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Susitna-Watana Hydroelectric Project Document
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Title:
Vegetation and wildlife habitat mapping study in the upper and middle
Susitna River
SuWa 36
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Prepared by ABR, Inc.--Environmental Research & Services
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2012 Environmental Studies
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Susitna-Watana Hydroelectric Project document number 36
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[Anchorage, Alaska : Alaska Energy Authority, 2013]
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February 2013
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iii, 19 p.
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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
Prepared for
Alaska Energy Authority
Prepared by
ABR, Inc.–Environmental Research & Services
February 2013
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page i February 2013
TABLE OF CONTENTS
Summary ....................................................................................................................................... iii
1. Introduction ........................................................................................................................1
2. Study Objectives.................................................................................................................1
3. Study Area ..........................................................................................................................2
4. Methods ...............................................................................................................................2
4.1. Deviations from the 2012 Study Plan ................................................................3
4.2. Classification and Mapping of Vegetation and Wildlife Habitats .....................3
4.3. Field Survey .......................................................................................................4
5. Results .................................................................................................................................5
5.1. Historic Vegetation Map Review .......................................................................5
5.2. 2012 Field Summary ..........................................................................................6
5.3. 2012 Mapping Efforts ........................................................................................7
6. Discussion............................................................................................................................7
7. References ...........................................................................................................................7
8. Tables ..................................................................................................................................9
9. Figures ...............................................................................................................................14
LIST OF TABLES
Table 1. General vegetation types. ................................................................................................ 10
Table 2. General vegetation types and Level IV vegetation classes. ............................................ 11
LIST OF FIGURES
Figure 1. Study area and completed 2012 sampling transects for the Vegetation and Wildlife
Habitat Mapping Study. ........................................................................................................ 15
Figure 2. Typical topo sequence in the vegetation and wildlife habitat mapping study area,
2012. ...................................................................................................................................... 16
Figure 3. View of valley floor drumlinized terrain in the vegetation and wildlife habitat
mapping study area, 2012. .................................................................................................... 17
Figure 4. Wet Graminoid Meadow typical of inter-drumlin troughs found within the Lowland
physiography class in the vegetation and wildlife habitat mapping study area, 2012. ......... 18
Figure 5. Low deciduous shrub communities commonly found on low slopes and valley
bottoms in the vegetation and wildlife habitat mapping study area, 2012. ........................... 19
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page ii February 2013
LIST OF ACRONYMS AND SCIENTIFIC LABELS
Abbreviation Definition
AEA Alaska Energy Authority
APA Alaska Power Authority
ATV all-terrain vehicle
AVC Alaska Vegetation Classification
ELS Ecological Land Survey
FERC Federal Energy Regulatory Commission
ft Feet/foot
GIS geographic information system
GPS global positioning system
ha hectare(s)
ILP Integrated Licensing Process
ITU integrated terrain unit
km kilometer(s)
m meter(s)
NEPA National Environmental Policy Act
NWI National Wetlands Inventory
PM&E protection, mitigation, and enhancement
Project Susitna-Watana Hydroelectric Project
RM river mile
USACE U.S. Amy Corps of Engineers
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page iii February 2013
SUMMARY
A vegetation and wildlife habitat mapping study is being conducted to provide baseline
information on existing vegetation and wildlife habitats in the Susitna-Watana Hydroelectric
Project area. This information will be used to facilitate assessments of the potential impacts to
vegetation and wildlife habitats from the proposed Project. The Vegetation and Wildlife Habitat
Mapping Study is designed as a multi-year study, with work to be conducted in 2012 through
2014. The collection of field ground-reference data and the classification and mapping of
vegetation types in the study area (see Figure 1) were initiated in 2012.
During the 2012 field season, 36 sampling transects were surveyed for vegetation composition,
physiography, geomorphic unit (landform), macrotopography, microtopography (largely surface
form), and observations of wildlife use or human activity. Field data for the Vegetation and
Wildlife Habitat Mapping Study were collected simultaneously with the collection of field data
for the Wetland Mapping Study. Data were collected from 276 full field plots, and field
verifications (a rapid assessment technique to confirm previously documented conditions) were
performed at 85 field plots along the transects. Using Alaska Vegetation Classification (AVC)
criteria, 60 Level IV AVC vegetation classes, which can be grouped into 18 general vegetation
types, were documented. Field data were used in conjunction with high-resolution imagery to
classify and map vegetation types within the study area. Preliminary wildlife habitats will be
derived in 2013 from vegetation types, physiography, surface form (as needed), and disturbance
classes after substantial mapping of those attributes has been completed.
