difficulty of transportation associated with the mountains. The region is little developed and provides subsistence 

hunting and fishing, as well as recreational uses. Many 

extractable resources have been investigated and, in some 

cases, mined. These include gold, silver, copper, tungsten, 

zinc, lead, chromium, vanadium, antimony, barium, molybdenum, phosphate, and rare earth elements. Numerous sand 

and gravel operations have supported construction of the 

trans-Alaska pipeline service road.

Delineation Methods. - The ecoregion boundary primarily follows a generalized 600-m elevation contour. An 

exception occurs in the southeastern part of the ecoregion, 

where a 900-m contour was used. This is because the mountains at the 600-m level in the southeast are more widely 

spaced, have climatic characteristics more similar to those of 

interior regions, and have a different geologic origin than the 

rest of the Brooks Range. The boundary delineated generally corresponds with patterns shown on the relative CIR 

image. The transitional zones on the northern side of the 

ecoregion distinguish areas of "Moist Tundra," as depicted 

on the map "Major Ecosystems of Alaska," and lower elevation valleys penetrating from the Arctic Foothills Ecoregion. 

Transitional zones on the southern side distinguish "Upland 

Spruce-Hardwood Forest" ecosystems, as depicted on the 

map "Major Ecosystems of Alaska," along drainages adjacent to interior ecoregions.

References. - The information provided in this regional description has been compiled from Beikman (1980), 

Black (1955, 1969), Coulter and others (1962), Ferrians 

(1965), Ferrians and Hobson (1973), Gabriel and Tande 

(1983), Joint Federal-State Land Use Planning Commission 

for Alaska (1973), Karlstrom and others (1964), Langdon 

(1993), Larson and Bliss (written commun., 1992), Moore 

(written commun., 1993), Morgan (1979), Ping (written 

commun., 1993), Reiger and others (1979), Selkregg (1974), 

Spetzman (1959), U.S. Bureau of Mines (1992a, 1992b), 

U.S. Geological Survey (1964), Viereck and Little (1972), 

Viereck and others (1992), Wahrhaftig (1965), and 

WeatherDisc Associates, Inc. (1990).

104. INTERIOR FORESTED LOWLANDS 

AND UPLANDS

Distinctive Features. - The 269,000-km2 ecoregion represents a patchwork of ecological characteristics. Regionwide 

unifying features include a lack of Pleistocene glaciation, a 

continental climate, a mantling of undifferentiated alluvium 

and slope deposits, a predominance of forests dominated by 

spruce and hardwood species, and a very high frequency of 

lightning fires. On this backdrop of characteristics is superimposed a finer grained complex of vegetation communities 

resulting from the interplay of permafrost, surface water, fire, 

local elevational relief, and hillslope aspect (fig. 11).

Climate. - The ecoregion has a continental climate, 

with short, warm summers and long, very cold winters. 

Because the ecoregion is so large, there is much variation in 

temperature and precipitation from west to east. Total annual rain and snow generally increase with elevation. 

Temperature, while affected by elevation, is also influenced 

by distance from the ocean; maximum summer temperatures 

increase from west to east, and minimum winter temperatures decrease in the same pattern. Accordingly, variation in 

diurnal temperature increases from west to east.

Mean annual precipitation over most of the region 

ranges from 250 mm to 550 mm, with contribution from 

snowfall averaging from 125 cm to 205 cm. Most precipitation occurs during summer, mainly as a result of convective 

storms. Snow covers the landscape for half the year, lingering at higher altitudes, on north-facing slopes, and on shaded aspects. Average minimum winter temperatures vary from 

-18°C in the west to -35°C in the east; average maximum 

winter temperatures vary from -11°C in the west to -22°C in 

the east. Strong, stable temperature inversions are common 

in winter due to low sun angle and corresponding long-wave 

radiation cooling. Summer temperatures, averaging a minimum of 8°C to 11°C and a maximum of 17°C to 22°C, have 

less regional variation than winter temperatures. At lower 

elevations, temperatures usually remain above freezing from 

June through mid-September.

Terrain. - The Interior Forested Lowlands and Uplands 

Ecoregion consists of rolling lowlands, dissected plateaus, 

and rounded low to high hills. Most of the region lies 

between elevations from sea level to 500 m, but some hills 

rise over 700 m. Slope gradients are generally from 0° to 5°. 

The predominant geologic formations are derived from 

Mesozoic and Paleozoic sedimentary rocks, but extensive 

areas of volcanic deposits also occur. The region is surficially mantled by undifferentiated alluvium and slope 

deposits. There is little exposure of bedrock. Streams originating from within the ecoregion tend to be short, with the 

larger and longer streams originating from adjacent glaciated mountainous regions. Although thaw lakes and oxbow 

lakes occur throughout the ecoregion, lakes are not a pre-
18 ECOREGIONS OF ALASKA

Figure 11. Forest plant communities typical of the Interior Forested Lowlands and Uplands Ecoregion. The patterns and 

species composition of the communities are often controlled by the effects of permafrost, surface water, fire, relief, and hillslope aspect.

Figure 12. Initial recolonization by fireweed within recent bum. east of Tok in the Interior Forested Lowlands and Uplands 

Ecoregion. High frequency of lightning fires is a common characteristic.
INTERIOR FORESTED LOWLANDS AND UPLANDS 19

dominant landscape feature. The western portion of the 

ecoregion is underlain by thin to moderately thick permafrost, and the eastern portion has a discontinuous distribution of permafrost. The region was not glaciated during the 

Pleistocene epoch.

Soils. - Dominant soils of this ecoregion are Histic 

Pergelic Cryaquepts, Pergelic Cryaquepts, Aquic 

Cryochrepts, Pergelic Cryochrepts, Typic Cryochrepts, Typic 

Cryorthents, and Pergelic Cryumbrepts. Many upland soils 

were formed in silty, micaceous loess and colluvial material. 

Where mantles of loess are lacking, upland soils formed in 

stone and gravel weathered from local rock. Lowland soils 

were formed in silty alluvium and loess derived from the 

floodplains of large rivers. Soils are generally shallow, often 

overlying ice-rich permafrost. Those soils with permafrost, 

especially in the eastern portion of the ecoregion, are very 

susceptible to alteration upon disturbance of the organic mat. 

This is due to the relatively warm (>-1.5°C) permafrost temperature. Organic mat disturbance, as by wildfire, can result 

in warmer soil temperatures, lowered permafrost tables, and 

significant changes in soil physical properties and hydrology.

Vegetation. - Interrelationships among permafrost, surface water, fire, hillslope aspect, and soil characteristics result 

in a finely textured, complex pattern of vegetation across the 

ecoregion. Soil temperatures may differ greatly from air temperatures, so patterns in vegetation may not correspond with 

expected site conditions. Needleleaf, broadleaf, and mixed 

forests occur over a variety of sites. Tall scrub communities 

grow in areas of newly exposed alluvium, such as floodplains, streambanks, drainageways, and lake margins, on 

burned or otherwise disturbed areas, and near timberline. 

Low scrub communities occur in moist areas and on 

north-facing slopes. The wettest sites support tall scrub 

swamps, low scrub bogs, or scrub-graminoid communities. 

Recently burned areas (fig. 12) display a succession of recovery stages that include mesic forb herbaceous communities, 

mesic graminoid herbaceous communities, scrub communities, and broadleaf, needleleaf, and mixed forests.

Needleleaf forests are dominated by spruce and occur 

over a variety of site conditions. White spruce (Picea glaucd) occurs on warm, dry, south-facing hillslopes, along rivers 

where drainage is good and permafrost is lacking, and on well 

drained timberline sites. Dominant components of the understory include shrubs, such as resin birch (Betula glandulosd), 

prickly rose (Rosa acicularis), alder (Alnus spp.), willow 

(Salix spp.), buffaloberry (Shepherdia canadensis), high 

bushcranberry (Viburnum edule), and bearberry 

(Arctostaphylos spp.); herbs, such as twinflower (Linnaea 

borealis); and mosses, such as Hylocomium splendens, 

Pleurozium schreberi, and Cladonia spp.

Black spruce (Picea mariana) forests are found on 

floodplain terraces and flat to rolling uplands in well drained 

to poorly drained soils. Tamarack (Larix laricina) may be

associated with black spruce in wet bottomland areas. Low 

shrubs, such as Labrador-tea (Ledum groenlandicum and L. 

decumbens), prickly rose (Rosa acicularis), blueberry/cranberry (Vaccinium spp.), and resin birch (Betula glandulosd) 

are typically dominant in the understory. The ground has a 

patchy to continuous layer of mosses (for example, 

Pleurozium schreberi, Hylocomium splendens, Polytrichum 

spp., and Sphagnum spp.), and lichens (for example, 

Peltigera spp. and Cladonia spp.).

Broadleaf forests of balsam poplar (Populus balsamifera), quaking aspen (Populus tremuloides), or a mix of the 

two develop on the floodplains of meandering rivers. These 

forest stands follow the establishment of alder and willow 

thickets. The stands are subsequently replaced by white 

spruce (Picea glauca). Dominant understory species of 

broadleaf forests are alder (Alnus spp.), willow (Salix spp.), 

prickly rose (Rosa acicularis), and herbaceous species (for 

example, Equisetum spp., Calamagrostis canadensis, and 

Heracleum lanatum).

Mixed forests are dominated by combinations of spruce, 

paper birch, and quaking aspen. Dominant understory 

species include bluejoint (Calamagrostis canadensis), alder 

(Alnus spp.), bearberry (Arctostaphylos spp.), and 

Labrador-tea (Ledum spp.).

Most tall scrub communities are dominated by willows 

(Salix alaxensis, S. glauca, and S. lanata) and alders (Alnus 

crispa, A. tenuifolia, and A. sinuata), though communities 

near timberline may be dominated by birch (Betula glandulosa and B. papyri/era). Understory shrubs are usually sparse, 

but mosses (for example, Polytrichum spp., Hylocomium 

splendens, and Drepanocladus uncinatus) may be abundant.

Low scrub communities are dominated by open stands of 

willow (for example, Salix glauca, S. planifolia, and S. lanata), birch (Betula glandulosa and B. nana), alder (Alnus 

crispa), or mixes of these genera. Dominant understory 

shrubs may include cranberry/blueberry (Vaccinium spp.), 

bearberry (Arctostaphylos spp.), and Labrador-tea (Ledum 

spp.). The ground is covered by a patchy to continuous layer 

of moss (for example, Hylocomium splendens, Pleurozium 

schreberi, Tomenthypnum nitens, andAulacomniumpalustre).

Tall scrub swamps are dominated by alder (Alnus 

tenuifolia and A. crispa) and willow (Salix planifolia and S. 

lanata). Low shrubs may be present in the understory, 

including leatherleaf (Chamaedaphne calyculata), high 

bushcranberry (Viburnum edule), sweetgale (Myrica gale), 

and spirea (Spiraea beauverdiana). Mosses (for example, 

Sphagnum spp.) are usually present.

Bogs support open low scrub or scrub-graminoid communities. The shrub component includes a number of willow species (for example, Salix planifolia, S. reticulata, S. 

barclayi, S. commutata, and S. fuscescens), birch (Betula 

glandulosa and B. nana), Labrador-tea (Ledum decumbens), 

blueberry/cranberry (Vaccinium uliginosum, V. vitis-idaea, 

and V. oxycoccos), bush cinquefoil (Potentilla fruticosa), 

sweetgale (Myrica gale), alder (Alnus tenuifolia), and bog-
20 ECOREGIONS OF ALASKA

rosemary (Andromeda polifolia). Sedge tussocks 

(Eriophorum vaginatum and Carex bigelowii) or other 

graminoids (for example, Calamagrostis canadensis, Carex 

aquatilis, and C. pluriflora ) are codominant with shrub 

species in some bogs. A continuous moss layer, commonly 

consisting of Sphagnum spp., Pleurozium schreberi, 

Hylocomium splendens, Dicranum spp., and Polytrichum 

spp., is present.

Recent burn areas are initially colonized by mesic forb 

herbaceous communities dominated by fireweed (Epilobium 

angustifoliuni). Mesic graminoid herbaceous communities 

develop when bluejoint (Calamagrostis canadensis) becomes 

dominant. The scrub communities that follow consist mainly 

of willows (Salix arbusculoides, S. barclayi, S. bebbiana, and 

5. scouleriana), accompanied by prickly rose (Rosa acicularis), buffaloberry (Shepherdia canadensis), and ericaceous 

species (for example, Ledum decumbens, L. groenlandicum, 

Vaccinium caespitosum, and V. vitis-idaea). Broadleaf forests 

dominated by quaking aspen (Populus tremuloides) often succeed the willow stage in upland areas on south-facing slopes, 

or on well drained river terraces. Paper birch (Betula 

papyri/era) stands succeed the willow stage on east-, west-, 

and occasionally north-facing slopes and flat areas. Mixed 

forest stands occur when spruce becomes established in the 

broadleaf stands. Needleleaf forests dominated by spruce 

eventually replace the mixed stands on many sites.

Wildfire. - Wildfires occur frequently in the Interior 

Forested Lowlands and Uplands Ecoregion. Fire size has 

ranged from less than 1 ha to 260,800 ha (the largest occurring in the Kuskokwim Mountains), with an average size of 

1,630 ha. Low annual precipitation, high summer temperatures, low relative humidity, frequent lightning storms, and 

trees having branches low to the ground are factors that make 

this ecoregion especially prone to wildfire. The fire season 

usually lasts from June through the beginning of August.

Land Use and Settlement. - The region is used primarily for subsistence and recreational hunting and fishing. 

Native inhabitants have descended from a number of 

Athabascan groups, such as the Koyukon, Kutchin, Tanana, 

Han, Tanacross, Upper Tanana, Upper Kuskokwim, 

Holikachuk, and Ingalik. Upland dwellers rely on large game 

(caribou and moose) as important sources of food and materials. Riverine groups depend heavily on salmon and freshwater fish (for example, whitefish, blackfish, and pike). Smaller 

mammals and ptarmigan provide secondary subsistence 

sources. Edible and medicinal plant parts are also collected.

Investigation and extraction of metals (for example, gold, 

silver, tin, tungsten, mercury, lead, platinum, nickel, zinc, 

chromium, cobalt, columbium, and copper) occur in many 

areas. Energy-related resources in the region include uranium 

and coal. Other extractable resources are antimony, bismuth, 

molybdenum, thorium, and rare earth elements. Sand and gravel operations have supported construction and road building.

Delineation Methods. - The ecoregion boundary abutting the Arctic Foothills in the northwest delineates where 

the forest ecosystems meet the arctic tundra ecosystems, as 

depicted on the map "Major Ecosystems of Alaska." The 

boundaries adjacent to the Brooks Range, the Ogilvie 

Mountains, the Ahklun and Kilbuck Mountains, the Alaska 

Range, and the Wrangell Mountains Ecoregions are based on 

a generalized 600-m elevation contour. The boundary adjacent to the Interior Highlands is based on a generalized 

500-m elevation contour. The boundary shared with the 

Interior Bottomlands and Yukon Flats Ecoregions eliminates 

from the Interior Forested Lowlands and Uplands Ecoregion 

those areas of low and very low terrain roughness that have 

"Bottomland Spruce-Poplar Forest," "Lowland 

Spruce-Hardwood Forest," or "Low Brush, Muskeg Bog" 

ecosystems, as shown on the map "Major Ecosystems of 

Alaska." The boundary adjoining the Subarctic Coastal 

Plains Ecoregion was based on where the coastal "Wet 

Tundra" and "Moist Tundra" ecosystems meet the interior 

forest ecosystems, also as shown on the map "Major 

Ecosystems of Alaska." Likewise, the boundary adjoining 

the Seward Peninsula was based on the extent of the forest 

ecosystems of the interior versus the brush and tundra 

ecosystems shown for the peninsula. The boundary shared 

with the Bristol Bay- Nushagak Lowlands Ecoregion is 

based on separating the coastal tundra and "Lowland 

Spruce-Hardwood Forest" of the Lowlands from the 

"Upland Spruce-Hardwood Forest" and small, scattered 

"Alpine Tundra" areas of the Interior. Transitional zones 

shown in the Interior Forested Lowlands and Uplands 

Ecoregion depict areas of isolated peaks greater than 600 m 

in elevation that are near borders of montane regions, and 

moist tundra ecosystems that are adjacent to coastal and bottomland regions.

References. - The information provided in this regional description has been compiled from Beikman (1980), 

Coulter and others (1962), Ferrians (1965), Gabriel and 

Tande (1983), Joint Federal-State Land Use Planning 

Commission for Alaska (1973), Karlstrom and others 

(1964), Kimmins and Wein (1986), Langdon (1993), Larson 

and Bliss (written commun., 1992), Moore (written commun., 1993), Morgan (1979), Ping (written commun., 1993), 

Pittman (1992), Reiger and others (1979), Selkregg (1974), 

Slaughter and Viereck (1986), Viereck (1989), U.S. Bureau 

of Mines (1992a, 1992b), U.S. Geological Survey (1987a), 

Viereck and Little (1972), Viereck and others (1986, 1992), 

Wahrhaftig (1965), and WeatherDisc Associates, Inc. 

(1990).

105. INTERIOR HIGHLANDS

Distinctive Features. - The 115,000-km2 discontinuous Interior Highlands Ecoregion is composed of rounded,
INTERIOR HIGHLANDS 21

low mountains, often surmounted by rugged peaks (fig. 13). 

The highlands primarily sustain dwarf scrub vegetation and 

open spruce stands, though graminoid herbaceous communities occur in poorly drained areas. Mountains in most parts 

of this region rise to at least 1,200 m, and many rise higher 

than 1,500 m. Most of the higher peaks were glaciated during the Pleistocene epoch.

Climate. - The ecoregion has a continental climate. 

Although no long-term weather data are available, certain 

generalizations can be made regarding temperature and precipitation. First, an orographic effect on precipitation causes the highlands to receive more precipitation than the surrounding, lower elevation areas. Second, summer temperatures probably decrease with elevation. Because of steep and 

persistent winter temperature inversions at lower elevations, 

it is difficult to generalize the relative pattern of winter temperatures in the highlands versus in the surrounding areas.

Terrain. - The ecoregion consists of steep, rounded 

ridges, often capped by rugged peaks. Elevations range from 

500 m in the valleys to greater than 1,500 m on the peaks 

(some peaks rise above 1,800 m). Slope gradients commonly 

range from 5° to 15°, but lower gradient slopes are typical 

around the margins of the ecoregion. The mountains have 

much more exposed bedrock than the surrounding hills of the 

Interior Forested Lowlands and Uplands Ecoregion. Geologic 

formations of the Interior Highlands consist of Paleozoic and 

Precambrian metamorphic rocks, felsic volcanic rocks, and 

intrusive rocks. Outlying parts of the ecoregion, in the 

Kuskokwim Mountains and Nulato Hills, have Cretaceous 

and Lower Paleozoic sedimentary rocks. The northern portions of the ecoregion are underlain by continuous permafrost, 

and the central and southern portions are underlain by discontinuous permafrost. Permafrost and frost-related ground features are evident, including low mounds, gelifluction lobes, 

frost boils, and stone stripes. Many of the peaks were glaciated during the Pleistocene epoch.

Soils. - Dominant soils are Histic Pergelic Cryaquepts, 

Typic Cryochrepts, Pergelic Cryumbrepts, Lithic 

Cryorthents, and Typic Cryorthods. Most soils are shallow, 

formed in very stony or gravelly material weathered from 

local rock. The permafrost table is shallow and soils are 

poorly drained; however, they are generally too shallow over 

bedrock for ground-ice to form. Barren, rocky peaks and 

stony and bouldery slopes are common. Alluvium and colluvium cover the valley floors. Soils with permafrost are 

very susceptible to alteration upon disturbance of the organic mat because of the relatively warm (>-1.5°C) permafrost 

temperature. Organic mat disturbance, as by wildfires, can 

result in warmer soil temperatures, lowered permafrost 

tables, and significant changes in soil physical properties and 

hydrology.

Vegetation. - The highest elevations are barren of vegetation. Dwarf scrub communities, dominated by species of 

mountain-avens, ericads, and willow, are widespread in sites 

exposed to wind. Lower elevations are generally more protected from wind and have a denser vegetation cover that can 

include open needleleaf forests and woodlands. Areas of 

poor soil drainage support mesic graminoid herbaceous 

communities.

Mountain-avens dwarf scrub communities are dominated by several species of Dryas (for example, D. octopetala, 

D. integrifolia, and D. drummondii). Sedges (for example, 

Carex scirpoidea, C. misandra, C. bigelowii and Kobresia 

myosuroides) and lichens (for example, Alectoria spp., 

Cetraria spp., and Cladina spp.) may codominate with 

Dryas. Also common are prostrate willows (Salix reticulata 

and S. phlebophylla) and ericaceous species (for example, 

Vaccinium spp., Cassiope tetragona, Arctostaphylos spp., and 

Empetrum nigrum). Mosses (for example, Tomenthypnum 

nitens, Rhytidium rugosum, and Hylocomium splendens) are 

abundant in Dryas—sedge communities.

Ericaceous dwarf scrub communities are also widespread. Bearberry (Arctostaphylos alpina or A. rubra) and 

cranberry/blueberry (Vaccinium spp.) are the common dominants, though other ericaceous shrubs (for example, Ledum 

decumbens, Empetrum nigrum, and Cassiope tetragona), 

prostrate willows (Salix phlebophylla and S. rotundifolia), 

and fruticose lichens (for example, Cladina spp., Cetraria 

spp., and Stereocaulon tomentosum) may be common or 

codominant. Mosses (for example, Dicranum spp., 

Rhacomitrium lanuginosum, Tomenthypnum nitens, and 

Hylocomium splendens) are common.

Willow dwarf scrub communities are dominated by willow (for example, Salixpolaris, S. reticulata, and S. arctica). 

Other dwarf shrubs (for example, Empetrum nigrum, 

Cassiope lycopodioides, Dryas spp., Vaccinium spp., and 

Ledum decumbens) are common and may codominate with 

willows. Mosses (for example, Dicranum spp. and 

Aulacomnium spp.) can be common.

Open needleleaf forests and woodlands are often dominated by white spruce (Picea glauca) or codominated by 

white spruce and black spruce (P. mariana). Other tree 

species in these communities include paper birch (Betula 

papyri/era) and quaking aspen (Populus tremuloides). The 

open shrub layer commonly includes resin birch (Betula 

glandulosa), alder (Alnus crispa and A. sinuata), willow 

(Salix planifolia and S. lanata), prickly rose (Rosa acicularis), buffaloberry (Shepherdia canadensis), and other ericaceous shrubs. The ground is covered by a continuous layer 

of mosses (for example, Pleurozium schreberi, Hylocomium 

splendens, Polytrichum spp., and Dicranum spp.). Lichens 

(for example, Cladonia spp.) provide significant cover at 

some sites.

Mesic graminoid herbaceous communities consist of 

sedge tussocks (for example, Eriophorum vaginatum and 

Carex bigelowii) surrounded by mosses. Low shrubs (for
22 ECOREGIONS OF ALASKA

Figure 13. Rounded mountains, often surmounted by rugged peaks, are typical of the Interior Highlands Ecoregion. 

Vegetation communities consist of alpine tundra and open spruce stands.

Figure 14. Relatively flat terrain of Interior Bottomlands Ecoregion. Soil drainage is usually poor. Black spruce and low 

ericaceous shrubs are common on slightly raised peat deposits. Various forbs and graminoid species occur in vegetated wetlands. Vegetation communities are subject to periodic flooding from local rivers.
INTERIOR BOTTOMLANDS 23

example, Betula nana and several ericaceous species) may 

also grow between tussocks.

Wildfire. - Occurrence of wildfires in the Interior 

Highlands Ecoregion is very common. Fire records indicate 

a range in size from less than 1 ha to greater than 82,000 ha, 

with an average size of 640 ha. The occurrence of fires can 

be related to the relatively warm and dry summer climate of 

interior Alaska and frequent lightning storms. Fire season is 

usually from June through the beginning of August.

Land Use and Settlement. - The ecoregion primarily 

provides resources for subsistence and recreational hunting 

and fishing. The highlands have historically been used by a 

number of Athabascan groups. Hunting for large game (for 

example, moose, caribou, and sheep) is supplemented by 

hunting for smaller mammals (such as ground squirrels). 

Streams supporting salmon and freshwater fish provide additional food and materials. Plants are collected for edible and 

medicinal purposes.

Many minerals have been mined, although most operations have ceased production. Important mining elements 

have included gold, silver, tin, tungsten, lead, copper, mercury, zinc, platinum, chromium, antimony, asbestos, molybdenum, and rare earth elements. Energy-related resources 

have included uranium and coal.

Delineation Methods. - The ecoregion boundary was 

delineated based on a generalized 500-m elevation contour. 

This elevation often, but not always, coincides with areas of 

"Alpine Tundra" on the map of "Major Ecosystems of Alaska." 

"Upland Spruce-Hardwood Forest" covers the rest of the 

region. Patterns on the relative CIR image generally agree with 

the boundary depicted on the ecoregion map. Transitional 

zones represent areas where upland peaks are widely scattered 

(approximately 10 km or farther from other peaks).

References. - The information provided in this regional 

description has been compiled from Beikman (1980), Coulter 

and others (1962), Fenians (1965), Fenians and Hobson 

(1973), Gabriel and Tande (1983), Joint Federal-State Land 

Use Planning Commission for Alaska (1973), Karlstrom and 

others (1964), Langdon (1993), Larson and Bliss (written 

commun., 1992), Moore (written commun., 1993), Morgan 

(1979), Ping (written commun., 1993), Reiger and others (1979), 

Selkregg (1974), Slaughter and Viereck (1986), U.S. Bureau of 

Mines (1992a, 1992b), U.S. Geological Survey (1964, 1987a), 

Viereck and Little (1972), Viereck and others (1992), Wahrhaftig 

(1965), and WeatherDisc Associates, Inc. (1990).

