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Susitna-Watana Hydroelectric Project Document
ARLIS Uniform Cover Page
Title:
Vegetation and wildlife habitat mapping study in the upper and middle
Susitna basin, Study plan Section 11.5 : Initial study report -- Part A:
Sections 1-6, 8-10
SuWa 223
Author(s) – Personal:
Author(s) – Corporate:
ABR, Inc.-Environmental Research & Services
AEA-identified category, if specified:
Initial study report
AEA-identified series, if specified:
Series (ARLIS-assigned report number):
Susitna-Watana Hydroelectric Project document number 223
Existing numbers on document:
Published by:
[Anchorage : Alaska Energy Authority, 2014]
Date published:
June 2014
Published for:
Alaska Energy Authority
Date or date range of report:
Volume and/or Part numbers:
Final or Draft status, as indicated:
Document type:
Pagination:
iii, 26, 1 p.
Related work(s):
The following parts of Section 11.5 appear in separate files:
Part A ; Part B ; Part C.
Pages added/changed by ARLIS:
Notes:
Contents: Part A. Sections 1-6, 8-10 -- Appendix A. Commonly sampled wildlife habitat types.
All reports in the Susitna-Watana Hydroelectric Project Document series include an ARLIS-
produced cover page and an ARLIS-assigned number for uniformity and citability. All reports
are posted online at http://www.arlis.org/resources/susitna-watana/
Susitna-Watana Hydroelectric Project
(FERC No. 14241)
Vegetation and Wildlife Habitat Mapping Study in the
Upper and Middle Susitna Basin
Study Plan Section 11.5
Initial Study Report
Part A: Sections 1-6, 8-10
Prepared for
Alaska Energy Authority
Prepared by
ABR, Inc.—Environmental Research & Services
June 2014
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY
IN THE UPPER AND MIDDLE SUSITNA BASIN (11.5)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Part A - Page i June 2014
TABLE OF CONTENTS
1. Introduction ....................................................................................................................... 1
2. Study Objectives................................................................................................................ 1
3. Study Area ......................................................................................................................... 2
4. Methods and Variances in 2013 ....................................................................................... 2
4.1. Develop Mapping Materials from Historical and Current Data ............................. 3
4.1.1. Variances......................................................................................... 3
4.2. ITU Mapping and Derivation of Wildlife Habitats ................................................. 4
4.2.1. Variances......................................................................................... 5
4.3. Field Surveys .......................................................................................................... 5
4.3.1. Variances......................................................................................... 7
5. Results ................................................................................................................................ 7
5.1. ITU Mapping and Derivation of Wildlife Habitat Types ....................................... 7
5.2. Field Surveys .......................................................................................................... 8
6. Discussion........................................................................................................................... 9
6.1. Ecoregions in the Study Area ................................................................................. 9
6.2. Occurrence and Distribution of Wildlife Habitats ................................................ 11
7. Completing the Study ..................................................................................................... 12
8. Literature Cited .............................................................................................................. 13
9. Tables ............................................................................................................................... 14
10. Figures .............................................................................................................................. 22
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY
IN THE UPPER AND MIDDLE SUSITNA BASIN (11.5)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Part A - Page ii June 2014
LIST OF TABLES
Table 5.1-1. Description of Physiographic Types Identified in the Vegetation and Wildlife
Habitat Mapping Study Area, Susitna-Watana Hydroelectric Project, 2013.......................... 15
Table 5.1-2. Vegetation Classes Sampled in the Vegetation and Wildlife Habitat Mapping Study
Area, Susitna-Watana Hydroelectric Project, 2013. ............................................................... 17
Table 5.2- 1. Preliminary Descriptions of Wildlife Habitat Types Expected to be Mapped in the
Vegetation and Wildlife Habitat Mapping Study Area, Susitna-Watana Hydroelectric Project,
2013......................................................................................................................................... 19
LIST OF FIGURES
Figure 3-1. Vegetation and Wildlife Habitat Mapping Study Area and Ground-reference Plots
Sampled in 2013, Susitna-Watana Hydroelectric Project. ...................................................... 23
Figure 5.2-1. Preliminary Wildlife Habitat Mapping in Upland and Lowland Physiographic Units
in the Vegetation and Wildlife Habitat Mapping Study Area. ................................................ 24
Figure 5.2-2. Preliminary Wildlife Habitat Mapping in Riverine and Upland Physiographic Units
in the Vegetation and Wildlife Habitat Mapping Study Area. ................................................ 25
Figure 5.2-3. Preliminary Wildlife Habitat Mapping in Subalpine and Alpine Physiographic
Units in the Vegetation and Wildlife Habitat Mapping Study Area. ...................................... 26
APPENDICES
Appendix A: Commonly Sampled Wildlife Habitat Types
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY
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LIST OF ACRONYMS, ABBREVIATIONS, AND DEFINITIONS
Abbreviation Definition
AEA Alaska Energy Authority
APA Alaska Power Authority
ArcGIS ESRI's geographic information system for mapping and analysis
AVC Alaska Vegetation Classification
CIRWG Cook Inlet Region Working Group
CFR Code of Federal Regulations
ELS Ecological Land Survey
ESRI Environmental Systems Research, Incorporated
FERC Federal Energy Regulatory Commission
GIS geographic information system
GPS global positioning system
ILP Integrated Licensing Process
ISR Initial Study Report
ITU Integrated Terrain Unit
LRR land resource regions
MLRA major land resource areas
NWI National Wetlands Inventory
PM&E protection, mitigation and enhancement
PRM Project River Mile
Project Susitna-Watana Hydroelectric Project
QA/QC quality assurance/quality control
RSP Revised Study Plan
SPD study plan determination
USACE U.S. Army Corps of Engineers
USR Updated Study Report
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY
IN THE UPPER AND MIDDLE SUSITNA BASIN (11.5)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Part A - Page 1 June 2014
1. INTRODUCTION
On December 14, 2012, Alaska Energy Authority (AEA) filed its Revised Study Plan (RSP) with
the Federal Energy Regulatory Commission (FERC or Commission) for the Susitna-Watana
Hydroelectric Project No. 14241 (Project), which included 58 individual study plans (AEA
2012). Section 11.5 of the RSP described the Vegetation and Wildlife Habitat Mapping Study in
the Upper and Middle Susitna Basin. On February 1, 2013, FERC staff issued its study plan
determination (February 1 SPD) for 44 of the 58 studies, approving 31 studies as filed and 13
with modifications. RSP Section 11.5 was one of the 31 studies approved with no modifications.
In this study, vegetation and wildlife habitats in the Upper and Middle Susitna River Basin
(where the Watana Reservoir and Project infrastructure is proposed) are being identified in the
field, classified, and mapped from aerial imagery. The mapping area encompasses the inundation
zone of the proposed Watana Reservoir, the Watana Dam site and associated infrastructure, and
the three possible corridors for the Susitna-Watana Transmission Line and the Susitna-Watana
Road. RSP Section 11.5 provided goals, objectives, and proposed methods for data collection
regarding vegetation and wildlife habitat mapping.
Following the first study season, FERC’s regulations for the Integrated Licensing Process (ILP)
require AEA to “prepare and file with the Commission an initial study report describing its
overall progress in implementing the study plan and schedule and the data collected, including an
explanation of any variance from the study plan and schedule.” (18 CFR 5.15(c)(1)) This Initial
Study Report (ISR) on the Vegetation and Wildlife Habitat Mapping Study in the Upper and
Middle Susitna River Basin has been prepared in accordance with FERC’s ILP regulations and
details AEA’s status in implementing the study, as set forth in the FERC-approved RSP (referred
to herein as the “Study Plan”).