After the field season, the original vegetation mapping for the Alaska Power Authority (APA)
Project, prepared by Kreig and Associates in 1987, was obtained from the Alaska Department of
Fish and Game and was assessed for current accuracy by comparison with recent aerial imagery.
The 1987 vegetation mapping was found to be reasonably accurate, but only at a relatively
coarse-scale (roughly equivalent to Level III AVC vegetation classes). The 1987 vegetation
mapping will be used to help select field plots for this study and for other wildlife survey studies
for the Project in 2013 and 2014.
As noted above, the vegetation and habitat data collected in 2012 represent only the first year of
work in a multi-year mapping study of vegetation and wildlife habitats for the Project. The data
from 2012 will be combined with those collected in 2013 and 2014 to prepare complete
vegetation and wildlife habitat maps for the Project (see Section 11.5 in the Revised Study Plan
[AEA 2012]). If warranted by the results of the 2012 work, the specific field and office methods
used to identify, delineate, and map vegetation and habitat types within the study area may be
refined (based on consultation with Alaska Energy Authority (AEA) and other licensing
participants).
The vegetation types identified in the study area to-date typify this region of Alaska. Because of
the large size of the Project and study area, a number of different vegetation types have been
encountered, ranging from those comparable to the coastal Cook Inlet area (in the west near Gold
Creek) to those more typical of interior areas of Alaska (in the east near the Oshetna River and
the north near Cantwell).
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 1 February 2013
1. INTRODUCTION
The Alaska Energy Authority (AEA) is preparing a License Application that will be submitted to
the Federal Energy Regulatory Commission (FERC) for the Susitna-Watana Hydroelectric
Project (Project) using the Integrated Licensing Process (ILP). The Project is located on the
Susitna River, an approximately 300-mile-long river in Southcentral Alaska. The Project’s dam
site would be located at river mile (RM) 184.
The Vegetation and Wildlife Habitat Mapping Study is a multi-year effort initiated in 2012. This
report provides the results of the 2012 work, based on the 2012 Vegetation and Wildlife Habitat
Mapping Study plan (AEA 2012a). This study provided data to inform the Revised Study Plan
(RSP) filed with FERC in December 2012, and will be incorporated into the Exhibit E of the
License Application and FERC’s National Environmental Policy Act (NEPA) analysis for the
Project license.
In 2012, field ground-reference surveys to collect current data on vegetation and wildlife habitat
parameters and preliminary mapping of vegetation types in the study area (see Study Area
below) were conducted. Additionally, an accuracy assessment of the vegetation map prepared in
the 1980s for the Alaska Power Authority’s Susitna Hydroelectric Project (APA Project) was
performed.
2. STUDY OBJECTIVES
The overall goals of the Vegetation and Wildlife Habitat Mapping Study are to prepare baseline
maps of the existing vegetation and wildlife habitats in areas in the Upper and Middle Susitna
basin (upstream of Gold Creek) that could be directly affected by Project development. This
mapping information will be used in AEA’s License Application to assess impacts to both
vegetation and wildlife resources from the proposed Project, and to develop any necessary
protection, mitigation, and enhancement (PM&E) measures (see RSP Section 11.5 in AEA
2012b). When completed, the wildlife habitat maps will be used to estimate quantitatively the
impacts of habitat loss and alteration for a selected set of bird, mammal, and amphibian species
evaluated during the FERC licensing process (see RSP Section 10.19 in AEA 2012b). The
wildlife habitat mapping prepared in this study will be one of the primary pieces of information
used to evaluate impacts to wildlife species.
The specific objectives of the Vegetation and Wildlife Habitat Mapping Study are to identify,
delineate, and map vegetation and wildlife habitat types in the Upper and Middle Susitna basin to
reflect current conditions as indicated on recent aerial imagery for the study area. The multi-year
study was initiated in 2012 and will be continued in 2013 and 2014. Results from the 2012 work
will be used to fine-tune the field investigations and the mapping of current vegetation and
wildlife habitats in the study area.