106. INTERIOR BOTTOMLANDS

Distinctive Features. - The 103,000-km2 ecoregion is 

composed of flat to nearly flat bottomlands along larger

rivers of interior Alaska. The bottomlands are dotted with 

thaw and oxbow lakes (fig. 14). Soils are poorly drained and 

shallow, often over permafrost. Predominant vegetation 

communities include forests dominated by spruce and hardwood species, tall scrub thickets, and wetlands.

Climate. - The ecoregion has a continental climate. 

The bottomlands in the west receive more annual precipitation than those in the east. Annual precipitation ranges 

from 280 mm to 400 mm, and annual snowfall from 95 cm 

to 205 cm. Average daily minimum temperatures in winter 

range from -33°C to -26°C. Average daily maximum winter 

temperatures range from -22°C to -17°C. Summer temperatures have lows of about 7°C and highs of about 22°C. 

Summer maximum temperatures generally increase from 

west to east. Temperatures usually remain above freezing 

throughout the summer (June through August), though they 

may dip below freezing during this time.

Terrain. - The ecoregion is typified by flat to nearly flat 

bottomlands, with some inclusions of local hills. Most areas in 

the bottomlands have a slope gradient of less than 1°. 

Elevations range from 120 m in the west to 600 m in the east. 

Fluvial and aeolian (for example, large areas of stabilized 

dunes) deposits of mixed origin cover most of the region, but 

outwash gravel and morainal deposits occur in some areas, such 

as the Northway-Tanacross lowland. Permafrost is widespread, 

but it ranges from isolated masses to a continuous thin layer. 

The ecoregion is strongly associated with riparian features; 

meandering streams and side sloughs are prevalent. Oxbow 

lakes and thaw lakes are numerous. Morainal lakes occur in a 

few areas, where Pleistocene glaciers from the Alaska Range 

reached the edge of this ecoregion. The Interior Bottomlands 

Ecoregion was not glaciated during the Pleistocene epoch.

Soils. - Principal soils are Histic Pergelic Cryaquepts, 

Pergelic Cryaquepts, Aquic Cryochrepts, Typic Cryochrepts, 

and Typic Cryofluvents. Most soils formed in micaceous 

loess and alluvial materials. On flat areas away from the 

main river channels, soils are shallow over permafrost, poorly drained, and nearly always wet. On the slightly higher levees, soils are well drained and permafrost is deep or absent. 

Soils with permafrost are very susceptible to alteration upon 

disturbance of the organic mat because of the relatively warm 

(>-1.5°C) permafrost temperature. Organic mat disturbance, 

as by wildfire, can result in warmer soil temperatures and 

lowered permafrost tables. Soil physical properties may 

change, as well as hydrology, on any upland position.

Vegetation. - Needleleaf, broadleaf, and mixed forest 

stands occur on a variety of sites in the Interior Bottomlands 

Ecoregion. Tall scrub communities form thickets on floodplains. The wettest sites support a variety of wetland communities, such as low scrub bogs, wet graminoid herbaceous 

meadows, and wet forb herbaceous marshes and meadows.
24 ECOREGIONS OF ALASKA

Needleleaf forests are dominated by white spruce (Picea 

glaucd), black spruce (Picea mariand), or a combination of the 

two. Closed stands of white spruce occupy young river terraces 

where soil drainage is good. Understory vegetation consists primarily of low and dwarf scrub, such as ericaceous species (for 

example, Vaccinium vitis-idaea and V. uliginosum, Ledum 

groenlandicum, and Empetrum nigrum) and dwarf arctic birch 

(Betula nand). Herbaceous species, such as twinflower 

(Linnaea borealis) and horsetail (Equisetum sylvaticum and E. 

arvense), are common. A well-developed moss layer (mainly 

of feathermosses, such as Hylocomium splendens, Pleurozium 

schreberi, and Rhytidiadelphus triquetrus) is typical.

Closed stands of black spruce occur on well-drained to 

poorly drained floodplain soils. Associated woody species 

include white spruce (Picea glaucd), paper birch (Betula 

papyri/era), American green alder (Alnus crispa), prickly 

rose (Rosa acicularis), willow (Salix spp.), Labrador-tea 

(Ledum groenlandicum), bog blueberry (Vaccinium uliginosum), and mountain-cranberry (V vitis-idaed). The moss 

layer varies from patchy to continuous and generally includes 

Hylocomium splendens and Pleurozium schreberi. 

Sphagnum species may occur on wetter sites. Foliose lichens 

(for example, Peltigera aphthosa and P. canina) are common.

Stands codominated by white spruce and black spruce 

have a tall shrub understory of alder (Alnus crispa) and willow (Salix bebbiana and S. scouleriand). Other understory 

components are similar to those found in white spruce stands 

and black spruce stands.

Colder, wetter soils support black spruce woodlands, 

where the tall shrub (for example, Alnus crispa, Betula glandulosa, Salix lanata, S. planifolia, and S. glaucd) understory is 

a much more important component of the ecosystem than in 

the closed forest stands. Ericaceous shrubs (for example, 

Vaccinium uliginosum, V. vitis-idaea, Ledum decumbens, L. 

groenlandicum, and Empetrum nigrum) are common, and 

herbaceous cover, dominated by sedges (Carex spp. and 

Eriophorum vaginatum) and grasses (for example, 

Calamagrostis canadensis), ranges from sparse to dense. 

Mosses (Hylocomium splendens, Pleurozium schreberi, and 

Sphagnum spp.) and lichens (Nephroma arcticum, Cladonia 

spp., Cladina spp., Cetraria spp., and Peltigera spp.} provide 

continuous ground cover.

Broadleaf forests consist of closed stands of Balsam 

poplar (Populus balsamiferd). The understory consists of 

shrubs, such as alder (Alnus crispa and A. tenuifolia), willow 

(Salix spp.), prickly rose (Rosa acicularis), high bushcranberry (Viburnum edule), and red-osier dogwood (Cornus 

stolonifera), as well as a dense herb layer of species such as 

northern bedstraw (Galium boreale), dwarf dogwood 

(Cornus canadensis), and bluebell (Mertensiapaniculatd).

Mixed forests form where paper birch codominates in 

stands with black spruce and white spruce, and where white 

spruce codominates in stands with balsam poplar.

Tall scrub communities are dominated by willow (for 

example, Salix alaxensis and S. glaucd) or alder (Alnus crispa

or A. sinuatd). The understory is usually sparse, though 

mosses (for example, Polytrichum spp., Hylocomium splendens, and Drepanocladus uncinatus) may be common. Herb 

cover ranges from sparse to dense, including bluejoint 

(Calamagrostis canadensis), horsetail (Equisetum arvense), 

monkshood (Aconitum delphinifolium), fireweed (Epilobium 

latifolium and E. angustifoliuni), bluebell (Mertensia paniculatd), and lady fern (Athyriumfilix-femind).

Low scrub bogs are characterized by open, low mixed 

shrubs and tussock-forming sedges. Resin birch (Betula glandulosd), dwarf arctic birch (B. nand), narrow-leaf 

Labrador-tea (Ledum decumbens), bog blueberry (Vaccinium 

uliginosum), mountain-cranberry (V. vitis-idaea), and sedge 

tussocks (for example, Eriophorum vaginatum) are the most 

common species. Mosses (for example, Sphagnum spp., 

Pleurozium schreberi, and Hylocomium splendens) form a 

continuous mat between tussocks.

Wet graminoid herbaceous meadows are typically dominated by tall sedges (for example, Carex aquatilis, C. rostrata, C. saxatilis, and C. sitchensis). Woody plants are scarce. 

Mosses (for example, Sphagnum spp.) can be common.

Wet forb herbaceous marshes are characterized by an 

open cover of wetland emergent species. Horsetail 

(Equisetum fluviatile) typically dominates the communities, 

though buckbean (Menyanthes trifoliata) and marsh fivefinger (Potentilla palustris) are common associates. Aquatic 

mosses often are present.

Wet forb herbaceous meadows are dominated by nongraminoid herbaceous species, (for example, Equisetum 

arvense, E. variegatum, Caltha palustris, and Juncus arcticus,), though grasses and sedges may be present.

Wildfire. - Occurrence of wildfires in the Interior 

Bottomlands Ecoregion is very common. Fire records indicate a range in size from less than 1 ha to 325,150 ha (the 

largest in Kanuti Flats), with an average size of 2,260 ha. A 

high occurrence of lightning storms, a warm and dry summer 

climate, and stands of vegetation with branches low to the 

ground aid the ignition and spread of wildfire. Fire season 

generally lasts from June through the beginning of August.

Land Use and Settlement. - Most of the settlements in 

the Alaskan interior occur in the bottomlands because of the 

food sources and transportation routes provided by rivers. 

The ecoregion is used for subsistence and recreational hunting and fishing. Native inhabitants include several 

Athabascan groups (for example, Ingalik, Koyukon, Tanana, 

and Holikachuk). The riverine systems of the bottomlands 

provide salmon and other fish that are important sources for 

subsistence. A variety of mammals (for example, caribou, 

moose, beaver, and muskrat) and birds (for example, geese 

and ducks), drawn to the water, are also hunted for food and 

materials. Edible greens, roots, and berries round out the diet.

Extractable metals are found in certrain areas, such as 

near the confluence of the Yukon and Tanana Rivers, where
YUKON FLATS 25

Figure 15. Water-worked basin of the Yukon Flats Ecoregion covered by numerous thaw and oxbow lakes. Annual precipitation is insufficient to maintain many lakes, which are replenished by yearly flooding of the Yukon River (center, flowing 

from east to west) during spring breakup of river ice.

gold and silver occur. An assortment of other metal and nonmetal resources have also been mined, but to a much smaller degree. There is some logging activity. Limited agricultural efforts have occurred along the Tanana River.

Delineation Methods. - The ecoregion boundary was 

based on areas where low and very low terrain roughness 

coincide with the distribution of the "Bottomland 

Spruce-Poplar Forest," "Lowland Spruce-Hardwood Forest," 

and "Low Brush, Muskeg-Bog" classes shown on the map 

"Major Ecosystems of Alaska." Transitional areas are not 

indicated because areas not consistent with the above criteria 

were not included in the ecoregion.

References. - The information provided in this regional description has been compiled from Beikman (1980), 

Coulter and others (1962), Drury (1956), Ferrians (1965), 

Gabriel and Tande (1983), Hall (1991), Joint Federal-State 

Land Use Planning Commission for Alaska (1973), 

Karlstrom and others (1964), Langdon (1993), Larson and 

Bliss (written commun., 1992), Markon (1992), Moore 

(written commun., 1993), Morgan (1979), Ping (written 

commun., 1993), Reiger and others (1979), Selkregg (1974), 

Shasby (unpub. mapping 1985), Talbot and Markon (1988, 

1986), Talbot and others (1986), U.S. Bureau of Mines

(1992a, 1992b), U.S. Fish and Wildlife Service (1987a), 

U.S. Geological Survey (1964, 1987a), Viereck (1989), 

Viereck and Little (1972), Viereck and others (1992), 

Wahrhaftig (1965), and WeatherDisc Associates, Inc. (1990).

107. YUKON FLATS

Distinctive Features. - The 33,000-km2 Yukon Flats 

Ecoregion is a relatively flat, marshy basin floor in east central Alaska that is patterned with braided and meandering 

streams, numerous thaw and oxbow lakes, and meander scars 

(fig. 15). Surrounding the basin floor is a variable band of 

more undulating topography with fewer water bodies (fig. 16). 

In many respects, the ecoregion is similar to the Interior 

Bottomlands Ecoregion. However, the Yukon Flats 

Ecoregion differs in climatic characteristics. Temperatures 

in the Flats tend to be more extreme than in the Bottomlands. 

For example, summers in the Flats are warmer and winters 

are colder than in other areas of comparable latitude. The 

Flats also receive less annual precipitation than the 

Bottomlands. Forests dominated by spruce and hardwood 

species, tall scrub communities, and wet graminoid herbaceous communities are the predominant vegetation types.
26 ECOREGIONS OF ALASKA

Figure 16. Undulating topography covered by dense forests of black spruce interspersed with small lakes along the periphery of the Yukon Flats Ecoregion.

Figure 17. Widespread forests of the Yukon Flats Ecoregion occupying sites representing an array of soil drainage characteristics often formed by changes in river courses. Tall scrub thickets occur on alluvial deposits subject to periodic flooding. 

Tall scrub swamps and wet graminoid herbaceous communities occupy the wettest sites.
YUKON FLATS 27

Climate. - The Yukon Flats Ecoregion has a continental 

climate. The mountains surrounding the ecoregion isolate it 

from the weather systems affecting the neighboring regions. 

Consequently, summer temperatures tend to be higher than 

at other places of comparable latitude and winter temperatures tend to be colder. Average daily temperatures in winter range from lows of about -34°C to highs of about -24°C. 

Average daily temperatures in summer range from lows of 

just above freezing to highs of about 22°C (the ecoregion is 

the only place north of the Arctic Circle where a temperature 

of 38°C has been recorded). Although temperatures usually 

remain above freezing from June through August, freezing 

can occur in any month.

Annual precipitation is low, averaging 170 mm. 

Average annual snowfall is 115 cm. Precipitation is not sufficient to maintain water levels in many lakes. Levels are 

primarily maintained by the yearly flooding of the region 

that accompanies spring breakup of ice on the Yukon River.

Terrain. - The central portion of the ecoregion is flat, 

becoming more undulating along the edges. Elevations range 

from 90 m to greater than 250 m. Slope gradient is generally less than 1° in the center of the ecoregion, and 1° to 2° at 

the edges. The region is mantled by Quaternary alluvial 

deposits. Aeolian silt and sand deposits cover some areas. 

The Yukon River drains the ecoregion, assisted by numerous 

meandering and braided tributaries and side sloughs. 

Permafrost is present in most areas, except beneath rivers and 

large thaw lakes. Thaw lakes are abundant, as are oxbow 

lakes. The region was free from glaciation during the 

Pleistocene epoch.

Soils. - Principal soils are Histic Pergelic Cryaquepts, 

Pergelic Cryaquepts, Aquic Cryochrepts, and Pergelic 

Cryochrepts. Most soils formed from silty alluvium and 

loess from the floodplains of the large rivers. On flat areas 

away from the main river channels, soils are poorly drained, 

commonly overlain by peat, and have a shallow permafrost 

table. Soils on the natural levees are better drained and consist of silty and sandy sediments. Many of the soils are subject to flooding. Soils with permafrost are very susceptible 

to alteration upon disturbance of the organic mat, due to the 

relatively warm (>-1.5°C) permafrost temperature. Organic 

mat disturbance, as by wildfire, can result in warmer soil 

temperatures and lowered permafrost tables. Soil physical 

properties may change, as well as hydrology, on any upland 

position.

Vegetation. - Needleleaf, broadleaf, and mixed forests 

are widespread and occupy sites representing an array of soil 

drainage characteristics. Tall scrub thickets occur on alluvial 

deposits subject to periodic flooding. Tall scrub swamps and 

wet graminoid herbaceous communities occupy the wettest 

sites (fig. 17).

Needleleaf forests of white spruce (Picea glaucd) are

found on well drained sites. Willow (for example, Salix bebbiana) commonly dominates the understory shrub layer. 

Foliose lichens (for example, Parmelia spp. and Peltigera 

spp.), along with feathermosses, cover the ground.

Needleleaf forests dominated by black spruce (Picea 

mariana) grow in open stands where drainage is poor. 

Common understory shrubs are resin birch (Betula glandulosa), narrow-leaf Labrador-tea (Ledum decumbens), crowberry (Empetrum nigrum), and bog blueberry (Vaccinium 

uliginosum). Feathermosses are common.

Broadleaf forests dominated by quaking aspen (Populus 

tremuloides) and balsam poplar (Populus balsamifera) occur 

on floodplains. Common understory shrubs include willow 

(Salix spp.), prickly rose (Rosa acicularis), and buffaloberry 

(Shepherdia canadensis).

Mixed forests consist of closed stands of white spruce 

and paper birch (Betula papyri/era) or white spruce and balsam poplar (Populus balsamifera) on the better drained alluvial soils; poorly drained soils support stands of black spruce 

(Picea mariana) and paper birch.

Understory constituents of the broadleaf and mixed forest communities generally include a tall shrub layer of alder 

(for example, Alnus crispa and A. tenuifolia) and willow 

(Salix spp.) and a low shrub layer of prickly rose (Rosa acicularis) and high bushcranberry (Viburnum edule). An herb 

layer is common and typically includes bluejoint 

(Calamagrostis canadensis), bluebell (Mertensia 

paniculata), and horsetail (Equisetum spp.).

Tall scrub communities are dominated by willows (generally Salix alaxensis, S. arbusculoides, S. barclayi, S. lanata, and S. sitchensis), alders (Alnus crispa, A. sinuata, and A. 

tenuifolia), or a mix of willows and alders. Herbs (for example, Calamagrostis canadensis, Epilobium angustifolium, 

Geranium erianthum, and Aconitum delphinifolium) and 

mosses (for example, Hylocomium splendens, Polytrichum 

spp., and Drepanocladus uncinatus) may be abundant or 

sparse.

Tall scrub swamp communities are dominated or 

codominated by alder (Alnus tenuifolia) and willow (Salix 

planifolia and S. lanata). The low shrub layer typically 

includes currant (Ribes spp.), high bushcranberry (Viburnum 

edule), and prickly rose (Rosa acicularis). Bluejoint 

(Calamagrostis canadensis), sedge (Carex aquatilis), horsetail (Equisetum spp.), and marsh fivefinger (Potentillapalustris) are common herbs. Mosses (for example, Sphagnum 

spp., Mnium spp., and feathermosses) are usually present.

Wet graminoid herbaceous communities are dominated by 

sedges (for example, Carex aquatilis, C. rostrata, C. saxatilis, 

and C. sitchensis). Other herbaceous vegetation, such as horsetail (Equisetum arvense), may codominate with sedges. 

Mosses (for example, Sphagnum spp.) can be common.

Wildfire. - Occurrence of wildfires in the Yukon Flats 

Ecoregion is common. The recorded range in size has been 

from less than 1 ha to 32,370 ha. Mean fire size is 685 ha.
28 ECOREGIONS OF ALASKA

Land Use and Settlement. - The region is populated by 

several small villages. The primary land use is subsistence 

and recreational hunting and fishing. The Kutchin 

Athabascans have historically inhabited the Yukon Flats basin. 

They depend on the rivers to provide salmon and freshwater 

fish, a main dietary staple. Hunting for caribou and moose is 

also important, supplemented by hunting for smaller mammals. Edible and medicinal greens, roots, and berries are collected. Gold has been the only major mined commodity.

Delineation Methods. - The ecoregion boundary was 

based on areas where low and very low terrain roughness 

coincide with the "Bottomland Spruce-Poplar Forest," 

"Lowland Spruce-Hardwood Forest," and "Low Brush, 

Muskeg-Bog" classes shown on the map "Major Ecosystems 

of Alaska." Transitional zones separate the central core of the 

region, where very low terrain roughness occurs, from the 

peripheral, low surface roughness areas. The "core" area corresponds with patterns evident on the relative CIR image.

References. - The information provided in this regional description has been compiled from Beikman (1980), 

Coulter and others (1962), Ferrians (1965), Gabriel and 

Tande (1983), Joint Federal-State Land Use Planning 

Commission for Alaska (1973), Karlstrom and others 

(1964), Langdon (1993), Larson and Bliss (written commun., 1992), Moore (written commun., 1993), Morgan 

(1979), Ping (written commun., 1993), Reiger and others 

(1979), Selkregg (1974), U.S. Bureau of Mines (1992a, 

1992b), U.S. Fish and Wildlife Service (1987b), U.S. 

Geological Survey (1964, 1987a), Viereck and Little (1972), 

Viereck and others (1992), Wahrhaftig (1965), and 

WeatherDisc Associates, Inc. (1990).

108. OGILVIE MOUNTAINS

Distinctive Features. - The 11,000-km2 Ogilvie 

Mountains Ecoregion, along the eastern edge of Alaska, consists of flat-topped hills eroded from a former plain (fig. 18) 

and broad pediment slopes built up from mountains that are 

much subdued from their former stature. Karst topography is 

common. Mesic graminoid herbaceous communities and tall 

scrub communities are widespread throughout the region. 

Forest communities occupy lower hillslopes and valleys.

Climate. - The Ogilvie Mountains have a continental climate. No perennial weather stations are located in this region. 

Precipitation and temperature characteristics, interpolated 

from stations outside the region, include an annual precipitation of about 500 mm in the hills to 650 mm in the higher 

mountains, annual snowfall from 130 cm to 205 cm across the 

region, daily winter temperatures ranging from lows of -32°C 

to highs of -22°C, and daily summer temperatures ranging 

from lows of 8°C to highs of 22°C.

Terrain. - The ecoregion consists predominantly of 

flat-topped hills eroded from a former plain. Pediment 

slopes, extending across broad valleys to the foothills of the 

current, subdued mountains, are characteristic of the 

plateaus. Erosional scarps in sedimentary rock occur in 

many localities. Weathered limestone is exposed at higher 

elevations, and talus and rubble mantle the lower mountainsides. Elevations range from 900 m to greater than 1,300 m. 

Slope gradients are generally less than 5°. The region is 

composed of metamorphic and sedimentary rocks, primarily 

dolomite, phyllite, argillite, limestone, shale, chert, sandstone, and conglomerate. Karst topography is common. 

Most of the region is underlain by permafrost; related features include pingos, earth hummocks, peat polygons, stone 

stripes, and beaded streams. Ponds and thermokarst basins 

occur in valley bottoms. The Ogilvie Mountains Ecoregion 

was not glaciated during the Pleistocene epoch.

Soils. - Principal soils of the Ogilvie Mountains 

Ecoregion are Histic Pergelic Cryaquepts, Typic 

Cryochrepts, and Pergelic Cryorthents. Soils formed in 

gravelly or stony material weathered from local rock. Soils 

in valleys formed from deep, loamy, alluvial sediments from 

the surrounding uplands. Areas near large floodplains are 

commonly mantled with silty loess. Rock fragments cover 

the lower mountainsides.

Vegetation. - Mesic graminoid herbaceous communities dominated by tussock-forming sedges are widespread 

and occur on sites exposed to wind. Needleleaf, broadleaf, 

and mixed forest communities occupy lower hillslopes and 

valleys. Tall scrub communities occur extensively at lower 

elevations and can extend above the timberline.

Mesic graminoid herbaceous communities are dominated by sedges (for example, Eriophorum vaginatum and 

Carex bigelowii). Mosses (for example, Drepanocladus spp. 

and Sphagnum spp.) commonly occur between sedge tussocks. Dwarf shrubs, such as dwarf arctic birch (Betula 

nana) and ericaceous species (for example, Ledum decumbens, Vaccinium vitis-idaea, V. uliginosum, and Empetrum 

nigrum), are often present.

Needleleaf forests dominated by white spruce (Picea 

glaucd) occur in well drained valleys and on protected sites. 

The more open forest stands typically have a tall shrub layer 

of alder (Alnus crispa and A. sinuatd) and willow (Salix 

planifolia and S. lanata), and a low shrub layer dominated by 

buffaloberry (Shepherdia canadensis) and prickly rose (Rosa 

acicularis). The ground supports a continuous mat of feathermosses (for example, Pleurozium schreberi and 

Hylocomium splendens). Closed forest stands generally lack 

a tall shrub layer but have a low shrub layer of bog blueberry (Vaccinium uliginosum), mountain-cranberry (V. 

vitis-idaea), bearberry (Arctostaphylos rubra), Labrador-tea 

(Ledum groenlandicum), crowberry (Empetrum nigrum), 

and resin birch (Betula glandulosa).
OGILVIE MOUNTAINS 29

Figure 18. The Ogilvie Mountains Ecoregion consists of flat-topped hills and broad pediment slopes vegetated by tussock 

tundra communities, alpine shrubs, mosses, and lichens. Forest communities occupy lower hillslopes and valleys. (Photo 

courtesy of Ken Winterberger, Forest Service, Forestry Sciences Laboratory, Anchorage.)

Figure 19. The Subarctic Coastal Plains Ecoregion is typified by numerous lakes surrounded by wet tundra communities, 

resulting from a shallow permafrost table and wet soils. The climate is affected by both maritime and continental influences.
30 ECOREGIONS OF ALASKA

Broadleaf forests of quaking aspen (Populus tremuloides) and balsam poplar (Populus balsamiferd) occupy 

well-drained warmer sites and recently exposed alluvial 

deposits. A tall shrub layer of willow (Salix spp.) is common. A low shrub layer generally includes prickly rose 

(Rosa acicularis) and buffaloberry (Shepherdia canadensis).

Mixed forests on poorly drained lowlands are dominated by black spruce (Picea mariana) and paper birch (Betula 

papyri/era). The understory consists of tall shrubs (for 

example, Alnus crispa, Salix bebbiana, and S. scouleriana) 

and low shrubs (for example, Rosa acicularis, Viburnum 

edule, Ribes triste, and Spiraea beauverdiana).

Mixed forests of well drained sites result from the invasion of white spruce into stands of aspen and balsam poplar 

(see broadleaf forest description above).

Tall scrub communities form dense thickets dominated 

by birch (Betula glandulosa) and willow (for example, Salix 

alaxensis, S. arbusculoides, S. planifolia, and S. lanata).

