HomeMy WebLinkAboutAPA420.__._-_..__.__........•............_-_....._-_.__.._-----_··········--l
:=:::::q=1'o
=(0=(0
~(Y)
~==-==O"'=0 c 0
~I.!)
~ SUS~TNAi!!!!!!!!S5iiS;(Y)
(Y)
!
I i
l
I
I Prl!P2:,ad tel":
I.I II.
• --.-......lII'Jlm!
HYDROELECTR!C PROJECT
ENVIRONMENTAL t=1l:poP.'r
TASK 7: ENV!AONMENTAL
PLANT ECOLOGY -Hl80
MAy' 1981
Tetre,biel
i ftvitOtl"..!·fttal
$p~(j;iaU/t/. It=)•
---.t\Lr\SKA POV'iER }\UTHORITY _.._...
i
i
i
I.
_
>r"""'"',
-
"1--__
ENVIRONMENTAL STUDIES ANNUAL REPORT 1980
SUBTASK 7.12 PLANT ECOLOGY STUDIES
MAY 1981
Yerle,trial
EnvironMental
Speciali,t"Inc.
-
-
N
M,.....
coco
M
ooo
LO
LO,.....
M
M
AR~l..JIS
Alaska Resources
Library &Information ServIces
Anchorage,Alask~t
ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
ENVIRONMENTAL STUDIES ANNUAL REPORT 1980
SUBTASK 7.12 PLANT ECOLOGY STUDIES
MAY 1981
by
UNIVERSITY OF ALASKA
Agricultural Experiment Station
Palmer,Alaska 99645
and
TERRESTRIAL ENVIRONMENTAL SPECIALISTS,Inc.
Phoenix,New York 13135
for
ACRES AMERICAN,INCORPORATED
Liberty Bank Building,Main at Court
Buffalo,New York 14202
-
-
SUMMARY
The vegetation/habitat types found in the Upper Susitna River Basin and
the floodplain down to Talkeetna ~ere described,classified,and mapped.
Reconnaissance of many locations throughout the study area was made in
summer 1980 to obtain information on species composition and community
structure.Ocular estimates of the cover of each species in each layer
of vegetation were made,and these data were used to classify the vege-
tation according to the system developed by Viereck and Dyrness (1980).
High altitude (U2)color infrared photography and LANDSAT imagery were
used to map the vegetation cover types.Maps were produced at the
scales of 1:250,000 and 1 :24,000 for the entire basin and direct impact
areas,respectively.Additionally,the area extending 16 km in any
direction from the proposed impoundment areas is in the process of being
mapped at a scale of 1:63,360.A 1:24,000 scale map of apparent wet-
lands was also produced,based on the 1 :24,000 scale vegetation map and
the wetlands classification system (Cowardin et ~.1979)used by the
U.S.Fish and Wildlife Service.
Results of reconnaissance surveys of the vegetation/habitat types show
that at least 243 species in 130 genera and 55 families are present in
the Upper Susitna River Basin.Of these 21 represented extensions of
the previously known ranges ?f the species.Special effort was made to
locate any species which are currently under review by theU.S.Fish
and Wildlife Serivce for possible status as endangered or threatened.
Although some potential habitats of these species were located,none of
the species were found.Foot and helicopter surveys were also made of
several lakes and ponds within the direct impact areas to determine the
composition and structure of plant communities occurring in or near the
water.
The major vegetation/habitat types found in the study area are low mixed
shrub,woodland and open black spruce,sedge-grass tundra,mat and
cushion tundra,and birch shrub.These vegetation/habitat types are
typical of what is found covering vast areas of Alaska and northern
Canada.Characteristically,these types are found on cold,wet soils
ARLISAla,,,i,,,R
L "b ,,1'.<:\.esour.1 rary o.f ...ces
.Ui."'f'.J fCH 11"a--I'Si\,.,''."<-<on ervl
n...f.n hi ~r;H.'.f:'.."'.1 k ces.,~,,-~as a
--
.-
and exhibit slow or stunted growth.Less than 3%of the area is vege-
tated by deciduous or mixed conifer-deciduous forests which,by con-
trast,have more robust growth characteristics.Deciduous and mixed
conifer-deciduous forests occur primarily along the Susitna River where
soils are better drained and a longer growing season exists.Conse-
quently,a large portion of deciduous and mixed forests found in the
study area will be destroyed by the proposed impoundments.Other vege-
tation/habitat types --mixed shrub,birch shrub,tall shrub,and
spruce --will also be lost by inundation,but in small degree relative
to their availability across the entire Upper Susitna River Basin.
If that vegetation/habitat which is destroyed is found to have con-
siderable importance as browse for moose,there may be some opportunity
to create replacement browse supplies in adjacent areas either by
burning or by clearing to stimulate regrowth of palatable shrubs.
Generally speaking,however,losses of vegetation can not be mitigated.
However,in those situations where the vegetation is only temporarily
destroyed (eg:construction sitesy roads,and borrow sites)revegetation
by mulching and seeding with native -species may quickly restore ground
cover.Natural revegetation following fertilization also appears prom-
ising in mitigating temporary losses of vegetation.
-
TABLE OF CONTENTS
SUMMARY
LIST OF TABLES
LIST OF FIGURES
Page
1 -INTRODUCTION ---------------------------------------------------1
2 -METHODS --------------------------------------------------------2
2.1 -Definition of Study Area ---------------------------------2
2.2 -Vegetation Cover/Habitat Mapping -------------------------2
2.3 -Qualitative Assessments ----------------------------------4
2.3.1 -Sampling Locations -------------------------------------4
2.3.2 -Vegetation Characteristics -----~-----------------------7
2.3A3 -Physical Characteristics -------------------------------7
2.3.4 -Wildlife Habitat ---------------------------------------8
2.3.5 -Wetlands -----------------------------------------------9
2.4 -Endangered and Threatened Species ------------------------9
3 -RESULTS AND DISCUSSION OF BASELINE STUDY -----------------------11
3.1 -Introduction ---------------------------------------------11
3.2 -General Description of Study Area ------------------------11
3.3 -Floristics -----------------------------------------------13
3.4 -Preliminary Vegetation/Habitat Type Maps -----------------13
3.5 -Preliminary Vegetation/Habitat Type Descriptions ---------28
3.5.1 -Forest Types -------------------------------------------28
3.5.2 -Tundra Types ----------------------------------.;.--------46
3.5.3 -Shrubland Types ----------------------------------------53
3.5.4 -Herbaceous Types ---------------------------------------60
3.5.5 -Unvegetated Types --~-----------------------------------61
3.6 -Wetlands ---------------~---------------------------------61
3.6.1 -Identification and Mapping of Wetlands -----------------61
3.6.2 -Vascular Aquatic Plants --------------------------------62
3.6.2.1 -Introduction -----------------------------------------62
3.6.2.2 -Results and Discussion -------------------------------66
3.7 -Endangered,Threatened,Rare,and Noteworthy Species -----71
3.7.1 -Endangered,Threatened,and Rare Species ---------------71
3.7.2 -Noteworthy Species -------------------~-----------------78
4 -IMPACT ASSESSMENT ----------------.;.-----------------------------82
4.1 -Construction Impacts -------------------------------------82
4.2 -Operation Impacts ----------------------------------------84
4.2.1 -Impoundment Areas --------------------------------------84
4.2.2 -Downstream Floodplain ----------------------------------84
5 -MITIGATION -----------------------------------------------------86
5.1 -Avoidance ------------------------------------------------86
5.2 -Compensation ---~-----------------------------------------86
6 -REFERENCES -----------------------------------------------------88
7 -AUTHORITIES CONTACTED ------------------------------------------92
LIST OF TABLES
Table Page
1.Vegetation/habitat types (and sample location numbers)
sampled in Upper Susitna River Basin,1980.----------------5
2.Preliminary list of plant species,identified during summer
1980 in Upper Susitna River Basin.-------------------------14
3.Hectares and percentage of total area covered by vegetation/
habitat types on 1 :250,000 scale map (Figure 3).-----------25
4.Hectares of different vegetation types to be impacted
compared with total nectares of those types in the entire
Upper Susitna River Basin.---------------------------------26
Cover percentages for total vegetation,vertical strata,and
plant species in woodland conifer vegetation/habitat type in
Upper Susitna River Basin.---------------------------------31
Cover percentages for total vegetation,vertical strata,and
plant species in open conifer vegetation/habitat type in
Upper Susitna River Basin.---------------------------------30
Cover percentages for total vegetation,vertical strata,and
plant species in open black spruce vegetation/habitat type
in Upper Susitna River Basin.------------------------------33
5.