2. STUDY OBJECTIVES
As established in the Study Plan (RSP Section 11.5.1), the overall goals of the study are to
classify and prepare maps of the existing vegetation and wildlife habitats in the Upper and
Middle Susitna River Basin (upstream of Gold Creek; see Section 3, Study Area, below). This
multi-year study was initiated in 2012 and will be continued through the next year of study. The
mapping information from this study eventually will be used in AEA’s License Application, to
assess the potential impacts to both vegetation and wildlife habitat resources from development
of the proposed Project, and to prepare any necessary protection, mitigation, and enhancement
(PM&E) measures to minimize impacts to those resources. When completed, the wildlife habitat
mapping will be used to evaluate habitat use by birds, mammals, and amphibians (Study 10.19,
Evaluation of Wildlife Habitat Use), and to estimate quantitatively the impacts of habitat loss
and alteration for birds, mammals, and amphibians during the FERC licensing process. The
wildlife habitat mapping prepared in this study will be one of the primary pieces of information
used to evaluate impacts to wildlife species from the proposed Project.
This study is being conducted in close coordination with the Wetland Mapping Study in the
Upper and Middle Susitna Basin (Study 11.7). In the field, data are being collected for both
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY
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studies at each sampling plot, and the mapping efforts for both studies are being performed
concurrently (i.e., each map polygon is being coded with the attributes needed to map vegetation,
wildlife habitats, and wetlands).
The specific objectives of the vegetation and wildlife habitat mapping study are to classify,
delineate, and map vegetation and wildlife habitat types in the Upper and Middle Susitna River
Basin based on current aerial imagery for the study area.
3. STUDY AREA
As established by RSP Section 11.5.3, the study area comprises a 4-mi buffer surrounding those
areas that would be directly altered or disturbed by development of the proposed Project (Figure
3-1), including the three alternative corridors for the Susitna-Watana transmission lines and
access road, Watana Dam and Watana Camp sites, and maximum normal pool elevation of the
Watana Reservoir (2,050 ft). The Chulitna Corridor runs east-west north of the Susitna River
connecting to the Alaska Intertie and the Alaska Railroad near Chulitna station at Chulitna Pass.
Another east-west alternative, the Gold Creek Corridor, runs south of the Susitna River to the
Alaska Intertie and the Alaska Railroad at Gold Creek station. A third alternative, the Denali
Corridor, runs north-south, and would connect the Project dam site with the Denali Highway
over a distance of about 44 miles and then would run west along the existing Denali Highway to
connect to the Alaska Intertie near Cantwell.
In areas paralleling the Susitna River between the Project dam site and Gold Creek station
(Figure 3-1), vegetation and wildlife habitats within the study area will be mapped up to the
study area boundary of the Riparian Vegetation Study Downstream of the Proposed Susitna-
Watana Dam (Study 11.6). In the riparian vegetation study (Study 11.6), successional riparian
vegetation and wildlife habitats will be mapped in areas downstream of the Project dam site
along the Susitna River. Mapping methods in the vegetation and wildlife habitat mapping study
and the riparian vegetation study (Study 11.6) are compatible, and seamless vegetation and
wildlife habitat maps for the Project will be produced, which will include the areas above and
below the Project dam site. The alteration of successional vegetation and wildlife habitats
downstream of the Project dam site (due to changes in instream flow, groundwater/surface water
interactions, ice processes, and fluvial geomorphic features in the Susitna River) will be
addressed in the riparian vegetation study (Study 11.6).
4. METHODS AND VARIANCES IN 2013
In the mapping of vegetation in the study area, which is a multi-year effort to be completed in the
next study season, the identification of vegetation types at the Level IV of Viereck et al. (1992)
is being done by interpretation of aerial image-signatures on recent aerial. Detailed field ground-
reference data collected over three field seasons will be used to link vegetation information and
other landscape data to the image-signatures and facilitate the identification and delineation of
vegetation and wildlife habitat types.
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY
IN THE UPPER AND MIDDLE SUSITNA BASIN (11.5)
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The mapping of wildlife habitats is being conducted using an integrated approach based on
Integrated Terrain Unit (ITU) mapping methods developed for Ecological Land Surveys (ELS)
studies, which have been conducted in tundra, boreal forest, and coastal regions in Alaska (see
Jorgenson et al. 2003 for an example study in Southcentral Alaska). The ITU mapping approach
involves mapping individual terrain units such as vegetation type, physiography, surface form,
and disturbance type, and then combining them into composite units, which represent the range
of landcover variation in the study area. When deriving wildlife habitats, the composite ITUs are
then aggregated into a smaller set of ecologically important categories that represent the habitats
used by wildlife in the study area (see Section 4.3, ITU Mapping and Derivation of Wildlife
Habitats, below).
In 2012, the accuracy of the vegetation data from the vegetation map prepared in the 1980s by
Kreig and Associates (1987) for the Alaska Power Authority’s Susitna Hydroelectric Project
(APA Project) was assessed by the study team (ABR 2013). When evaluated in relation to
current aerial imagery, the 1987 vegetation map was not highly accurate at the Level IV of The
Alaska Vegetation Classification (AVC) (Viereck et al. 1992); accuracy improved when
evaluating the map polygons at a coarser scale roughly equivalent to the Level III in the AVC.
Because of these reasons, the mapping of Kreig and Associates (1987) is being used primarily to
determine vegetation structure (a Level III attribute) and not dominant species plus vegetation
structure (Level IV attributes). The 1987 vegetation map data are being used to help in mapping
when determining where Level III vegetation types occur, and in field survey preparations in the
allocation of field sampling plots by vegetation type.
4.1. Develop Mapping Materials from Historical and Current Data
The methods for developing mapping materials for this study in 2013 were implemented as
described in RSP Section 11.5.4.1 with no variances.
All available historical and current data layers that can be used to facilitate the mapping of
vegetation and wildlife habitats have been compiled and are being managed in an ArcGIS
geodatabase. These data include current, high-resolution (0.3- to 1-ft pixels) aerial photography
and satellite imagery for the study area, National Wetlands Inventory (NWI) mapping, and
existing, historical vegetation mapping for the study area (Kreig and Associates 1987). The
historical vegetation map layer (Kreig and Associates 1987) has been updated to ArcGIS 10.1
format for use in this study. Additional high-resolution imagery, for those portions of the study
area where only moderate-resolution (5-m [16-ft] pixels) imagery was available previously, was
acquired by AeroMetric (now Quantum Spatial) in July and August 2013. This new digital
imagery was prepared in both natural color and infrared formats and, as of late fall 2013, was
being used for this study.
4.1.1. Variances
In 2013, there were no variances from the methods described in RSP Section 11.5.4.1 to compile
and develop historical and current mapping materials.
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY
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4.2. ITU Mapping and Derivation of Wildlife Habitats
The ITU mapping methods and the derivation of wildlife habitat types for this study in 2013
were implemented as described in RSP Section 11.5.4.2 with no variances.
The mapping of ITU variables and the derivation of wildlife habitats is an on-going multi-year
study that will be completed after the next study season. In 2013, the mapping of vegetation
types and other ITU variables was done by digitizing polygons on-screen using ArcGIS software.
Map polygon boundaries were determined by interpretation of high-resolution (0.3- to 1-ft
pixels) aerial image-signatures supported by ground-reference survey data collected in 2012 and
2013. Each map polygon was attributed for a Level IV vegetation type (Viereck et al. 1992),
physiography class, surface form class, and disturbance type. The Level IV vegetation classes of
Viereck et al. (1992), with additions by the study team for undescribed types and nonvegetated
land cover types, are defined by vegetation structure and dominant plant species (e.g., Open
White Spruce Forest, Closed Tall Alder Shrub, Subarctic Lowland Sedge Wet Meadow).
Physiography types represent broad, landscape-scale geomorphic features and landscape position
(e.g., riverine, lacustrine, lowland, upland, subalpine, and alpine). Surface forms are finer scale
geomorphic features, in this case in boreal forest environments (e.g., ridge crest, toe slope, kettle
basin, point bar); the surface-form classes being used were modified from Washburn (1973) and
Jorgenson et al. (2003). The disturbance types being used were modified from a list defined by
the study team for previous ELS studies in both remote and developed areas in Alaska (see
Jorgenson et al. 2003 for an example).