Wildfire. - Occurrence of wildfires in the Ogilvie 

Mountains Ecoregion is low. Size of burn ranges from less 

than 1 ha to 18,650 ha, with an average of 1,050 ha.

Land Use and Settlement. - There are only a few permanent settlements in this ecoregion. The region has traditionally been used for subsistence hunting and fishing by 

descendants of the Kutchin Athabascans. Larger streams are 

fished for salmon and freshwater species. Caribou, moose, 

and small mammals are the major terrestrial game. Edible 

and medicinal plants are also collected.

Gold, silver, platinum, and tin have been mined in this 

region, though mining is not extensive. Prospective sources 

of other metals and of energy-related commodities (coal, 

petroleum, and uranium) have been investigated.

Delineation Methods. - The ecoregion boundary was 

delineated using a generalized 600-m elevation contour, 

which somewhat corresponded with patterns shown on the 

relative CIR image. Information was insufficient to map 

transitional areas.

References. - The information provided in this regional description has been compiled from Beikman (1980), 

Coulter and others (1962), Ferrians (1965), Gabriel and 

Tande (1983), Joint Federal-State Land Use Planning 

Commission for Alaska (1973), Karlstrom and others 

(1964), Langdon (1993), Larson and Bliss (written commun., 1992), Moore (written commun., 1993), Morgan 

(1979), Ping (written commun., 1993), Oswald and Senyk 

(1977), Reiger and others (1979), Selkregg (1974), U.S. 

Bureau of Mines (1992a, 1992b), U.S. Geological Survey 

(1964, 1987a), Viereck and Little (1972), Viereck and others 

(1992), Wahrhaftig (1965), and WeatherDisc Associates, Inc. 

(1990).

109. SUBARCTIC COASTAL PLAINS

Distinctive Features. - The 91,000-km2 ecoregion mainly includes coastal plains of the Kotzebue Sound area and the 

Yukon and Kuskokwim River delta area. Flat, lake-dotted 

coastal plains and river deltas are characteristic of the region 

(fig. 19). Streams have very wide and serpentine meanders. 

Soils are wet and the permafrost table is shallow, providing 

conditions for wet graminoid herbaceous communities, the 

predominant vegetation type. The region is affected by both 

maritime and continental climatic influences.

Climate. - Climate is transitional between maritime and 

continental influences. In general, the southern portion of 

the region has warmer temperatures and receives more precipitation than the northern portion. Average annual precipitation varies from about 250 mm around Kotzebue Sound to 

500 mm in the Yukon-Kuskokwim lowlands. Annual snowfall is approximately 100 cm in the north and ranges from 

105 cm to 150 cm in the south. Temperatures in winter range 

from average daily lows of -25°C in the north and -20°C to 

-15°C in the south, to average daily maximums of -16°C in 

the north and -10°C in the south. July and August are usually frost-free months over most of the region. Average daily 

minimum temperatures in summer range from 6°C in the 

north to a couple of degrees warmer in the south. Average 

summer daily maximum temperatures vary from 13°C to 

17°C in both the northern and southern sections of the ecoregion, generally increasing inland from the coast.

Terrain. - The ecoregion is comprised mainly of flat, 

poorly drained coastal plains with shallow permafrost 

tables. Low hills of basalt surmounted by cinder cones and 

broad shallow volcanic craters occur in some locations, creating a range in regional elevation from sea level to greater 

than 120 m. Slope gradients in the plains are generally less 

than 1°. The region is predominantly covered by older 

coastal deposits of interstratified alluvial and marine sediments. Quaternary mafic and undifferentiated volcanic 

rocks occur in the western part of the Yukon-Kuskokwim 

lowlands and on Nunivak and St. Lawrence Islands. 

Cretaceous intermediate volcanic rocks occur in the 

Selawik Wildlife Refuge area. Only the northernmost portion of the ecoregion, around Kotzebue, was subject to 

Pleistocene glaciation. Continuous thin to moderately thick 

permafrost underlies the entire region. Thaw lakes and 

thaw sinks are numerous. Pingos are common around the 

Selawik River area. Streams are sluggish and have very 

wide meanders.

Soils. - Dominant soils are Histic Pergelic Cryaquepts 

and Pergelic Cryofibrists. Soils are shallow over permafrost 

and are constantly wet. Soils have formed from stratified 

silty and sandy alluvial deposits that, in many areas, have 

additionally incorporated deposits of volcanic ash and loess.
SUBARCTIC COASTAL PLAINS 31

Figure 20. White and black spruce stands growing on old river 

meander scars in the southern portion of the Subarctic Coastal 

Plains Ecoregion.

Soils on Nunivak Island formed in very gravelly and stony 

materials derived from basaltic rock.

Vegetation. - Standing water is almost always present 

in this ecoregion. Wet graminoid herbaceous communities, 

such as wet meadows and bogs, predominate in saturated 

soils. Peat mounds, barren sand dunes, and volcanic soils 

support dwarf scrub communities dominated by ericaceous 

species. In areas where peat or alluvium accumulation and 

growing season temperatures are sufficient, as in the southern section of the ecoregion, invasion by trees is possible, 

and stands of needleleaf forests occur (fig. 20).

Wet meadows are typically dominated by sedges (for 

example, Eriophorum angustifolium and Car ex spp.). 

Mosses (for example, Sphagnum spp.) are common and may 

codominate with sedges.

Bogs develop where peat mounds and polygonal ridges 

provide drained substrates for woody plants, such as ericaceous shrubs (for example, Empetrum nigrum, Ledum 

decumbens, Loiseleuria procumbens, Vaccinium vitis-idaea, 

and Andromeda polifolia}. Sedges are common or codominant with woody species. Sphagnum species usually dominate the moss layer.

Dwarf scrub communities are typically dominated by 

crowberry (Empetrum nigrum}. Many other ericaceous 

species (for example, Vaccinium vitis-idaea, V. uliginosum, 

Ledum decumbens, Loiseleuria procumbens, and 

Arctostaphyios alpina) and dwarf willows are common in 

these communities. Fruticose lichens (for example, 

Alectoria spp., Cladina spp., and Cetraria spp.) often 

codominate with shrubs. Mosses (for example, 

Rhacomitrium spp., Hypnum spp., Polytrichum spp., 

Sphagnum spp., and Dicranum spp.) are also common.

Needleleaf forests consist of black spruce (Picea mariana) and white spruce (P. glauca}. Alder (Alnus spp.), willow (Salix spp.), birch (Betula glandulosa and B. nand), and 

ericaceous shrubs (Vaccinium vitis-idaea, Ledum decumbens, and Empetrum nigrum} may be found in the understory. Mosses (for example, Sphagnum spp., Dicranum spp., 

Hypnum spp., Polytrichum spp., Hylocomium splendens, and 

Pleurozium schreberi) cover the ground.

Wildfire. - Occurrence of wildfires in the Subarctic 

Coastal Plains Ecoregion is low. Fires generally range in size 

from less than 1 ha to 4,050 ha. Mean burn size is 280 ha.

Land Use and Settlement. - Small permanent and seasonal settlements occur throughout the region, primarily 

adjacent to rivers or along the coast. The eastern end of 

Kotzebue Sound was settled by the Kotzebue Sound Inuit, 

who rely on small ocean mammals (for example, seals), 

land mammals (for example, caribou), fish (for example, 

pink and chum salmon), and migratory birds and their eggs 

as important sources of food and materials. The western 

end of Kotzebue Sound and the northeastern portion of 

Norton Sound were settled by the Bering Strait Inuit, who 

depend more heavily on large marine mammals (for example, beluga whale, bowhead whale, and walrus). The 

remainder of the ecoregion was settled by the Yup'ik. The 

Yup'ik of St. Lawrence Island rely on walrus as a main 

source of food and materials. Bowhead whales and seals 

are also important. The Yukon-Kuskokwim Delta Yup'ik 

depend primarily on salmon, but other fish, seals, beluga 

whales, and terrestrial mammals are also important. 

Migratory waterfowl and their eggs provide resources during the spring. Edible and medicinal greens and berries are 

collected during summer.

Though mining is not extensive in this region, gold and 

silver have been extracted.

Delineation Methods. - The ecoregion boundary represents the coincidence of low and very low terrain roughness 

and the "Wet Tundra" and "Moist Tundra" ecosystems por-
32 ECOREGIONS OF ALASKA

trayed on the map "Major Ecosystems of Alaska." In the 

Yukon-Kuskokwim portion, areas that are north of the 

Yukon River include both ''Wet Tundra" and "Moist Tundra" 

and exclude the forests of the interior regions. South of the 

Yukon River, only "Wet Tundra" is included because the 

"Moist Tundra" grades into the adjacent Ahklun and Kilbuck 

Mountains Ecoregion. Transition zones eliminate "Moist 

Tundra" from the periphery of the Subarctic Coastal Plains 

Ecoregion.

References. - The information provided in this regional 

description has been compiled from Beikman (1980), Coulter 

and others (1962), Ferrians (1965), Fleming (written commun., 

1993), Gabriel and Tande (1983), Joint Federal-State Land Use 

Planning Commission for Alaska (1973), Karlstrom and others 

(1964), Langdon (1993), Larson and Bliss (written commun., 

1992), Moore (written commun., 1993), Morgan (1979), Ping 

(written commun., 1993), Reiger and others (1979), Selkregg 

(1974), U.S. Bureau of Mines (1992a, I992b), U.S. Geological 

Survey (1964, 1987a), Viereck and Little (1972), Viereck and 

others (1992), Wahrhaftig (1965), WeatherDisc Associates, 

Inc. (1990), and Wibbenmeyer and others (1982).

110. SEWARD PENINSULA

Distinctive Features. - Some of the oldest geologic formations in Alaska provide a backdrop for the 47,000-km2 , 

predominantly treeless Seward Peninsula Ecoregion (fig. 21). 

Mesic graminoid herbaceous communities and low scrub 

communities occupy extensive areas. The ecoregion is surrounded on three sides by water, yet this has little ameliorating effect on the climate. Winters tend to be long and harsh 

and summers short and cool.

Climate. - Long, severe winters are typical of this ecoregion. Overall climatic characteristics range from maritime (a 

narrow strip along the coast), to transitional between maritime and continental influences (most of the region), to continental (in the eastern portion). Winds are persistent and 

strong throughout the region. Approximately 10 weeks are 

frost-free each summer. All weather stations in the region are 

located at the lower elevations. Annual precipitation is heaviest in late summer and early fall, occurring as rain. Mean 

annual precipitation ranges from 250 mm to 510 mm at lower 

elevations, with 100 cm to 190 cm of snowfall occurring. 

Mean annual precipitation for the highlands, interpolated 

from lowland data, exceeds 1,000 mm, and snowfall may be 

as much as 250 cm. Average daily minimum temperature in 

winter ranges from -24°C to -19°C, and average daily maximum from -16°C to -11°C. Average daily minimum temperature in summer ranges from 1 °C to 6°C, and maximum from 

13°C to 17°C. Temperatures are generally warmer in the 

southern portions of the region.

Terrain. - The ecoregion has narrow strips of coastal 

lowlands that grade into extensive uplands of broad convex 

hills and flat divides. Small, isolated groups of rugged 

mountains occur in a few locations. Elevation ranges from 

sea level to 500 m for most of the region; the higher mountains climb to 1,400 m. Slope gradients are generally from 

0° to 5° in the lowlands and hills, but typically from 5° to 15° 

in the mountains. Geologic parent materials include 

Paleozoic sediments and metamorphosed volcanic rocks and 

Precambrian volcanic rocks. Highland areas are possible 

Cenezoic uplifts of these formations. An extensive area of 

Quaternary or Tertiary volcanic rock occurs in the northeastern part of the ecoregion.

Permafrost is continuous throughout the ecoregion, 

ranging from a thin to a moderately thick layer. Related 

features, such as gelifluction lobes (fig. 22) and stone 

stripes on sloping areas, frost scars on low knolls, and polygons in level valley bottoms, are common. Streams draining interior basins travel through narrow canyons across 

broad uplands. Lowlands have numerous thaw lakes, but 

lakes are rare in the highlands. Except for the highest elevations, the region was unglaciated during the Pleistocene 

epoch.

Soils. - Predominant soils are Histic Pergelic 

Cryaquepts, Pergelic Cryaquepts, Typic Cryochrepts, 

Pergelic Cryumbrepts, Lithic Cryorthents, and Pergelic 

Cryorthents. Soils are generally poorly drained and shallow 

over permafrost. Soils on hillslopes and ridges formed in 

very gravelly residual materials over weathered bedrock. 

Soils in valleys and on lower slopes formed mainly in colluvial and alluvial sediments.

Vegetation. - The coastal beaches, rolling hills, and 

mountains in this ecoregion provide a variety of climate and 

substrate characteristics. Mesic graminoid herbaceous communities (fig. 23) and low scrub communities occupy extensive areas on hills and lower mountain slopes. Saturated or 

flooded soils sustain wet graminoid herbaceous communities. Tall scrub vegetation occurs along streams and on 

floodplains. Ridgetops and higher elevations are barren or 

support dwarf scrub communities.

Mesic graminoid herbaceous communities are dominated by tussock-forming sedges. Low scrub communities 

result when woody species colonize the area between tussocks. Principal sedges are Eriophorum vaginatum and 

Carex bigelowii. Woody species include dwarf arctic birch 

(Betula nana), resin birch (B. glandulosa), mountain-cranberry (Vaccinium vitis-idaea), bog blueberry (V. uliginosurri), diamondleaf willow (Salix planifolia), netleaf willow (S. reticulata), and crowberry (Empetrum nigrum). 

Mosses (for example, Pleurozium schreberi, Hylocomium 

splendens, Aulacomnium spp., and Sphagnum spp.) are 

prevalent, and lichens (for example, Cetraria cucullata, C. 

islandica, Cladonia spp., Cladina rangiferina, and
SEWARD PENINSULA 33

Figure 21. Coastal plains, rolling hills, low mountains, and lava flats of the Seward Peninsula Ecoregion. A lack of trees is 

noticeable across all terrain types.

Figure 22. Gelifluction lobes in the Bendeleben Mountains of the Seward Peninsula Ecoregion.
34 ECOREGIONS OF ALASKA

Thamnolia subuliformis) can be common.

Wet graminoid herbaceous communities consist of 

sedges (for example, Carex aquatilis, C. lyngbyaei, C. rostrata, C. saxatilis, C. sitchensis, and Eriophorum angustifolium) and grasses (for example, Calamagrostis canadensis 

and Arctophilafulva).

Tall scrub communities are dominated by willow (for 

example, Salix alaxensis, S. glauca, S. planifolia, and S. lanatd). Birch (for example, Betula nana) may codominate with 

willow in some areas. Other woody constituents include alder 

(Alnus sinuata and A. crispd) and shrubby cinquefoil 

(Potentillafruticosa). A dense herb layer may be present, typically including oxytrope (Oxytropis spp.), vetch (Astragalus 

spp.), dwarf fireweed (Epilobium latifolium), wormwood 

(Artemisia spp.), and bluejoint (Calamagrostis canadensis). 

Mosses (for example, Polytrichum spp., Hylocomium splendens, and Drepanocladus uncinatus) can be abundant.

Dwarf scrub communities are composed of low shrubs, 

grasses, and lichens. Communities are dominated by mountain-avens (Dryas octopetala and D. integrifolia) or codominated by a combination of mountain-avens and sedge (for 

example, Carex scirpoidea. C. misandra, and C. bigelowii) 

or mountain-avens and lichens (for example, Alectoria spp., 

Cetraria spp., and Cladina spp.). Other typical shrubs 

occurring in these communities are willows (Salix reticulata 

and S. phlebophylla) and ericads (for example, Cassiope 

tetragona, Empetrum nig rum, Arctostaphylos spp., 

Vaccinium vitis-idaea, and V. uliginosum). Mosses (for 

example, Tomenthypnum nitens, Rhytidium rugosum, and 

Hylocomium splendens) can be common.

Wildfire. - Occurrence of wildfires in the Seward 

Peninsula Ecoregion is common. Burns range in size from 

less than 1 ha to 109,260 ha, with an average size of 2,815 ha. 

Mosses and lichens dry out during summer, allowing fire to 

spread readily through the tundra. Fire season is usually from 

June through August.

Land Use and Settlement. - Population is low and small 

settlements are scattered throughout the region. The land has 

been historically used for subsistence hunting and fishing by 

the Bering Strait Inuit. Their livelihood has depended on large 

marine mammals, such as bowhead whales, beluga whales, 

and walrus. Winter ice fishing and seal hunting are important 

to supplement spring and summer ocean catches. Away from 

the coast, streams provide salmon and freshwater fish. Large 

game (for example, caribou) and smaller mammals (for example, rabbits, squirrels, muskrats, and beaver) are also taken. 

Reindeer herding is unique to this area.

A number of metallic elements, including antimony, 

barium, gold, lead, silver, tin, tungsten, and zinc occur in the 

region. Numerous mines, including many gold mines, are 

scattered throughout large parts of the region. Other important metals include copper, mercury, platinum, and uranium. 

Antimony, bismuth, and coal have also been mined.

Delineation Methods. - The ecoregion boundary delineates a break between the forested ecosystems of interior 

Alaska and the nonforested peninsula. One of the characteristic features of the Seward Peninsula is the age of the 

bedrock geologic formations; the transitional area on the 

ecoregion map excludes the more recent geologic formations 

along the eastern portion of the ecoregion from the older formations throughout the core of the region.

References. - The information provided in this regional 

description has been compiled from Beikman (1980), Coulter 

and others (1962), Ferrians (1965), Gabriel andTande (1983), 

Joint Federal-State Land Use Planning Commission for 

Alaska (1973), Karlstrom and others (1964), Langdon 

(1993), Larson and Bliss (written commun., 1992), Moore 

(written commun., 1993), Morgan (1979), Ping (written 

commun., 1993), Pittman (1992), Reiger and others (1979), 

Selkregg (1974), U.S. Bureau of Mines (1992a, 1992b), 

U.S. Geological Survey (1964, 1987a), Viereck and Little 

(1972), Viereck and others (1992), Wahrhaftig (1965), and 

WeatherDisc Associates, Inc. (1990).

111. AHKLUN AND KILBUCK MOUNTAINS

Distinctive Features. - Located in southwestern Alaska 

off Bristol and Kuskokwim Bays, the 51,000-km2 ecoregion 

is composed of steep, sharp, often ringlike groupings of 

rugged mountains separated by broad, flat valleys and lowlands (fig. 24). The mountains were glaciated during the 

Pleistocene epoch, but only a few small glaciers persist. 

Dwarf scrub communities are the predominant vegetation 

cover in the mountains. Tall scrub and graminoid herbaceous communities are common in valleys and on lower 

mountain slopes. Valley bottoms may support stands of 

spruce and hardwood species.

Climate. - Climate is affected by both maritime and 

continental influences. Average annual precipitation 

ranges from 1,020 mm in the lowlands to 2,030 mm in the 

higher mountains. Average annual snowfall ranges from 

205 cm to 510 cm, with a similar distribution pattern. 

Winter temperatures have an average daily minimum of 

-16°C and a maximum of -8°C. Mean summer temperatures have daily lows averaging about 8°C and daily highs 

of about 16°Cto 19°C.

Terrain. - This mountainous ecoregion is composed of 

strongly deformed sedimentary and volcanic rocks of late 

Paleozoic and Mesozoic age and includes some bodies of 

older schist. Ringlike mountain groupings have resulted 

from small granitic masses surrounded by more resistant 

hornfels. Slope gradients over most of the region are from 

0° to 8°, but steeper slopes are not uncommon (occurring 

across 7 percent of the area), and summits are very steep and
AHKLUN AND KILBUCK MOUNTAINS 35

Figure 23. Mesic graminoid herbaceous communities often occupy hills and lower mountain slopes of the Seward Peninsula 

Ecoregion.

Figure 24. Typical sharp mountain ridges encircling glacial lakes of the Ahklun and Kilbuck Mountains Ecoregion. 

Mountain groupings are separated by broad valleys.
36 ECOREGIONS OF ALASKA

Figure 25. Ericaceous dwarf scrub-graminoid community of the 

Ahklun and Kilbuck Mountains Ecoregion. Prostrate dwarf scrublichen vegetation grows on the hilltop in the background. (Photo 

taken by Carl Markon, Hughes STX Corporation, U.S. Geological 

Survey, EROS Alaska Field Office, Anchorage.)

sharp. Broad lowlands separate mountain groups. Regional 

elevations rise from sea level to more than 1,500 m. Streams 

are generally shallow and have radial drainage patterns; most 

are incised in bedrock gorges. A number of long, narrow, 

and often deep glacial lakes have formed in U-shaped valleys. The region was heavily glaciated during the 

Pleistocene epoch, and a few small cirque glaciers persist on 

higher mountains. Permafrost is discontinuous at higher elevations, and isolated masses occur at lower elevations.

Soils. - Principal soils are Histic Pergelic Cryaquepts, 

Pergelic Cryaquepts, Typic Cryochrepts, Lithic 

Cryumbrepts, Pergelic Cryumbrepts. Pergelic Cryorthods. 

Typic Haplocryods, and Typic Humicryods. Mountain soils 

formed in very stony and gravelly colluvial material over 

bedrock. Valleys soils formed in glacial till.

Vegetation. - Upper slopes and summits of mountains 

are exposed to harsh climatic conditions. Lower slopes and 

valleys offer more protected sites for vegetation establishment. Dwarf scrub communities are widespread in the 

mountains (fig. 25). Valleys provide an array of soil 

drainage conditions that support different vegetation communities (fig. 26). Sites with better drainage support needleleaf, broadleaf and mixed forest stands, and tall scrub communities. Mesic graminoid herbaceous communities occur 

over a range of dry to wet soils. The wettest sites are colonized by low scrub communities and wet graminoid herbaceous communities.

Dwarf scrub communities are dominated either by ericaceous shrubs (for example. Arctostaphylos alpina, Vaccinium 

vitis-idaea, V. uliginosum, Empetrum nigrwn, and Ledum 

decumbens), or by a mix of mountain-avens (Diyas octopetala) and dwarf arctic birch (Betula nand). Lichens (for example, Cladina spp., Cetraria spp., Stereocaulon tomentosum, 

Thamnolia vermicularis, Cladonia spp., and Alectoria spp.) 

may be sparse or may codominate with shrubs.

Valley bottoms may support needleleaf forests dominated by white spruce, broadleaf forests dominated by balsam 

poplar (Populus balsamifera), or mixed forests of white 

spruce and paper birch (Betula papyri/era). White spruce 

forests are dominated by Picea glauca. Resin birch (Betula 

glandulosd) dominates the low shrub layer. Common herbs 

include Linnaea borealis, Calamagrostis canadensis, and 

Equisetum spp. A nearly continuous cover of feathermosses 

(for example, Pleurozium schreberi and Hylocomium splendens) is typical. Lichens (for example. Cladonia spp.) are 

particularly common in open areas.

Balsam poplar forests are dominated by Populus balsamifera in the overstory. Understory composition varies, 

usually including willow (Salix spp), alder (Alnus spp.), high 

bushcranberry (Viburnum edule), prickly rose (Rosa acicularis), bluejoint (Calamagrostis canadensis), and feathermosses (Hylocomium splendens and Pleurozium schreberi).

Spruce-paper birch forests are dominated by white 

spruce (Picea glauca) and paper birch (Betula papyri/era). 

Shrubs, such as willow (Salix bebbiana and S. scouleriana), 

alder (Alnus crispa), prickly rose (Rosa acicularis), and high 

bushcranberry (Viburnum edule), are common. Typical 

herbs are bluejoint (Calamagrostis canadensis) and horsetail 

(Equisetum arvense). Cover by mosses (for example, 

Hylocomium splendens, Dicranum spp., Hypnum spp., and 

Rhacomitrium spp.) is patchy.

Tall scrub communities are dominated by willow (for 

example, Salix alaxensis, S. planifolia, and S. glauca). alder 

(for example, Alnus crispa and A. sinuata), or a mix of ericaceous shrubs (for example, Empetrum nigrum, Ledum 

decumbens, Vaccinium vitis-idaea, V. uliginosum, and 

Arctostaphylos alpina), dwarf arctic birch (Betula nand), and 

sedges (for example, Carex spp.). Mosses (for example, 

Hypnum spp., Dicranum spp., and Polytrichum spp.) may be 

common or absent.
AHKLUN AND KILBUCK MOUNTAINS 37

Figure 26. Vegetation communities showing patterns related to slope position and drainage characteristics in the Ahklun and 

Kilbuck Mountains Ecoregion. Low scrub communities grow in drainage tracks. Dwarf scrub-lichen communities grow on 

better drained sites that are more exposed to wind, such as on the tops of lower rounded summits and at middle and upper 

slopes. Low and dwarf scrub communities occur in open, low, flat areas.

Figure 27. Subtly rolling terrain of the Bristol Bay-Nushagak Lowlands Ecoregion. The region has better drainage than 

other coastal lowlands.
38 ECOREGIONS OF ALASKA

Mesic graminoid herbaceous communities are dominated by bluejoint (Calamagrostis canadensis), which forms 

meadows that may include other herbaceous species (for 

example, Carex spp., Eriophorum spp., and Epilobium 

angustifolium).

Low scrub communities include low scrub-sedge tussock 

bogs, ericaceous scrub bogs, and low sweetgale-graminoid 

bogs. Low scrub-sedge tussock bogs are codominated by low 

woody plants (for example, Betula glandulosa, B. nana, and 

Vaccinium vitis-idaed) and tussock-forming sedges (for 

example, Eriophorum vaginatuni). Mosses (for example, 

Sphagnum spp. and Rhacomitrium spp.) provide a nearly continuous mat between tussocks.