,-
6.-
,~ft!J,.7.
8.Cover percentages for total vegetation,vertical strata,and
plant species in open white spruce vegetation/habitat type
in Upper Susitna River Basin.------------------------------34
9.Cover percentages for total vegetation,vertical strata,and
plant species in closed deciduous forest (birch and balsam
poplar)vegetation/habitat type in Upper Susitna River
Basin.-----------------------------------------------------37
10.Cover percentages for total vegetation,vertical strata,and
plant species in open birch deciduous forest vegetation/
habitat type in Upper Susitna River Basin.-----------------38
11.Cover percentages for total vegetation,vertical strata,and
plant species in closed balsam poplar forest vegetation/
habitat type in Upper Susitna River Basin.-----------------40
12.Cover percentages for total vegetation,vertical strata,and
plant species in closed birch deciduous forest vegetation/
habitat type in Upper Susitna River Basin.-----------------41
13.Cover percentages for total vegetation,vertical strata,and
plant species in closed aspen forest vegetation/habitat type
in Upper Susitna River Basin.------------------------------42
LIST OF TABLES (Continued)
Cover percentages for total vegetation,vertical strata,and
plant species in closed mixed conifer deciduous forest
vegetation/habitat type in Upper Susitna River Basin.------44
Cover percentages for total vegetation,vertical strata,and
plant species in open mixed conifer deciduous forest
vegetation/habitat type in Upper Susitna River Basin.------45
16.Cover percentages for total vegetation,vertical strata,and
plant species in wet sedge-grass tundra vegetation/habitat
type in Upper Susitna River Basin.-------------------------48
17.Cover percentages for total vegetation,vertical strata,and
plant species in mesic sedge-grass tundra vegetation/habitat
type in Upper Susitna River Basin.-------------------------49
18.Plant species list in herbaceous alpine tundra in Upper
Susitna River Basin in summer 1980.------------------------51
~Table
14.-
15.
~
-
-
-
19.Cover percentages for total vegetation,vertical strata,and
plant species in closed mat and cushion tundra vegetation/
habitat type in Upper Susitna River Basin.-----------------52
20.Cover percentages for total vegetation,vertical strata,and
plant species in closed tall alder vegetation/habitat type
in Upper Susitna River Basin.--------------------~---------54 -
21.Cover percentages for total vegetation,vertical strata,and
plant species in open tall alder vegetation/habitat type
in Upper Susitna River Basin.---------------------~--------56
22.Cover percentages for total vegetation,vertical strata,and
plant species in closed low shrub vegetation/habitat type
in Upper Susitna River Basin.------------------------------57
23.Cover percentages for total vegetation,vertical strata,and
plant species in open low shrub vegetation/habitat type in
Upper Susitna River Basin.---------------------------------58
24.Vegetation and wetland classes found in the proposed Susitna
impoundment and borrow areas.------------------------------63
25.Aquatic plant survey,Susitna Hydroelectric Project,August
1980.------------------------------------------------------67
26.List of endangered and threatened plant species sought in
the August 1980 survey.------------------------------------73
27.Vascular plant species in the Upper Susitna River Basin
which are outside their range as reported by Hulten (1968).-79
-
LIST OF FIGURES
~1.
2.
1"""
3.
4.
5.
fl-
6.
7.-
8.
9.-
,~
Page
Vegetation mapping areas of Upper Susitna River Basin.------3
Sample locations.-------------------------------------------6
Vegetation map of Upper Susitna River Basin.----~---back pocket
Vegetation map of proposed Susitna Hydroelectric impact
areas.----------------------------------------accompanying maps
Wetland map of Susitna Hydroelectric Project impoundment and
borrow areas.---------------------------------accompanying maps
Locations of lakes and ponds surveyed for vascular aquatic
plants in August 1980.--------------------------------------65
Schematic representation of the dominant vegetation
associated with many lakes and ponds of the Upper Susitna
Basin.------------------------------------------------------72
Areas surveyed for threatened and endangered species in the
Susitna-West Fork Glacier area.----------------~------------75
Areas surveyed for threatened and endangered species in the
Watana Creek-Susitna River area.----------------------------77
,....
-
-
1 -INTRODUCTION
The overall objective of the Plant Ecology Studies is to map and char-
acterize the vegetation/habitat types occurring in the areas to be
affected by the proposed Susitna Hydroelectri~Project,predict impacts
that will result from the proposed facilities,and to provide prelim-
inary mitigation options.Specifically,during 1980 our objectives were
to produce preliminary vegetation maps and qualitative descriptions of
each vegetation type mapped.Additionally,we were to survey the Upper
Susitna River impact areas for plant species currently being reviewed by
the U.S.Fish and Wildlife Service for protection under the Endangered
Species Act of 1973.'
.,-1
-
--
.-
-
2 -t·1ETHODS
2.1 -Definition of Study Area
The area of study during 1980 included all of the Upper Susitna River
drainage and the floodplain of the Susitna River from Gold Creek to
Talkeetna.Some portions of this area were studied more intensively
than others.The scale at which the different areas were mapped is
presented on Figure 1 and gives some indication of how the study effort
was distributed;more attention was given to areas that were mapped at
.larger scales,since these are the areas of direct impact.
2.2 -Vegetation Cover/Habitat Mapping
Vegetation of the entire Upper Susitna River drainage (Figure 1)was
mapped at a scale of 1:250,000.Vegetation adjacent to and within 16
km of the Upper Susitna River was mapped at a scale of 1 :63,360.The
vegetation within the proposed impact areas (i.e.,impoundments,areas
within 0.8 km of impoundments,floodplain from Portage Creek to Talkeetna,
and borrow sites)was mapped at a scale of 1:24,000.The classification
system developed by Viereck and Dyrness (1980)was utilized in the
mapping effort.
to1apping at all three scales began with the entire Upper Susitna River
drainage being subdivided into major physiographic regions by the inter-
pretation of winter and summer LANDSAT imagery.Vegetation units on
1:120,000 scale high altitude (U-2)color infra-red (erR)photography of
representative areas of each physiographic region were then delineated and
identified according to Viereck and Dyrness (1980).The 1 :120,000 scale
prints,with attached overlays,were then taken into the field and as
many delineated vegetation units verified as possible;field checks were
distributed across each of the major physiographic regions,with em-
phasis being placed on those vegetation types which were IllOSt difficult
2
1 1 )')1 })1 .,~l I -..~1 1 »1,
::..~rII.l~......!'~,..