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 2 February 2013
3. STUDY AREA
The 2012 study area for the Vegetation and Wildlife Habitat Mapping Study consisted of a 5-
mile buffer surrounding those areas that would be directly altered or disturbed by development of
the Project (Figure 1). Note that the buffer for the study area has since been changed to 4 miles
based on subsequent agency consultation conducted during 2012 (see RSP Section 11.5 in AEA
2012b). The areas that could be affected directly or disturbed by Project development include
three possible alternatives for road and transmission lines (Chulitna, Gold Creek, and Denali),
the proposed reservoir inundation area, dam site, and supporting infrastructure surrounding the
dam site. The Chulitna Corridor would include transmission lines and a road running north of the
Susitna River toward the west to connect to the Alaska Intertie and the Alaska Railroad near the
Chulitna station. Another east–west corridor configuration, the Gold Creek Corridor, would
follow a route south of the Susitna River running west to Gold Creek station. A third corridor,
the Denali Corridor, runs north and would connect the dam site to the Denali Highway by road
over a distance of about 44 miles. If transmission lines are run along the Denali Corridor, they
would also need to run west along the existing Denali Highway to connect to the Alaska Intertie
near the community of Cantwell. In areas paralleling the Susitna River between the dam site and
Gold Creek, vegetation and wildlife habitats within the study area buffer will be mapped up to
the boundary of the Riparian Vegetation Study area. Vegetation and wildlife habitats in riparian
areas downstream of the proposed dam will be mapped in the Riparian Vegetation Study (see
RSP Section 11.6 in AEA 2012b). Mapping methods in the Vegetation and Wildlife Habitat
Mapping Study and Riparian Vegetation Study are compatible, and the final map products will
result in vegetation and wildlife habitats being mapped consistently in the Project area above the
proposed dam and in riparian areas downstream of the dam site.
High-resolution aerial imagery is required for the mapping of vegetation and wildlife habitats.
Suitable high-resolution imagery (0.3- to 1-foot pixels) is not yet available for the entire study
area, but it is anticipated that additional imagery will be acquired during the 2013 field season
(the new imagery will include both natural color and infrared formats). Thus, the 2012 detailed
mapping of vegetation and wildlife habitats types is currently limited to those areas with high-
resolution imagery, which includes a section surrounding the Upper Susitna River (covers the
southwestern part of the reservoir inundation zone and small portions of the Gold Creek
corridor), and another section in the vicinity of Cantwell at the northern end of the Denali
corridor.
4. METHODS
The procedures for the mapping of vegetation and wildlife habitats for the Project area will
follow protocols developed by ABR for Ecological Land Survey (ELS) studies in Alaska (see
below and RSP Section 11.5 in AEA 2012b). Vegetation and other landscape attributes
important in determining the use of habitats by wildlife will be mapped by interpretation of
imagery signatures on recent aerial imagery for the Vegetation and Wildlife Habitat Mapping
Study area. Detailed field ground-reference data collected over three field seasons will be used to
link vegetation information and other landscape data to the imagery signatures and facilitate the
identification and delineation of vegetation and wildlife habitat types.
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 3 February 2013
4.1. Deviations from the 2012 Study Plan
The 2012 study plan for the Vegetation and Wildlife Habitat Mapping Study (AEA 2012b)
indicated that the historic vegetation mapping prepared for the APA Project (Kreig and
Associates 1987) would be assessed for accuracy and updated prior to the field surveys to serve
as a preliminary vegetation map for the study area. The objective of the preliminary mapping
was to identify a set of characteristic vegetation types within the study area to guide field survey
plot locations, and to allow field verification of the preliminary mapping. Instead, in 2012, field
plots were located within the prominent image signatures in each major physiographic class,
which often is the first step in a multi-year vegetation and wildlife habitat mapping project. In
2013 and 2014, preliminary vegetation mapping will be available to support the selection of field
plots and facilitate the field verification of that vegetation mapping. Thus, the lack of preliminary
mapping prior to the 2012 field surveys will not affect the quality or accuracy of the final
vegetation and wildlife habitat maps.
Additionally, no efforts were made in 2012 to prepare a preliminary set of wildlife habitat types
as was indicated in the 2012 study plan for this study. Preliminary wildlife habitats could not be
prepared because no preliminary vegetation mapping was available. As noted above, preliminary
wildlife habitats will be derived in 2013 after substantial mapping of vegetation types,
physiography, surface form, and disturbance classes have been completed. Those preliminary
wildlife habitat types will be presented for review in the Initial Study Report (ISR), to be filed
with FERC in February 2014.
4.2. Classification and Mapping of Vegetation and Wildlife Habitats
We are employing an integrated, multivariate approach to the classification and mapping of
vegetation and wildlife habitats in the study area based on methods developed for ELS studies
conducted in tundra, boreal forest, and coastal regions in Alaska (see Jorgenson et al. 2002 for an
example study in Southcentral Alaska). This integrated mapping approach involves mapping
terrain units such as vegetation type, physiography, surface form, and disturbance type, and then
combining them into units of ecological importance (in this case wildlife habitats).