In 2013, vegetation and the other ITU variables in the study area were mapped at a scale of
1:2,000. The minimum mapping polygon size for vegetated habitats is 1.0 acre and 0.25 acres for
water bodies. The Wetland Mapping Study in the Upper and Middle Susitna Basin (Study 11.7)
covers the same areas mapped for wildlife habitats but uses smaller minimum mapping sizes (0.5
acres for vegetated wetlands and 0.1 acre for water bodies); the smaller minimum mapping sizes
in Study 11.7 are used because of specific wetland permitting requirements for that study.
Because fine-scale mapping of ITU boundaries is possible only with the use of high-resolution
imagery, the detailed mapping of ITU variables prior to the 2013 field season was limited to two
areas with high-resolution imagery: (1) a corridor around the Upper Susitna River, which covers
the southwestern portion of the Watana Reservoir, and portions of the Gold Creek Corridor; and
(2) in the vicinity of Cantwell and adjacent portions of the Parks and Denali highways in the
Denali Corridor. For those areas lacking high-resolution imagery prior to the 2013 field season,
moderate-resolution RapidEye imagery (5-m [16-ft] pixels), in a false natural-color format, was
used to determine preliminary vegetation and wildlife habitat classes and select field sampling
transects for survey work in 2013. Additional high-resolution imagery for the study area was
acquired in July and August 2013, as is noted above (see Section 4.1, Develop Mapping
Materials from Historical and Current Data).
A preliminary map of ITU boundaries was completed for a portion of the areas where high-
resolution imagery was available prior to the 2013 field season and was used to define a set of
characteristic vegetation types that occur in the mapped areas. This information was used to
guide the field survey efforts in 2013. In particular, the preliminary mapping and the available
aerial imagery was used to focus the field surveys on (1) those vegetation and other ITU types, as
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY
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determined from aerial image-signatures elsewhere in the study area, that are less well
represented in the preliminary mapping completed prior to the 2013 field season; (2) those
vegetation and ITU types that had been more challenging to identify from aerial image-
signatures during the preliminary mapping efforts; and (3) those vegetation and ITU types for
which less field ground-truth information was available to confirm the range in variation in
image-signature types. In addition, results from the 2012 field surveys (ABR 2013) were used to
identify vegetation types and other ITU types that had been under-sampled in the field so that
those types could be targeted for additional sampling in the 2013 field survey.
For this report, a preliminary set of vegetation and wildlife habitat types for the study area was
prepared from the mapping that was completed as of end of October 2013. To derive the
preliminary set of wildlife habitat types, two of the four ITU attributes assigned to each map
polygon (vegetation type and physiography) were combined to produce a large number of
multivariate habitat types. These initial habitat types then were aggregated into a smaller set of
derived habitat types that share similar characteristics considered important to the wildlife
species that occur in the study area. In the derivation of the preliminary wildlife habitats,
vegetation structure, dominant plant species, and physiographic position were the primary factors
used to represent wildlife habitat quality. In the last year of study, during the development of the
final set of wildlife habitat types for this study, information on surface forms, disturbance type,
and soil drainage will be added, as needed to refine the set of wildlife habitat types. The
development of wildlife habitats is an iterative process tailored to the specific set of wildlife
species to be evaluated for impacts from the proposed Project (see Study 10.19, Evaluation of
Wildlife Habitat Use), and the final set of wildlife habitat types will be developed with input
from the wildlife researchers working on the Project so that the habitats will be representative of
those known to be used by birds, mammals, and amphibians in the study area. In this process,
researchers will rely on the Project-specific observations of wildlife habitat use and, as needed,
the literature describing wildlife-habitat associations in Alaska.
When the ITU mapping is completed, a rigorous QA/QC review process will be performed using
tools developed by the study team and the Wetlands Data Verification Toolset developed by the
NWI program to identify digitizing anomalies (e.g., incorrect attribute codes, unattributed
polygons, adjacent polygons with the same coding, and digital slivers [null polygons < 0.01 acre
in size]). The NWI toolset was created using the Environmental Systems Research, Incorporated
(ESRI) Model Builder (http://www.fws.gov/wetlands/Data/Tools-Forms.html).
4.2.1. Variances
In 2013, there were no variances from the methods described in RSP Section 11.5.4.2 for the
mapping of ITU variables and the derivation of wildlife habitats.
4.3. Field Surveys
The field survey methods for this study in 2013 were implemented as described in RSP Section
11.5.4.3 with no variances.
Field ground-reference data to link to aerial-image signatures were collected during summer
2013. In 2013, eight scientists (four teams of two each) collected vegetation, wildlife habitat, and
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wetlands ground-reference data in two separate field survey efforts: July 1–11 and July 30 –
August 8. The field surveys were organized so as to collect data for as many habitat types as
possible in a way that maximizes efficiency (numerous different habitat types were sampled in a
day) and safety (topographic hazards such as traversing steep bluffs and creek crossings were
avoided).
The preliminary ITU mapping completed prior to the 2013 field survey (described below; see
Section 4.3, ITU Mapping and Derivation of Wildlife Habitats), along with both the high- and
moderate-resolution imagery available for those portions of the study area where no preliminary
mapping had yet been completed, was used to select sampling transects for the 2013 field
surveys (Figure 3-1).The field sampling transects (1.5–3.0 km [0.93–1.86 mi]) long were focused
on vegetation and other ITU types that were less well represented in the preliminary mapping,
more challenging to identify from aerial image-signatures, for which less field data were
available to confirm the range in aerial image-signatures, and/or were under-sampled during the
first year of field surveys in 2012. The sampling transects were designed to cross a number of
different habitats during each survey day. On each transect, 6–10 full ground-reference plots,
which included a formal wetland determination (see Study 11.7, Wetland Mapping Study in the
Upper and Middle Susitna Basin), were sampled depending on the length of the transect and/or
the number of distinct habitat types encountered. Field plots were sampled along transects
located within the major physiographic types in the study area, including riverine, lacustrine,
lowland, upland, subalpine, and alpine areas. When transitional habitats or areas not readily
discernible from image-signature features alone were encountered in the field, additional plots
were surveyed.
To maximize efficiency in data collection, at each ground-reference plot, data were collected for
vegetation and wildlife habitat mapping as well as wetlands mapping. At each plot, a standard
U.S. Army Corps of Engineers (USACE) wetland determination and data form was completed
(Environmental Laboratory 1987, USACE 2007; see the Wetland Mapping Study in the Upper
and Middle Susitna Basin [Study 11.7]). Data elements recorded included visual cover estimates
of all vascular plant species present (generally within a 10-m [33-ft] radius plot of relatively
homogeneous vegetation), soil profile descriptions, and hydrologic observations. The size and
shape of the ground-reference plots were modified as needed, however, depending on the extent
of the plant community being sampled (e.g., narrower plots were used in riparian fringe habitats).
The plant data recorded for the wetland determination are sufficient to accurately classify a site
at the Level IV of the AVC (Viereck et al. 1992). A mobile Trimble® Nomad™ series GIS unit
was used to record the wetland-determination field data (using the WetForm database), and to
record global positioning system (GPS) coordinates for each plot. WetForm is a commercially
available (Ecotone Corp.) relational database used to record wetlands site data in the field, and it
facilitates the preparation of electronic copies of the 2007 Regional Supplement dataform
(USACE 2007) for each wetland determination plot.