"'\~
TO CANTWELL-
...:-....~:.~.l:.
'.W'.
·.mrl\
KEy'
mii:!:i'!i}ii!ii!:!;tl
111111111
W22L1
,J'fI':"':~J4:\t,
SCALES
1:2.4,000
1:63,360
1:250,000
SCALE
,.,.........==:J
o :I 10 '1:1 20 MILES
·1
I Arn 'l,·t r 1-r 1~,\"\,-\.~
r~/.
!';;
.......-.../I.~>)..
(7'~,A!''
(.WEST A'J',
10/1~~~)
A )
I'"(\\A,"'i)
(
BASIN.BOUNDARY r<'r~l\~~':)...'I""~*'.,~""\<\1\1,'\\,,{~,,-..(.1-
-$-<Il'l'~~.\\',-(,,",,It~'::"-."~....CREE .?"'...;~O ~C-.......'\U1"\'E K DENALI HIGHWAY ~
....c:...~',,~-,~~EE'I;.·4f ~
",,';j 111111111 "":::.!R«lY ,,i'l 11111.I1l1t 1111 ,..I _#~:s
-.";:;.:;J--y
""-;;1---
......:::J~
..,,:;,""'"--e:;.:..-,
:'\
.~
y ~3"11111111 \'~..i '[r1 ""';:.).""
-<V J ~~L..>..j
~~
(/~
~.F?~Y.SUSITNA .\).~
i LAKE y'~~~
V y .(j LOUISE:
r,~~.I-LJ-l...L..L L.L ~LJ
It'1tv IJ.FIGURE IY~II VEGETATION MAPPING AREAS
(l2L ,0./L~.f<'(L..IJ.J\,UI UPPER SUSIT~:RIVER BASIN
w
":;{'
-
.-
r
I
to interpret on aerial photography;helicopter availability also was a
factor in determining which areas could be checked.Enlargements of the
1:120,000 scale eIR photography at the 1 :24,000 and 1 :63,360 scales were
obtained as transparencies,and vegetation units were then redelineated
on mylar overlays.The 1 :250,000 scale mapping was done on an overlay
of a summer LANDSAT image;in each case,field-checked copies of the
1:120,000 scale eIR prints were consulted for more accurate delineation
of vegetation types.Experience gained during the summer in inter-
preting the tones and textures of eIR prints was also used in the re-
mapping of the vegetation.Finally,overlay maps were traced on subdued
positive transparencies of corresponding USGS topographic maps,thus
producing final maps which could later be duplicated.The 1:63,360
scale map has not reached this final stage of completion.
2.3 -Qualitative Assessments
2.3.1 -Sampling Locations
Reconnaissance level surveys were made of each major vegetation
type.Areas surveyed were selected based on the aerial photo-
graphy.Some areas were chosen because we were unsure of what
vegetation type was represented by certain colors and textures on
the photographs.Others were selected because more sample points
were needed in a particular vegetation type.The desired number
of sample points in a vegetation type was based on extent of that
type and on severity of impact from the Susitna Hydroelectric
Project.In other words,more points were sampled in vegetation
types of large extent and in the impoundment areas.The actual
.sample area was chosen because of its homogeneity.The size of an
area sampled depended on the size of the homogeneous area,the
number of people sampling the area,and the available time.The
areas and types sampled during the 1980 field season (June,July,
and August)are indicated on Table 1 and Figure 2.
4
Table 1
Vegetation/habitat types (and sample location numbers)sampled in
Upper Susitna River Basin,1980.
Vegetation/habitat Type
Mat and cushion tundra
Sedge-grass tundra
Herbaceous tundra
Wet sedge-grass
Open black spruce
Woodland black spruce
Open white spruce
Woodland white spruce
Closed birch forest
Open birch forest
Closed balsam poplar
Open balsam poplar
Closed aspen
Closed mixed conifer-deciduous forest
Open mixed conifer-deciduous forest
Closed tall shrub
Open tall shrub
Low shrub
Willow shrub
Sample Location Number a/
1-8
9-10
11
12-14
15-17
18-22
23-27
28
29-32
33-34
35-36
37
38
39-41
42-49
50-52
53
54-62
63-64
""""I
~Sample locations are given in Figure 2.
5
J]~-lJ
J
I
"...__"....I
..J ..J ...._--~"..
j
TO CANTWELL_
J
2.0MILES
I
1510
SCALE
5o
Figure 2.
Vegetation/habitat types
sample locations in
Upper Susitna River Basin~1980.
J
I
i
r~_~,---'\.I"./..-.....,'\
,..._/.,
)'I
".II ,I J \
L,\",.",-r"
I \
I IIWEST"",(~O1>I'n ~\.
I ,~
J
C"I
2.3.2 -Vegetation Characteristics
Species composition and community structure information was
collected at each area sampled.Ocular estimates were made of
the cover of each plant species in each layer of vegetation.Cover
is the vertical projection of living plant parts on the ground and
is measured as a percentage of area covered.The ground layer
consisted of all herbaceous species and all woody species less than
0.5 m tall.The shrub layer consisted of woody species taller than
0.5 m but less than 2.5 cm dbh (diameter breast height).Under-
story vegetation was woody species between 2.5 cm and 10.0 cm dbh.
Overstory vegetation consisted of species larger than 10.0 cm dbh.
"Shrub layer"refers to a layer of vegetation whereas the term
"s hrub ll refers to the life form of woody species not considered
trees such as Betula glandu10sa,~.nana,Alnus spp.,Empetrum
nigrum,and others.Some tall shrubs such as Alnus may be taller
than short trees such as Picea mariana which occurred scattered in
wet areas.Hence,height is not a good distinguishing charac-
teristic for these life forms in this vegetation.
A woody species could occur in anyone or combination of layers in
a given stand.Cover was also estimated for each layer of vege-
tation without regard to species.Cover values are not additive
because of overlapping layers.In other words,if a species has
15%shrub layer cover and a 10%ground layer cover,its overall
cover would be at least 15%but may be less than 25%if parts of
the taller individuals occur above the shorter individuals.
Similarly,the sum of the cover percentages in a stand may exceed
100%.
2.3.3 -Physical Characteristics
The objective of this portion of the qualitative assessment was to
collect data that would describe characteristics of the physical
7
.-
environment which could be closely associated with the occurrence
of a particular vegetation/wildlife habitat type.One person on
the survey team was assigned to record the physical variables at
each site where the vegetation was described.Elevation was deter-
mined from topographic maps or the altimeter of the helicopter.
Degree of slope typical of the site was measured with an ABNEY
level.Aspect was determined with the use of a compass and re-
corded in degrees.Position was also recorded with reference to
elevational location of the site with respect to the land form on
which it occurs (e.g.canyon site;mid,upper,or lower level;
mountain top;etc.).