Ericaceous scrub bogs are dominated by Empetrum 

nigrum, Vaccinium vitis-idaea, V. uliginosum, V. oxycoccus, 

and Ledum decumbens. Sedges (for example, Carex spp. 

and Trichophorum caespitosum) are common or codominant. The moss layer is usually dominated by Sphagnum 

species, though other species (for example, Dicranum spp.) 

may be common. Lichens (for example, Cladina spp.} are 

present on mounds.

Sweetgale-graminoid bogs are dominated by sweetgale 

(Myrica gale), bluejoint (Calamagrostis canadensis), sedges 

(Carex spp.), and clubrush (Trichophorum caespitosum). 

Other woody and herbaceous species may be present. 

Mosses (for example, Sphagnum spp., Rhacomitrium spp., 

and Hypnum spp.) are abundant.

Wet graminoid herbaceous communities include sedge 

wet meadows and sedge-moss bogs. Several species of 

sedge (for example, Carex aquatilis and C. lyngbyaei) dominate sedge wet meadows. Sedge-moss bogs are dominated 

by mosses (principally Sphagnum spp.) and low sedges (for 

example, Eriophorum russeolum, Carex spp., and 

Trichophorum caespitosum).

Wildfire. - Occurrence of wildfires in the Ahklun and 

Kilbuck Mountains Ecoregion is very low. Recorded burns 

have ranged in size from less than 1 ha to 80 ha, averaging 

about 20 ha.

Land Use and Settlement. - Permanent settlements are 

limited to the coastal margins of the ecoregion. The region 

has traditionally provided hunting and fishing resources to 

the people of the Bristol Bay and Yukon-Kuskokwim Delta 

Yup'ik groups. Their primary resources for subsistence have 

been salmon and freshwater fish, seals, and beluga whales. 

Terrestrial mammals, particularly caribou, provide a secondary resource. Migratory waterfowl and their eggs are an 

important source of food in early spring. Edible and medicinal plants are collected. Gold, silver, platinum, lead, mercury, zinc, and borax have all been mined in this ecoregion.

Delineation Methods. - The ecoregion boundary outlines 

a group of mountains that exceed 600 m in elevation, with 

some adjustment in order to include areas shown as "Moist

Tundra," "Alpine Tundra," "Upland Spruce-Hardwood 

Forest," and "High Brush" on the map "Major Ecosystems of 

Alaska." These latter two ecosystem types are considered transitional with adjacent regions. Also transitional are areas of 

very low terrain roughness on the west side and of low and 

very low terrain roughness on the east side. Excluded from the 

Ahklun and Kilbuck Mountains Ecoregion are areas of 

"Lowland Spruce-Hardwood Forest" and "Wet Tundra."

References. - The information provided in this regional 

description has been compiled from Beikman (1980), Coulter 

and others (1962), Ferrians (1965), Gabriel and Tande (1983), 

Joint Federal-State Land Use Planning Commission for 

Alaska (1973), Karlstrom and others (1964), Langdon 

(1993), Larson and Bliss (written commun., 1992), Moore 

(written commun., 1993), Morgan (1979), Ping (written 

commun., 1993), Reiger and others (1979), Selkregg (1974), 

U.S. Bureau of Mines (1992a, 1992b), U.S. Geological Survey 

(1964, 1987a), Viereck and Little (1972), Viereck and others 

(1992), Wahrhaftig (1965), WeatherDisc Associates, Inc. 

(1990), and Wibbenmeyer and others (1982).

112. BRISTOL BAY-NUSHAGAK LOWLANDS

Distinctive Features. - This 61,000-km2 lowland 

ecoregion is located in southwestern Alaska off Bristol Bay. 

The region has rolling terrain, formed from morainal 

deposits (fig. 27). Soils of the lowlands are somewhat better 

drained than soils of the Subarctic Coastal Plains Ecoregion. 

Dwarf scrub communities are widespread, but large areas of 

wetland communities occur. Lakes are scattered throughout 

the lowlands, but are not nearly as numerous as in the 

Subarctic Coastal Plains.

Climate. - Climate is transitional between maritime and 

continental influences. Average annual precipitation varies 

greatly from location to location, ranging from 330 mm to 

860 mm, with contributions from annual snowfall ranging 

from 75 cm to 250 cm. There is less geographic variation in 

temperatures. Daily winter low temperatures average -15°C 

in the Nushagak Lowlands and -10°C along the Alaska 

Peninsula. Daily winter highs average near freezing 

throughout the region. Daily summer low temperatures 

average just above freezing, and highs average about 18°C.

Terrain. - The Bristol Bay-Nushagak Lowlands 

Ecoregion consists of rolling lowlands, with elevations ranging from sea level to 150 m and slope gradients of generally 

less than 2°. The region was glaciated during the Pleistocene 

epoch and is covered by glacial moraine and outwash. 

Deposits tend to be coarse near the mountains of adjacent 

ecoregions, grading to fine sand along the coast. Sand dunes 

are found along sea bluffs, river bluffs, and past and current 

shorelines of larger lakes. Parts of the lowlands are mantled
BRISTOL BAY-NUSHAGAK LOWLANDS 39

by silt and peat. Most streams arise from nearby mountainous ecoregions, and many are headwatered in lakes in 

ice-carved basins. The lowland is dotted with morainal and 

thaw lakes. Isolated masses of permafrost occur in the 

Nushagak Lowland area. The southern half of the region is 

generally free from permafrost.

Soils. - Dominant soils are Typic Haplocryands, Typic 

Vitricryands, Fluvaquentic Cryofibrists, Histic Pergelic 

Cryaquepts, Pergelic Cryaquepts, and Typic Cryochrepts. 

Most soils formed in volcanic ash deposits of various thickness 

underlain by gravelly glacial till, outwash deposits, or silty 

alluvium. Coastal plain soils formed in gravelly alluvium, cinders, or weathered rock blanketed with thick sedge peat.

Vegetation. - Dwarf scrub communities grow on relatively well drained mineral soils and are the dominant vegetation type in this ecoregion (fig. 28). Wetland communities 

vegetate large areas; poorly drained slopes and terraces are 

colonized by low scrub bog communities, and poorly 

drained lowlands are colonized by wet graminoid herbaceous communities and wet forb herbaceous communities. 

Of more limited distribution are broadleaf and mixed forest 

stands that grow on the floodplains of major rivers.

Dwarf scrub communities are dominated by ericaceous 

species (typically Empetrum nigrum). Lichens (for example, 

Alectoria spp., Cetraria spp., and Cladonia spp.} may be 

codominant. A number of other woody species (for example, 

Ledum decumbens, Loiseleuria procumbens, Arctostaphylos 

alpina, Salix spp., and Dryas octopetala) may be present. 

Mosses (for example, Sphagnum spp. and Dicmnum spp.) 

are common in most stands. Dwarf arctic birch (Betula 

nana) may invade these communities when peat accumulation provides a deeper rooting zone.

Low scrub bog communities are codominated by woody 

species (for example, Betula glandulosa, B. nana, Ledum 

decumbens, Vaccinium vitis-idaea, V. uliginosum, and 

Empetrum nigrum) and tussock-forming sedges (for example, Eriophorum vaginatum). Mosses (primarily Sphagnum 

spp.} form a nearly continuous mat.

Wet graminoid herbaceous communities include fresh 

sedge marshes, wet sedge meadows, sedge-moss bog meadows, and halophytic sedge wet meadows. Fresh sedge marshes are comprised almost entirely of tall emergent sedges (for 

example, Scirpus validus or Eleocharis palustris). As plant 

detritus and sediments accumulate, these communities may 

be replaced by wet sedge meadows dominated by Carex 

species. Mosses (for example, Dicmnum spp., Polytrichum 

spp., and Sphagnum spp.) may be abundant in meadows.

Sedge-moss bog meadows occur in peat-filled depressions. Low sedges (for example, Eriophorum russeolum, 

Carex spp., and Trichophorum caespitosum) are dominant 

and are rooted along with other herbs (for example, 

Potentilla palustris) in a mat of sphagnum mosses.

Halophytic sedge wet meadows occur in coastal areas

and are dominated by Carex lyngbyaei. Other important 

graminoid constituents include Eriophorum spp. and 

Calamagrostis canadensis.

Wet forb herbaceous communities mainly include fresh 

herb marshes colonized principally by emergent herbs (for 

example, Menyanthes trifoliata, Potentilla palustris, and 

Equisetum fluviatile). Aquatic mosses (for example, 

Sphagnum spp.) are common.

Broadleaf forest communities are dominated by birch 

(Betula papyri/era) or codominated by birch and other tree 

species (for example, Populus balsamifera). A tall shrub 

understory is common, consisting of willow (for example, 

Salix bebbiana and S. scouleriana) and alder (Alnus crispa 

and A. sinuata). A low shrub understory typically includes 

prickly rose (Rosa acicularis), high bushcranberry 

(Viburnum edule), and resin birch (Betula glandulosa). 

Dwarf dogwood (Cornus canadensis) and fire weed 

(Epilobium angustifolium) are common forbs. Mixed forest 

communities result where white spruce (Picea glauca) 

codominates with birch.

Wildfire. - Occurrence of wildfires in the Nushagak 

Lowlands portion of the ecoregion is low. The range in 

recorded burn size is from less than 1 ha to 1,820 ha, averaging 870 ha. Fire data are not available for the portion of 

the ecoregion along the Alaska Peninsula.

Land Use and Settlement. - Permanent settlements 

occur primarily along the coast or adjacent to the larger 

rivers. The region is used primarily for commercial fishing 

and processing and for subsistence and recreational hunting 

and fishing. The northern half of the region was settled by 

the Bristol Bay Yup'ik, and the southern half was settled by 

the Koniag. These two groups are descended from the 

Bering Sea Yup'ik and the Pacific Yup'ik, respectively. 

Coastal communities rely primarily on marine resources (for 

example, whales, seals, salmon, halibut, sea lions, sea otters, 

clams, mussels, and seaweed). Away from the coast, salmon 

and terrestrial mammals (for example, caribou and moose) 

are more important. Edible and medicinal greens, roots, and 

berries are also collected.

Delineation Methods. - The ecoregion boundary is 

generally based on inclusion of the "Moist Tundra," "Wet 

Tundra," and "Lowland Spruce-Hardwood Forest" ecosystems and an exclusion of "High Brush," "Alpine Tundra," 

and "Upland Spruce-Hardwood Forest" ecosystems, as 

depicted on the map "Major Ecosystems of Alaska." 

Transitional zones occur where "Upland Spruce-Hardwood 

Forest" penetrates from the Ahklun and Kilbuck Mountains 

Ecoregion to the west, and in areas having moderate to high 

terrain roughness, as shown on the terrain roughness map.

References. - The information provided in this regional description has been compiled from Beikman (1980),
40 ECOREGIONS OF ALASKA

Figure 28. Distribution of vegetation communities indicates a relationship with hillslope position and drainage characteristics in the Bristol Bay-Nushagak Lowlands Ecoregion. Dwarf shrubs, graminoid species, and lichens grow in well drained 

areas. Scattered small communities of alder occur on hillslopes. Graminoid marsh communities grow in depressions.

Figure 29. Alaska Peninsula Mountains Ecoregion typically shrouded in clouds. Soils, formed from volcanic ash and cinder, are highly erodible and restrict the development of vegetation.
ALASKA PENINSULA MOUNTAINS 41

Black (1951), Coulter and others (1962), Fenians (1965), 

Gabriel and Tande (1983), Joint Federal-State Land Use 

Planning Commission for Alaska (1973), Karlstrom and others 

(1964), Langdon (1993), Larson and Bliss (written commun., 

1992), Moore (written commun., 1993), Morgan (1979), Ping 

(written commun., 1993), Reiger and others (1979), Selkregg 

(1974), U.S. Bureau of Mines (1992a, 1992b), U.S. Geological 

Survey (1964, 1987a), Viereck and Little (1972), Viereck and 

others (1992), Wahrhaftig (1965), WeatherDisc Associates, 

Inc. (1990), and Wibbenmeyer and others (1982).

113. ALASKA PENINSULA MOUNTAINS

Distinctive Features. - The 48,000-km2 ecoregion is 

composed of rounded, folded and faulted sedimentary ridges 

intermittently surmounted by volcanoes. The mountains 

were heavily glaciated during the Pleistocene epoch. A maritime climate prevails, and the region is generally free of permafrost. Many soils formed in deposits of volcanic ash and 

cinder over glacial deposits and are highly erodible (fig. 29). 

Vegetation cover commonly consists of dwarf scrub communities at higher elevations and on sites exposed to wind, and 

low scrub communities at lower elevations and in more protected sites.

Climate. - Climate has a predominantly maritime influence, as is evident from the higher precipitation and lower 

seasonal and diurnal fluctuations in air temperatures than in 

ecoregions having continental or transitional climates. 

Annual precipitation varies greatly from location to location 

along the coast, with coastal areas receiving from 600 mm to 

3,300 mm. High elevations in the mountains average more 

than 4,060 mm of precipitation each year. Mean annual 

snowfall ranges from 55 cm to 150 cm along the coast and 

exceeds 510 cm in the higher mountains. Winter daily minimum temperatures average from -11°C to -6°C throughout 

the region; daily maximum temperatures average from -2°C 

to 1°C. Summer temperatures range from lows of about 6°C 

to highs of about 15°C.

Terrain. - The region is characterized by rounded 

ridges, 300 m to 1,200 m high, surmounted at varying intervals by rugged volcanic peaks, 1,400 m to 2,600 m high. 

The mountains are dissected by many drainageways. Slope 

gradients are usually from 0° to 11°, but steeper slopes occur 

across 7 percent of the region. Geological formations consist of stratified Jurassic, Cretaceous, and Tertiary sediments, 

and undifferentiated Quaternary volcanic rocks. The region 

was heavily glaciated during the Pleistocene epoch. Most of 

the volcanoes reached their acme following Pleistocene 

glaciation. Glaciers persist on volcanoes. Many features of 

glacial erosion are present, such as cirques and U-shaped 

valleys. The ecoregion is generally free from permafrost.

Streams draining to the Pacific Ocean are short and have

steep gradients. Streams draining to the Bering Sea become 

braided when they reach the rolling lowlands of the Bristol 

Bay-Nushagak Lowlands Ecoregion to the north. Many 

streams are glacier fed. Lakes have been formed by 

moraines, or have formed in ice-carved basins.

Soils. - Dominant soils are Typic Haplocryands and Typic 

Vitricryands. Glacial deposits cover all but the highest parts of 

ridges. Soils, formed in deposits of volcanic ash and cinder 

that mantle the glacial deposits, are highly erodible. Mountain 

peaks, rock escarpments, and talus slopes have little or no soil 

cover. Some depressions are filled with fibrous peat.

Vegetation. - Dwarf scrub communities are widespread 

in this ecoregion, occurring at higher elevations and on 

windswept areas (fig. 30). Low scrub communities grow on 

sites more protected from wind and at lower elevations. Tall 

scrub communities grow at lower elevations and along hillslope drainages. Floodplains and south-facing slopes support broadleaf forest stands. Poorly drained areas are colonized by low scrub bog communities and mesic graminoid 

herbaceous communities.

Dwarf scrub communities are generally dominated by 

crowberry (Empetrum nigrum). Accompanying shrubs 

include other ericads (for example, Vaccinium vitis-idaea, V. 

uliginosum, and Arctostaphylos alpind), arctic willow (Salix 

arctica), and white mountain-avens (Dryas octopetald). 

Mosses (for example, Dicranum spp., Hypnum spp., 

Polytrichum spp., and Rhacomitrium spp.) and lichens (for 

example, Alectoria spp., Cladonia spp., Cladina spp., and 

Cetraria spp.) are common.

Low scrub communities are dominated by willow (for 

example, Salix glauca, S. lanata, and S. planifolia). Dwarf 

shrubs (for example, Betula nana, Vaccinium vitis-idaea, V. 

uliginosum, Ledum decumbens, Dryas spp., and Salix reticulata) and forbs (for example, Calamagrostis canadensis, 

Festuca altaica, Carex bigelowii, and Artemisia spp.) colonize the understory. Mosses (for example, Polytrichum spp. 

and Hypnum spp.) form a patchy to continuous mat cover.

Tall scrub communities consist primarily of alder (for 

example, Alnus sinuata) or a mix of alder and willow (Salix 

alaxensis, S. barclayi, S. planifolia, and S. glauca). Low 

shrubs (for example, Betula glandulosa, B. nana, Vaccinium 

vitis-idaea, V. uliginosum, and Ledum decumbens} may be 

common or absent in the understory.

Broadleaf forests are dominated by balsam poplar 

(Populus balsamifera). A tall shrub understory of alder and 

willow is usually present. Bluejoint (Calamagrostis canadensis) is important in the herbaceous layer. Mosses (commonly 

feathermoss species) provide extensive ground cover.

Low scrub bogs are typically dominated by ericaceous 

species, such as crowberry (Empetrum nigrum), narrow-leaf 

Labrador-tea (Ledum decumbens), mountain-cranberry 

(Vaccinium vitis-idaea), bog blueberry (V. uliginosum), and 

bog cranberry (V. oxycoccus). Sedges (for example,
42 ECOREGIONS OF ALASKA

Figure 30. Dwarf scrub communities are common on the middle slopes and some of the higher slopes of the Alaska 

Peninsula Mountains Ecoregion. Willow grows along the lower slopes. The beach ridges along the shore are vegetated by 

willow and alder. (Photo courtesy of Keith Trexler, National Park Service. Anchorage.)

Figure 31. Typical landscape of the Aleutian Islands Ecoregion, composed of a chain of sedimentary islands overtopped by 

steep volcanoes. Bare rock and rubble occur on volcanic cones, peaks, and high ridgetops. Dwarf shrub tundra communities 

occur at higher elevations and in windswept areas. Moist tundra communities are found at lower elevations and in protected 

sites. (Photo courtesy of Leslie Kerr, Fish and Wildlife Service, Anchorage.)
ALEUTIAN ISLANDS 43

Eriophorum spp. and Carex spp.) and forbs (for example, 

Potentilla palustris and Menyanthes trifoliata) are common. 

Sphagnum mosses are always present and are usually the 

dominant mosses. Lichens (for example, Cladina spp. and 

Cetraria spp.) occur on mounds.

Mesic graminoid herbaceous communities primarily 

consist of meadows dominated by bluejoint (Calamagwstis 

canadensis) or a mix of bluejoint and various herbs (for 

example, Epilobium angustifolium, Heracleum lanatum, 

Athyrium filix-femina, and Equisetum arvense).

Wildfire. - No fire data are available for the Alaska 

Peninsula.

Land Use and Settlement. - Settlements are located 

mainly along the coastline. The region is used primarily for 

commercial fishing and processing and for subsistence and 

recreational hunting and fishing. The area was historically 

occupied by the Koniag, of the Pacific Yup'ik people. 

Marine resources, such as whales, seals, salmon, halibut, 

cod, rockfish, sea lions, sea otters, porpoises, shellfish, sea 

urchins, bivalves, and seaweed, have been the basis for subsistence. Terrestrial mammals (for example, caribou, moose, 

ground squirrel, and hare) are of secondary importance. 

Plant greens, roots, and berries are collected for food and 

medicinal purposes.

Several metals have been mined in this ecoregion, including gold, silver, lead, and copper. Energy-related resources, 

such as coal and petroleum, have also been extracted.

Delineation Methods. - The boundary separating the 

Alaska Peninsula Mountains from the Bristol Bay-Nushagak 

Lowlands is based on the inclusion of "Alpine Tundra" and 

"High Brush" ecosystems and on the exclusion of "Moist 

Tundra" and "Wet Tundra" ecosystems, as shown on the map 

"Major Ecosystems of Alaska." The boundary separating the 

Alaska Peninsula Mountains from the Aleutian Islands is 

based on general climate information; the exact placement of 

the line is somewhat arbitrary. Because the Alaska Peninsula 

Mountains Ecoregion is narrow and environmental gradients 

are steep, it is not possible to delineate transitional areas at the 

current scale of mapping.

References. - The information provided in this regional description has been compiled from Beikman (1980), 

Coulter and others (1962), Fenians (1965), Joint FederalState Land Use Planning Commission for Alaska (1973), 

Karlstrom and others (1964), Langdon (1993), Larson and 

Bliss (written commun.. 1992), Moore (written commun., 

1993), Morgan (1979), Ping (written commun., 1993), 

Reiger and others (1979), Selkregg (1974), U.S. Bureau of 

Mines (1992a, 1992b), U.S. Geological Survey (1964, 

1987a), Viereck and Little (1972), Viereck and others 

(1992), Wahrhaftig (1965), WeatherDisc Associates, Inc. 

(1990), and Wibbenmeyer and others (1982).

114. ALEUTIAN ISLANDS

Distinctive Features. - The 12,000 km2 Aleutian 

Islands Ecoregion in southwestern Alaska is composed of a 

chain of sedimentary islands (eroded from older volcanic 

formations) that are crowned by steep volcanoes (fig. 31). 

Maritime climate prevails. The region is south of the winter 

sea ice pack and is generally free from permafrost. 

Vegetation cover mainly consists of dwarf scrub communities at higher elevations and on sites exposed to wind, and of 

graminoid herbaceous communities in more protected sites.

Climate. - The Aleutian Islands have a maritime climate. 

Annual precipitation varies greatly from place to place, from 

as little as 530 mm to as much as 2,080 mm at sea level weather stations. Annual snowfall averages from 85 cm to 250 cm 

at the same stations. In general, smaller islands receive less 

precipitation than larger islands. Winter daily low temperatures average from -7°C to -2°C, and daily highs average from 

2°C to 5°C. Summer daily temperatures average from lows of 

4°C to highs of 10°C to 13°C. The frost-free season usually 

lasts from May through mid-September.

Terrain. - The ecoregion is composed of a chain of 

islands exposed along the crest of a submarine ridge. Most 

of the islands, formed of blockfaulted Tertiary sediments 

derived from earlier igneous processes, are surmounted by 

volcanoes of Tertiary and Quaternary Age. Regional elevations range from sea level to greater than 1,900 m. Most 

high volcanoes have icecaps or small glaciers. Lowlands 

have slope gradients less than 1°, but mountains are steep, 

with gradients almost always greater than 5°. The islands 

have been intensely glaciated (though only the easternmost 

portion was glaciated during the Pleistocene epoch), and evidence of glacial erosion is common. The region is generally 

free from permafrost, but periglacial erosional processes are 

active because of the cold, wet climate.

Streams are short and swift. Many enter the sea as 

waterfalls. In areas of porous volcanic rock, stream courses 

are widely spaced and are filled with water only during 

exceptionally heavy rains. Many small lakes occupy irregular ice-carved basins in rolling topography on the glaciated 

islands. Lakes fill a few volcanic craters and calderas.

Soils. - Dominant soils are Typic Haplocryands and 

Typic Vitricryands. Most soils formed in deposits of volcanic ash or cinders over basaltic bedrock. Bare rock and 

rubble occur on volcanic cones, peaks, and high ridgetops. 

Volcanic material generally grades from coarse to fine with 

increasing distance from active volcanoes. Organic soils 

occupy depressions and some broad valley bottoms.

Vegetation. - Vegetation cover at higher elevations and 

on windswept areas consists of dwarf scrub communities 

dominated by willow or crowberry. Mesic graminoid herba-
44 ECOREGIONS OF ALASKA

Figure 32. Spruce-hardwood forests, the most widespread vegetation community of the Cook Inlet Ecoregion. The area has 

one of the mildest climates in Alaska and, consequently, is generally free from permafrost.

I 'vflt /' I ? ! 4

,T,* f f J, *\ A.,*

Figure 33. Forest stand with POCKCIS 01 wimc s^iutc or white spruce mixed with birch in the Cook Inlet Ecoregion.
COOK INLET 45

ceous and dry graminoid herbaceous communities occur at 

lower elevations and in protected sites. Low scrub communities grow in bogs having thick peat deposits.

Willow dwarf scrub communities are dominated by 

Salix arctica, S. rotundifolia, and S. ovalifolia. Other common shrubs are crowberry (Empetrum nigruni), 

mountain-cranberry (Vaccinium vitis-idaea), bog blueberry 

(V. uliginosum), mountain-avens (Dryas spp.), cassiope 

(Cassiope lycopodioides), and narrow-leaf Labrador-tea 

(Ledum decumbens). Herbs, (for example, Carex spp. and 

Saxifraga spp.) and mosses (for example, Dicranum spp. and 

Aulacomnium spp.) are common.

Crowberry dwarf scrub communities are dominated by 

Empetrum nigrum. Aleutian mountain-heath (Phyllodoce 

aleuticd), cassiope (Cassiope stelleriana), dwarf blueberry 

(Vaccinium caespitosum), and meadow-spirea (Luetkea 

pectinatd) are typical constituents of these communities. 

Mosses are common. Lichens (for example, Cladonia spp.) 

are common in many stands.

Mesic graminoid herbaceous communities primarily 

consist of meadows, where bluejoint (Calamagrostis 

canadensis) is codominant with a variety of other herbs (for 

example, Epihbium angustifolium, Equisetum arvense, 

Carex spp., and Festuca spp.).

Dry graminoid herbaceous communities occur in coastal 

areas, such as near coastal marshes and at the bases of cliffs. 

Hair-grasses (Deschampsia spp.) provide nearly all of the 

vegetation cover.

Low scrub bog communities are dominated by ericaceous species (for example, Empetrum nigrum, Vaccinium 

uliginosum, V vitis-idaea, V oxycoccus, Andromeda polifolia, and Ledum decumbens). Sedges (for example, 

Eriophorum angustifolium, Trichophorum caespitosum, 

Carex pluriflora, and C. pauciflora) are common or codominant. Sphagnum species are always present and are usually 

the dominant mosses. Feathermosses may be common. 