Additional vegetation and wildlife habitat data elements were recorded digitally in the field on an
Android tablet computer using a customized data entry program which links directly to a
relational database (Microsoft Access). Additional vegetation information recorded included the
Level IV vegetation class (Viereck et al. 1992) and the percent areal cover data for structural
classes of vascular and nonvascular plants (trees, saplings, tall shrubs, low shrubs, dwarf shrubs,
tall herbs, low herbs, floating aquatics, aquatic plants, mosses, and lichens); these data were
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recorded to assist in defining vegetation and wildlife habitat types and evaluating the use of
wildlife habitats by birds, mammals, and amphibians. The site characteristics recorded at each
plot included physiography, surface form, and any disturbances, as described by Jorgenson et al.
(2003) and Schick and Davis (2008), as well as slope and aspect (in degrees), digital photos (of
the site, vegetation, and soils), and GPS coordinates. Observations of recreational use,
subsistence use, and wildlife use (e.g., nests, dens, scat, tracks) and other site characteristics that
reflect habitat quality also were recorded at each plot.
In addition to the full ground-reference plots, rapid map-verification plots were sampled to help
facilitate the vegetation and wildlife habitat mapping efforts. Map-verification plots were
sampled in habitats which had been previously well documented with full ground-reference plots
at other sites; the map-verification plots were used to improve map accuracy by increasing the
number of documented habitat types tagged to particular aerial image-signatures. At these plots,
a limited set of data was recorded, including cover estimates for the dominant vascular plant
species, Level IV vegetation class (Viereck et al. 1992), physiography class, site photos, and
GPS coordinates. No soils information was recorded at map-verification plots.
To support the survey efforts of other botanical and wildlife studies being conducted for the
Project, the locations of incidental observations of rare plants, invasive plants, wildlife species,
or significant wildlife habitat features (e.g., raptor nests) were documented when encountered.
4.3.1. Variances
In 2013, there were no variances from the field sampling methods described in the RSP Section
11.5.4.3.
5. RESULTS
5.1. ITU Mapping and Derivation of Wildlife Habitat Types
Data developed in support of this study are available for download in the following files at
http://gis.suhydro.org/reports/isr:
• ISR_11_5_VEG_Data_ABR.gdb
• ISR_11_5_VEG_Plot_and_Classif.accdb
Although the ITU mapping is not yet complete for the study area, a preliminary set of 46 wildlife
habitat types was developed for review in this report (Table 5.2-1; Figure 5.2-1 through Figure
5.2-3). As the field survey data collected in 2013 continues to be reviewed, additional field data
are collected in the next study season, and as the mapping of ITU variables continues in next
study season, the set of wildlife habitat types to be mapped in the study area is expected to
change. The preliminary wildlife habitat types presented in this report represent the integration of
two primary ITU variables (physiography and vegetation type). The habitat types were derived
by combining physiography and vegetation type and then aggregating into a smaller set of
habitats based primarily on shared vegetation structure and physiography, although in some
cases the dominant species occurrence information from the Level IV AVC vegetation types was
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preserved (e.g., Lowland Low and Tall Birch-Ericaceous Scrub vs. Lowland Low and Tall
Willow Scrub). As the mapping of the study area continues in next study season, and as specific
wildlife habitat-use requirements become evident (through collaboration with the wildlife
researchers working on the Project), a final set of wildlife habitat types will be developed. Two
other ITU variables (surface form and disturbance type) and soil drainage as well also are
expected to be integrated, as needed, into the final classification of wildlife habitat types.
5.2. Field Surveys
Data developed in support of this study are available for download in the following file at
http://gis.suhydro.org/reports/isr:
• ISR_11_5_VEG_Plot_and_Classif.accdb
During the two survey periods in 2013, 619 full ground-reference plots and 297 map-verification
plots were sampled along 77 transects. On the ground-reference plots, the full range of
physiographic types present in the study area was sampled (Table 5.1-1). Subalpine, lowland,
and upland physiographic classes were the most commonly sampled (n = 193, 142, and 141,
respectively). Alpine and riverine classes were the next most commonly sampled (n = 64 and 59,
respectively), and the Lacustrine physiographic class was the least commonly sampled in 2013
(n = 20).
In the north-south trending portion of the Denali Corridor, the ground-reference plots sampled
were primarily in subalpine physiographic areas, while in the east-west trending portion of the
Denali Corridor (along the Denali Highway), a mix of upland and lowland physiographic types
were most commonly sampled. The physiographic types sampled at ground-reference plots in the
Chulitna Corridor were predominantly alpine or subalpine, while the ground-reference plots
sampled in the Gold Creek Corridor were predominated by a mix of upland and subalpine
physiographic types. The ground-reference plots sampled in the vicinity of the Watana Dam site
and Watana Reservoir were predominated by a mix of subalpine, upland, and lowland
physiographic types. Riverine and lacustrine physiographic types generally were sampled
throughout the study area, although ground-reference plots in riverine physiographic classes
were most commonly sampled in the east-west trending portion of the Denali Corridor.
At the ground-reference plots sampled in 2013, 67 Level IV AVC vegetation classes were
recorded (Table 5.1-2). Combined with the data from the 2012 field work for this study (ABR
2013), a total of 73 vegetation classes were sampled in the two field seasons. The data from 2013
include 13 vegetation classes not sampled in 2012: Spruce-Aspen Woodland, Spruce-Paper Birch
Woodland, Black Spruce-White Spruce Woodland, Mixed Conifer Woodland, Wet Bryophyte,
Subarctic Lowland Sedge Mesic Meadow, Open Dwarf Dry Shrub Birch-Ericaceous Shrub,
Dwarf White Spruce Woodland, Closed Low Shrub Birch, Open Low Shrub Birch, Open Low
Shrub Birch-Ericaceous Shrub Bog, and Open Low Ericaceous Shrub.
In 2013, forest vegetation classes were most commonly sampled at ground-reference plots at
lower elevations in the vicinity of the Watana Dam site and Watana Reservoir and in the east-
west trending portion of the Denali Corridor, while shrub and herbaceous vegetation classes were
sampled throughout the study area. Ground-reference plots characterized by forest and low-shrub
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vegetation classes predominated in the east-west trending portion of the Denali Corridor, and low
shrub and wet graminoid-herbaceous vegetation classes were most common in the north-south
trending portion of the Denali Corridor. Ground-reference plots sampled in both the Gold Creek
and Chulitna corridors were predominated by a mix of dwarf-, low-, and tall-shrub vegetation
classes. Ground-reference plots sampled in the vicinity of the Watana Dam site and Watana
Reservoir were predominated by forest and low-shrub vegetation classes.
6. DISCUSSION
The field data collection efforts and the mapping prepared in 2013 were conducted as planned
and described in the study plan. Field data collection and mapping efforts in 2013 were
performed with no variances (see Section 4, Methods and Variances, above), and all indications
are that the data are of sufficient quality to meet the study objectives. The vegetation and wildlife
habitat mapping study is on-going, with field data QA/QC, aerial image interpretation, and ITU
mapping currently occurring. From the work completed as of the end of October 2013, the ITU
field and mapping data were used to develop a set of preliminary habitat types. This preliminary
set of habitat types will serve as the template for the development of the final set of wildlife
habitat types to be prepared for the USR. The progress of the study to date is sufficient to meet
the study objectives with an additional year of field data collection and ITU mapping.
As specified in RSP Section 11.5.7, no data from other Project studies are required as inputs to
complete the mapping of vegetation and wildlife habitats in this study. The mapping of
vegetation types and other ITU variables along with the wetland classes for the Wetland
Mapping Study in the Upper and Middle Susitna Basin (Study 11.7), however, will be conducted
concurrently so that the classification of the ITU map polygons for this study will benefit from
the concurrent review of the field data for this study and Study 11.7. The vegetation and wildlife
mapping study team also will work closely with the wildlife researchers on the Project (Studies
10.5 through 10.18) in the development of the final set of wildlife habitat types. In this process,
review comments on the preliminary wildlife habitat types from the wildlife researchers will be
taken into account so that the final mapped habitat types are representative of the habitats used
by wildlife species in the study area. Similarly, the study team will work with researchers from
the Riparian Vegetation Study Downstream of the Proposed Susitna-Watana Dam (Study 11.6)
in developing a set of wildlife habitat types for riparian areas downstream of the Watana Dam
site.