Soil pits were dug whenever time permitted,and the horizons of
each described in terms of depth,texture,color,wetness,and
structure.Texture and color were described in common soil clas-
sification terms.Wetness was recorded as saturated,wet,moist,
or dry.The pits were dug to a depth of at least 30 cm or until
frost or rock was encountered.Parent material was identified in
each case.In addition,core samples of approximately 20 cm depth
were taken from 5 to 8 locations within the site.The samples were
placed in a common plastic bag,labelled,and sealed for later
texture and chemical analysis.They were stored in a cool place.
2.3.4 -Wildlife Habitat
The focus of this part of the qualitative assessment was descrip-
tion of ungulate habitat values for each community/habitat type.
Secondarily,record was made of presence or sign of other wildlife
species,such as birds,small mammals,and bears.
Available browse,browse utilization,browse vigor,pellet groups,
and comments relative to wildlife habit~t were recorded.Specifics
are discussed in the Plant Ecology Procedures Manual (p.13).
8
2.3.5 -Wetlands
All land within the proposed impact areas was also classified
according to Cowardin et~.(1979)into appropriate wetland
classes.A map delineating wetland types was constructed using the
vegetation/habitat maps following the same procedures given in
Section 2.2.The only difference was that the vegetation units
were replaced with appropriate wetland classes.This was done with
little consideration of soil moisture conditions,since this infor~
mation was mostly unavailable to us.Presence of steep slope and
likely good drainage was interpreted to rule out classification as
wetland in some cases where the vegetation cover did indicate the
possibility of wetland.Obviously,this is a very risky procedure
without actual soils data for interpretation.
Foot surveys were made of several ponds and lakes and their peri-
pheral wet areas within the impoundment areas and adjacent uplands.
During the surveys,species composition,dominance and total cover
(relative to amount of water)were estimated.Elevation,estimated
rooting depth,and width of surrounding wetland were recorded.
Surrounding wetland was limited by definition to the Lacustrine-
Limnetic-Emergent Wetland-Vascular wetland class of Cowardin et~.
(1979).Many of the remaining ponds and lakes,not surveyed on
foot,were examined by helicopter overflights to ensure similarity
among ponds and to search for new species.
2.4 -Endangered and Threatened Species
No plant species are presently officially listed for Alaska by federal
or state authorities as endangered or threatened,however,37 are cur-
rently under review by the U.S.Fish and Wildlife Service (USF&WS
1980).Most of these species were also discussed by Murray (1980).The
general habitat requirements and occurrence of these plant species were
known from previous taxonomic and ecological studies in Alaska and from
9
information on the Alaskan flora by Hulten (1968).Following a review
of this information and contact \"lith local experts,10 species 'that could
possib1y occur in the phytogeographic region of the Upper Susitna River
were identified.Potential habitat for these species was then selected
for closer investigation.
In August 1980,a helicopter and foot survey was made of each of the
selected areas.Special attention was given to micro sites where the
species in question might occur.Since calophytic species could possibly
occur,soils having free carbonates were located by using geologic maps
which indicated calcareous rock materials and by testing with 10%hydro-
chloric acid.
10
r-
I
I'"'"",
3 -RESULTS AND DISCUSSION OF BASELINE STUDV
3.1 -Introduction
During summer 1980,preliminary maps and descriptions of vegetation/
habitat types were constructed for approximately 4 million acres of
forest,shrub and tundra lands in the Upper Susitna River Basin.
Vegetation/habitat information includes descriptions of flora,threat-
ened and endangered species,physical site characteristics,wetlands,
and aquatic species.
3.2 -General Description of Study Area
The Upper Susitna River Basin is located in the Pacific Mountain physio-
graphic division in southcentral Alaska (Joint Federal-State Land Use
Planning Commission for Alaska 1973).The Susitna River drains parts of
the Alaska Range on the north and parts of the Talkeetna Mountains on
the south.Many areas along the east-west portion of the river,between
the confluences of Portage Creek and the Oshetna River,are steep and
covered with conifer,deciduous,and mixed conifer and deciduous forests.
Flat benches occur at the tops of these banks and usually contain low
shrub or woodland conifer communities.Low mountains rise from these
benches and are covered by sedge-grass tundra and mat and cushion tundra.
The southeastern portion of the study area between the Susitna River and
Lake Louise is characterized by extensive flat areas covered with low
shrubland and woodland conifer communities which are often intermixed
and difficult to distinguish in the field or on aerial photographs
because of intergradations.The area along the Susitna River between
the ~~aclaren River and the Denali Highway is covered with woodland and
open spruce stands. Farther east the area has more low shrubland cover.
The Clearwater Mountains north of the Denali Highway have extensive
tundra vegetation.The floodplain of the Susitna River north of the
11
"..,
,,,,,",
..
Denali Highway has woodland spruce and willow stands.The Alaska Range
contains most of the permanent snowfields and glaciers in the study
area.
The steep portions and some adjacent areas along the east-west portions
of the river are considered in the closed spruce-hardwood forest type of
Viereck and Little (1972),the moderately high mixed evergreen and
deciduous forest map unit of Spetzman (1963),and the upland spruce
hardwood forest of the Joint Federal-State Land Use Planning Commission
of Alaska (1973).This type of vegetation is found mainly along rivers
in the southcentral and interior regions of the state.
The benches bordering the east-west portion of the river and the area
around the Maclaren River are classified as moist tundra in all three of
the previously mentioned maps.This moist tundra classification in-
cludes herbaceous meadows as well as shrub dominated areas.These areas
occur around the Brooks Range,on the Seward Peninsula,and near the
Killuck Mountains.
The extensive flats in the lower Oshetna River and Lake Louise areas are
considered open,low growing spruce forests by Viereck and Little (1972),
low mixed evergreen and deciduous forests by Spetzman (1963),and low-
land spruce-hardwood forests by the Joint Federal-State Land Use Planning
Commission of Alaska (1973).Viereck and Little's (1972)description
appears most appropriate since the area is covered primarily by spruce
stands with treeless bogs.This type generally occurs just above the
closed spruce-hardwood stands (Viereck and Little 1972)or the bottom-
land spruce poplar stands (Joint Federal-State Land Use Planning Com-
mission of Alaska 1973).
The vegetation along the lower mountains and the lower slopes of the
higher mountains was classified as alpine tundra by Viereck and Little
(1972)and the Joint Federal-State Land Use Planning Commission (1973)
and barren and sparse dry tundra by Spetzman (1963).Some of these
areas were mapped as rock while other areas were mapped as sedge-grass
tundra or mat and cushion tundra in this study,whereas the previous
12
-I
maps included the rock in the alpine tundra.Some areas which were
mapped as rock do have some important pioneering species growing in
crevices,but the plants provided neglible ground cover.This vege-
tation grows on mountains throughout the state.
3.3 -Floristics
Table 2 contains a preliminary list of plant species which have been
tentatively identified from the Upper Susitna River Basin.There are
243 vascular plant species occurring in 130 genera in 55 families.Some
collected specimens have yet to be identified and others need to be
verified by experts in the field.This is particularly true for the
Carex and Salix genera.The families which contained the most species
were Compositae,Salicaceae,Rosaceae,Gramineae,Cyperaceae,and
Ericaceae.The Salicaceae family was also important from the standpoint
of canopy cover,wildlife usage,and pioneering on gravel bars,whereas
the Compositae contributed relatively minor cover.The genus Salix
contained 17 species,tentatively,while Carex had 10 species and
Saxifraga had 9 species.
Seven genera of lichen which included at least 11 species were identi-
fied while five taxa of mosses were identified.More extensive work on
lichens and mosses will likely identify many more species of mosses and
lichens.