Lichens may occur on mounds.

Wildfire. - No fire data are available for the Aleutian 

Islands.

Land Use and Settlement. - Settlements are sparse and 

are primarily located along the coastline. The native populations of the islands are Aleut. They depend on marine 

resources (for example, Steller sea lions, seals, otters, and 

whales) for subsistence. Caribou and salmon are important 

sources of food and materials in the eastern part of the 

region. Tidal waters provide additional resources, such as 

algae, chitons, fish, mussels, urchins, octopus, and sea otters. 

Birds (for example, cormorants, gulls, murres, and puffins) 

and their eggs augment the traditional diet. Edible and medicinal plants are also collected.

Delineation Methods. - The ecoregion boundary separates the islands of the Aleutian chain from those immediately

south and west of the Alaska Peninsula. The boundary is based 

primarily on climate information. A lack of sufficient information detail prohibits the delineation of transitional areas.

References. - The information provided in this regional 

description has been compiled from Beikman (1980), Coulter 

and others (1962), Ferrians (1965), Joint Federal-State Land 

Use Planning Commission for Alaska (1973), Karlstrom and 

others (1964), Langdon (1993), Larson and Bliss (written 

commun., 1992), Moore (written commun., 1993), Morgan 

(1979), Ping (written commun., 1993), Reiger and others 

(1979), Selkregg (1974), U.S. Bureau of Mines (1992a, 

1992b), U.S. Geological Survey (1964, 1987a), Viereck and 

Little (1972), Viereck and others (1992), Wahrhaftig (1965), 

and WeatherDisc Associates, Inc. (1990).

115. COOK INLET

Distinctive Features. - Located in the south central part 

of Alaska adjacent to the Cook Inlet, the 28,000-km2 ecoregion has one of the mildest climates in the State. The climate, the level to rolling topography, and the coastal proximity have attracted most of the settlement and development 

in Alaska. The region has a variety of vegetation communities (fig. 32) but is dominated by stands of spruce and hardwood species. The area is generally free from permafrost. 

Unlike many of the other nonmontane ecoregions, the Cook 

Inlet Ecoregion was intensely glaciated during the 

Pleistocene epoch.

Climate. - The climate is affected by both maritime and 

continental influences. Average annual precipitation ranges 

from 380 mm to 680 mm across the region. Annual snowfall averages from 160 cm to 255 cm. Winter temperatures 

range from lows of -15°C to highs of -5°C, and temperature 

inversions are common. Summer temperatures vary from 

lows of about 5°C to highs of about 18°C. May through 

September are usually frost-free.

Terrain. - The level to rolling terrain of this ecoregion 

is shaped by ground moraine, drumlin fields, eskers, and outwash plains, remnants of Pleistocene glaciation. Elevations 

range from sea level to 600 m. Slope gradients are generally less than 3°. Bedrock consists of poorly consolidated 

Tertiary coal-bearing rocks. Marine and lake deposits mantle portions of the region, and a considerable part of the lowlands has been blanketed by aeolian materials. Hundreds of 

small lakes, swamps, and bogs have developed in areas of 

stagnant ice topography and on ground moraines. The 

region was intensely glaciated during the Pleistocene epoch. 

There is currently little permafrost.

Soils. - Dominant soils are Haplocryands, Sphagnic 

Borofibrists, Terric Borosaprists, Typic Borohemists, Andic
46 ECOREGIONS OF ALASKA

Haplocryods, and Andic Humicryods. Surface soil layers 

formed in loess blown from the floodplains of glacial 

streams and in volcanic ash blown from mountains to the 

west. Subsurface soil layers formed predominantly in 

glacial deposits, and range from gravelly clay loam to very 

gravelly sandy loam. The subsurface soil layers on alluvial 

terraces and outwash plains are waterworked, very gravelly 

sand. Soils in depressions holding fens and bogs are organic and consist of peat.

Vegetation. - A variety of vegetation communities 

occur in the ecoregion. Needleleaf, broadleaf, and mixed 

forests are the most widespread (fig. 33). Tall scrub communities form thickets on periodically flooded alluvium, 

such as occurs on floodplains, along streambanks, and in 

drainageways. Mesic graminoid, graminoid herbaceous, and 

low scrub graminoid communities occur over a range of 

moist to dry sites. Poorly drained lowlands support low 

scrub communities. The wettest sites are colonized by tall 

scrub swamp, low scrub bog, wet forb herbaceous, and wet 

graminoid herbaceous vegetation (fig. 34).

Needleleaf forests are dominated by white spruce (Picea 

glauca), black spruce (P. mariana), and Sitka spruce (Picea 

sitchensis). Broadleaf forests are dominated by quaking 

aspen (Populus tremuloides), balsam poplar (P. balsamifera), black cottonwood (P. trichocarpa), and paper birch 

(Betula papyrifera). Mixed forests are codominated by combinations of these needleleaf and broadleaf species.

White spruce forests grow on well drained soils. Black 

spruce, paper birch, balsam poplar, and aspen may codominate with white spruce. A low shrub layer is typical, including birch (for example, Betula glandulosa and B. nana), ericaceous species (for example, Vaccinium vitis-idaea, V. uliginosum, Ledum groenlandicum, and Empetrum nigrum), buffaloberry (Shepherdia canadensis), and prickly rose (Rosa 

acicularis). Herbaceous cover varies, depending upon openness of stands. Common species are Equisetum spp., 

Linnaea borealis, and Calamagrostis canadensis. 

Feather-mosses (for example, Hylocomium splendens and 

Pleurozium schreberi) form a nearly continuous layer.

Aspen forests grow on relatively warm, dry slopes. 

Stands may also contain balsam poplar (Populus balsamifera), spruce (Picea glauca and P. mariana), and paper birch 

(Betula papyrifera). Alder (Alnus crispa) and willow (Salix 

bebbiana) commonly provide a tall shrub layer. The low 

shrub layer includes prickly rose (Rosa acicularis), buffaloberry (Shepherdia canadensis), and high bushcranberry 

(Viburnum edule). The herb layer is patchy, and mosses and 

lichens provide little cover.

Paper birch forests are common on moderately well to 

well drained upland sites. White spruce and black spruce 

may be present. Alders (Alnus crispa and A. sinuata), willows (Salix spp.), and, in open stands, resin birch (Betula 

glandulosa) occur as a tall shrub layer. Prickly rose (Rosa 

acicularis), high bushcranberry (Viburnum edule), and ericaceous shrubs provide low shrub cover. In closed forest 

stands, Calamagrostis canadensis dominates the herb layer, 

and mosses and lichens are rare. In more open stands, the 

ground is covered by feathermosses (for example, 

Hylocomium splendens and Pleurozium schreberi).

Forests dominated by black spruce or a mixture of black 

spruce and paper birch colonize poorly drained areas. Alders 

(Alnus crispa) usually provide a tall shrub layer. Common 

lower shrubs are prickly rose (Rosa acicularis), willow 

(Salix spp.), Labrador-tea (Ledum groenlandicum), and ericaceous species. Feathermosses (for example, Pleurozium 

schreberi and Hylocomium splendens) form a patchy to continuous moss layer. Sphagnum mosses may occur on the 

wetter sites. Foliose lichens (for example, Peltigera aphthosa and P. canina) are common.

Floodplains and active alluvial fans support relatively 

pure or mixed stands of Sitka spruce (Picea sitchensis), black 

cottonwood (Populus trichocarpa), balsam poplar (P. balsamifera), and paper birch (Betula papyrifera). When present, the tall shrub component consists of alder and willow. 

Lower shrubs typically include prickly rose (Rosa acicularis), high bushcranberry (Viburnum edule), and devilsclub 

(Oplopanax horridus). Herbaceous species vary with forest 

type. Gymnocarpium dryopteris, Athyrium filix-femina, and 

Tiarella trifoliata occur in Sitka spruce stands; Calamagrostis 

canadensis and Equisetum spp. occur with black cottonwood; 

Calamagrostis canadensis, Mertensia paniculata, and 

Epilobium angustifolium occur with balsam poplar. 

Feathermosses are found in some of these communities.

Tall scrub thickets are dominated by alders (Alnus 

crispa, A. tenuifolia, A. sinuata), willows (Salix alaxensis, S. 

brachycarpa, and S. planifolia), or a combination of alders 

and willows. Mosses (for example, Hylocomium splendens, 

Drepanocladus uncinatus, and Polytrichum spp.) may be 

abundant.

Dry to mesic sites support mesic graminoid, graminoid 

herbaceous, and low scrub graminoid communities. 

Examples are communities dominated by dry fescue 

(Festuca altaica), communities codominated by midgrasses 

(Festuca altaica, F. rubra, Deschampsia beringensis, and 

Poa eminens) and forbs (for example, Aconitum delphinifolium and Mertensia paniculata), and communities codominated by midgrasses (Festuca altaica, Calamagrostis purpurascens, Agropyron spicatum, Poa spp., Bromus pumpellianus) and low shrubs (for example, Vaccinium vitis—idaea, 

Empetrum nigrum, Salix reticulata, and S. lanata), respectively. Nonsphagnaceous mosses are common in all of these 

community types. Lichens may be common or absent.

Mesic to moist sites support mesic graminoid communities dominated by bluejoint (Calamagrostis canadensis), 

graminoid herbaceous communities codominated by bluejoint and herbs (for example, Epilobium angustifolium, 

Angelica lucida, Athyrium filix-femina, Equisetum arvense, 

and E. fluviatile), or low scrub graminoid communities dominated by bluejoint and low shrubs (for example, Alnus sinu-
COOK INLET 47

Figure 34. Wet graminoid herbaceous communities, such as this sedge meadow, commonly occur in shallow basins in the 

Cook Inlet Ecoregion.

ata). Feathermosses form a patchy layer on the ground.

Low scrub communities are dominated by willows (for 

example, Salix glauca and S. lanata) or a mixture of willows 

and birch (for example, Betula glandulosa}. The herbaceous 

layer typically includes graminoid species (for example, 

Calamagmstis canadensis, Carex spp., and Festuca altaica}. 

Mosses (for example, feathermosses) form a patchy to continuous mat.

Tall scrub swamps are dominated by alder (for example, 

Alnus tenuifolia) or combinations of alder (A. tenuifolia} and 

willow (Salix planifolia and S. lanata}. Cover by low shrubs 

varies, but typical constituents are high bushcranberry 

(Viburnum edule}, currant (Ribes spp.}, prickly rose (Rosa 

acicularis), and Pacific red elder (Sambucus callicarpd). 

Sedges (Carex spp.}, bluejoint (Calamagrostis canadensis}, 

dwarf dogwood (Cornus canadensis), and horsetail 

(Equisetum spp) are typical herbaceous species. Mosses (for 

example, feathermosses and Sphagnum spp.} are common 

but discontinuous.

Low scrub bog communities include those dominated 

by low mixed shrubs (for example, Betula glandulosa, B. 

nana, Ledum decumhens, Vaccinium vitis-idaea, and V. uliginosum) and tussock-forming sedges (for example, 

Eriophorum vagina turn), ericaceous species (for example, 

Vaccinium vitis-idaea, V. uliginosum, Ledum decumbens, 

Empetrum nigrum, and Andromeda polifolia}, a mixture of

birch (for example, Betula glandulosa and B. nana) and ericaceous species, and a mixture of willow (for example, Salix 

barclayi and S. commutata) and graminoid species (for 

example, Calamagrostis canadensis and Carex spp.}. Other 

low shrubs (for example, Chamaedaphne calyculata and 

Andromeda polifolia} may be present in any of these bog 

communities. A nearly continuous mat of mosses (for example, Sphagnum spp. and feathermosses) occurs in low 

scrub-sedge tussock communities.

Wet forb herbaceous communities are dominated by 

nongraminoid species, including horsetail (for example, 

Equisetum fluviatile}, buckbean (Menyanthes trifoliata), 

marsh fivefinger (Potentilla palustris}, and marsh-marigold 

(Caltha palustris). Mosses and floating or submerged aquatic plants may be abundant.

Freshwater wet graminoid herbaceous communities are 

dominated by sedges (Carex spp.} or a mixture of sedges and 

low shrubs (for example, Myrica gale and Salix spp.}. Mosses 

are common. Coastal areas may be dominated by salt-tolerant grasses (for example, Puccinellia spp.}, sedges (for example, Carex lyngbyaei}, and forbs (for example, Honckenya 

peploides, Triglochin maritimum. and Plantago maritima}.

Wildfire. - Occurrence of wildfires in the Cook Inlet 

Ecoregion is low. The size of burns varies from less than 

1 ha to 2,270 ha, averaging 160 ha.
48 ECOREGIONS OF ALASKA

Figure 35. Extensive systems oi valley glaciers in the Alaska Range Ecoregion. Features of glacial erosion, such as cirques 

and U-shaped valleys, are common.

Land Use and Settlement. - The Cook Inlet Ecoregion 

is the most populated region in Alaska. Summer and winter 

recreational activities occur extensively throughout the region. 

Agricultural activities are limited largely to the Susitna Valley, 

but they also occur on the Kenai Peninsula. Numerous gas 

and oil wells dot the Trading Bay area, and some are scattered 

about the Kenai Peninsula. Many oil platforms occupy the 

Cook Inlet. Timber production occurs on the west shore of 

Cook Inlet and in some areas along the Susitna River.

The Tanaina, a group of Pacific Athabascans, were the 

native inhabitants of the ecoregion. Their traditional diet 

included salmon, moose, and caribou, although these were 

supplemented by beaver, hare, ground squirrel, grouse, 

ptarmigan, migratory waterfowl, whitefish, blackfish, and 

pike. Edible greens, berries, and roots were also collected.

Extractable resources have included metals (for example, gold, silver, platinum, tin, copper, and tungsten) and 

energy—related commodities (for example, coal and uranium). Numerous sand and gravel operations support construction and road building activities.

Delineation Methods. - The ecoregion boundary represents areas less than 600 m in elevation. The boundary corresponds well with patterns on the relative CIR image. 

Transitional areas include the "Upland Spruce-Hardwood 

Forest" areas, depicted on the map "Major Ecosystems of 

Alaska," that occur along the interface with the surrounding 

mountainous ecoregions.

References. — The information provided in this regional 

description has been compiled from Beikman (1980), Black 

(1951), Coulter and others (1962), Ferrians (1965), Gabriel 

and Tande (1983), Joint Federal-State Land Use Planning 

Commission for Alaska (1973), Karlstrom and others (1964), 

Langdon (1993), Larson and Bliss (written commun., 1992), 

Moore (written commun., 1993), Morgan (1979), Ping (written commun., 1993), Reiger and others (1979), Selkregg 

(1974), U.S. Bureau of Mines (1992a, 1992b), U.S. 

Geological Survey (1964, 1987a), Viereck and Little (1972), 

Viereck and others (1992),Wahrhaftig (1965), and 

WeatherDisc Associates, Inc. (1990).

116. ALASKA RANGE

Distinctive Features. - The mountains of south central 

Alaska, the Alaska Range, are very high and steep. The 

117,000-km2 ecoregion is covered by rocky slopes, icefields, 

and glaciers (fig. 35). Much of the area is barren of vegetation. Dwarf scrub communities are common at higher elevations and on windswept sites where vegetation does exist. 

The Alaska Range has a continental climatic regime, but 

because of the extreme height of many of the ridges and 

peaks, annual precipitation at higher elevations is similar to 

that measured for some ecoregions having maritime climate.

Climate. - Climate is influenced by continental factors.
ALASKA RANGE 49

Weather data for the region are from lower elevation stations. Daily winter low temperatures average about -25°C 

and daily highs about -3°C at these stations. Daily summer 

low temperatures for the same areas average about 2°C and 

daily highs about 18°C. Mean annual precipitation in the 

lowlands is approximately 380 mm, with snowfall ranging 

from 150 cm to 305 cm at various stations. Estimated average annual precipitation for the higher mountains peaks is 

2,030 mm, with estimated snowfall at 1,015 cm.

Terrain. - The ecoregion consists of steep, rugged mountain ridges separated by broad valleys. Elevations are 600 m in 

the lower valleys (sea level in the southwestern portion of the 

ecoregion), often rising to greater than 3,900 m on mountains 

peaks (Mt. McKinley is higher than 6,100 m). Slope gradients, 

which are almost always greater than 5° on hillslopes, exceed 

25° on some mountains. The southern portion of the ecoregion 

is underlain by granitic batholiths intrusive into moderately 

metamorphosed, highly deformed Paleozoic and Mesozoic 

volcanic and sedimentary rocks. Large active volcanoes occur 

in this area. The central and eastern portions of the ecoregion 

are part of a broad syncline having Cretaceous rocks in the center and Paleozoic and Precambrian rocks on the flanks.

The ecoregion was heavily glaciated during the 

Pleistocene epoch, and extensive systems of valley glaciers 

still radiate from the higher mountains. Rock glaciers are common. Gelifluction features are well developed. Permafrost is 

discontinuous in this ecoregion; however, its full extent is 

unknown. Streams are swift and braided, and most are headwatered in glaciers. Many large lakes occupy the glaciated valleys within the southern part of the ecoregion. Lakes in the 

central and eastern part of the ecoregion are relatively rare for 

a glaciated area; most occur either as rock-basin lakes or as 

collections of small ponds in areas of ground moraine.

Soils. - Much of the ecoregion consists of rocky slopes, 

icefields, and glaciers. Where soil development has 

occurred, principal soils are Lithic Cryorthents, Pergelic 

Cryaquepts, Pergelic Ruptic-Histic Cryaquepts, Typic 

Cryochrepts, Pergelic Cryumbrepts, and Typic Cryumbrepts. 

Most soils are stony and shallow over bedrock, or bouldery 

colluvial or glacial deposits. Soils on lower slopes and in 

valleys are typically poorly drained, with a shallow permafrost table. Soils on upper hillsides and ridgetops are 

often well drained, very gravelly, and shallow over bedrock. 

These soils usually do not retain sufficient moisture for 

ice-rich permafrost.

Vegetation. - Much of the ecoregion is barren of vegetation. Dwarf scrub communities are most common where 

vegetation does occur, growing on well drained, windswept 

sites. More protected slopes provide moist to mesic sites 

that support low or tall scrub communities (fig. 36). Open 

needleleaf forests and woodlands occur on well drained sites 

in some valleys and on lower hillslopes (fig. 37).

Dwarf scrub communities are typically dominated by 

mountain-avens (Dryas octopetala, D. integrifolia, and D. 

drummondii), ericaceous species (for example, Vaccinium 

vitis-idaea, V uliginosum, Cassiope tetragona, 

Arctostaphylos alpina, and A. rubra), or combinations of 

these species. Graminoid species, such as sedges (for example, Carex scirpoidea and C. bigelowii) and alpine holygrass 

(Hierochloe alpina), may be present and may even codominate with shrubs, as may lichens (for example, Alectoria spp., 

Cetraria spp., Cladonia spp., and Thamnolia spp.). Forbs 

(for example, Oxytropis nigrescens, Hedysarum alpinum, 

Minuartia spp., Anemone spp., and Saxifraga spp.) and mosses (for example, Tomenthypnum nitens, Hylocomium splendens, and Polytrichum spp.) typically form the ground layer 

of these communities.

Low scrub communities are dominated by birch (Betula 

glandulosa and B. nana) and ericaceous shrubs (for example, 

Vaccinium vitis-idaea, V. uliginosum, Ledum decumbens, 

Arctostaphylos spp., and Empetrum nigrum), or by willows 

(for example, Salix glauca, S. planifolia, and S. lanata). Other 

shrubs commonly found in these communities include 

red-fruit bearberry (Arctostaphylos rubra), bog blueberry 

(Vaccinium uliginosum), mountain-avens (Dryas spp.), netleaf 

willow (Salix reticulata), and arctic willow (S. arctica). 

Common herbs are fescue grass (Festuca altaica), alpine holygrass (Hierochloe alpina), Bigelow sedge (Carex bigelowii), 

arctic sweet coltsfoot (Petasites frigidus), and arctic wormwood (Artemisia arctica). Mosses (for example, Hylocomium 

splendens and Pleurozium schreberi) form patchy to continuous mats. Lichens (for example, Cetraria spp. Stereocaulon 

tomentosum, and Cladonia spp.) can be abundant.

Tall scrub communities occur at altitudinal treeline, 

along streambanks, in drainages, and on floodplains. These 

communities are dominated by willow (Salix alaxensis, S. 

arbusculoides, S. planifolia, and S. lanata), alder (Alnus sinuata and A. crispa), a mixture of willow and alder, or a mixture of willow and birch (Betula glandulosa). Low shrubs, 

such as Alaska bog willow (Salix fuscescens), Beauverd 

spirea (Spiraea beauverdiana), narrow-leaf Labrador-tea 

(Ledum decumbens), and bog blueberry (Vaccinium uliginosum), occur in the more open stands. Understory herbs 

include polar grass (Arctagrostis latifolia), fescue grass 

(Festuca altaica), Bigelow sedge (Carex bigelowii), and 

large-flowered wintergreen (Pyrola grandiflora). Mosses 

(for example, Polytrichum spp., Hylocomium splendens, and 

Drepanocladus uncinatus) may be abundant in wetter stands. 

Lichens (for example, Cladonia spp. and Stereocaulon 

tomentosum) are locally abundant in drier stands.

Needleleaf forests and woodlands are dominated by 

white spruce (Picea glauca) or white spruce mixed with 

black spruce (P. mariana). The understory typically consists 

of low woody vegetation, such as white mountain-avens 

(Dryas octopetala), red-fruit bearberry (Arctostaphylos 

rubra), arctic willow (Salix arctica), crowberry (Empetrum 

nigrum), and mountain-cranberry (Vaccinium vitis-idaea).
50 ECOREGIONS OF ALASKA

Figure 36. Mountains with middle to lower slopes blanketed with low and tall scrub communities in the Alaska Range 

Ecoregion. Deciduous (for example, Populus spp.) and coniferous (Picea spp.) trees often follow water tracks downslope. 

(Photo courtesy of Beverly Friesen, Saint Mary's College of Minnesota, Winona.)

Figure 37. White spruce woodlands on well drained lower slopes and valleys in the Alaska Range Ecoregion. The understory is resin birch.
COPPER PLATEAU 51

Mosses (for example, Pleurozium schreberi and Rhytidium 

rugosum) grow in moist depressions. Fruticose lichens (for 

example, Cetraria spp.) are scattered throughout the understory vegetation mat.

Wildfire. - Occurrence of wildfires in the Alaska Range is 

low. Fires have ranged in size from less than 1 ha to 3,290 ha, 

with the majority of the largest fires occurring in the central and 

eastern portion of the ecoregion. Average area burned per fire 

over the entire region is about 90 ha.

Land Use and Settlement. - The few permanent settlements in this ecoregion are below 750 m elevation. The 

region is used primarily for recreation and subsistence hunting and fishing. Native inhabitants of the Alaska Range 

belong to several Athabascan groups, primarily the Tanaina, 

Ahtna, and Tanacross. Their livelihoods depend on salmon 

and freshwater fish (for example, whitefish, blackfish, and 

pike), large mammals (caribou, moose, and dall sheep), 

smaller fur-bearing mammals (for example, beaver, hare, 

and ground squirrel), and edible plants. Many extractable 

resources occur in this ecoregion; these include metals (for 

example, gold, silver, lead, copper, tungsten, platinum, zinc, 

chromium, mercury, and tin), energy-related commodities 

(for example, coal and uranium), and other commodities (for 

example, antimony, bismuth, and molybdenum).

Delineation Methods. - The ecoregion boundary follows a generalized 600-m elevation contour for separating 

the Alaska Range from the interior forested ecoregions. A 

generalized 900-m elevation contour was used to separate the 

Alaska Range Ecoregion from the Copper Plateau Ecoregion. 

The Matanuska River is the boundary between the geological 

formations of the Alaska Range and those of the Chugach 

Mountains. The mountain pass along Jack Creek and the 

upper Nabesna River forms the boundary between the Alaska 

Range and Wrangell Mountains Ecoregions. Transitional 

zones are areas less than 600 m in elevation along river 

drainages, areas where mountains higher than 600 m become 

more widely spaced (approximately >10 km apart), and areas 

having upland spruce-hardwood forest vegetation.

References. - The information provided in this regional 

description has been compiled from Beikman (1980), Coulter 

and others (1962), Ferrians (1965), Gabriel and Tande (1983), 

Joint Federal-State Land Use Planning Commission for 

Alaska (1973), Karlstrom and others (1964), Langdon 

(1993), Larson and Bliss (written commun., 1992), Moore 

(written commun., 1993), Morgan (1979), Ping (written 

commun., 1993), Reiger and others (1979), Selkregg (1974), 

U.S. Bureau of Mines (1992a, 1992b), U.S. Geological 

Survey (1964, 1987a), Viereck and Little (1972), Viereck and 

others (1992), Wahrhaftig (1965), WeatherDisc Associates, 

Inc. (1990), and Wibbenmeyer and others (1982).

117. COPPER PLATEAU

Distinctive Features. - The 17,000-km2 Copper 

Plateau Ecoregion in south central Alaska occupies the site 

of a large lake that existed during glacial times. The nearly 

level to rolling plain has many lakes and wetlands (fig. 38). 

Soils are predominantly silty or clayey, formed from glaciolacustrine sediments. Much of the region has a shallow permafrost table, and soils are poorly drained. Black spruce 

forests and tall scrub, interspersed with wetlands, are the 

major types of vegetation communities.

Climate. - The ecoregion has a continental climate. 