6.1. Ecoregions in the Study Area
Land resource regions (LRRs) and major land resource areas (MLRAs) in Alaska were defined
by the USDA-NRCS (2004) using climatic, physiographic, biological, and ecological features,
properties, and relationships. LRRs represent broad regions of the state that share similar
climatic conditions, patterns, and processes, and MLRAs represent subregional areas with shared
physiographic and geomorphic patterns and processes. The vegetation and wildlife habitat
mapping study area spans two LRRs (Southern Alaska and Interior Alaska) and three MLRAs
(the Cook Inlet Mountains subregion in Southern Alaska, and the Interior Alaska Mountains and
Copper River Basin subregions in Interior Alaska; USDA-NRCS 2004). The Cook Inlet
Mountains subregion encompasses the vast majority of both the Chulitna and Gold Creek
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corridors. The easternmost extent of the Watana Reservoir extends into the Copper River Basin
subregion, while the remainder of the study area (the Denali Corridor, the easternmost portions
of the Chulitna and Gold Creek corridors, and the majority of the Watana Dam site and Watana
Reservoir) is located within the Interior Alaska Mountains subregion.
The Cook Inlet Mountains subregion includes portions of the Talkeetna, Kenai, and Chugach
mountains that drain into the Cook Inlet Lowlands MLRA and Cook Inlet, as well as portions of
the Alaska and Aleutian ranges (USDA-NRCS 2004). Portions of Denali National Park and
Preserve, Lake Clark National Park and Preserve, Kenai National Wildlife Refuge, and Chugach
National Forest are located within the Cook Inlet Mountains subregion. Rugged mountains,
deeply incised with narrow to broad, high-gradient valleys dominate the terrain in this subregion.
The climate is characterized by short summers with moderate to cold winters, with an average
frost-free period of 60–80 days. During the 2013 field surveys, 15 transects were sampled in the
Cook Inlet Mountains subregion, within the Chulitna and Gold Creek corridors. These transects
were dominated by alpine and subalpine physiography, and dwarf to low-shrub vegetation
classes typical of the mountains within this subregion.
The Copper River Basin subregion includes portions of the Talkeetna, Chugach, and Wrangell
Mountains, and the Copper River Plateau (USDA-NRCS 2004). Glenallen is the largest
community within the Copper River Basin MLRA, and portions of the Wrangell-St. Elias
National Park and Preserve are located within this subregion. Undulating plains and rolling hills
dominate the terrain, with lakes and interconnecting wetlands in shallow basins. Most of this
subregion drains into the Copper River. The subarctic continental climate of this subregion is
characterized by brief, warm summers and long, cold winters, with an average frost-free period
of 35–90 days. The Copper River Basin MLRA is located within the discontinuous permafrost
zone, and near-surface permafrost is common in fine-textured sediments on plains, stream
terraces, and gentle slopes. Two survey transects were sampled in the Copper River Basin
subregion in 2013, and they were predominantly in lowland physiographic areas. Vegetation
classes sampled within the Copper River Basin subregion ranged from forested to wet
herbaceous vegetation classes, which is typical for this subregion.
The Interior Alaska Mountains subregion includes the high mountain slopes and glaciated hills
and plains in the Alaska Range and in the Talkeetna, Chugach, and Wrangell mountains, the
northern portions of the Aleutian Range that drain into the upper Tanana and Kuskokwim rivers,
and the Copper River Plateau (USDA-NRCS 2004). This subregion is primarily undeveloped
and includes portions of Denali National Park and Preserve, Wrangell St-Elias National Park and
Preserve, and Tetlin National Wildlife Refuge. High rugged mountains, low rounded hills, and
extended footslopes along the base of mountains dominate the terrain, with narrow to broad
high-gradient valleys dissecting the mountains. This subregion drains to the Tanana River,
Kuskokwim River, Copper River Basin, the Cook Inlet Lowlands, and Cook Inlet. The subarctic
continental climate of this subregion is characterized by brief, warm summers and long, cold
winters, with an average frost-free period of 50–80 days. The Interior Alaska Mountains MLRA
is located within the discontinuous permafrost zone, with near-surface permafrost generally
restricted to fine-textured sediments on stream terraces and swales on hills and footslopes. The
majority (60) of the 77 survey transects sampled in 2013 were in the Interior Alaska Mountains
subregion; these transects were located within the Denali Corridor, in the study area just to the
north of the Watana Dam site, and in the study area surrounding the proposed Watana Reservoir.
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The north-south and east-west trending portions of the Denali Corridor exhibit different aspects
of the Interior Alaska Mountains subregion: high-gradient valleys in the mountains and extended
footslopes, respectively. The north-south trending portion of the Denali Corridor is dominated by
subalpine physiography and dwarf to low shrubs typical of the broad, high-gradient valleys in
this subregion. In contrast, the east-west trending portion of the Denali Corridor is dominated by
a mix of upland and lowland physiography, with forested and low-shrub vegetation classes
typical of extended footslopes in this subregion.
The physiographic and vegetation classes sampled in the three MLRAs in the study area in 2013
should not be interpreted as the expected distribution of classes in the final ITU mapping. In
particular, land-access restrictions precluded sampling at lower elevations in most of the Gold
Creek Corridor, in much of the study area surrounding the Watana Dam site, and in the western
portion of the Watana Reservoir (Figure 3-1). Extensive lower elevation forests are visible in the
aerial imagery for these areas, but few of those forest vegetation classes were sampled in the
field. Similarly, alpine physiography dominates the north-south trending portion of the Denali
Corridor in the aerial imagery, but the field survey efforts were focused on the more difficult-to-
distinguish subalpine physiographic vegetation classes.
6.2. Occurrence and Distribution of Wildlife Habitats
Lacustrine habitats within the study area are limited to open water bodies over 20 acres in size
and the associated habitats directly influenced by lacustrine processes (Table 5.1-1). Large water
bodies that meet the criteria for lacustrine physiography occur sparsely throughout the study
area, and are concentrated near the south side of Deadman Mountain in the Denali Corridor and
in the Fog Lakes area south of the Susitna River. Lacustrine Graminoid Marsh and Lacustrine
Wet Graminoid Meadow are examples of herbaceous-dominated wildlife habitats that occur
adjacent to water bodies and that differ in hydrologic characteristics (Table 5.2-1).
Riverine wildlife habitats in the study area are often characterized by low- and tall-shrub
vegetation on well-drained seasonally flooded substrates (Table 5.2-1, Figure 5.2-2). To date, a
small number of Riverine Needleleaf Forests have been sampled in the study area, and similarly,
very little data are available for Riverine Moist Mixed Forests, and no data are available for
Riverine Broadleaf Forests. This is due to a combination of limited occurrence and limited
access for surveys: the areas most likely to support mixed and broadleaf riverine forests are in
the Gold Creek Corridor where access currently is limited. Rivers and streams in the study area
include both upper and lower perennial rivers and streams, including the Susitna River (upstream
of the Project dam site), the Nenana River, and their clear water tributaries. The preliminary
wildlife habitat mapping shown in Figure 5.2-2 illustrates how ITU combinations of
physiography and vegetation type are aggregated to derive both Riverine and Upland wildlife
habitat types.
Lowland physiography, for the purposes of this study, is identified at a local scale (Table 5.1-1),
and as such, is not synonymous with a broad region of lowlands occurring below mountain
ranges, such as the Cook Inlet or Kenai lowlands. The local-scale lowland physiography used in
this study is intended to portray water-gathering, and generally concave landscape features
capable of supporting wetland complexes. Examples include broad glacial-scour features that
form linear troughs on upland hillsides, concave toeslopes, and abandoned floodplain features.