The method of combining various integrated terrain units (ITUs) allows for the preparation of a
number of thematic maps, depending on specific study needs. For the Project, a vegetation map
at Level IV of the Alaska Vegetation Classification (Viereck et al. 1992; hereafter refered to as
Level IV vegetation classes) will be prepared as well as a wildlife habitat map based on
combinations of ITUs that best reflect use by the wildlife species of interest in the Project area.
In 2012, the mapping of vegetation types in the study area was initiated. A set of preliminary
wildlife habitats will be derived in 2013 after substantial mapping of vegetation types,
physiography, surface form, and disturbance classes has been completed. Those preliminary
wildlife habitat types will be presented for review in the ISR, to be filed with FERC in February
2014.
In 2012, data from existing vegetation maps prepared for the APA Project (Kreig and Associates
1987) were evaluated for correspondence to the recent aerial imagery being used for mapping
vegetation. Vegetation attributes in the 1987 map were coded within the “Strataveg” field using
the preliminary Alaska Vegetation Classification scheme (Viereck and Dyrness 1980). Coding
under the Strataveg field included information on major and minor vegetation components, in
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 4 February 2013
which the major component represented the land-cover type present in at least 75 percent of the
area represented by each map polygon (Kreig and Associates 1987). ABR converted the major
Strataveg components to Viereck vegetation codes (based on Level IV vegetation classes) and
general vegetation codes (roughly equivalent to Viereck Level III vegetation classes) to assess
map accuracy. The two new fields were evaluated for current accuracy on an individual polygon
basis by comparing the vegetation codes with recent aerial imagery at several locations within
the study area.
4.3. Field Survey
Field ground-reference data to link to imagery signatures were collected during summer 2012.
Field data were collected along transects designed to access the primary physiographic classes
(Alpine, Subalpine, Upland, Lowland, Lacustrine, and Riverine) in the study area, while
maximizing safety and efficiency. Transect length ranged from approximately 1.5–3.0 kilometers
(5,000–10,000 feet) and 8–12 pre-selected field plot locations were allocated along each transect.
Transects were not always straight lines because they were designed specifically to allow the
sampling of different land cover types within the physiographic classes noted above. Transect
length and complexity were designed to allow a field team to complete data collection along one
transect per day. Field plots were pre-selected to facilitate the collection of ground-reference data
from as many vegetation and habitat types as possible (identified by differences in image
signature color and texture in addition to aspect, elevation, and physiographic class). Transects
were located (Figure 1) in those portions of the study area for which there currently is high-
resolution aerial imagery (see Study Area above).
At each field plot, the vegetation and wildlife habitat mapping data for this study were collected
concurrently with data on wetlands for the Wetland Mapping Study (ABR 2013). Data were
collected at the pre-selected field plot locations noted above and at additional plot locations
established in the field (where new, transitional, or under-sampled land cover types were
encountered). As described in the 2012 study report for the Wetland Mapping Study, U.S. Army
Corps of Engineers (USACE) standard data collection methods (Environmental Laboratory
1987; USACE 2007) were used for the wetland determinations. Those wetland determination
methods include estimates of vascular plant species cover and soil profile descriptions, which are
also standard wildlife habitat mapping variables used by ABR. A Trimble® Nomad™ series
mobile geographic information systems (GIS) unit was used to record the wetlands data, the
global positioning system (GPS) coordinates of each field plot, and to provide access to the aerial
imagery in the field. In addition to data on plant cover and soils, the Level IV vegetation class
and data on physiography, geomorphic unit (landform), macrotopography, microtopography
(largely surface form), and observations of wildlife use (e.g., trails, browse, scat) and/or human
use (e.g., hunting activities, all-terrain vehicle [ATV] trails) were recorded at each plot using an
Android tablet computer and a customized data-entry form designed to link directly to a
relational database (Microsoft Access).
All data were recorded within a 10-meter (33-feet) radius of homogenous vegetation at each field
plot, although the size and dimensions of the field plots were modified where necessary to
accurately characterize the plant community (e.g., narrow plots were used in some riverine
habitats). The absolute cover of each vascular plant species within each field plot was visually
estimated. Soil pits were excavated to approximately 18 inches deep or to the depth of the active
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 5 February 2013
layer, if shallower, and the soil profile was described. Soil color was identified using the Munsell
Soil Color Charts (2009). Digital photos of soils and vegetation were taken at each plot.