Weather stations are located along the eastern side of the 

region. There, winter temperatures range from lows of about 

-27°C, to highs of about -16°C. Summer temperatures are 

more consistently distributed throughout the area, with average lows of about 4°C and average highs of about 21°C. 

Annual precipitation is lowest in the south and highest in the 

north, ranging from 250 mm to 460 mm. Snowfall distribution patterns are comparable, ranging from 100 cm in the 

south to 190 cm in the north. Although frost can occur in any 

month, temperatures warm enough for plant growth generally occur over a period of 11 weeks.

Terrain. - The ecoregion has smooth to rolling terrain. 

Elevations vary from 420 m to 900 m, with slope gradients 

generally less than 2°. The region is mantled in Pleistocene 

proglacial lake deposits that are tens to hundreds of meters 

thick. Most rivers head in glaciers from the surrounding 

mountains. Wind-blown deposits from local floodplains 

have developed into dunes along most of the glacial streams. 

The overall drainage pattern is poorly defined, but the lower 

stretches of the larger rivers are deeply incised in narrow valleys. The continuous permafrost layer ranges from thin to 

moderately thick. The permafrost table is close to the 

ground surface, resulting in abundant thaw lakes. The permafrost table is deep or absent in some of the very gravelly 

and sandy material. Lakes have formed in abandoned meltwater channels and morainal depressions.

Soils. - Principal soils are Histic Pergelic Cryaquepts, 

Aquic Cryochrepts, Typic Cryochrepts, Pergelic Cryaquolls, 

and Typic Cryoborolls. The major soils formed in silty aeolian mantles overlying calcareous silty and clayey glaciolacustrine sediments and, in places, gravelly glacial drift. 

Organic soils occupy some depressions. Most of the soils 

have a shallow permafrost table and are poorly drained. 

Well drained soils occur in upland areas disturbed by wildfire or in very gravelly deposits where permafrost is deep or 

absent. Soils with permafrost are very susceptible to alteration upon disturbance of the organic mat, because of the relatively warm (>-1.5°C) permafrost temperature. Organic 

mat disturbance, as by wildfire, can result in warmer soil 

temperatures, lowered permafrost tables, and significant
52 ECOREGIONS OF ALASKA

Figure 38. Widespread black spruce forest and small lakes typically encircled by bog communities are common in the 

Copper Plateau Ecoregion. The area is mantled with fine-textured glaciolacustrine sediments. Depth to permafrost is shallow 

and soils are poorly drained.

changes in soil physical properties and hydrology.

Vegetation. - Vegetation communities in the ecoregion 

reflect characteristics of the poor soil drainage and shallow 

permafrost table. Needleleaf forests and woodlands dominated by black spruce are the most common communities. 

Better drained sites, such as those occurring along streams, 

on the larger floodplains, and on south-facing slopes of very 

gravelly moraines, support needleleaf forests dominated by 

white spruce, broadleaf forests dominated by black cottonwood or aspen, and tall scrub communities. Wetlands are 

common and support low scrub bogs and wet graminoid 

herbaceous communities.

Black spruce (Picea mariana) forests and woodlands 

may include a tall shrub layer dominated by willow (for 

example, Salix planifolia and S. glauca) and resin birch 

(Betula glandulosa), a low shrub layer of ericaceous species 

(for example, Ledum groenlandicum, Vaccinium vitis-idaea, 

and V. uliginosum), and herbs (for example, Eriophorum 

spp., Carex spp., and Equisetum spp.). Moss cover (for 

example, feathermosses and Sphagnum spp.} is patchy to 

continuous. Lichens (for example, Cladonia spp., Cladina 

spp., and Cetraria spp.) are often present.

White spruce (Picea glauca) and balsam poplar 

(Populus balsamifera) stands commonly have a low shrub 

layer that includes prickly rose (Rosa acicularis) and buffaloberry (Shepherdia canadensis). Species of

Calamagrostis and Equisetum are typical of the herb layer.

Quaking aspen (Populus tremuloides) stands have a low 

shrub understory that typically includes prickly rose (Rosa 

acicularis), a number of ericaceous species (for example, 

Vaccinium vitis-idaea, V. uliginosum, and Arctostaphylos 

uva-ursi), and buffaloberry (Shepherdia canadensis). The 

ground cover usually consists of herbs (for example, Cornus 

canadensis and species of Calamagrostis and Pyrola) and 

mosses (for example, Drepanocladus spp., Hylocomium 

splendens, and Polytrichum spp.).

Low scrub bogs are dominated by birch (Betula glandulosa and B. nana) and ericaceous shrubs (for example, 

Vaccinium vitis-idaea, V. uliginosum, Ledum decumbens, 

Empetrum nigrum, and Andromeda polifolia). Sedges 

(Carex spp.) and other herbs are common in the understory. 

Sphagnum mosses are abundant at most sites.

Wet graminoid herbaceous communities are typically 

dominated by sedges (for example, Eriophorum angustifolium and Carex spp.) or codominated by sedges and herbs (for 

example, Menyanthes trifoliata, Petasites frigidus, and 

Potentilla palustris). Mosses (for example, Sphagnum spp.) 

are common.

Wildfire. - Occurrence of wildfires in the Copper 

Plateau Ecoregion is low. Size of burn typically is small, ranging from less than 1 ha to about 40 ha, with a mean of 5 ha.
WRANGELL MOUNTAINS 53

Figure 39. The Wrangell Mountains Ecoregion is extensively covered by ice fields and glaciers. Most slopes are barren of 

vegetation; however, dwarf scrub communities predominate where vegetation does occur. (Photo courtesy of M. Woodbridge 

Williams, National Park Service, Anchorage.)

Land Use and Settlement. - A few small settlements 

occur in the region. The region has traditionally been used 

for subsistence hunting and fishing by the Ahtna 

Athabascans. Their principal resources for food and materials are salmon and freshwater fish, large game (for example, 

caribou and moose), small fur-bearing mammals (for example, beaver, hare, and ground squirrel), and edible plants. 

Some mining activities have occurred, such as those related 

to extraction of gold and selenium.

Delineation Methods. - A generalized 900-m elevation 

contour was used to delineate the boundary of the Copper 

Plateau Ecoregion. This boundary corresponds with patterns 

on the relative CIR image. Because the ecoregion is typified 

by features that relate to low and very low terrain roughness, 

steeper, more variable terrain has been depicted as transitional.

References. - The information provided in this regional description has been compiled from Beikman (1980), 

Black (1951), Coulter and others (1962), Ferrians (1965), 

Gabriel and Tande (1983), Joint Federal-State Land Use 

Planning Commission for Alaska (1973), Karlstrom and others (1964), Langdon (1993), Larson and Bliss (written commun., 1992), Moore (written commun., 1993), Morgan 

(1979), Ping (written commun., 1993), Reiger and others 

(1979), Selkregg (1974), U.S. Bureau of Mines (1992a, 

1992b), U.S. Geological Survey (1964, 1987a), Viereck and

Little (1972), Viereck and others (1992), Wahrhaftig (1965), 

and WeatherDisc Associates, Inc. (1990).

118. WRANGELL MOUNTAINS

Distinctive Features. - The 29,000-km2 Wrangell 

Mountains Ecoregion consists of steep, rugged mountains of 

volcanic origin that are extensively covered by ice fields and 

glaciers (fig. 39). Most slopes are barren of vegetation. Dwarf 

scrub tundra communities, consisting of mats of low shrubs, 

forbs, grasses, and lichens, predominate where vegetation does 

occur. The climate has harsh winters and short summers.

Climate. - Climate is primarily affected by continental 

influences. The only weather station within the region is 

located at McCarthy. There, winter low temperatures average -34°C, and winter highs average -9°C. Mean summer 

low temperature is 3°C, and mean summer high is 22°C. 

The average number of frost-free days each year is somewhat less than 2 months. McCarthy receives an average of 

410 mm of precipitation per year, of which 175 cm is snow. 

Higher elevations may receive 2,030 mm of precipitation 

annually, including 255 cm of snow.

Terrain. - The ecoregion represents a large group of 

shield and composite volcanoes of Cenezoic age; Mount
54 ECOREGIONS OF ALASKA

Figure 40. Typical glacial till parent material in valley soils of the Wrangell Mountains Ecoregion. Deposits, such as these 

left by the receding Kennicott Glacier, can deeply mantle valley floors and provide considerable sediment loading to streams.

Wrangell remains an active volcano. These volcanic formations lie over Paleozoic and Mesozoic sedimentary and volcanic rocks. The terrain is steep and rugged, with most slope 

gradients exceeding 7° and many (15 percent of the ecoregion) surpassing 15°. Elevations start at 600 m, and most of 

the largest peaks are 3,900 m or more, with a couple of peaks 

exceeding 4,880 m. The mountains were glaciated during 

the Pleistocene epoch, and extensive glaciation persists. 

Permafrost is discontinuous. Streams headwater in glaciers, 

and their drainages radiate outward from the region. There 

are few lakes.

Soils. - Much of the landscape consists of steep rocky 

slopes, icefields, and glaciers. Soil development has resulted in thin, stony soils that are shallow over bedrock or bouldery deposits. Most soils have formed in very stony and 

gravelly colluvial material. Soils in valleys and on footslopes have formed in glacial till (fig. 40), with a thin mantle of volcanic ash or loess in some places. Most soils are 

poorly drained, but well drained soils do occur in very gravelly material at the foot of high ridges, on some south-facing 

slopes, and on hilly moraines at lower elevations. Principal 

soils are Lithic Cryorthents, Typic Cryorthents, Pergelic 

Cryochrepts, and Pergelic Cryumbrepts.

Vegetation. - Most slopes in the mountains are barren of 

vegetation. Dwarf scrub communities dominate where vegetation does occur, growing on well drained, windy sites. Tall 

scrub communities occur along drainages and on floodplains. 

Broad ridges, valleys, and hilly moraines at lower elevations 

support needleleaf forests dominated by white spruce or 

broadleaf forests dominated by paper birch or aspen.

Dwarf scrub communities are dominated by mountain-avens (Dryas drummondii, D. integrifolia, and D. 

octopetala), ericaceous shrubs (for example, Vaccinium 

vitis-idaea and V. uliginosum), or willow (for example, 

Salix rotundifolia, S. polaris, S. reticulata, and S. arctica). 

Typical herbaceous vegetation includes Carex spp., Festuca 

spp., Anemone spp., and Saxifraga spp. Lichens (for example, Cladina spp., Cetmria spp., and Cladonia spp.} may 

provide substantial cover and may codominate with shrubs.

Tall scrub communities are dominated by willow (for 

example, Salix lanata, S. alaxensis, S. barclayi, and S. planifolia) and alder (for example, Alnus sinuata). The understory 

consists of herbs, typically including both graminoid and 

broad-leaved species, and mosses (primarily feathermosses).

Forests dominated by white spruce (Picea glauca) typically include understory shrubs, such as willow (Salix spp.), 

alder (Alnus spp.), and birch (Betula spp.). A nearly continuous layer of feathermosses covers the ground.

Forests dominated by paper birch (Betula papyri/era) or 

quaking aspen (Populus tremuloides) are typically accompanied by an understory shrub layer, including alder (Alnus 

spp.), willow (Salix spp.), prickly rose (Rosa acicularis), and
PACIFIC COASTAL MOUNTAINS 55

high bushcranberry (Viburnum edule). Herbaceous cover is 

variable, often including species such as bluejoint 

(Calamagrostis spp.), horsetail (Equisetum spp.), and twinflower (Linnaea horealis). A layer of mosses (primarily 

feathermosses) or, on drier sites, lichens is common under 

open stands of paper birch.

Wildfire. - Occurrence of lightning fires in the Wrangell 

Mountains is very low. Gabriel and Tande (1983) report no 

fires during the 22-year period of record examined.

Land Use and Settlement. - Perennial settlements are 

rare, mostly located in the lower valleys. The region has traditionally provided subsistence resources for Athabascans of 

the Upper Tanana and Ahtna groups. Salmon and freshwater fish, caribou, moose, dall sheep, beaver, hare, and ground 

squirrels are typical sources of food and materials. Edible 

and medicinal plants are also collected.

A belt of copper deposits lies on the south side of the 

region and has been economically important. Other important metals have included silver, gold, lead, and zinc.

Delineation Methods. - The Chitina River, up through 

Logan Glacier, was used to separate the geologic formations 

of the Wrangell Mountains Ecoregion from those of the 

Pacific Coastal Mountains Ecoregion. The mountain pass 

along Jack Creek and the upper Nabesna River forms the 

boundary between the Wrangell Mountains and the Alaska 

Range Ecoregions. A generalized 900-m elevation contour 

was used to separate the Wrangell Mountains from the 

Copper Plateau. Moderate to very high terrain roughness 

was used to distinguish the mountains from the bottomlands 

of the Tetlin National Wildlife Refuge, to the north. The 

boundary between the Wrangell Mountains and the Interior 

Highlands Ecoregions was based on a generalized 600-m 

elevation contour. Transitional areas are those having vegetation other than alpine tundra ecosystems.

References. - The information provided in this regional 

description has been compiled from Beikman (1980), Coulter 

and others (1962), Ferrians (1965), Gabriel and Tande (1983), 

Joint Federal-State Land Use Planning Commission for 

Alaska (1973), Karlstrom and others (1964), Langdon 

(1993), Larson and Bliss (written commun., 1992), Moore 

(written commun., 1993), Morgan (1979), Reiger and others 

(1979), Selkregg (1974), U.S. Bureau of Mines (1992a, 

1992b), U.S. Geological Survey (1964, 1987a), Viereck and 

Little (1972), Viereck and others (1992), Wahrhaftig (1965), 

and WeatherDisc Associates, Inc. (1990)

119. PACIFIC COASTAL MOUNTAINS

Distinctive Features. - The steep and rugged mountains along the southeastern and south central coast of Alaska

receive more precipitation annually than either the Alaska 

Range or Wrangell Mountains Ecoregions. Glaciated during 

the Pleistocene epoch, most of the 106,000-km2 ecoregion is 

still covered by glaciers and ice fields. Most of the area is 

barren of vegetation (fig. 41), but where plants do occur, 

dwarf and low scrub communities dominate.

Climate. - Climate for most of the ecoregion is transitional between maritime and continental influences. There are 

no long-term weather stations in this ecoregion. Climatic patterns within the region are affected by elevation, latitude, and 

geographic position. Interpolation of data from the low-elevation stations of the adjacent coastal ecoregion estimates an 

annual precipitation ranging from 2,030 mm to greater than

Figure 41. Glaciers and ice fields, remaining since the 

Pleistocene epoch, are typical of the Pacific Coastal Mountains 

Ecoregion. The ecoregion is predominantly barren of vegetation, 

but alpine tundra communities occur where conditions permit. 

(Photo courtesy of Ray Koleser, Forest Service, Forestry Sciences 

Laboratory, Anchorage.)
56 ECOREGIONS OF ALASKA

7,000 mm, increasing with elevation and in a south-to-north 

direction. Estimated annual snowfall ranges from 510 cm to 

2,030 cm and follows the same distribution pattern.

Terrain. - Steep, rugged mountains covered by many 

active glaciers are typical of this ecoregion. Elevations 

range from sea level to more than 4,500 m. Higher parts of 

the ecoregion are buried in ice fields, from which valley and 

piedmont glaciers radiate. Slope gradients for most of the 

region are greater than 7°; slope gradients for 5 percent of 

the region exceed 20°. Geologic formations of Cretaceous 

and Upper Jurassic sediments occur extensively throughout 

the Chugach Mountains. Tertiary to Cretaceous (Paleozoic 

in some places) intrusive rock occurs throughout the southeastern portion of the ecoregion. The Chugach Mountains 

are underlain by isolated masses of permafrost. The mountains of the southern half of the region are generally free of 

permafrost. The ecoregion was extensively glaciated during 

the Pleistocene epoch, and many glaciers remain. Features 

typical of glaciated terrain, such as aretes, horns, cirques, U-- 

shaped valleys, and morainal deposits in valleys and on 

lower hillslopes, are abundant. Streams are short and swift, 

and headwatered in glaciers. Lakes lie in ice-carved basins.

Soils. - Most areas are covered by glaciers, ice fields, or 

rock outcrops. Where soil development has occurred, soils 

have formed in gravelly till and colluvium. Soils on steep 

ridges are shallow over bedrock. Dominant soils are Lithic 

Cryorthents, Andic Cryumbrepts, Pergelic Cryumbrepts, 

Typic Cryumbrepts, Typic Haplocryods, Andic Humicryods, 

Lithic Humicryods, and Typic Humicryods.

Vegetation. - The principal nature of this ecoregion is 

alpine slopes barren of vegetation or dwarf and low scrub 

communities in areas where vegetation does occur. There 

are many areas where needleleaf forests, originating in adjacent, lower elevation ecoregions, colonize mesic sites along 

drainageways.

Dwarf scrub communities are typically dominated by 

mountain heath (Phyllodoce aleutica). Associated shrubs 

include cassiope (Cassiope mertensiana and C. stelleriand), 

meadow-spirea (Luetkea pectinata), bog blueberry (Vaccinium 

uliginosum), and dwarf blueberry (V. caespitosum).

Low scrub communities dominated by ericaceous 

shrubs (for example, Cladothamnus pyrolaeflorus) form 

dense thickets at lower elevations in the ecoregion where 

snow cover persists until late spring.

Needleleaf forest stands are dominated by hemlock 

(Tsuga heterophylla or T. mertensiana) and subalpine fir 

(Abies lasiocarpa) or by Sitka spruce (Picea sitchensis). The 

understory layer consists of ericaceous shrubs (for example, 

Vaccinium alaskaense, V. ovalifolium, and Menziesia ferruginea), raspberry (Rubus spp.), currant (Ribes spp.), and devilsclub (Oplopanax horridus}. The forest floor is typically 

covered by herbs (for example, Tiarella trifoliata and

Streptopus spp.} and a number of fern species.

Wildfire. - Wildfire information is only available for 

the northern portion of the ecoregion, in the Chugach 

Mountains, where occurrence is very low. Burn areas have 

ranged in size from less than 1 ha to 40 ha, averaging 4 ha.

Land Use and Settlement. - Permanent settlements are 

rare in this ecoregion, primarily occurring at the lower elevations. The eastern half of the region has historically been 

used by the Tlingits, and the western half has been used by 

the Chugach and Eyak peoples. Moose, mountain goat, and 

smaller mammals are hunted in the mountains. Streams 

yield salmon and freshwater fish. Coastal areas provide 

marine resources as well as coastal birds and their eggs. 

Edible greens, roots, and berries are also collected.

In addition to subsistence and recreational hunting and 

fishing, the region has supplied a variety of metallic elements 

(for example, gold, silver, copper, zinc, lead, tungsten, iron, 

nickel, platinum, barium, and chromium), nonmetallic elements (for example, antimony, arsenic, and molybdenum), and 

energy-related commodities (coal, petroleum, and uranium).

Delineation Methods. - The boundary of the southern 

section of the ecoregion excludes the western hemlock-Sitka 

spruce forests of the Pacific Coast. The northern boundary 

is based on Logan Glacier, along the interface with the 

Wrangell Mountains; a generalized 900-m elevation contour, along the interface with the Copper Plateau; the 

Matanuska River, along the interface with the Alaska Range; 

and a generalized 600-m elevation contour, along the interface with the Cook Inlet Ecoregion. Transitional areas are 

those having forests.

References. - The information provided in this regional 

description has been compiled from Beikman (1980), Coulter 

and others (1962), Ferrians (1965), Gabriel and Tande (1983), 

Joint Federal-State Land Use Planning Commission for Alaska 

(1973), Karlstrom and others (1964), Langdon (1993), Larson 

and Bliss (written commun., 1992), Moore (written commun., 

1993), Morgan (1979), Ping (written commun., 1993), Reiger 

and others (1979), Selkregg (1974), U.S. Bureau of Mines 

(1992a, 1992b), U.S. Forest Service (1992), U.S. Geological 

Survey (1964, 1987a), Viereck and Little (1972), Viereck and 

others (1992), Wahrhaftig (1965), and WeatherDisc Associates, 

Inc. (1990).

120. COASTAL WESTERN HEMLOCK-SITKA 

SPRUCE FORESTS

Distinctive Features. - Located along the southeastern 

and south central shores of Alaska, the terrain of this 

61,000-km2 ecoregion is a result of intense glaciation during 

late advances of the Pleistocene epoch. The deep, narrow
COASTAL WESTERN HEMLOCK-SITKA SPRUCE FORESTS 57

r

Figure 42. The Coastal Western Hemlock-Sitka Spruce Forests Ecoregion has deep, narrow bays and steep, dissected valley 

walls covered by highly productive forests. The ecoregion receives large amounts of precipitation and has the mildest winter temperatures of all ecoregions in Alaska. (Photo courtesy of Ken Winterberger, Forest Service, Forestry Sciences Laboratory,

bays, steep valley walls that expose much bedrock, thin 

moraine deposits on hills and in valleys, very irregular coastline, high sea cliffs, and deeply dissected glacial moraine 

deposits covering the lower slopes of valley walls are all evidence of the effects of glaciation. The region has the mildest 

winter temperatures in Alaska, accompanied by large 

amounts of precipitation. Forests of western hemlock and 

Sitka spruce are widespread (fig. 42).

Climate. - The ecoregion has a maritime climate, with 

cool summers and mildly cold winters. Moderate to heavy 

precipitation occurs throughout the year, though storms are 

most frequent and heavy during the winter. Surface winds 

are moderate to strong, with prevailing winds coming from 

the south or southeast. The average frost-free season is 

about 7 months. Mean annual precipitation ranges from 

1,350 mm to 3,900 mm, depending on location. Mean annual snowfall ranges from 80 cm to 600 cm. Daily minimum 

temperature in winter is about -3°C at many weather stations, and daily maximum temperature averages about 3°C. 

Mean daily minimum temperature in summer is about 7°C, 

and maximum temperature is about 18°C.

Terrain. - The ecoregion includes the steep footslopes, 

alluvial fans, floodplains, outwash plains, scattered

moraines, river terraces, and river deltas of the Pacific 

coastal mountains. Elevations climb from sea level to 500 m 

(including some local mountains up to 1,000 m). Slope gradients range from 0° to 28°, with a median of 5°. Geologic 

formations are Lower Tertiary interbedded sedimentary, volcanogenic, and volcanic rocks in the Prince William Sound 

area. Upper Cretaceous sandstone and slate on Kodiak 

Island, and Mesozoic volcanic and intrusive rock along with 

Mesozoic and Paleozoic sediments in the southeastern portion of the ecoregion. More recent formations are dunes of 

aeolian sand that border some of the floodplains throughout 

the ecoregion. Nearly all of the ecoregion was subject to late 

glacial advances during the Pleistocene epoch, although no 

glaciers remain. The region is generally free from permafrost. Most streams originate from the mountain glaciers 

of adjoining ecoregions; exceptions are streams on islands. 

Lakes are plentiful in some areas and absent in others.

Soils. - Dominant soils are Terric Cryohemists, Andic 

Cryaquods, Andic Humicryods, Lithic Humicryods, and 

Typic Humicryods. Soils near the mountains formed in 

gravelly and stony moraine deposits or in a mantle of volcanic ash over the morainal deposits. Soils of river deltas, 

terraces, alluvial fans, and floodplains formed in waterlain 

silts and clays. Poorly drained depressions are filled with
58 ECOREGIONS OF ALASKA

fibrous peat. Many parts of the ecoregion are susceptible to 

flooding or to inundation by tidewater. Ash-influenced soils 

are located on Kruzof Island and areas of Baranof Island.

Vegetation. - The relatively long growing season, high 

annual precipitation, and mild temperatures of this ecoregion 

support a large variety of coastal forest, scrub, and wetland 

communities. Forests, which may be dominated by needleleaf or broadleaf species, or a mixture of both, predominate. 

Scrub communities are dominated by tall shrubs, low shrubs, 

or dwarf shrubs. Wetland sites support tall scrub swamps, 

low scrub bogs, wet graminoid herbaceous communities, 

and wet forb herbaceous communities.

A large variety exists in the dominant and codominant 

constituents of forested communities. Western hemlock 

(Tsuga heterophylld) and Sitka spruce (Picea sitchensis) are 

the two most typifying species of the region, but a variety of 

other trees also occur, including silver fir (Abies amabilis), 

subalpine fir (A. lasiocarpa), lodgepole pine (Pinus contorta), Pacific yew (Taxus brevifolia), alder (Alnus rubra), and 

black cottonwood (Populus trichocarpa). Understory vegetation varies somewhat with forest type. Typical woody 

species include alder (Alnus spp.), willow (Salix spp.), currant (Ribes spp.), salmonberry (Rubus spectabilis), prickly 

rose (Rosa acicularis), red-fruit bearberry (Arctostaphylos 

rubra), cranberry/blueberry (for example, Vaccinium 

alaskaense, V. ovalifolium, and V. parvifolium), high 

bushcranberry (Viburnum edule), dwarf dogwood (Cornus 

canadensis), devilsclub (Oplopanax horridus), and five-leaf 

bramble (Rubus pedatus). Herbaceous cover is supplied by 

bluebell (Mertensia paniculata), false lily-of-the-valley 

(Maianthemum dilatatum), laceflower (Tlarella trifoliata), 

deer cabbage (Fauria crista-galli), twisted stalk (Streptopus 

spp.), goldthread (Coptis aspleniifolia), sedge (Carex spp.), 

reed-grass (Calamagrostis spp.), and ferns (for example, 

Gymnocarpium dryopteris, Dryopteris dilatata, Athyrium 

filix-femina, and Blechnum spicant). Mosses (for example, 

Hylocomium splendens, Pleurozium schreberi, and 

Drepanocladus uncinatus) are common.