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Lowland physiographic features support a range of habitats from small open-water ponds and
wet meadows to low-lying and poorly drained forest habitats dominated by needleleaf species
(Table 5.2-1). A typical lowland wetland complex within the study area is characterized by a
core of poorly drained habitats (e.g., Lowland Wet Graminoid Meadow, Lowland Ponds) with a
fringe of drier shrub and forest types (e.g., Lowland Spruce Forest, Lowland Low and Tall
Willow Scrub) (Figure 5.2-1).
Many of the mature forest types in the study area occur in areas of Upland physiography (Table
5.2-1). Upland Moist Mixed Forest primarily is found at lower elevations in the Gold Creek
Corridor. Upland Spruce Forests are more prevalent in the east-west trending portion of the
Denali Corridor along the Denali Highway, and in the far eastern portion of the proposed Watana
Reservoir within the Copper River Basin MLRA (in which spruce forests typical of Interior
Alaska are dominant). One upland habitat type (Upland Spruce Woodland with Tall Shrub
Understory) was developed specifically to address breeding landbird habitat-use patterns
observed during the field surveys for the Landbird and Shorebird Migration, Breeding, and
Habitat Use Study (Study 10.16). Large areas of upland physiography in the study area support
low- and tall-shrub habitats, including the common Upland Moist Birch-Ericaceous Scrub.
Upland Moist Birch-Ericaceous Scrub is dominated by shrub birch and occurs primarily on low
to mid-slope areas to the north and east of Devils Canyon.
Areas of subalpine physiography (Table 5.1-1) in the study area span a wide elevational gradient
from treeline to the upper limit of low-shrub growth. The transition to extremely well-drained,
rocky alpine physiography typically occurs on middle to upper slopes at approximately 3,500 ft
above sea level. Much of the study area falls within the subalpine zone, including the high, upper
slopes of the Gold Creek Corridor; many of the broad, high, glacial valleys traversed by the
Chulitna Corridor; and the north-south trending portion of the Denali Corridor. Subalpine
wildlife habitat types range from wet, permanently flooded types to dry dwarf-shrub and barren
types (Table 5.2-1, Figure 5.2-3).
Alpine physiography (Table 5.1-1) is found at high elevations, typically above 3,500 ft in those
portions of the Talkeetna Mountains and the Alaska Range that intersect with the study area.
Steep, rugged, well-drained, and largely unvegetated terrain dominates the alpine zone.
Vegetated habitats including Alpine Moist Dwarf Scrub, Alpine Moist Graminoid-Forb Meadow,
Alpine Wet Sedge Meadow, and Alpine Wet Sedge-Shrub Meadow occur on a limited basis in
shallow terrain breaks, protected snowbed sites, and in the headwaters of streams (Table 5.2-1).
7. COMPLETING THE STUDY
[Section 7 appears in the Part C section of this ISR.]
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8. LITERATURE CITED
ABR (ABR, Inc.—Environmental Research & Services). 2013. Vegetation and wildlife habitat
mapping study in the Upper and Middle Susitna Basin. Prepared for the Alaska Energy
Authority, Anchorage, AK, by ABR, Inc., Fairbanks and Anchorage, AK. 19pp.
Available online at http://www.susitna-watanahydro.org/type/documents/. Accessed
October 2013.
AEA (Alaska Energy Authority). 2012. Revised Study Plan: Susitna-Watana Hydroelectric
Project FERC Project No. 14241. December 2012. Prepared for the Federal Energy
Regulatory Commission by the Alaska Energy Authority, Anchorage, Alaska. Available
on-line at http://www.susitna-watanahydro.org/study-plan.Accessed October 2013.
Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Technical
Report Y-87-1, U.S. Army Corps of Engineers, Engineer Waterway Experiment Station,
Vicksburg, MS. 90 pp + appendices.
Jorgenson, M. T., J. E. Roth, S. F. Schlentner, E. R. Pullman, and M. Macander. 2003. An
Ecological Land Survey for Fort Richardson, Alaska. Technical Report ERDC/CRREL
TR-03-19. U.S. Army Corps of Engineers, Engineer Research and Development Center,
Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire. 100 pp.
Kreig and Associates. 1987. Susitna Hydroelectric Project, vegetation mapping final report and
user guide. Prepared by Ray A. Kreig and Associates, Inc., Anchorage, for Harza–Ebasco
Susitna Joint Venture, Anchorage. 92 pp. [APA Doc. No. 3509]
Schick, C.T., and W.A. Davis. 2008. Wildlife habitat mapping and evaluation of habitat use by
wildlife at the Stewart River Training Area, Alaska. Prepared for Alaska Army National
Guard, Fort Richardson, AK, by ABR, Inc., Anchorage, AK. 54 pp.
USACE (U.S. Army Corps of Engineers). 2007. Supplement to the Corps of Engineers Wetland
Delineation Manual: Alaska Region Version 2.0. Wetlands Regulatory Assistance
Program, U.S. Army Corps of Engineers, Engineer Research and Development Center,
Vicksburg, MS. 72 pp. + appendices.
United States Department of Agriculture (USDA) Natural Resources Conservation Service
(NRCS). 2004. Land Resource Regions and Major Land Resource Areas of Alaska. 91pp.
Available on-line at: http://www.ak.nrcs.usda.gov/technical/lrr.html. Accessed November
2013.
Viereck, L. A.,C. T. Dyrness, A. R. Batten, and K. J. Wenzlick. 1992. The Alaska vegetation
classification. General Technical Report PNW-GTR-286. Portland, OR: U.S. Department
of Agriculture, Forest Service, Pacific Northwest Research Station. 278 pp.
Washburn, A. L. 1973. Periglacial Processes and Environments. Edward Arnold, London,
England.
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9. TABLES
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Table 5.1-1. Description of Physiographic Types Identified in the Vegetation and Wildlife Habitat Mapping Study Area,
Susitna-Watana Hydroelectric Project, 2013.
Physiography Elevation Characteristics Typical Wildlife Habitats Example Photograph
Alpine (A) Above tree
line and
above low-
shrub
zone;
mostly
> 3500’ asl
Defined by elevation
and corresponding lack
of trees or tall and low
shrubs; dwarf shrubs
and wet meadows may
be present; most
extensive along
ridgelines, on saddles,
and north-facing slopes.
Barren to partially barren
ridgelines, dwarf
ericaceous shrub-lichen
communities on ridge
crests and shoulders,
and moist dwarf scrub in
nivation hollows.
Subalpine (S) Above tree
line, within
tall- and
low-shrub
zone;
mostly
~2500–
3500’ asl
Defined by elevation
and corresponding lack
of trees; tall shrubs may
be present; often
steeply sloping.
Low open birch, birch-
willow, or ericaceous-
birch scrub on hillsides;
tall alder scrub in
drainages; and wet
herbaceous meadows.
Upland (U) Below tree
line
Water-shedding terrain;
typically well-drained,
dry to moist mineral
soils; often located on
slopes.
Moist forests; low open
birch, birch-willow, or
ericaceous-birch scrub
on hillsides; and moist to
dry herbaceous
meadows.
Lowland (L) Below tree
line
Water-gathering terrain;
typically moist to wet
with organic soils;
located in valley
bottoms, lower slopes,
toeslopes, and benches
with concave or level
topography and wet
habitats.
Wet sedge meadows,
marshes (permanently
flooded), and shrub
bogs/swamps.
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Physiography Elevation Characteristics Typical Wildlife Habitats Example Photograph
Lacustrine (P) Any Driven by lacustrine
processes in which the
water body is the
dominant feature;
includes the water body,
shallow water zones,
and adjacent wetlands
where water levels are
controlled by the lake.
Open water, emergent
wet sedge marshes in
lacustrine margins,
shrub swamps, and
floating bog mats.