Verification plots (a rapid assessment technique to provide replication for previously
documented conditions) also were sampled to collect additional data to support the mapping
efforts. At verification plots, data on dominant vascular plant species, National Wetlands
Inventory (NWI) wetland classes, and Level IV vegetation classes were recorded, in addition to
site photographs and GPS coordinates. Verification plots were typically conducted in areas
where the land cover characteristics had been documented in the data from full field plots. Data
from the verification plots will be used to improve map accuracy by increasing the number of
documented land cover data elements tagged to particular aerial imagery signatures.
5. RESULTS
5.1. Historic Vegetation Map Review
The vegetation mapping prepared by Kreig and Associates (1987) encompasses 646,701.4
hectares and is centered on the upper Susitna River drainage, extending from near the confluence
of the Oshetna and Susitna rivers in the east to just downstream of Devils Canyon in the west and
into alpine areas in the adjacent Talkeetna Mountains.
To assess the current accuracy of the 1980s vegetation mapping, the mapped polygons were
compared to current aerial imagery. No historic imagery in a digital format is currently available
to evaluate the accuracy of the original mapping in a GIS. First, the attributes of the original map
polygons were converted to the equivalent Level IV vegetation classes, which resulted in 59
vegetation types (Table 1). Then the mapped vegetation classes were compared to selected areas
on the current high-resolution imagery for the study area and, in general, the mapped Level IV
vegetation classes were quite specific and did not match the range of image signatures in the
current imagery. Given this general lack of concurrence between the Level IV vegetation classes
and the current imagery signatures, the accuracy of the map was assessed at a broader spatial
scale. For this assessment, the 59 mapped Level IV vegetation classes were aggregated into 24
more general vegetation types, which primarily reflect vegetation structure. Based on a visual
spot-check review, this process resulted in a better overall agreement between vegetation classes
and the image signatures on the current imagery. Approximately 550 polygons did not have
vegetation attributes assigned to them in 1987, and vegetation classes were not assigned to those
polygons using the current available imagery. For the purposes of this 2012 study report, those
data were considered missing.
The most common general vegetation classes in the historic vegetation mapping were Open and
Closed Low Shrub types, accounting for 40.1 percent of the entire mapped area. The mapped
Level IV vegetation classes indicate that the majority of the low-shrub communities were
dominated by willow or shrub birch. Dry Dwarf Shrub also was a common type, accounting for
14.1 percent of the mapped area, presumably as a result of including subalpine and alpine
regions, which are beyond the boundaries of the current mapping study area for the Project.
Open Needleleaf Forest accounted for 10.6 percent of the 1987 map area, and was concentrated
along lower slopes of the Upper Susitna River valley and in low-lying areas at the eastern end of
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 6 February 2013
the map area. The originally mapped Level IV vegetation classes indicate that the needleleaf
forests are mixed stands of white and black spruce.
In 2013 and 2014, to the extent possible, the historic vegetation mapping data will be used to
guide the current mapping of vegetation in the study area and to assist in field-planning efforts
for the Vegetation and Wildlife Habitat Mapping Study. The 1980s vegetation mapping will be
used at the vegetation-structure level (see Table 1), which is roughly equivalent to Viereck Level
III vegetation classes.
5.2. 2012 Field Summary
During summer 2012, two teams of two scientists collected vegetation, wildlife habitat, and
wetlands data during two survey periods: June 19–27 and July 30 –August 8. A total of 276 full
field plots and 85 verification plots were sampled along 36 transects during the two survey
periods. Sixty Level IV vegetation classes were identified and sampled in the 276 field plots
(Table 2).
Field plots were located in six physiographic classes: Alpine, Subalpine, Upland, Lowland,
Lacustrine, and Riverine. The Alpine, Subalpine, and Upland classes occur along a mountainside
topographic gradient ranging in elevation from approximately 4,000 to 500 feet at the valley
bottom. The study area generally follows the broad Susitna and Nenana River valleys and
includes steep mountainsides and crests along the edges. Landforms within the mountainous
regions are typically associated with mass movement (talus slopes) or periglacial processes (frost
features; Dean 1980). Substrates in these areas tend to be rocky and well-drained and the
physiographic classes are typically characterized by distinct differences in plant species
composition (Figure 2). The valley bottoms throughout the study area are predominantly a mix
of Upland (typically drumlinized features) and Lowland (intervening depressions), resulting
from glaciofluvial processes during successive glaciations and de-glaciations (Dean 1980).
Upland surfaces are often comprised of impermeable till material, and the intervening Lowlands
are water bodies (Figure 3) or Wet Graminoid Meadow vegetation composed of obligate wetland
sedges (Figure 4). These same land cover types also may occur along mountain toeslopes.