3.4 -Preliminary Vegetation/Habitat Type Maps
The two vegetation/habitat maps that have been produced to date are the
1:250,000 scale (Figure 3 -see back packet)and 1 :24,000 scale (Figure
4 -see accompanying map).The 1:63,360 scale map is currently nearing
completion.
It should be noted that there is seldom a distinct line of demarcation
between vegetation/habitat types when viewed on aerial photographs or in
13
Table 2
Preliminary list of plant ~pecies,identified during summer 1980 in
Upper Susitna River Basin.-
Pteridophyta
Aspidiaceae
Dryopteris dilatata (Hoffm.)Gray
Dryopteris fragrans (L.)Schott
Gymnocarpium dryopteris (L.)Newm.
Athyriaceae
Cystopteris fragilis (L.)Bernh.
Cystopteris montana (Lam.)Bernh.
Woodsia alpina (Bolton)S.F.Gray
Equisetaceae
Equisetum arvense L.
Equisetum fluviatile L.ampl.Ehrh.
Equisetum pratense L.
Equisetum silvaticum L.
Equisetum variegatum Schleich.
Isoetaceae
Isoetes muricata Our.
Lycopodiaceae
Lycopodium alpinum L.
Lycopodium annotinum L.
Lycopodium clavatum L.
Lycopodium complanatum L.
Lycopodium selago L.ssp.selago
Gymnospermae
Cupressaceae
Juniperus communis L.
Pinaceae
Picea glauca (Moench)Voss
Picea mariana (Mill.)Britt.,
Sterns &Pogg.
14
Shield fern
Fragrant shield-fern
Oak-fern
Fragile-fern
Mountain fragile-fern
Alpine woodsia
Meadow horsetail
Swamp horseta i1
Meadow horsetail
Woodland horsetail
Variegated scouring-rush
Quillwort
Alpine clubmoss
Stiff clubmoss
Running clubmoss
Ground cedar
Fir clubmoss
Common juniper
White spruce
Black spruce
.-
-
Monocotyledoneae
Cyperaceae
Carex aquatilis Wahlenb.
Carex bigelowii Torr.
Carex cap;llar;s L.
Carex concinna R.Br.
Carex f;lifolia Nutt.
Carex limosa L.
Carex loliacea L.
Carex membranacea Hook.
Carex podocarpa C.B.Clarke
Carex rhynchophysa C.A.Mey.
Carex spp.
Er;ophorum angustifolium Honck.
Eriophorum scheuchzeri Hoppe
Er;ophorum vaginatwn L.
Tr;chophorum caespitosum (L.)
Hartm.
Gramineae
Agropyron Spa
Agrostis scabra Willd.
Afrost;s Spa
A opecurus alpinus Sm.
Arctagrostis latifolia (R.Br.)
Griseb.
,Calamagrostis canadensis (Michx.)
Beauv.
Calamagrostis purpurascens R.Br.
Danthonia intermed;a Vasey
Oeschampsis/·atropurpurea (Wahlenb.)
Scheel~
Deschampsia caespitosa (L.)Beauv.
Festuca alta;ca Trin.
Festuca rubra L.Call.
Hierochloe alpina (Swartz)Roem.&
Schult.
Hierochloe odorata (L.)Wahlenb.
Phleum commutatum Gandoger
Poa arct;ca R.Br.
Poa palustris L.
Trisetum spicatum (L.)Richter
Iridaceae
Iris setosa Pel las
15
Water sedge
Bigelow sedge
Hairlike sedge
Low northern sedge
Thread-leaf sedge
Shore sedge
Sedge
Fragile sedge
Short-stalk sedge
Sedge
Sedge
Tall cottongrass
White cottongrass
Tussock cottongrass
Tufted clubrush
Wheatgrass
Tickle grass
Bent grass
Mountain foxtail
Polargrass
Bluejoint
Purple reedgrass
Timber oatgrass
Mountain hairgrass
Tufted hairgrass
Fescue grass
Red fescue
Alpine holygrass
Vanilla grass
Timothy
Arctic bluegrass
Bluegrass
Downy oatgrass
Wi 1d i ri s
Juncaceae
Juncus arcticus Willd.
Juncus castaneus Sm.
Juncus drummondii E.r1ey.
Juncus mertensianus Bong.
Luzula campestri~/(L.)DC.
ex DC.&Lam.-
Luzula confusa Lindeb.
Luzula multiflora (Retz.)Lej.
Luzula parviflora (Ehrh.)Desv.
Luzula tundricola Gorodk.
Luzula wahlenbergii Rupr.
Li 1i aceae
Lloydia serotina (L.)Rchb.
Streptopus amplexifolius (L.)DC.
Tofieldia coccinea Richards
Tofieldia eusjlla (Michx.)Pers.
Veratrum vlride Ait.
Zygadenus elegans Pursh
Orchidaceae
Platanthera convallariaefolia
(Fisch.)Lindl.
Platanthera hyperborea (L.)Lindl.
Potamogetomaceae
Potamogeton epihydrous Raf.
Potamogeton filiformis Pers.
Potamogeton gramineus L.
Potamogeton perfoliatus L.
Potamogeton robbinsii Oakes
Sparganiaceae
Sparganium angustifolium ~ichx.
Dicotyledoneae
Araliaceae
Echinopanax horridum (Sm.)
Decne.&Planch.
16
Arctic rush
Chestnut rush
Drummond rush
~1ertens rush
Woodrush
Northern woodrush
Woodrush
Small-flowered woodrush
Tundra woodrush
Wahlenberg woodrush
Alp lily
Cucumber root
Northern asphodel
Scotch asphodel
Helebore
Elegant death camas
Orchis family
Orchis family
Nuttall pondweed
Filiform pondweed
Pondweed
Clasping-leaf pondweed
Robbins pondweed
Narrow-leaved burreed
Devil 's club
Betulaceaef/
Alnus crispa (Ait.)Pursh
Alnus sinuata (Reg.)Rydb.
Betula glandulosa Michx.
Betul a nana L.
Betula ~dentalis Hook.
Betula papyrifera Marsh.
Boragi naceae
Mertensia raniculata (Ait.)G.Don
Myosotis a pestris F.W.Schmidt
Callitrichaceae
Callitriche hermaphroditica L.
Callitriche verna L.
Campanulaceae
Campanula lasiocarpa Cham.
Caprifoliaceae
Linnaea borealis L.
Viburnum edule (Michx.)Raf.
Caryophyllaceae
Minuartia obtusiloba (Rydb.)House
Silene acaulis L.
Stellaria sp.
wi Ihelmsia physodes (Fisch.)McNeill
Compositae
Achillea borealis Bong.
Achillea sibirica Ledeb.
Antennaria alpina (L.)Gaertn.
Antennaria monocephala DC.
Antennaria rosea Greene
Arnica amplexicaulis Nutt.ssp.prima
f"1aguire
Arnica frigida C.A.Mey.
Arnica lessingii Gree~e
Artemisia alaskana Rydb.
Artemisia arctica Less.
Artemisia tilesii Ledeb.
Aster sibiricus L.
Erigeron humilis Graham
Hferacium triste Willd.
Petasites frigidus (L.)Franch.