Riverine (R) Any More than just a
proximal relationship
with rivers and streams;
riverine communities
show evidence of
influence by riverine
processes, particularly
hydrology.
Seasonally flooded
riverine scrub (willow,
alder, and/or balsam
poplar); dry riverbanks
where the presence of a
river or stream and well-
drained soils drops the
water table to create a
dry micro-habitat.
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Table 5.1-2. Vegetation Classes Sampled in the Vegetation and Wildlife Habitat Mapping Study Area, Susitna-Watana
Hydroelectric Project, 2013.
Level IV Vegetation Class1 Code n (2012)2 n (2013)2
Barren Bbg 1 4
Partially Vegetated Bpv 4 4
Closed Quaking Aspen-Balsam Poplar Forest Fbcap 1 Open Quaking Aspen Forest Fboa 1 1
Open Paper Birch Forest Fbob 2 2
Open Paper Birch-Balsam Poplar Forest Fbobp 1 Open Balsam Poplar Forest Fbop 2 1
Open Paper Birch-Balsam Poplar-Spruce Fmobps 1 Open Spruce-Paper Birch Fmosb 9 5
Open Spruce-Balsam Poplar Forest Fmosp 1 1
Spruce-Quaking Aspen Woodland Fmwsa 1
Spruce-Paper Birch Woodland Fmwsb 2
Open Black Spruce Forest Fnobs 9 11
Open White Spruce Forest Fnows 2 16
Black Spruce Woodland Fnwbs 16 12
Black Spruce-White Spruce Woodland Fnwbw 1
Mixed Conifer Woodland Fnwmc 3
White Spruce Woodland Fnwws 14 53
Wet Bryophyte Hbbw 1
Midgrass-Herb Hgdgh 1 5
Midgrass-Shrub Hgdgs 3
Bluejoint Meadow Hgmb 2 11
Bluejoint-Shrub Hgmbs 3 4
Moist Seral Grass-Herb Meadow Hgmgh 3 3
Moist Grass-Herb Meadow Tundra Hgmght 1 5
Subarctic Lowland Sedge Mesic Meadow Hgmsl 1
Moist Sedge-Shrub Tundra Hgmss 2 10
Moist Sedge-Willow Tundra Hgmswt 3 1
Fresh Sedge Marsh Hgwfs 7 16
Subarctic Lowland Graminoid-Herb Wet Meadow Hgwgh 1 3
Subarctic Lowland Sedge Bog Meadow Hgwsb 11 11
Subarctic Lowland Sedge Wet Meadow Hgwsl 16 23
Subarctic Lowland Sedge-Moss Bog Meadow Hgwsmb 8 3
Subarctic Lowland Sedge-Shrub Wet Meadow Hgwss 8 8
Wet Sedge Meadow Tundra Hgwst 2 18
Wet Sedge-Willow Tundra Hgwswt 2 2
Dryas-Sedge Dwarf Shrub Tundra Sdds 1 2
Dryas Dwarf Shrub Tundra Sddt 4 1
Bearberry Dwarf Shrub Tundra Sdeb 1 2
Cassiope Dwarf Shrub Tundra Sdec 1 9
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Level IV Vegetation Class1 Code n (2012)2 n (2013)2
Crowberry Dwarf Shrub Tundra Sdee 2 11
Ericaceous-Lichen Dwarf Shrub Tundra Sdel 4 13
Ericaceous Dwarf Shrub Tundra Sdet 4 17
Vaccinium Dwarf Shrub Tundra Sdev 3 10
Open Dwarf Dry Shrub Birch-Ericaceous Shrub Sdobe 9
Willow Dwarf Shrub Tundra Sdwt 1 6
Open Dwarf Black Spruce Sfobs 2 8
Open Dwarf White Spruce Sfows 1 2
Dwarf Black Spruce Woodland Sfwbs 1 9
Dwarf White Spruce Woodland Sfwws 2
Closed Low Shrub Birch Shrub Slcb 1
Closed Low Shrub Birch-Ericaceous Shrub Slcbe 6 12
Closed Low Shrub Birch-Willow Shrub Slcbw 1 2
Closed Low Sweetgale Meadow Slcm 1 2
Closed Low Willow Slcw 1 11
Open Low Shrub Birch Slob 7
Open Low Shrub Birch-Ericaceous Shrub Bog Slobb 5
Open Low Mesic Shrub Birch-Ericaceous Shrub Slobe 32 40
Open Low Shrub Birch-Willow Slobw 1 19
Open Low Sweetgale-Graminoid Bog Slocg 2 3
Open Low Ericaceous Shrub Sloe 7
Open Low Ericaceous Shrub Bog Sloeb 7 2
Open Low Willow Slow 7 38
Open Low Willow-Graminoid Shrub Bog Slowg 1 5
Closed Tall Alder Stca 14 14
Closed Tall Alder-Willow Shrub Stcaw 4 Closed Tall Willow Shrub Stcw 9 17
Open Tall Alder Stoa 12 3
Open Tall Alder-Willow Stoaw 2 Open Tall Shrub Birch Stob 7 9
Open Tall Scrub, post burn or disturbance Stod 1 Open Tall Willow Stow 8 17
Water W 1 59
Total 276 619
Notes:
1 Following Viereck et al. 1992, with additions by ABR for undescribed vegetation classes and non-vegetated
land-cover types.
2 Sample sizes (number of ground-reference plots surveyed) in 2012 and 2013.
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Table 5.2- 1. Preliminary Descriptions of Wildlife Habitat Types Expected to be Mapped in the Vegetation and Wildlife
Habitat Mapping Study Area, Susitna-Watana Hydroelectric Project, 2013.
Physiography Wildlife Habitat Type Description1
Lacustrine Lacustrine Graminoid Marsh Permanently flooded communities with low plant diversity; dominated
by wetland-obligate, tall, coarse sedges; primarily limited to lake
margins.
Lacustrine Wet Graminoid Meadow Wet graminoid meadows occupying lacustrine fringe environments.
Lake Permanently flooded water bodies greater than 20 acres in size.
Riverine Riverine Barrens Barren to partially vegetated (< 30% cover) point bars; substrates are
well-drained sands and gravels.
Riverine Low Willow Scrub Low willow-dominated communities usually occupying point bars along
active river channels.
Riverine Moist Mixed Forest Mature forest stands composed of paper birch and white spruce;
typically occupying upland banks of the Susitna or Nenana Rivers.
Riverine Needleleaf Forest Mature forest stands composed primarily of white spruce; typically
occupying upland banks of the Susitna or Nenana Rivers, but may be
found along banks of smaller tributaries.
Riverine Tall Alder or Willow Scrub Found along banks of small tributaries and larger rivers; mixed tall
alder and willow stands, either open (25 to 75% cover) or closed
(> 75% cover).
Rivers and Streams Permanently flooded upper and lower perennial rivers and streams
found throughout the study area.
Lowland Lowland Pond Permanently flooded water bodies less than 20 acres in size; often a
component of a larger sloping wetland system.
Lowland Disturbed Graminoid
Meadow
Wet meadows dominated by bluejoint grass; commonly occurring
around abandoned beaver dams.
Lowland Ericaceous Scrub Bog Wet meadows dominated by ericaceous shrubs; soils are saturated
histosols; typically located on margins of sloping lowland wetland
complexes.
Lowland Low and Tall Birch-
Ericaceous Scrub
Low-to tall-shrub communities dominated by shrub birch, often with a
dwarf ericaceous shrub understory.
Lowland Low and Tall Willow Scrub Low- to tall-shrub communities dominated by willow species.
Lowland Moist Sedge-Shrub
Meadow
Herbaceous plant communities co-dominated by wetland sedges and
low deciduous shrubs (often willows).
Lowland Wet Graminoid Meadow Plant communities primarily dominated by wetland-obligate sedge
species; forbs and/or deciduous shrubs can be co-dominant.