Riverine physiographic classes include the active floodplains of the Nenana and Susitna rivers
and major tributaries. Lacustrine physiographic classes include lakes and ponds and Fresh Sedge
Marsh vegetation along lake and pond margins.
As with the historic data from the 1987 vegetation map, the 60 Level IV vegetation classes
identified in 2012 were consolidated into a smaller set of 18 more general vegetation types
(Table 2).
Wet Graminoid Meadow (n=55 field plots)—including subalpine tundra, lacustrine marsh, and
lowland meadows—was the most abundant general vegetation type sampled. Wet Graminoid
Meadow communities were dominated by sedges, either coarse robust sedges (e.g., Carex
aquatilis and C. sitchensis) or smaller and more delicate sedges (e.g., Tricophorum cespitosum,
Carex chordorrhiza, C. limosa, and C. magellanica), often with subdominant shrubs.
Low and tall shrub communities in both open and closed forms were also commonly sampled.
The low shrub communities tended to be dominated by shrub birch or ericaceous species (Figure
5); willow-dominated communities were less abundant and associated primarily with rivers and
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 7 February 2013
streams. Closed Tall Shrub communities were primarily tall alder and alder–willow vegetation
types.
Moist Dwarf Shrub (ericaceous), Needleleaf Woodland, and Open Needleleaf Forest also
accounted for a significant portion of the plots sampled in 2012. The needleleaf forest types
range from woodland canopy cover (10–25 percent cover) to open canopy cover (26–60 percent
cover). The dominant tree species include both white and black spruce. For habitats with
woodland canopies, the trees may be stunted and dwarfed with a relatively open understory or an
understory composed of tall closed shrub. Needleleaf woodlands and forests occupy lower and
middle slopes and raised ridges in glacially modified terrain.
5.3. 2012 Mapping Efforts
The mapping of vegetation types in the study area in 2012 was initiated after the field season and
will be continued in 2013, along with the mapping of physiography, surface form, and
disturbance classes. In 2013, preliminary wildlife habitats will be derived after substantial
mapping of vegetation types, physiography, surface form, and disturbance classes has been
completed, and after the relationships among those variables in the study area has been
established. The preliminary vegetation and wildlife habitat types mapped in the study area will
be presented for review in the ISR, to be filed with FERC in February 2014.
6. DISCUSSION
The vegetation and wildlife habitat data collected in 2012 represent the first year of work in a
multi-year mapping study of vegetation and wildlife habitats for the Project. The data from 2012
will be combined with those collected in 2013 and 2014 to prepare comprehensive vegetation
and wildlife habitat maps for the Project. The data collected in 2012 also served as a guide for
planning the 2013 and 2014 field programs for this study.
7. REFERENCES
ABR, Inc. 2013. Wetland Mapping Study in the Upper and Middle Susitna Basin. Susitna-
Watana Hydroelectric Project FERC Project No. 14241. February 2013. Prepared for the
Alaska Energy Authority by ABR, Inc, Anchorage, Alaska.
AEA (Alaska Energy Authority). 2012a. Vegetation and Wildlife Habitat Mapping Study.
Susitna-Watana Hydroelectric Project FERC Project No. 14241. May 2012.
http://www.susitna-watanahydro.org/wp-content/uploads/2012/05/B-
S1_2012_VegWildlifeHabMap_SP_2012-02-02.pdf.
AEA. 2012b. Vegetation and Wildlife Habitat Mapping Study in the Upper and Middle Susitna
Basin. Revised Study Plan: Susitna-Watana Hydroelectric Project FERC Project No.
14241, Section 11.5. December 2012. Prepared for the Federal Energy Regulatory
Commission by the Alaska Energy Authority, Anchorage, Alaska.
Dean, K. G. 1980. Surficial Geology of the Susitna-Chulitna River Area, Alaska. Part I: Text.
Prepared for Land and Resource Planning Section, Division of Research and
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Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 8 February 2013
Development, Alaska Department of Natural Resources. University of Alaska, Fairbanks,
AK. 36 pp.
Jorgenson, M. T., J. E. Roth, S. F. Schlentner, E. R. Pullman, and M. Macander. 2002. An
Ecological Land Survey for Fort Richardson, Alaska. Prepared for U.S. Army Alaska,
Directorate of Public Works, Fort Richardson, AK, by ABR, Inc., Fairbanks, AK. 142 pp.