Petasites sagittatus (Banks)Gray
17
American green alder
Sitka alder
Resin birch
Dwarf arctic birch
Water birch
Paper birch
Tall bluebell
Forget-me-not
Water starwort
Vernal water-starwort
Mountain harebell
Twin-flower
High bush cranberry
Alpine sandwort
~1oss campion
Starwort
~1erckia
YarrO\'i
Siberian yarrow
Alpine pussytoes
Pussy toes
Pussy toes
Arnica
Arnica
Arnica
Alaska wormwood
Wormwood
Wormwood
Si beri an-aster
Fleabane daisy
Woolly hawkweed
Arctic sweet coltsfoot
Arrowleaf sweet coltsfoot
-
-
Senecio atropurpureus (Ledeb.)
Fedtsch.
Senecio Tugens Richards.
Senecio sheldonensis Pors.
Solidago multiradiata Ait.
Taraxacum sp.
Cornaceae
Cornus canadensis L.
Crassulaceae
Sedum rosea (L.)Scop.
Cruciferae
Cardamine bellidifolia L.
Cardamine pratensis L.
Ca rdami ne umbe 11 ata Greene
Draba nivalis L;ljebl.
Draba stenoloba Ledeb.
Diapensiaceae
Diapensia lapponica L.
Elaeagnaceae
Shepherdia canadensis (L.)Nutt.
Empetraceae
Empetrum nigrum L.
Ericaceae
Andromeda polifolia L.
Arctostaphylos alpina (L.)Spreng.
Arctostaphylos rubra (Rehd.&Wilson)
Fern.
Arctostaphylos uva-ursi (L.)Spreng.
Cassiope tetragona(L.)D.Don
c/.Ledum decumbens (Ait.)Small-
Ledum groenlandicum Oeder
Lo;seleur;a procumbens (L.)Desv.
Oxycoccus microcarpus Turcz.
Rhododendron lapponicum (L.)Wahlenb.
Vaccinium caeseitosum Michx.
Vacc;n;um uli~lnosum L.
Vaccinium v;tls-idaea L.
18
Ragwort
Rag\'JOrt
Sheldon groundsel
Northern goldenrod
Dandelion
Bunchberry
Roseroot
Alpine bittercress
Cuckoo flower
Bittercress
Rockcress
Rockcress
Diapensia
Soapberry
Crowberry
Bog rosemary
Alpine bearberry
Red-fruit bearberry
Bearberry
Four angle mountain
heather
Northern Labrador tea
Labrador tea
Alpine azalea
Swamp cranberry
Lapland rosebay
Dwarf blueberry
Bog blueberry
Mountain cranberry
Fumariaceae
Corydalis pauciflora (Steph.)Pers.
Gentianaceae
Gentiana glauca Pall.
Gentiana propingua Richards.
Menyanthes trifoliata L.
Swertia perennis L.
Geraniaceae
Geranium erianthum DC.
Haloragaceae
Hippuris vulgaris L.
Leguminosae
Astragalus aboriginumb,ichards.
Astragalus alpinus L.-
Astragalus umbel latus Bunge
Hedysarum alpinum L.
Lupinus arcticus S.Wats.
Oxytropis maydelliana Trautv.
Oxytropis nigrescens (Pall.)Fisch.
Oxytropis viscida Nutt.
Lentibulariaceae
Pin~uicula villosa L.
Utrlcularia vUlgaris L.
Myricaceae
~1yri ca gale L.
Nymphaceae
Nuphar polysepalum Engelm.
Onagraceae
Epilobium angustifolium L.
Epilobium latifolium L.
Epilobium palustre L.
19
Few-flowered corydalis
Glaucous gentian
Gentian
Buckbean
Gentian
Northern geranium
Common marestail
Milk-vetch
rHl k-vetch
t1i 1k-vetch
Alpine sweet-vetch
Arctic 1upine
Maydell oxytrope
Blackish oxytrope
Vlscid oxytrope
Hairy butterwort
Common bladderwort
Sweet gale
Yellow pond lily
Fireweed
Dwarf fireweed
Swamp willow-herb
....
r,
-
Orobanchaceae
Boschniakia rossica
(Cham.&Schlecht.)Fedtsch.
Polemoniaceae
Polemonium acutiflorum Willd.
Polygonaceae
Oxyria digtna (L.)Hill
Polygonumistorta L.
Polygonum viviparum L.
Rumex arcticus Trautv.
Rumex sp.
Portulacaceae
Claytonia sarmentosa C.A.Mey.
Primulaceae
Dodecatheon frigidum Cham.&
Schlecht.
Primula cunei folia Ledeb.
Trientalis europaea L.
pyrolaceae
Pyrola grandiflora Radius
Pyro 1a mi nor L.
pyrola secunda L.
Ranunculaceae
Aconitum delphinifolium DC.
Anemone narcissiflora L.
Anemone parviflora Michx.
Caltha leptose ala DC.
Ranuncu us confervoides (E.Fries)
E.Fries
Ranunculus nivalis L.
Ranunculus occidentalis Nutt.
Ranunculus pygmaeus Wahlenb.
Ranunculus sp.
Tha 1i ctrum a1pi num L.
Thalictrum sparsiflorum Turcz.
20
Poque
Jacob's ladder
t~ounta in sorrel
Meadow bistort
Alpine bistort
Arctic dock
Dock
Spring-beauty
Northern shooting star
Wedge-leaf primrose
-...Arctic starflower
Large-flower wintergreen
Lesser wintergreen
One-sided wintergreen
Monkshood
Anemone
Northern anemone
Mountain marsh-marigold
Hater crowfoot
Snow buttercup
Western buttercup
Pygmy buttercup
Buttercup
Arctic meadowrue
Few-flower meadowrue
.-
Rosaceae
Dryas drummondii Richards.
Dryas octopetala L.
Geum ross;;(R.Br.)Ser.
LUetkea pectinata (Pursh)Ktze.
Potentilla biflora Willd.
Potentilla fruticosa L.
Potentilla hyparctica Malte
Potent;lla palustris (L.)Scop~
Rosa acicularis Lindl.
RUDUs arcticus L.
Rubus chamaemorus L.
Rubus i daeus L.
Rubus pedatus Sill.
Sanguisorba stipulata Raf.
Sibbald;a procumbens L.
Sorbus scopul;na Greene
Spiraea beauverdiana Schneid.
Rubiaceae
Galium boreale L.
Galium trifidum L.
SalicaceaeY
Populus balsamifera L.
Populus tremuloides Michx.
Salix alaxensis (Anderss.)COy.
Salix arbusculoides Anderss.
Salix arctic~Pall.
Salix barclayi Anderss.
Salix brachycarpa Nutt.
Salix fuscescens Andefss.
Salix glauca L.
Salix lanata L.subsp.richardsonii
(Hook)A.Skwortz.
Salix monticola Bebb
Salix novae-angliae Anderss.
Salix phlebophylla Anderss.
Salix planifolia Pursh ssp.
pl anifol ia
Salix lanifolia Pursh ssp.
pulchra Cham.)Argus
Salix polaris Wahlenb.
Salix reticulata L.
Salix rotundifolia Trautv.
Salix scouleriana Barratt
Salix sp.