Lowland Spruce Forest Needleleaf forests with open (25 to 60% cover) to woodland (< 25%
cover) canopies; primarily occurs at the margins of larger wetland
complexes or abandoned floodplains.
Lowland Graminoid Marsh Permanently flooded communities with low plant diversity; dominated
by wetland-obligate, tall, coarse sedges; limited in extent (primarily in
the margins of surface-water impoundments within larger wetland
complexes).
Lowland Low Myrica Scrub Low-shrub communities dominated by Myrica gale; generally found in
transition areas between larger wetland complexes and adjacent
forests.
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IN THE UPPER AND MIDDLE SUSITNA BASIN (11.5)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Part A - Page 20 June 2014
Physiography Wildlife Habitat Type Description1
Upland Upland Dry Dwarf Birch-Ericaceous
Scrub
Dwarf-shrub communities dominated by shrub birch and ericaceous
shrubs; typically occupies convex, well-drained, and exposed surfaces
below treeline.
Upland Moist Birch-Ericaceous
Scrub
Commonly occurring type throughout the study area; primarily low
shrub birch-dominated communities on well-drained surfaces below
treeline.
Upland Moist Broadleaf Forest Mature, open (25 to 60% cover) aspen- or birch-dominated forests,
generally occurring on steep south-facing lower slopes.
Upland Moist Graminoid Meadow Rarely occurring type; moist graminoid-dominated plant communities
occurring below treeline, often with an herbaceous component.
Upland Moist Low Willow Scrub Low willow communities, both closed (> 75% cover) and open (25 to
75% cover), occurring on a variety of surfaces below treeline; typically
associated with drainage features or in the margins of wetland
complexes.
Upland Moist Mixed Forest Mature mixed forests with open (25 to 60% cover) to woodland (< 25%
cover) canopies; found predominantly at low elevations within the Gold
Creek Corridor.
Upland Moist Tall Alder Scrub Tall alder communities, both closed (> 75% cover) and open (25 to
75% cover) canopies; typically occurs on upland terrain below treeline.
Upland Moist Tall Willow Scrub Tall willow communities, both closed (> 75% cover) and open (25 to
75% cover) canopies; typically occurs on upland terrain below treeline.
Upland Spruce Forest Needleleaf forests with open (25 to 60% cover) to woodland (< 25%
cover) canopies; occurs in well-drained upland areas.
Upland Spruce Woodland with Tall
Shrub Understory
Needleleaf woodlands (< 25% cover) with a prominent tall-shrub
understory, often dominated by alder; typically occurs below and
adjacent to Subalpine Tall Alder Scrub.
Subalpine Alpine and Subalpine Tarn Permanently flooded water bodies in the subalpine zone; depressional
features with very little lacustrine fringe development.
Subalpine Dry Barrens Well-drained barren areas found on mid-slopes or on convex features
in exposed subalpine areas (2500–3500 ft asl).
Subalpine Moist Birch-Ericaceous
Scrub
Low-shrub communities dominated by shrub birch and ericaceous
shrubs; occurs on mid-slopes near the subalpine/upland boundary as
forest grades into tundra.
Subalpine Moist Dwarf Shrub Scrub Dwarf-shrub communities occurring on well-drained convex surfaces
between 2500 and 3500 ft asl; composed of a variety of prostrate,
deciduous and evergreen ericaceous shrubs; lichens are common.
Subalpine Moist Graminoid-Shrub
Meadow
Dwarf shrubs and graminoids co-dominate this subalpine plant
community, which is typically found on sheltered mid-slopes.
Subalpine Moist Herb Meadow Forb-dominated moist communities found within the subalpine zone.
Subalpine Tall Alder Scrub Generally closed (> 75% cover) canopy tall alder communities found
near treeline.
Subalpine Tall Willow Scrub Closed (> 75% cover) and open (25 to 75% cover) canopy willow
communities occur near treeline.
Subalpine Wet Sedge-Shrub
Meadow
Wet sedge communities dominated by wetland-obligate sedges; found
in low lying areas in broad subalpine valleys or in small patches at the
margins of subalpine tarns.
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY
IN THE UPPER AND MIDDLE SUSITNA BASIN (11.5)
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FERC Project No. 14241 Part A - Page 21 June 2014
Physiography Wildlife Habitat Type Description1
Subalpine Low Willow Scrub Closed (> 75% cover) and open (25 to 75% cover) canopy low willow
communities occupying extensive lower slope terrain within broad
subalpine valleys; often poorly drained with surface water present.
Subalpine Sedge Marsh Permanently flooded sedge-dominated communities; limited to small
concavities and margins of subalpine tarns.
Alpine Alpine Dry Barrens Barren rock and scree generally above 3500 ft asl.
Alpine Moist Dwarf Shrub Scrub Dry dwarf-shrub communities dominated by prostrate alpine dwarf
shrubs; forbs are co-dominant and there is often significant lichen
cover.
Alpine Moist Graminoid-Forb
Meadow
Graminoid- and forb-dominated communities in protected sites in the
alpine zone.
Alpine Wet Sedge Meadow Wet meadows dominated by wetland-obligate sedge species; small
patches form in concave depressions in alpine areas.
Alpine Wet Sedge-Shrub Meadow Wet communities co-dominated by wetland-obligate sedges and dwarf
deciduous shrubs; surface water typically present; occurs in drainage
features and terrain concavities.
Alpine and Subalpine Tarn Permanently flooded water bodies in the alpine zone; depressional
features with very little lacustrine fringe development.
Notes:
1 In the AVC (Viereck et al. 1992), tall shrubs are defined as > 1.5 m (4.9 ft) in height, low shrubs are < 1.5m
(4.9 ft) in height, and dwarf shrubs are < 20cm (8 in) in height.
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY
IN THE UPPER AND MIDDLE SUSITNA BASIN (11.5)
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FERC Project No. 14241 Part A - Page 22 June 2014
10. FIGURES
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY IN THE UPPER AND MIDDLE SUSITNA BASIN (11.5)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Part A - Page 23 June 2014
Figure 3-1. Vegetation and Wildlife Habitat Mapping Study Area and Ground-reference Plots Sampled in 2013, Susitna-Watana Hydroelectric Project.
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY IN THE UPPER AND MIDDLE SUSITNA BASIN (11.5)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Part A - Page 24 June 2014
Figure 5.2-1. Preliminary Wildlife Habitat Mapping in Upland and Lowland Physiographic Units in the Vegetation and Wildlife Habitat Mapping
Study Area.
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY IN THE UPPER AND MIDDLE SUSITNA BASIN (11.5)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Part A - Page 25 June 2014
Figure 5.2-2. Preliminary Wildlife Habitat Mapping in Riverine and Upland Physiographic Units in the Vegetation and Wildlife Habitat Mapping
Study Area.
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY IN THE UPPER AND MIDDLE SUSITNA BASIN (11.5)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Part A - Page 26 June 2014
Figure 5.2-3. Preliminary Wildlife Habitat Mapping in Subalpine and Alpine Physiographic Units in the Vegetation and Wildlife Habitat Mapping
Study Area.
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY
IN THE UPPER AND MIDDLE SUSITNA BASIN (11.5)
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FERC Project No. 14241 June 2014
PART A - APPENDIX A: COMMONLY SAMPLED WILDLIFE HABITAT
TYPES
INITIAL STUDY REPORT VEGETATION AND WILDLIFE HABITAT MAPPING STUDY
IN THE UPPER AND MIDDLE SUSITNA BASIN (11.5)
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FERC Project No. 14241 Part A – Appendix A - Page 1 June 2014
Alpine Moist Dwarf Shrub Scrub Subalpine Low Willow Scrub
Upland Spruce Forest
Upland Moist Birch-Ericaceous Scrub
Lowland Wet Graminoid Meadow Riverine Low Willow Scrub