Kreig and Associates. 1987. Susitna Hydroelectric Project, vegetation mapping final report and
user guide. Report prepared by Ray A. Kreig and Associates, Inc., Anchorage, for Harza–
Ebasco Susitna Joint Venture, Anchorage. 92 pp. [APA Doc. No. 3509]
Munsell Soil Color Charts. 2009. Revised edition. Gretag Macbeth, New Windsor, NY.
USACE (U.S. Army Corps of Engineers). 2007. Regional supplement to the corps of Engineers
Wetland Delineation Manual: Alaska Region (Version 2.0). ERDC/EL TR-07-24.
September 2007. Wetlands Regulatory Assistance Program. U.S. Army Engineer
Research and Development Center, Vicksburg, MS. 130 pp.
Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Technical
Report Y-87-1. Vicksburg, MS: U.S. Army Engineer Waterways Experiment Station.
(http://el.erdc.usace.army.mil/wetlands/pdfs/wlman87.pdf)
Viereck, L. A., and C. T. Dyrness. 1980. A preliminary classification for the vegetation of
Alaska. General Technical Report PNW-106, Portland, OR. U.S. Forest Service, Pacific
Northwest Forest and Range Experiment Station, 38 pp.
Viereck, L. A., C. T. Dyrness, A. R. Batten, and K. J. Wenzlick. 1992. The Alaska vegetation
classification. Gen. Tech. Rep. PNW-GTR-286. Portland, OR: U.S. Department of
Agriculture, Forest Service, Pacific Northwest Research Station. 278 pp.
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
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8. TABLES
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Table 1. General vegetation types.
Derived in 2012 from the historic vegetation map prepared by Kreig and Associates (1987) for
the APA Project.
General Vegetation Type Area (ha) % of Total Area
Water 15,192.5 2.3
Wet Graminoid Meadow 4,533.1 0.7
Moist Graminoid Meadow 1,479.4 0.2
Moist Dwarf Shrub (ericaceous) 4,494.2 0.7
Dry Graminoid Meadow 46.6 <0.01
Dry Forb Meadow 3.9 <0.01
Dry Dwarf Shrub 91,488.3 14.1
Open Low Shrub 138,118.4 21.4
Closed Low Shrub 121,113.6 18.7
Open Tall Shrub 17,192.2 2.7
Closed Tall Shrub 17,422.1 2.7
Dwarf Forest Woodland 3,213.7 0.5
Open Dwarf Forest 9,939.6 1.5
Closed Dwarf Forest 1,493.0 0.2
Broadleaf Woodland 546.2 0.1
Mixed Woodland 3,466.1 0.5
Needleleaf Woodland 24,584.5 3.8
Open Mixed Forest 19,918.2 3.1
Open Broadleaf Forest 1,347.9 0.2
Open Needleleaf Forest 68,838.0 10.6
Closed Mixed Forest 19,717.7 3.0
Closed Broadleaf Forest 2,989.8 0.5
Closed Needleleaf Forest 12,832.9 2.0
Barrens 44,802.7 6.9
No Attributes 21,926.9 3.4
TOTAL 646,701.4 100.0
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
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Table 2. General vegetation types and Level IV vegetation classes.
From Viereck et al. (1992) identified in the vegetation and wildlife habitat mapping study area,
Susitna-Watana Hydroelectric Project, Alaska, 2012. Level IV vegetation classes are nested below
each general vegetation type. Samples sizes (n) are the number of field plots of each type sampled.