Scrub communities range from tall scrub to dwarf scrub. 

Tall scrub communities are dominated by willow (for example, Salix alaxensis, S. planifolia, S. lanata, and S. sitchensis), alder (Alnus tenuifolia), or a mix of willow and alder. 

An understory scrub layer is typically absent, but cover by 

herbs (for example, Calamagrostis canadensis, Festuca 

altaica, Equisetum spp., Epilobium spp., Mertensia paniculata, Aconitum delphinifolium, and Athyrium filix-femina) 

may be dense. Mosses (for example, Polytrichum spp., 

Hylocomium splendens, and Drepanocladus uncinatus) form 

a patchy to continuous mat.

Low scrub communities are dominated by copperbush 

(Cladothamnus pyrolaeflorus) or by a mix of willow (for 

example, Salix glauca, S. planifolia, and S. lanata) and alder 

(for example, Alnus sinuata). Although copperbush communities generally have no significant associated species, communities dominated by willow and alder are often accompanied by ericaceous shrubs (for example, Arctostaphylos 

alpina, Empetrum nigrum, and Vaccinium vitis-idaea) and 

nonsphagnaceous mosses.

Dwarf scrub communities occur at higher elevation, 

where sites are exposed to harsh climatic elements. 

Mountain-heath (Phyllodoce aleutica) is the dominant 

species. Associated dwarf shrubs include cassiope (Cassiope 

mertensiana and C. stelleriana), meadow-spirea (Luetkea 

pectinata), bog blueberry (Vaccinium uliginosum), dwarf 

blueberry (V. caespitosum), Nootka lupine (Lupinus 

nootkatensis), Sitka valerian (Valeriana sitchensis), and roseroot (Sedum rosea). Mosses and lichens can be common.

Tall scrub swamps are usually dominated by alder 

(Alnus tenuifolia) but are sometimes dominated or codominated by willow (for example, Salix planifolia or S. lanata). 

Typical herbs are bluejoint (Calamagrostis canadensis) and 

horsetail (Equisetum spp.).

Low scrub bogs are dominated by low ericaceous shrubs 

(for example, Empetrum nigrum, Vaccinium oxycoccus, 

Andromeda polifolia, and Kalmia Polifolia), a mixture of 

willow (Salix spp.) and graminoid species (for example, 

Calamagrostis canadensis, Carex aquatilis, and C. pluriflora), or a mixture of sweetgale (Myrica gale) and graminoid 

species (Calamagrostis canadensis, Trichophorum spp., and 

Carex spp.). Mosses (usually including Sphagnum spp.) 

occur at most sites.

Wet graminoid herbaceous communities are dominated 

by sedges (for example, Scirpus validus, Eleocharis palustris, and Carex spp.), a mixture of sedges and mosses (principally Sphagnum spp.), or a mixture of sedges and shrubs 

(Myrica gale or Salix spp.). Woody plants are lacking from 

the first two community types, and lichens are lacking from 

all three.

Wet forb herbaceous communities are typically dominated by one or more of the following: swamp horsetail 

(Equisetum spp.), yellow marsh-marigold (Caltha palustris), 

buckbean (Menyanthes trifoliata), and marsh fivefinger 

(Potentilla palustris). Woody plants and lichens are lacking 

from these communities, though aquatic mosses are common.

Wildfire. - Lightning fires are rare in this ecoregion; 

however, no data have been recorded regarding the frequency and size of burns.

Land Use and Settlement. - Population is concentrated along small stretches of flat coastal areas. Timber harvest 

and mining are the primary economic activities. A variety of 

metallic elements occur in this ecoregion, including gold, 

copper, silver, zinc, lead, iron, platinum, titanium, barium, 

nickel, cobalt, and chromium. Nonmetallic elements include 

antimony, arsenic, calcium, molybdenum, and sulfur. 

Energy-related commodities, such as coal, uranium, and 

petroleum, have also been investigated and mined.

The ecoregion has traditionally been populated by
SUMMARY 59

Tlingit and Haida groups in the eastern half and by Eyak, 

Chugach, Uneqkurmuit, and Koniag peoples in the western 

half. Mainland dwellers base their subsistence on salmon, 

eulachon (an important source of oil), moose, and mountain 

goat. Because island dwellers have access to smaller salmon 

runs, they make more use of marine resources, such as herring, halibut, and seaweed. Both mainland and island groups 

supplement their diets with deer, birds (for example, cranes, 

ducks, geese, grouse, and ptarmigan) and their eggs, seals 

(hunted at rookeries), intertidal resources (for example, 

clams, cockles, and chitons), and edible plants.

Delineation Methods. - The ecoregion boundary is 

based on the extent of "Coastal Western Hemlock-Sitka 

Spruce Forest," as shown on the maps "Major Ecosystems of 

Alaska" and forest types (Powell and others, 1993). This 

boundary corresponds with patterns on the relative CIR 

image. Because individual land units are small and environmental gradients are steep, it is not possible to delineate transitional zones at the current scale of mapping.

References. - The information provided in this regional 

description has been compiled from Beikman (1980), Coulter 

and others (1962), Fenians (1965), Joint Federal-State Land 

Use Planning Commission for Alaska (1973), Karlstrom and 

others (1964), Langdon (1993), Larson and Bliss (written 

commui)., 1992), Moore (written commun., 1993), Morgan 

(1979), Ping (written commun., 1993), Powell and others 

(1993), Reiger and others (1979), Selkregg (1974), U.S. 

Bureau of Mines (1992a, 1992b), U.S. Forest Service (1992), 

U.S. Geological Survey (1964, 1987a), Viereck and Little 

(1972), Viereck and others (1992), Wahrhaftig (1965), and 

WeatherDisc Associates, Inc. (1990).

SUMMARY

We have mapped and described 20 ecoregions of Alaska 

to serve as a framework for organizing and interpreting environmental data relevant to a wide range of regional ecological concerns. Examples of applications for the map include 

the assessment of natural resources (for example, regional 

chemical, physical, and biological characteristics of surface 

waters, soil erosion potential, and wildlife habitat diversity) 

and effects research (for example, potential regional ecological effects from environmental contaminants or climate 

change). The map can also be used in developing strategies 

for locating field sites or in evaluating how well existing 

research sites are distributed across ecoregions or along 

regional environmental gradients.

The regional descriptions accompanying the map indicate the degree of ecological variability occurring within 

each ecoregion. This information can be used to infer the 

relative density of sample sites needed to represent each 

ecoregion and the within-region areas over which field sample information can be extrapolated.

The ecoregion map was compiled by synthesizing information on the geographic distribution of environmental factors such as climate, physiography, geology, soils, permafrost, glaciation, hydrology, and vegetation. The synthesis was a qualitative assessment of the distributional patterns 

of these factors and their relative importance in influencing 

the nature of the landscape from place to place. The actual 

placement of ecoregion boundaries was achieved by following boundaries from a selected subset of mapped references 

that best integrated the patterns of the major factors of interest for each ecoregion.

An accuracy assessment was not performed on the map of 

Alaskan ecoregions. There are several problems associated 

with determining map accuracy, such as inability to sufficiently field sample the number of variables that define each ecoregion, inability to sample a sufficient number of (largely inaccessible) field sites to represent the range of within-region 

ecological variability, and difficulty in designing a sampling 

strategy that reconciles the differences in informational resolution between field samples and the ecoregion map. It may 

be more appropriate to assess the utility of the ecoregion map 

for different needs than to assess its accuracy. This is because 

the ecoregion boundaries have been delineated to be generally correct for a number of purposes but not necessarily precise 

for any singular purpose or variable.

The 20 ecoregions of Alaska are being aggregated into 

coarser ecological units for developing a North American 

map of ecoregions. A map of ecoregions has already been 

developed for Canada and has been integrated across the 

international border with the map of Alaskan ecoregions. 

Also under way are efforts to delineate ecoregions of other 

northern circumpolar areas to promote international programs 

involved with assessing and monitoring global resources.

ACKNOWLEDGMENTS

We are grateful to the many people who contributed 

their expertise, materials, and general support for this project. Carl Markon, Hughes STX Corporation., USGS EROS 

Alaska Field Office, coordinated field reconnaissance, furnished extensive information on Alaskan ecosystems, and 

provided review and discussion on draft versions of the 

ecoregion map and text. A number of people donated an 

assortment of unpublished information. Thomas Loveland, 

USGS EROS Data Center, Donald Ohlen, Hughes STX 

Corporation, USGS EROS Data Center, and Michael 

Fleming, Hughes STX Corporation, USGS EROS Alaska 

Field Office, provided unpublished maps derived from various methods of synthesizing Advanced Very High 

Resolution Radiometer satellite data to depict relative patterns in photosynthetic activity across Alaska. Norman Bliss 

and Kevin Larson, Hughes STX Corporation, USGS EROS 

Data Center, provided a series of maps based on soil compo-
60 ECOREGIONS OF ALASKA

nents, textures, and slopes. Joseph Moore, Soil 

Conservation Service, edited the discussions on regional soil 

characteristics to reflect more recent field information than 

that published in the 1979 Alaska Soil Survey; Chien-Lu 

Ping, Agricultural and Forestry Experiment Station, 

University of Alaska, Palmer Research Center, provided corrections for the soils information in an early draft of the table 

of major ecoregion characteristics. Douglas Brown, Forest 

Service, Rocky Mountain Forest and Range Experiment 

Station, supplied a digital data base showing the type, location, and status of mines in Alaska. Daniel Binkley, Forest 

Sciences Department, Colorado State University, and Sara 

Wesser, National Park Service, provided information on vegetation of the Noatak River Valley. lan Marshall, Ed Wiken, 

and Denis DeMarchi, all of Environment Canada, and Scott 

Smith, Agriculture Canada, helped to integrate the ecoregional boundaries delineated for Alaska with those delineated for Canada. Valuable reviews were contributed by: Leslie 

Viereck, Forest Service, Pacific Northwest Research Station, 

Institute of Northern Forestry, Robert Lipkin and Gerald 

Tande, Alaska Natural Heritage Program, The Nature 

Conservancy, Ken Winterberger, Forest Service, Pacific 

Northwest Research Station, Anchorage Forestry Sciences 

Laboratory, Walt Stieglitz and Anthony DeGange, U.S. Fish 

and Wildlife Service, Tom Newbury, Minerals Management 

Service, Dave Carneggie, USGS EROS Data Center, Page 

Spencer, National Park Service, David Swanson, Soil 

Conservation Service, and Jim Hawkings, Canadian Wildlife 

Service. Roger Hoffer, Forest Sciences Department, 

Colorado State University, administered Colorado State 

University's cooperative participation in this project and 

provided critical reviews of this report and of all proposals 

leading up to this report. We gratefully acknowledge the significant contributions in production of this report by Sablou 

Gabriel and Darla Larsen, and the cartographic work by John 

Hutchinson, all of Hughes STX Corporation, USGS EROS. 

This work was partially funded under Environmental 

Protection Agency Cooperative Agreement #CR820070.

REFERENCES

Bailey, R.G., Zoltai, S.C., and Wiken, E.B., 1985, Ecological

regionalization in Canada and the United States: Geoforum,

v. 16, no. 3, p. 265-275. 

Bailey, R.G., Avers, P.E., King, T., and McNab, W.H., 1994,

Ecoregions and subregions of the United States: Reston, U.S.

Department of Agriculture, Forest Service, scale 1:7,500,000. 

Barbour, M.G., Burk, J.H., and Pitts, W.D., 1987, Terrestrial plant

ecology (2d ed.): Menlo Park, The Benjamin/Cummings

Publishing Company, Inc., 634 p. 

Beikman, H.M., 1980, Geologic map of Alaska: Washington, D.C.,

U.S. Geological Survey, scale 1:2,500,000. 

Binnian, E.F., and Ohlen, D.O., 1992, The 1991 Alaska AVHRR

twice-monthly composites: EROS Data Center, U.S. Geological

Survey CD-ROM set, 1 disc.

Black, R.F., 1951, Eolian deposits of Alaska: Arctic, v. 4, no. 2,

p. 89-111. 

—— 1955, Permafrost and ground water in some representative

areas - Arctic slope: U.S. Geological Survey Professional Paper

264-F, p. 118-119.

1969, Geology, especially geomorphology, of northern

Alaska: Arctic, v. 22, no. 3, p. 283-295.

Coulter, H.W., Pewe, T.L., Hopkins, D.M., Wahrhaftig, C., 

Karlstrom, T.N.V., and Williams, J.R., 1962, Map showing 

extent of glaciations in Alaska: Miscellaneous Geologic 

Investigations Map 1-415, scale 1:2,500,000.

Crum, H.A., Steere, W.C., and Anderson, L.E., 1973, A new list 

of mosses of North America north of Mexico: The Bryologist, 

v. 76, no. 1, p. 85-130.

Davis, M.B., Woods, K.D., Webb, S.L., and Futyama, R.P., 1986, 

Dispersal versus climate: Expansion of Fagus and Tsuga into 

the Upper Great Lakes region: Vegetatio, v. 67, p. 93-103.

Drew, J.V., and Tedrow, J.C.F., 1962, Arctic soil classification and 

patterned ground: Arctic, v. 15, no. 2, p. 109-116.

Drury, W.H., Jr., 1956, Bog flats and physiographic processes in the 

Upper Kuskokwim River Region, Alaska: Cambridge, The Gray 

Herbarium of Harvard University, 130 p.

Egan, R.S., 1987, A fifth checklist of the lichen-forming, lichenicolous and allied fungi of the continental United States and 

Canada: The Bryologist, v. 90, no. 2, p. 77-173.

Eidenshink, J.C., 1992, The 1990 conterminous U.S. AVHRR data 

set: Photogrammetric Engineering & Remote Sensing, v. 58, 

no.6, p. 809-813.

Ferrians, O.J., Jr., 1965, Permafrost map of Alaska: Miscellaneous 

Geologic Investigations Map 1-445, scale 1:2,500,000.

Ferrians, O.J., Jr., and Hobson, G.D., 1973, Mapping and predicting permafrost in North America: A review, 1963-1973 [1], in 

Permafrost, North American Contribution to the Second 

International Conference, 1973: Yakutsk, U.S.S.R., National 

Academy of Science, p. 479-498.

Fitzpatrick-Lins, Kathy, Doughty, E.F., Shasby, M., and Benjamin, 

S., 1989, Alaska interim land cover mapping program-final 

report: U.S. Geological Survey Open-File Report 89-128,10 p.

Fleming, M.D., 1994, "Relative CIR": An image enhancement and 

visualization technique, in Pecora 12 Symposium: Land 

Information from Space-based Systems, Sioux Falls, South 

Dakota, August 24-26, 1993, Proceedings: Bethesda, American 

Society for Photogrammetry and Remote Sensing, p. 493.

Gabriel, H.W, and Tande, G.F., 1983, A regional approach to fire 

history in Alaska: Anchorage, U.S. Department of the Interior, 

Bureau of Land Management, BLM/AK/TR-83/09, 34 p.

Gallant, A.G., Whittier, T.R., Larsen, D.P., Omernik, J.M., and 

Hughes, R.M., 1989, Regionalization as a tool for managing 

environmental resources: U.S. Environmental Protection 

Agency, EPA/600/3-89/060, 152 p.

Hall, J.V., 1991, Wetland resources of Alaska [map]: U.S. Fish and 

Wildlife Service, National Wetlands Inventory, scale 

1:2,500,000.

Hopkins, D.M., 1959, Some characteristics of the climate in forest 

and tundra regions in Alaska: Arctic, v. 12, no. 4, p. 215-220.

Huete, A.R., and Jackson, R.D., 1988, Soil and atmosphere influences on the spectra of partial canopies: Remote Sensing of the 

Environment, v. 25, p. 89-105.

Huete, A.R., Jackson, R.D., and Post, D.F, 1985, Spectral response 

of a plant canopy with different soil backgrounds: Remote 

Sensing of Environment, v. 17, p. 37-53.
REFERENCES 61

Hughes, R.M., Larsen, D.P., and Omernik, J.M., 1986, Regional 

reference sites: A method for assessing stream potentials: 

Environmental Management, v. 10, no. 5, p. 629-635.

Hulten, Eric, 1968, Flora of Alaska and neighboring territories: 

Stanford, Stanford University Press, 1,008 p.

Joint Federal-State Land Use Planning Commission for Alaska, 

1973, Major ecosystems of Alaska [map]: U.S. Geological 

Survey, scale 1:2,500,000.

Karlstrom, T.N.V., Coulter, H.W., Fernald, A.T., Williams, J.R., 

Hopkins, D.M., Pewe, T.L., Drewes, H., Muller, E.H., and 

Condon, W.H., 1964, Surficial geology of Alaska: Miscellaneous 

Geologic Investigations Map 1-357, scale 1:1,584,000.

Kimmins, J.P., and Wein, R.W., 1986, Introduction of Van Cleve 

and others, eds., Forest ecosystems in the Alaskan taiga: New 

York, Springer-Verlag, p. 3-8.

Langdon, S.J., 1993, The native people of Alaska: Anchorage, 

Greatland Graphics, 96 p.

Loveland, T.R., Merchant, J.W., Ohlen, D.O., and Brown, J.F., 

1991, Development of a land-cover characteristics database for 

the conterminous U.S.: Photogrammetric Engineering & 

Remote Sensing, v. 57, no. 11, p. 1,453-1,463.

Markon, C.J., Fleming, M.D., and Binnian, E.F., 1995, 

Characteristics of Vegetation Phenology over the Alaska 

Landscape using AVHRR Time Series Data, Polar Record 31 

(177): 179-190 (1995). Printed in Great Britain.

Markon, C.J., 1992, Land cover mapping of the Upper Kuskokwim 

Resource Management Area, Alaska, using Landsat and a digital data base approach: Canadian Journal of Remote Sensing, 

v. 18, no. 2, p. 62-71.

Morgan, Lael, 1979, Alaska's native people: Alaska Geographic, 

v. 6, no. 3, 302 p.

Omernik, J.M., 1995, Ecoregions: A spatial framework for environmental management, in W.S. Davis and T. Simon eds., 

Biological assessment and criteria: Tools for water resource 

planning and decision making: Boca Raton, Florida, Lewis 

Publishers p. 49-62.

—— 1995, Ecoregions: A frame work for managing ecosystems: The 

George Wright Forum, v. 12, no. 1, p. 35-51. 

1987, Ecoregions of the conterminous United States: Annals of

the Association of American Geographers, v. 77, no. 1, p. 118-125. 

Oswald, E.T. and Senyk, J.P., 1977, Ecoregions of Yukon Territory:

Environment Canada, Canadian Forestry Service, 115 p. 

Pittman, T.L., 1992, The mineral industry of Alaska, 1990 Annual

Report: U.S. Department of the Interior, Bureau of Mines, 17 p. 

Powell, D.S., Faulkner, J.L., Darr, D.R., Zhu, Z., and MacCleery,

D.W., 1993, Forest resources of the United States, 1992: U.S.

Department of Agriculture, Forest Service, Rocky Mountain

Forest and Range Experiment Station, General Technical Report

RM-234, 132 p. 

Prentice, I.C., 1992, Climate change and long-term vegetation

dynamics, chap. 8 of Glenn-Lewin, D.C., Peet, R.K., and

Veblen, T.T., Plant succession: Theory and prediction: London,

Chapman & Hall, p. 293-339. 

Reiger, Samuel, Schoephorster, D.B., and Furbush, C.E., 1979,

Exploratory soil survey of Alaska: U.S. Department of

Agriculture, Soil Conservation Service, 213 p. 

Rubec, C.D.A., 1979, Applications of ecological (biophysical) land

classification in Canada in Canada Committee on Ecological

(Biophysical) Land Classification, 2d, Victoria, British Columbia,

1978, Proceedings: Ottawa, Lands Directorate, Environment

Canada, Ecological Land Classification Series, no. 7, 396 p.

Selkregg, L.L., 1974, Alaska regional profiles, six-volume looseleaf set: Anchorage, Joint Federal-State Land Use Planning 

Commission for Alaska.

Slaughter, C.W., and Viereck, L.A., 1986, Climatic characteristics 

of the taiga in interior Alaska, chap. 2 of Van Cleve, K., Chapin, 

F.S., III, Flanagan, P.W., Viereck, L.A., and Dyrness, C.T., eds., 

Forest ecosystems in the Alaskan taiga: New York, SpringerVerlag, p. 9-21.

Spetzman, L.A., 1959, Vegetation of the arctic slope of Alaska: 

U.S. Geological Survey Professional Paper 302-B, 58 p.

Talbot, S.S., Fleming, M.D., and Markon, C.J., 1986, Intermediatescale vegetation mapping of Kanuti National Wildlife Refuge, 

Alaska, using Landsat MSS digital data, in 1986 ASPRS-ACSM 

Fall Convention, Anchorage, Alaska, 1986, ASPRS Technical 

Papers: American Society for Photogrammetry and Remote 

Sensing, p. 392^06.

Talbot, S.S., and Markon, C.J., 1986, Vegetation mapping of 

Nowitna National Wildlife Refuge, Alaska, using Landsat MSS 

digital data: Photogrammetric Engineering & Remote Sensing, 

v. 52, no. 6, p. 791-799.

—— 1988, Intermediate-scale vegetation mapping of Innoko 

National Wildlife Refuge, Alaska, using Landsat MSS digital 

data: Photogrammetric Engineering & Remote Sensing, v. 54, 

no. 3, p. 377-383.

U.S. Bureau of Mines, 1992a, Minerals availability system 

non-proprietary (MASNP) database, tape documentation, 39 p.

—— 1992b, Minerals availability system non-proprietary (MASNP) 

database.

U.S. Fish and Wildlife Service, 1987a, Appendix B: Vegetation 

classification for the Selawik National Wildlife Refuge land 

cover map, Selawik National Wildlife Refuge, comprehensive 

conservation plan, environmental impact statement and wilderness review, final: Anchorage, U.S. Fish and Wildlife Service, 

Region 7, p. B1-B7.

—— 1987b, Yukon Flats National Wildlife Refuge comprehensive 

conservation plan, environmental impact statement, and wilderness review, final draft: Anchorage, U.S. Fish and Wildlife 

Service, p. 42-66.

U.S. Forest Service, 1992, Forest maps of the United States 1993 RPA 

Program: Southern Forest Experiment Station, Forest Inventory 

and Analysis CD-ROM, 1 disc.

U.S. Geological Survey, 1964, Mineral and water resources of 

Alaska: U.S. Geological Survey, p. 27-33.

—— 1987a, State of Alaska - map E, shaded relief edition: 

U.S. Geological Survey, scale 1:2,500,000.

—— 1987b, Alaska interim land cover mapping program: Data

Users Guide 7, 18 p.

U.S. Soil Conservation Service, 1981, Land resource regions and 

major land resource areas of the United States: USDA-SCS 

Agriculture Handbook 296, 156 p., 1 map sheet.

Viereck, L.A., 1989, Flood-plain succession and vegetation classification in interior Alaska in Land classifications based on vegetation: Applications for resource management, Fairbanks, 

Alaska, 1989, Proceedings: U.S. Department of Agriculture, 

Forest Service, Intermountain Research Station, p. 197-203.

Viereck, L.A., Dyrness, C.T., Batten, A.R., and Wenzlick, K.J., 

1992, The Alaska vegetation classification, General Technical 

Report PNW-GTR-286: U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Research Station, 278 p.

Viereck, L.A., and Little, E.L., Jr., 1972, Alaska trees and shrubs: 

U.S. Department of Agriculture, Forest Service, 265 p.
62 ECOREGIONS OF ALASKA

Viereck, L.A., Van Cleve, K., and Dyrness, C.T., 1986, Forest 

ecosystem distribution in the taiga environment, chap. 3 of Van 

Cleve, K., Chapin, F.S., III, Flanagan, P.W, Viereck, L.A., and 

Dyrness, C.T., eds., Forest ecosystems in the Alaskan taiga: 

New York, Springer-Verlag, p. 22-43.

Wahrhaftig, Clyde, 1965, Physiographic divisions of Alaska: 

U.S. Geological Survey Professional Paper 482, 52 p.

Walker, D.A., and Walker, M.D., 1991, History and pattern of disturbance in Alaskan arctic terrestrial ecosystems: A hierarchical 

approach to analyzing landscape change: Journal of Applied 

Ecology, v. 28, p. 244-276.

WeatherDisc Associates, Inc., 1990, World WeatherDisc 

CD-ROM, version 2.0: Seattle, WeatherDisc Associates.

Welsh, S.L., 1974, Anderson's flora of Alaska and adjacent parts of 

Canada: Provo, Brigham Young University Press, 724 p.

Whittier, T.R., Hughes, R.M., and Larsen, D.P., 1988, 

Correspondence between ecoregions and spatial patterns in 

stream ecosystems in Oregon: Canadian Journal of Fisheries 

and Aquatic Sciences, v. 45, no. 7, p. 1,264-1,278.

Whittier, T.R., Larsen, D.P., Hughes, R.M., Rohm, C.M., Gallant, A.L., 

and Omernik, J.M., 1987, The Ohio stream regionalization project: 

A compendium of results: Environmental Protection Agency, 

Environmental Research Laboratory EPA/600/3-87/025, 66 p.

Wibbenmeyer, Merlin, Grunblatt, J., Shea, L., 1982, User's 

guide for Bristol Bay land cover maps: State of Alaska, and 

U.S. Department of the Interior, 120 p.

Wiken, E.B., 1986, Terrestrial Ecozones of Canada: Lands 

Directorate, Environment Canada Ecological Land 

Classification Series 19, 26 p.