21
Drummond mountain-avens
White mountain-avens
Ross avens
Luetkea
Two-flower cinquefoil
Shrubby cinquefoil
Arctic cinquefoil
Marsh cinquefoil
Prickly rose
Nagoon berry
Cloudberry
Raspberry
Five-leaf bramble
Sitka burnet
Sibbaldia
Western mountain ash
Beauverd spirea
Northern bedstraw
Small bedstraw
Balsam popular
Quaking aspen
Fel tl eaf wi 11 ow
Littletree willow
Arctic willow
Barcl ay wi 11 ow
Barren-ground willow
Alaska bog willow
Grayleaf willow
Richardson willow
Park wi 11 ow
Tall blueberry willow
Skeletonleaf willow
Diamondleaf willow
Diamondleaf willow
Polar willow
Netl eaf wi 11 ow
Least willow
Scoul er wi 11 ow
Willow
-
Santalaceae
Geocaulon lividum (Richards.)Fern.
Saxifragaceae
Boykinia richardsonii (Hook.)Gray
Leptarrhena pyrolifolia (D.Don)Ser.
Parnassia palustris L.
Ribes triste Pall.
Saxifraga bronchialis L.
Saxifraga davurica Willd.
Saxifraga foliolosa R.Br.
Saxifraga hieracifolia Waldst.&Kit.
Saxifraga lyallii Engler
Saxifraga oppositifolia L.
Saxifraga punctata L.
Saxifraga serpYllifolia Pursh
Saxifraga tricuspidata Rottb.
Scrophulariaceae
Castilleja caudata (Pennell)Rebr.
Pedicularis capitata Adams
Pedicularis kanei Durand
Pedicularis labradorica Wirsing
Pedicularis parviflora J.E.Sm.var.
parviflora
Pedicularis sudetica Will~.
Pedicularis verticillata L.
Veronica wormskjoldii Roem.&Schult.
Umbelliferae
Angelica lucida L.
Heracleum lanatum Michx.
Valerianaceae
Valeriana capitata Pall.
Violaceae
Viola epipsila Ledeb.
22
Sandalwood
Richardson boykinia
Leather-leaf saxifrage
Northern Grass-of-Parnassus
Red currant
Spotted saxifrage
Saxifrage
Foliose saxifrage
Hawkweed-leaf saxifrage
Red-stem saxifrage
Purple mountain saxifrage
Brook saxifrage
Thyme-leaf saxifrage
Three-tooth saxifrage
Pale indian paintbrush
Capitate lousewort
Kane lousewort
Labrador lousewort
Lousewort
Lousewort
Whorled lousewort
Alpine speedwell
Wild celery
Cow parsnip
Capitate valerian
Harsh violet
,~
,~
.-
Nonvascular Plant Specles
Lichens
Cetraria cucullata (Bell.)Ach.
Cetraria islandica (L.)Ach.
Cetraria nivalis (L.)Ach.
Cetraria richardsoni;Hook.
Cetraria spp.
Cladonia alpetris (L.)Rabenh.
Cladonia mitis Sandst.
Cladonia rangiferina (L.)Web.
Cladonia spp.
Dactylina arctica (Hook.)Nyl.
Nephroma spp.
Peltigera spp.
Stereocaulon paschale (L.)Hoffm.
Thamnolia spp.
Mosses
eli ma ci um s p.
Hypnum spp.and other feather mos§,s
Paludella sguarrosa (Hedw.)Brid.-
Polytrichum spp.
Ptilium crista-castrensis (Hedw.)DeNot.
Sphagnum spp.
Rhacomitrium spp.
~Vascular plant species nomenclature according to Hulten (1968)
except where noted.Lichen nomenclature according to Thomson
(1979).Moss nomenclature according to Conard (1979).
bl Nomenclature according to Welsh (1974).
~Nomenclature according to Viereck and Little (1972).
~Nomenclature according to Crum (1976).
23
--I
the field.The delineation of vegetation/habitat types does,therefore,
require constant judgment as to the boundaries of each type.Another
important factor that should be considered in using the maps is that
there is a smallest mappable unit for each scale map~The smallest
units which can be mapped for the 1 :250,000 scale and 1:24,000 scale
maps are approximately 16 hectares and 4 hectares,respectively.Some
mapping units on the larger scale maps (1:24,000 and 1 :63,360)are more
specific than those on the smaller scale (1:250,000)but most are the
same.The main differences resulted by eliminating complexes and
delineating the forested areas by dominant tree species on the larger
scale maps.Smaller areas could be delineated on the larger scale maps.
The Viereck and Dyrness (1980)preliminary classification was used for
the mapping and offered a standard nomenclature which other studies on
the Susitna project could also use and have reproducible results.Level
III names were·used in most cases.However,Level IV names were used
for forested areas on the 1:24,000 and 1 :63,360 maps.In most cases
the key presented by Viereck and Dyrness (1980)was adequate for clas-
sification only at Levels I thro'ugh III,presumably because the clas-
sification is preliminary and lacks sufficient information to consis-
tently identify vegetation at Levels IV and V.Also,U-2 aerial imagery
is not consistently interpretable at lower hierarchical levels in this
preliminary classification.For these reasons,Level III was used.
The vegetation types which occurred,their total hectares,and the
percent of area covered are reported in Table 3 (1 :250,000)and Table 4
(1:24,000 scale maps);Table 4 gives the hectares and percentages for
each reservoir.The Devil Canyon and Watana dam locations with pool
elevations of 457 meters (1500 feet)and 671 meters (2200 feet),respec-
tively were assumed in these area determinations.
Level I types (which are based predominantly on life forms)that occur-
red in the Upper Susitna River Basin were Forest,Tundra,and Shrubland
(Table 3).Forest communities were those with at least 10%cover by
tree species regardless of how tall the individual trees were.Shrub-
land communities had at least 25%cover of erect to decumbent shrubs but
24
25
1 ~~·-l
Table 4
l }]1
Hectares of different vegetation types to be impacted compared with total hectares of those types in the entire Upper
Susitna River Basin.Number in parentheses is the percent of the vegetation type as found in the entire Upper Basin.
l •
-
were not located above or beyond the tree limit.Tundra stands were
those communities found above or beyond the limit of trees and were
dominated by shrub or herbaceous species.
Figure 3 illustrates the general overall distribution of different
vegetation/habitat types,and Table 3 gives rough percentages for cover
by each type.However,it should be remembered that much detail is lost
at the relatively small scale of Figure 3.Figure 4,on the other hand,
is larger scaled and allows inclusion of more detail,but it covers only
a limited portion of the Upper Susitna River Basin,namely,the impact
areas.Consequently,Table 4 is constructed to provide some indication
of the cover of vegetation/habitat types within the impact areas relative
to the total cover of those types across the entire basin.As alluded
to above,however,there are some problems with this approach.For ex-
ample,because closed birch forests were often too small to be delineated
at the smaller scale (Figure 3),but were circumscribab1e at the larger
scale (Figure 4),there is an apparent discrepancy in the total number
of hectares of that type when computed from each map.
Overall,however,Figure 3 does give a fair description of the distri-
bution and relative abundance of each vegetation/habitat type.Conifer
forests cover approximately 19%of the basin.They occupy a wide range
of sites,from the flood plains to the mountains,but they seldom occur
above 975 m elevation.
Deciduous forests --birch,aspen,and balsam poplar --and mixed
conifer -deciduous forests are much more restricted in distribution
and together cover only 2.5%of the area.As can be seen from Figure
3,these vegetation/habitat types are found primarily on south facing
slopes below 700 m elevation and in the Susitna River Valley below
Devil Canyon.Balsam poplar stands,in particular,are found only on
the flood plain (Figure 4).