General Vegetation Types and Level IV Vegetation Classes Code n
Water
Water W 1
Wet Graminoid Meadow
Fresh Sedge Marsh Hgwfs 7
Subarctic Lowland Graminoid–Herb Wet Meadow Hgwgh 1
Subarctic Lowland Sedge Bog Meadow Hgwsb 11
Subarctic Lowland Sedge Wet Meadow Hgwsl 16
Subarctic Lowland Sedge–Moss Bog Meadow Hgwsmb 8
Subarctic Lowland Sedge–Shrub Wet Meadow Hgwss 8
Wet Sedge Meadow Tundra Hgwst 2
Wet Sedge–Willow Tundra Hgwswt 2
Moist Graminoid Meadow
Bluejoint Meadow Hgmb 2
Bluejoint–Shrub Hgmbs 3
Moist Seral Grass–Herb Meadow Hgmgh 3
Moist Grass–Herb Meadow Tundra Hgmght 1
Moist Sedge–Shrub Tundra Hgmss 2
Moist Sedge–Willow Tundra Hgmswt 3
Dry Graminoid Meadow
Midgrass–Herb Hgdgh 1
Moist Dwarf Shrub (ericaceous)
Bearberry Dwarf Shrub Tundra Sdeb 1
Cassiope Dwarf Shrub Tundra Sdec 1
Crowberry Dwarf Shrub Tundra Sdee 2
Ericaceous–Lichen Dwarf Shrub Tundra Sdel 4
Ericaceous Dwarf Shrub Tundra Sdet 4
Vaccinium Dwarf Shrub Tundra Sdev 3
Willow Dwarf Shrub Tundra Sdwt 1
Dry Dwarf Shrub
Dryas–Sedge Dwarf ShrubTundra Sdds 1
Dryas Dwarf Shrub Tundra Sddt 4
Open Low Shrub
Open Low Mesic Shrub Birch–Ericaceous Shrub Slobe 32
Open Low Shrub Birch–Willow Slobw 1
Open Low Sweetgale–Graminoid Bog Slocg 2
Open Low Ericaceous Shrub Bog Sloeb 7
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General Vegetation Types and Level IV Vegetation Classes Code n
Open Low Willow Slow 7
Open Low Willow–Graminoid Shrub Bog Slowg 1
Closed Low Shrub
Closed Low Shrub Birch–Ericaceous Shrub Slcbe 6
Closed Low Shrub Birch–Willow Slcbw 1
Closed Low Sweetgale Meadow Slcm 1
Closed Low Willow Slcw 1
Open Tall Shrub
Open Tall Alder Stoa 12
Open Tall Alder–Willow Stoaw 2
Open Tall Shrub Birch Stob 7
Open Tall Scrub, post burn or disturbance Stod 1
Open Tall Willow Stow 8
Closed Tall Shrub
Closed Tall Alder Stca 14
Closed Tall Alder–Willow Stcaw 4
Closed Tall Willow Stcw 9
Dwarf Forest Woodland
Dwarf Black Spruce Woodland Sfwbs 1
Open Dwarf Forest
Open Dwarf Black Spruce Sfobs 2
Open Dwarf White Spruce Sfows 1
Open Broadleaf Forest
Open Quaking Aspen Forest Fboa 1
Open Paper Birch Fbob 2
Open Paper Birch–Balsam Poplar Fbobp 1
Open Balsam Poplar Fbop 2
Closed Broadleaf Forest
Closed Aspen–Balsam Poplar Fbcap 1
Needleleaf Woodland
Black Spruce Woodland Fnwbs 16
White Spruce Woodland Fnwws 14
Open Needleleaf Forest
Open Black Spruce Fnobs 9
Open White Spruce Fnows 2
Open Mixed Forest
Open Paper Birch–Balsam Poplar–Spruce Fmobps 1
Open Spruce–Paper Birch Fmosb 9
Open Spruce–Balsam Poplar Fmosp 1
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
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General Vegetation Types and Level IV Vegetation Classes Code n
Barrens
Barren Bbg 1
Partially Vegetated Bpv 4
TOTAL 276
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FERC Project No. 14241 Page 14 February 2013
9. FIGURES
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Figure 1. Study area and completed 2012 sampling transects for the Vegetation and Wildlife Habitat Mapping Study.
The Project area boundary shown is the version dated October 26, 2012, but the 5-mile buffer for the study area was drawn from the April 13, 2012 version of the Project area
boundary. In 2013 and 2014, a smaller 4-mile buffer study area will be used as noted in RSP Section 11.5 in AEA (2012b).
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
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Figure 2. Typical topo sequence in the Vegetation and Wildlife Habitat Mapping Study area, 2012.
Rocky, exposed, partially-vegetated areas in the Alpine physiographic class at the ridge crest, grading into the Subalpine class,
which is characterized primarily by low and tall shrub plant communities.
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Figure 3. View of valley floor drumlinized terrain in the Vegetation and Wildlife Habitat Mapping Study area, 2012.
The intervening troughs between raised drumlin ridges are often water bodies or wet graminoid plant communities.
FINAL REPORT VEGETATION AND WILDLIFE HABITAT MAPPING
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Figure 4. Wet Graminoid Meadow typical of inter-drumlin troughs found within the Lowland physiography class in the
Vegetation and Wildlife Habitat Mapping Study area, 2012.
2012 STUDY SEASON VEGETATION AND WILDLIFE HABITAT MAPPING
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FERC Project No. 14241 Page 19 February 2013
Figure 5. Low deciduous shrub communities commonly found on low slopes and valley bottoms in the Vegetation and
Wildlife Habitat Mapping Study area, 2012.
Willows and shrub birch are often the dominant shrub taxa.