__ 1979, Rationale and methods of ecological land surveys: An 

overview of Canadian approaches in Taylor, D.G., ed., 

Land/Wildlife Integration: Lands Directorate, Environment 

Canada Ecological Land Classification Series, N, p. 11-19.
APPENDIXES 1-3
Appendix 1.-Table of major environmental characteristics occurring in each ecoregion

Ecoregion

101. Arctic Coastal Plain

(50,000 km2)

(1,2,4, 6)c

102. Arctic Foothills

(124,000km2)

(1,2,4,6)

103. Brooks Range

(134,000km2)

(1,2,3,4,6,7)

104. Interior Forested

Lowlands and Uplands

(269,000 km2)

(2, 3, 6, 7)

Climate"

(Db

Arctic. Ann. precip.d

=140 mm. Ann. snowfall

30 cm to 75 cm. Avg.

daily min. temp, in winter is -30°C; avg. daily

max. in summer is =8°C.

Arctic. Ann. precip.

=140 mm, up to 190 mm

near Brooks Range.

Ann. snowfall 75 cm to

130 cm. Avg. daily min.

temp, in winter is -29°C;

avg. daily max. in summer is 11°C to 15°C.

Arctic. Ann. precip. at

Anaktuvuk Pass (the

only long-term weather

station in the region) 280

mm. Ann. snowfall 160

cm. Avg. daily min.

temp, in winter at

Anaktuvuk Pass is

-30°C; avg. daily max.

in summer for same

location is 16°C.

Continental. Ann. precip. 250-550 mm, usually increasing with elevation. Ann. snowfall 125

cm to 205 cm. Avg.

daily min. temp, in winter is -35°C to -18°C;

avg. daily max. in summer is 17°Cto22°C.

Physiography

(2)

Nearly level plain.

Elevations from sea level

to 180 me . Slope gradients <1°.

Broad, rounded ridges

and mesas in northern

section; irregular buttes,

mesas, long, linear

ridges, and undulating

plains and plateaus in

southern section.

Elevations from sea level

to 800 m. Slope gradients generally 0° to 5°.

Steep, rugged mountains.

Elevations from 500 m

to >2,400 m. Slope gradients generally 5° to

15°.

Rolling lowlands, dissected plateaus, and low

to high hills. Elevations

from sea level to 500 m.

Slope gradients generally

0° to 5°.

Geology

(3)

Quaternary deposits of

alluvial, glacial, and aeolian origin.

Northern section has

unconsolidated

Quaternary deposits of

glacial, alluvial, and aeolian origin. Southern

section has undifferentiated alluvial and colluvial deposits over

Jurassic and early

Cretaceous formations.

Stratified Paleozoic and

Mesozoic sedimentary

deposits. Much exposed

bedrock and rubble.

Predominantly Mesozoic

and Paleozoic sedimentary rocks, but also

extensive areas of volcanic deposits. Region is

covered by undifferentiated alluvium and slope

deposits. Little bedrock

exposure.

Permafrost

(4)

Underlain by continuous

thick permafrost.

Underlain by continuous

thick permafrost.

Underlain by continuous

thick permafrost.

Western portion underlain by thin to moderately thick permafrost.

Eastern portion underlain

by discontinuous permafrost.

Soils

(5)

Histic Pergelic

Cryaquepts and Pergelic

Cryaquepts.

Histic Pergelic

Cryaquepts, Pergelic

Cryaquepts, and Pergelic

Ruptic-Histic

Cryaquepts.

Pergelic Cryaquepts,

Pergelic Cryumbrepts,

and Lithic Cryorthents.

Histic Pergelic

Cryaquepts, Pergelic

Cryaquepts, Aquic

Cryochrepts, Pergelic

Cryochrepts, Typic

Cryochrepts, Typic

Cryorthents, and Pergelic

Cryumbrepts.

Ve

Wet gram

ceous com

dominate. 

communit

where mic

provides d

zone.

Mesic gra

ceous com

dominate. 

on other w

sites. Ope

along drai

Much of r

of vegetat

scrub com

drier sites

graminoid 

communit

moist site

leys.

Needlelea

and mixed 

dominate. 

communit

exposed a

burned or 

areas, and 

Low scrub 

and on no

slopes. T

swamps, 

and scrub

communit

areas.

"Climate information for nearly all ecoregions represents interpolations from very few weather stations. 

bNumbers below headings of environmental characteristics correspond with those listed in footnote c.

'Numbers indicate the mapped environmental characteristics most useful for distinguishing the ecoregion and do not necessarily reflect the primary ecological d

l=climate, 2=physiography, 3=geology, 4=permafrost, 5=soils, 6=vegetation, and 7=Pleistocene glaciation. 

Includes snow water equivalent. 

eElevation is in meters above mean sea level.
APPENDIX 1 - Table of major environmental characteristics. 65

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Ecoregion

109. Subarctic Coastal

Plains

(91,000 km2)

(2, 3, 4, 5, 6)

110. Seward Peninsula

(47,000 km2 )

(3,6)

Climate

(1)

Transitional. Ann. precip. 250 mm to 500 mm.

Ann. snowfall 100 cm in

north, 105 cm to 150 cm

in south. Avg. daily min.

temp, in winter is -25 °C

for the Kotzebue Sound

area and -20°C to -15°C

for the Cape Denbigh

and Yukon- Kuskokwim

Lowland areas; avg.

daily max. temp, in summer is 13°Cto 17°C.

Maritime to continental.

Ann. precip. 250 mm to

510 mm in the lowlands.

> 1,000 mm estimated for

the mountains. Ann.

snowfall 100 cm to

190 cm in the lowlands,

probably up to 250 cm in

the mountains. Avg.

daily min. temp, in winter is -24°C to -19°C;

avg. daily max. in summer is 13°Cto 17°C.

Physiography

(2)

Flat plains. Elevations

from sea level to > 120 m.

Slope gradients generally

<r.

Narrow strips of coastal

lowlands, extensive

uplands of broad convex

hills and flat divides,

small, isolated groups of

rugged mountains.

Elevations from sea level

to 500 m for most of

region, > 1,400 m on

high mountains. Slope

gradients generally 0° to

5°, up to 15° typical in

the mountains.

Geology Permafrost

(3) (4)

Older coastal deposits of Continuous thin to modinterstratified alluvial erately thick permafrost.

and marine sediments.

Includes areas of

Quaternary mafic and

undifferentiated volcanic

rocks in western part of

Yukon-Kuskokwim

Lowlands and on

Nunivak and St.

Lawrence Islands.

Cretaceous intermediate

volcanic rocks in

Selawik Wildlife Refuge

Area.

Paleozoic sediments and Continuously thin to

metamorphosed volcanic moderately thick perrocks and Precambrian mafrost.

volcanic rocks.

Highlands may be

Cenozoic uplifts of these

formations. Extensive

Quaternary or Tertiary

volcanic rock formations

in northeastern portion

of ecoregion.

Soils

(5)

Histic Pergelic

Cryaquepts and Pergelic

Cryofibrists.

Histic Pergelic

Cryaquepts, Pergelic

Cryaquepts, Typic

Cryochrepts, Pergelic

Cryumbrepts, Lithic

Cryorthents, and Pergelic

Cryorthents.

V

Wet gram

ceous com

dominate

communi

drained a

Needlele

southern 

region, w

and warm 

sufficient 

Mesic gr

ceous com

low scrub 

widespre

lower mo

graminoi

communi

areas. Ta

munities 

and on fl

Dwarf sc

ties in hig

lll.AhklunandKilbuck

Mountains

(51,000km2 )

(2, 3, 6, 7)

Transitional. Ann. precip. 1,020 mm in lowlands to 2,030 mm in

highlands. Ann. snowfall 205 cm in lowlands

to 510 cm in highlands.

Avg. daily min. temp, in

winter is — 16°C; avg.

daily max. in summer is

16°C to 19°C.

Steep, rugged mountain

groupings separated by

broad lowlands.

Elevations from sea level

to >1 ,500 m. Slope gradients generally 0° to 8°,

steeper slopes not

uncommon.

Strongly deformed sedimentary and volcanic

rocks of late Paleozoic

and Mesozoic age.

Small granitic masses

surrounded by more

resistant hornfels have

formed ringlike mountain groups.

Discontinuous permafrost at higher elevations, isolated masses at

lower elevations.

Histic Pergelic

Cryaquepts, Pergelic

Cryaquepts, Typic

Cryochrepts, Lithic

Cryumbrepts, Pergelic

Cryumbrepts, Pergelic

Cryorthods, Typic

Haplocryods, and Typic

Humicryods.

Dwarf sc

ties in mo

graminoi

communi

valley sit

graminoi

communi

scrub her

on wettes

Needlele

and mixe

on better 

sites.
Ecoregion

112. Bristol BayNushagak Lowlands

(61,000km2 )

(2. 3. 6, 7)

113. Alaska Peninsula

Mountains

(48,000 km2 )

(2, 3, 4, 6, 7)

114. Aleutian Islands

(12,000km2 )

(1, 3, 4, 6, 7)

Climate

(1)

Transitional. Ann. precip. 330 mm to 860 mm.

Ann. snowfall 75 cm to

250 cm. Avg. daily min.

temp, in winter is -15°C

to-10°C (higher in

south, lower in north);

avg. daily max. in summer is 18°C.

Maritime. Ann. precip.

600 mm to 3,300 mm in

coastal lowlands,

>4,060 mm at higher

elevations. Ann. snowfall 55 cm to 150 cm in

lowlands, >510 cm in

mountains. Avg. daily

min. temp, in winter is

-11°C to-6°C; avg.

daily max. in summer is

=15°C.

Maritime. Ann. precip.

530 mm to 2,080 mm at

sea level locations

(smaller islands may

have much less precip.).

Ann. snowfall 85 cm to

250 cm at same locations. Avg. daily min.

temp, in winter is -7°C

to - 2°C; avg. daily max.

in summer is 10°C to

13°C.

Physiography

(2)

Rolling lowlands.

Elevations from sea level

to 150 m. Slope gradients generally 0- 2°.

Rounded ridges overtopped by steep, rugged

mountains. Elevations

from sea level to 2,600 m.

Slope gradients generally

0° to 11°, steeper slopes

not uncommon.

Low mountains, often

overtopped by steep,

rugged mountains.

Elevations from sea level

to > 1,900m. Slope gradients <1° in lowlands.

>5° in mountains.

Geology

(3)

Quaternary glacial outwash and morainal

deposits, mantled in part

by silt and peat.

Stratified Jurassic,

Cretaceous, and Tertiary

sediments and undifferentiated Quaternary volcanic rocks.

Blockfaulted Tertiary

sediments surmounted

by undifferentiated

Quaternary and Tertiary

volcanic rocks.

Permafrost Soils

(4) (5)

Ranges from isolated Typic Haplocryands,

masses of permafrost to Typic Vitricryands,

areas free from per- Fluvaquentic

mafrost. Cryofibrists, Histic

Pergelic Cryaquepts,

Pergelic Cryaquepts, and

Typic Cryochrepts.

Generally free from per- Typic Haplocryands and

mafrost. Typic Vitricryands.

Generally free from per- Typic Haplocryands and

mafrost. Typic Vitricryands.

V

Dwarf sc

ties most 

better dr

scrub bo

graminoi

commun

forb herb

nities on 

sites. Br

mixed fo

ties on fl

major riv

Dwarf sc

ties at hi

and on w

Low scru

in more p

Of less e

ution are 

munities 

and at lo

broadlea

floodplai

facing sl

scrub bo

graminoi

commun

drained a

Dwarf sc

ties at hi

and on w

Mesic gr

ceous co

dry gram

ceous co

lower ele

sites pro

wind. L

in moist 
Ecoregion

115. Cook Inlet

(28,000 km2)

(1, 3, 4, 5, 6, 7)

116. Alaska Range

(117,000km2 )

(1,2,3,4,6,7)

117. Copper Plateau

(17,000km2 )

(2, 3, 4, 5, 6, 7)

Climate

(1)

Transitional. Ann. precip. 380 mm to 680 mm.

Ann. snowfall 160 cm to

255 cm. Avg. daily min.

temp, in winter is — 15°C;

avg. daily max. in summer is 18°C.

Continental. Weather

data available only for

low elevations. Ann.

precip. 380 mm at low

elevations, probably

=2,030 mm at high elevations. Ann. snowfall

150 cm to 305 cm at low

elevations, probably

-1,015 cm at high elevations. Avg. daily min.

temp, in winter is -25°C

at low elevations; avg.

daily max. in summer is

18°C at same locations.

Continental. Ann. precip. 250 mm to 460 mm.

Ann. snowfall 100 cm to

190 cm. Avg. daily min.

temp, in winter is

=-27°C; avg. daily max.

in summer is =21°C.

Physiography

(2)

Level to rolling terrain.

Elevations from sea level

to 600 m. Slope gradients generally 0° to 3°.

Steep, rugged mountains

and broad valleys.

Elevations from 600 m

(sea level in southwest

portion of ecoregion) to

>3,900 m (Mt. McKinley

>6,100m). Slope gradients generally 5° to 25°,

>25°on some mountains.

Level to gently rolling

plain. Elevations from

420m to 900m. Slope

gradients generally 0° to

2°

Geology Permafrost

(3) (4)

Poorly consolidated Generally free from perTertiary coal-bearing mafrost.

rocks mantled by glacial

moraine and outwash.

aeolian deposits, and

marine and lake

deposits.

Southern portion under- Discontinuous perlain by granitic mafrost.

batholiths intrusive into

moderately metamorphosed, highly deformed

Paleozoic and Mesozoic

volcanic and sedimentary rocks. This area

includes active volcanoes. Central and eastern portions of ecoregion

are a broad syncline having Cretaceous rocks in

the center and Paleozoic

and Precambrian rocks

on the flanks. Rocky

slopes, icefields, and

glaciers cover much of

region.

Pleistocene proglacial Thin to moderately thick

lake deposits. permafrost.

Soils

(5)

Haplocryands, Sphagnic

Borofibrists, Terric

Borosaprists, Typic

Borohemists, Andic

Haplocryods, and Andic

Humicryods.

Lithic Cryorthents,

Pergelic Cryaquepts,

Pergelic Ruptic- Histic

Cryaquepts, Typic

Cryochrepts, Pergelic

Cryumbrepts, and Typic

Cryumbrepts.

Histic Pergelic

Cryaquepts, Aquic

Cryochrepts, Typic

Cryochrepts, Pergelic

Cryaquolls, and Typic

Cryoborolls.

V

Needlelea

and mixe

spread. M

graminoid

herbaceou

scrub gra

nities in d

sites. Tal

nities on 

flooded a

scrub com

poorly dr

Tall scrub 

scrub bog

herbaceou

and wet g

herbaceou

on wettes

Much of 

of vegeta

scrub com

drier, win

Low scru

and tall s

ties on m

sites. Ne

and wood

well-drain

leys and l

Needlele

woodland

Broadlea

scrub com

needlelea

nated by 

better dra

scrub bog

graminoi

communi

areas.
APPENDIX 1 - Table of major environmental characteristics. 69

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70 APPENDIX 2.-Methodology for deriving the terrain roughness map

The terrain roughness map was derived from 1-km2 resolution digital elevation model (DEM) data using a raster based 

GIS. Procedures are listed below; common GIS terminology appears in italics.

1. The maximum change in local terrain elevation was 

calculated within a 5-kma radius around each pixel of the 

DEM data (an 11x11 differencing filter was applied over the 

DEM raster map}. This resulted in a new map where the 

original DEM data values were replaced by maximum elevation difference values. The maximum amount of local 

relief measured was 4,310 m.

2. Values on the maximum local relief map were then 

sorted (sliced) into consecutive classes so that each class represented a change in elevation of 10 m. This resulted in a 

map of 431 "relief change" classes.

3. The number of different relief change classes occurring within 25 km2 around each pixel was used to calculate 

local terrain variability (a 5x5 diversity filter was passed

over the pixels of the relief change class map). The resultant 

map depicted values representing the number of different 

classes that occurred in the vicinity of each pixel. The maximum number of classes recorded for a single pixel was 25, 

which was also the theoretical maximum.

4. The values on the local terrain variability map were 

sorted (reclassified) into five classes of terrain roughness: 

very low (0-2 terrain change classes within the 5 km2 vicinity of a pixel), low (3-5 change classes), moderate (6-10 

change classes), high (11-15 change classes), and very high 

(16-25 change classes).

5. The average terrain roughness class within 25 km2 of 

each pixel was determined (a 5x5 low-pass, averaging filter 

was applied to the raster map of the five classes of local terrain roughness). This effectively smoothed the local "noise" 

on the map of terrain roughness classes so that broad-scale 

patterns of the variability in local relief were more discernible on the final terrain roughness map.

a Five kilometers was selected as an appropriate resolution for defining 

"local" relief based on the level of generalization represented by the ecoregions.
APPENDIX 3.-List of Latin and common names of plant species mentioned in this report 71

TREES3

Abies amabilis 

Abies lasiocarpa 

Alnus rubra 

Betula papyri/era 

Larix laricina 

Picea glauca 

Picea mariana

Pacific silver fir 

Subalpine fir 

Red alder 

Alaska paper birch 

Tamarack, larch 

White spruce 

Black spruce

Picea sitchensis 

Pinus contorta 

Populus balsamifera 

Populus tremuloides 

Populus trichocarpa 

Taxus brevifolia 

Tsuga heterophylla 

Tsuga mertensiana

Sitka spruce 

Lodgepole pine 

Balsam poplar 

Quaking aspen 

Black cottonwood 

Pacific yew 

Western hemlock 

Mountain hemlock

SHRUBSb

Alnus crispa 

Alnus sinuata 

Alnus tenuifolia 

Andromeda polifolia 

Arctostaphylos alpina 

Arctostaphylos rubra 

Arctostaphylos uva-ursi 

Betula glandulosa 

Betula nana 

Cassiope lycopodioides 

Cassiope mertensiana 

Cassiope stelleriana 

Cassiope tetragona 

Chamaedaphne calyculata 

Cladothamnus pyrolaeflorus 

Cornus canadensis 

Cornus stolonifera 

Dryas drummondii 

Dryas integrifolia 

Dryas octopetala 

Empetrum nigrum 

Kalmia polifolia 

Ledum decumbens 

Ledum groenlandicum 

Loiseleuria procumbens 

Luetkea pectinata 

Menziesia ferruginea 

Myrica gale 

Oplopanax horridus 

Phyllodoce aleutica 

Potentilla fruticosa

American green alder

Sitka alder

Thinleaf alder

Bog-rosemary

Alpine bearberry

Red-fruit bearberry

Bearberry, kinnikinnik

Resin birch, bog birch

Dwarf arctic birch

Alaska cassiope

Mertens cassiope

Starry cassiope

Four-angled cassiope

Leatherleaf

Copperbush

Bunchberry, dwarf dogwood

Red-osier dogwood

Drummond mountain-avens

Entire-leaf mountain-avens

White mountain-avens

Crowberry

Bog kalmia

Narrow-leaf Labrador-tea

Labrador-tea

Alpine-azalea

Luetkea

Rusty menziesia

Sweetgale

Devilsclub

Blue mountain-heath

Bush cinquefoil

Ribes triste 

Rosa acicularis 

Rubus spectabilis 

Salix alaxensis 

Salix arbusculoides 

Salix arctica 

Salix barclayi 

Salix bebbiana 

Salix brachycarpa 

Salix commutata 

Salix fuscescens 

Salix glauca 

Salix lanata 

Salix ovalifolia 

Salix phlebophylla 

Salix planifolia 

Salix polaris 

Salix reticulata 

Salix rotundifolia 

Salix scouleriana 

Salix sitchensis 

Sambucus callicarpa 

Shepherdia canadensis 

Spiraea beauverdiana 

Vaccinium alaskaense 

Vaccinium caespitosum 

Vaccinium ovalifolium 

Vaccinium oxycoccos 

Vaccinium parvifolium 

Vaccinium uliginosum 

Vaccinium vitis-idaea 

Viburnum edule

American red currant 

Prickly rose 

Salmonberry 

Feltleaf willow 

Littletree willow 

Arctic willow 

Barclay willow 

Bebb willow 

Barren-ground willow 

Undergreen willow 

Alaska bog willow 

Grayleaf willow 

Richardson willow 

Ovalleaf willow 

Skeletonleaf willow 

Diamondleaf willow 

Polar willow 

Netleaf willow 

Least willow 

Scouler willow 

Sitka willow 

Pacific red elder 

Buffaloberry 

Beauverd spirea 

Alaska blueberry 

Dwarf blueberry 

Early blueberry 

Bog cranberry 

Red huckleberry 

Bog blueberry 

Mountain-cranberry 

High bushcranberry

a Nomenclature from Viereck and Little (1972), as cited in Viereck and others 

(1992).

b Nomenclature from Hulten (1968) and Welsh (1974), as cited in Viereck and others (1992).
72 ECOREGIONS OF ALASKA

HERBS'

Aconitum delphinifolium 

Agropyron spicatum 

Alopecurus alpinus 

Anemone spp. 

Angelica lucida 

Arctagrostis latifolia 

Arctophila fulva 

Artemisia arctica 

Astragalus spp. 

Athyrium filix-femina 

Blechnum spicant 

Bromus pumpellianus 

Calamagrostis canadensis 

Calamagrostis purpurascens 

Caltha palustris 

Carex aquatilis 

Carex bigelowii 

Carex lyngbyaei 

Carex misandra 

Carex pauciflora 

Carex pluriflora 

Carex rostrata 

Carex saxatilis 

Carex scirpoidea 

Carex sitchensis 

Coptis aspleniifolia 

Deschampsia beringensis 

Dryopteris dilafata 

Dupontia fischeri 

Eleocharis palustrus 

Epilobium angustifolium 

Epilobium latifolium 

Equisetum arvense 

Equisetum fluviatile 

Equisetum sylvaticum 

Equisetum variegatum

Monkshood

Bluebunch wheatgrass

Alpine foxtail

Anemone

Sea coast angelica

Polar grass

Pendent grass

Wormwood

Milk vetch

Lady fern

Deer fern

Brome grass

Bluejoint

Purple reed-grass

Yellow marsh-marigold

Water sedge

Bigelow sedge

Lyngbye sedge

Short-leaved sedge

Few-flowered sedge

Many-flowered sedge

Beaked sedge

No common name

Northern single-spike sedge

Sitka sedge

Goldthread

Bering hair-grass

Spinulose shield-fern

Tundra grass, dupontia

Spike rush

Fireweed

Dwarf fireweed

Meadow horsetail

Swamp horsetail

Woodland horsetail

Variegated scouring-rush

Eriophorum angustifolium 

Eriophorum russeolum 

Eriophorum vaginatum 

Fauria crista-galli 

Festuca altaica 

Festuca rubra 

Galium boreale 

Geranium erianthum 

Gymnocarpium dryopteris 

Hedysarum alpinum 

Heracleum lanatum 

Hierochloe alpina 

Honckenya peploides 

Juncus arcticus 

Kobresia myosuroides 

Linnaea borealis 

Lupinus nootkatensis 

Maianthemum dilatatum 

Menyanthes trifoliata 

Mertensia paniculata 

Minuartia spp. 

Oxytropis nigrescens 

Petasites frigidus 

Plantago maritima 

Poa eminens 

Potentilla palustris 

Puccinellia spp. 

Pyrola grandiflora 

Rubus pedatus 

Saxifraga spp. 

Scirpus validus 

Sedum rosea 

Streptopus spp. 

Tiarella trifoliata 

Trichophorum caespitosum 

Triglochin maritimum 

Valeriana sitchensis

Tall cottongrass

Russett cottongrass

Tussock cottongrass

Deer cabbage

Fescue grass

Red fescue

Northern bedstraw

Northern geranium

Oak fern

Alpine sweet-vetch

Cow parsnip

Alpine holygrass

Seabeach sandwort

Arctic rush

No common name

Twinflower

Nootka lupine

False lily-of-the-valley

Buckbean

Bluebell

Sandwort

Blackish oxytrope

Arctic sweet coltsfoot

Goose-tongue

Coastal bluegrass

Marsh fivefinger

Alkali grass

Large-flowered wintergreen

Five-leaf bramble

Saxifrage

Great bulrush

Roseroot

Twisted-stalk

Lace flower

Tufted clubrush

Maritime arrow grass

Sitka valerian

c Nomenclature from Viereck and Little (1972), as cited in Viereck and others 

(1992).
APPENDIX 3 - List of Latin and common names of plant species. 73

MOSSES d

Aulacomnium palustre 

Campylium stellatum 

Dicranum spp. 

Distichium capillaceum 

Drepanocladus uncinatus 

Hylocomium splendens 

Hypnum spp. 

Mnium spp.

No common name 

No common name 

No common name 

No common name 

No common name 

Feathermoss 

No common name 

No common name

Pleurozium schreberi 

Polytrichum spp. 

Rhacomitrium lanuginosum 

Rhytidiadelphus triquetrus 

Rhytidium rugosum 

Scorpidium spp. 

Sphagnum spp. 

Tomenthypnum nitens

Feathermoss 

No common name 

No common name 

No common name 

No common name 

No common name 

Sphagnum moss 

No common name

LICHENSe

Alectoria spp. 

Cetraria cucullata 

Cetraria islandica 

Cladina rangiferina 

Cladonia spp. 

Nephroma arcticum

No common name 

No common name 

No common name 

Reindeer lichen 

No common name 

No common name

Parmelia spp. 

Peltigera aphthosa 

Peltigera canina 

Stereocaulon tomentosum 

Thamnolia subuliformis 

Thamnolia vermicularis

No common name 

No common name 

Dog lichen 

No common name 

No common name 

Worm lichen

Nomenclature from Crum and others (1973), as cited in Viereck and others

(1992).

' Nomenclature from Egan (1987), as cited in Viereck and others (1992).