Tundra vegetation/habitat types are generally located above or beyond
the limit of forests.Approximately 24%of the basin is covered with
27
tundra (Table 3).Roughly half of the tundra is dominated by mesic or
wet sedge-grass vegetation/habitat types (Table 3).These generally
occur in the mountainous regions of the basin (Figure 3).Closely
associated with the mesic sedge-grass type is the mat and cushion tundra
(Figure 3).Mat and cushion tundra and complexes of mat and cushion/
sedge-grass tundra represent most of the remaining tundra situations
(Table 3).
Shrubland is the largest overall group of vegetation/habitat types
occurring in the Upper Susitna River Basin,covering almost 40%of the
total area (Table 3).Thirty percent is covered by shrub birch and
willow.These vegetation/habitat types are found at intermediate and
low elevations throughout the basin,but primarily on the broad flat
areas in the central,southern,and northeastern portions of the basin
(Figure 3).Tall shrub,dominated by alder,is the other principle
component of the shrubland,occupying approximately 8%of the basin.As
can be seen from Figures 3 and 4,this type is found in steep terrain
throughout the basin,and in large expanses at the western end of the
basin near Portage Creek.
Un vegetated areas (15%of the total area)consist primarily of rock,
snow,and ice,which are comllon at the highest elevations (i .e.the
mountain types).
3.5 -Preliminary Vegetation/Habitat Type Descriptions
3.5.1 -Forest Types
Forest vegetation/habitat types were located at the lower eleva-
tions of the study area.The average elevation of sampled areas
was 523 m.This type was divided according to the dominant tree
types (conifer,deciduous,or mixed)and then by tree crown cover
percent.Deciduo~s and conifer types had at least 75%of the tree
28
-
cover provided by deciduous or conifer trees,respectively.The
woodland type had between 10%and 25%tree cover and was only
observed for conifer stands.Open stands contained 25%to 50%tree
cover while closed stands had over 50%tree cover.The boundary
percentage between open and closed types was chosen as 50%rather
than the 60%that Viereck and Dyrness (1980)used since it was
easier to estimate on the aerial photography and in the field.
Field estimates were performed best from the air because the
Venetian blind effect of the trees caused overestimates from the
ground.
Conifer,deciduous,and mixed stands were observed in the field
with open canopies while only deciduous and mixed stands with
closed canopies were located in the field.One closed conifer area
appeared on the aerial photography in the Lake Louise area but was
not field checked.All forested stands had almost complete vege-
tation cover with 80%to 95%ground layer cover.
Spruce stands were dominated by white spruce (Picea glauca)or
black spruce (Picea mariana)and contained a well-developed ground
layer which accounted for most of the vegetation cover (Tables 5
and 6).Overstory provided almost one-fourth cover in open stands
but was almost negligible in the woodland stands.Open stands
contained trees at least several meters tall while woodland stands
were usually a collection of scattered,stunted trees.Hence,open
spruce had more overstory cover than woodland spruce.Shrub layer
provided more cover in the woodland stands than in open stands
(Tables 5 and 6).
Feather mosses covered as much ground as the trees in the open
spruce stands (Table 5).Low shrubs,such as crowberry (Empetrum
nigrum),northern Labrador tea (Ledum decumbens),bog blueberry
(Vaccinium uliginosum),and mountain cranberry (Vaccinium vitis-
idaea)accounted for much of the woody ground layer.Important
herbaceous species included bluejoint (Calamagrostis canadensis)
29
Table 5·
Cover percentages for total vegetation,vertical/strata,and plant
species in open conifer vegetation/habitat type-in Upper Susitna
River Basin in summer 1980.
Shrub layer (>0.5 m tall,<2.5 cm dbh)
Picea glauca White spruce
Picea mariana Black spruce
--
Category
Total vegetation
Overstory (>10 cm dbh)
Picea glauca
Picea mariana
Understory (2.5 -10 cm dbh)
Picea glauca
Pi cea mad ana
Ground layer «0.5 m tall)
Mosses,unidentified
Feather moSses
Ptilium spp.
Empetrum nigrum
Ledum decumbens
Vaccinium uliginosum
Vacc;n;um vitis-;daea
Equ;setumarvense
Esu;setum s;lvaticum
Llnnaea borealis
Picea mariana
Calamagrost;s canadensis
White spruce
Black spruce
White spruce
Black spruce
Feather moss
Crowberry
Northern Labrador tea
Bog blueberry
Mountain cranberry
Meadow horsetail
Woodland horsetail
Twinflower
Black spruce
Bluejoint
Average
Cover (%)£1
98
24
24
2
10
3
2
5
1
3
94
11
29
13
6
5
7
6
6
8
8
1
14
~Number of areas sampled was 9.
!V Includes only those species with at least 5%cover in anyone
area sampled.
30
Table 6
Cover percentages for total vegetation,vertical st~?ta,and plant
species in woodland conifer vegetation/habitat type-in Upper
Susitna River Basin in summer 1980.
Shrub layer (>0.5 m tall,<2.5 cm dbh)
Picea mariana Black spruce
~-
Category
Total vegetation
Overstory (>10 cm dbh)
Picea glauca
Understory (2.5 -10 cm dbh)
Picea mariana
Ground layer (<0.5 m tall)
Feather mosses
Sphagnum spp.
Empetrurri ni grum
Ledum decumbens
Ledum groen1andicum
Vaccinium u1iginosum
Equisetum silvaticum
Rubus arcticus
Rubus chamaemorus
Picea mariana
Carex bigelowii
Carex spp.
White spruce
Black spruce
Feather moss
Sphagnum moss
Crowberry
Northern Labrador tea
Labrador tea
Bog blueberry
Woodland horsetail
Nagoon berry
C10udberry
Black spruce
Bigelow sedge
Sedge
Average
Cover {%)b/
99
1
12
11
17
15
93
5
62
8
5
5
23
10
15
5
3
7
6
~Number of areas sampled was 6.
~Includes only those species with at least 5%cover in anyone
area sampled.
31
I'·...
and horsetails (Equisetum spp.).Open spruce stands were usually
found on slopes or f1at1ands·a1ong the rivers at elevations aver-
aging 487 m.
Woodland spruce stands had sphagnum mosses (Sphagnum spp.)as the
most important species providing ground cover (Table 6).All
woodland stands that were visited were black spruce.This vege-
tation/habitat type was usually found on the relatively level
benches where soils were poorly drained.Average elevation of
sampled areas was 620 m.Usually these trees were too small to
qualify for the overstory layer,which requires trunks with >10 cm
.dbh.Maximum heights were less than 2 m in some areas.Important
ground layer species included sedges (Carex spp.),woodland horse-
tail (Equisetum silvaticum),and low shrubs similar to those found
in the open spruce stands.Slightly over 30 identified species
were encountered in the woodland spruce vegetation/habitat type.
Woodland spruce sites graded into boggy areas where tree cover
might be less than 10%and the vegetation resembled muskegs.Low
birch shrub stands and woodland spruce were frequently difficult to
distinguish in the field because birch stands sometimes had scat-
tered trees which sometimes produced almost 10%cover.The small
size of trees created similar textures on the aerial photography
for woodland spruce and low birch shrub sites.These areas were
difficult to distinguish on the photographs since they had similar
colors (dark gray)and textures.
The structure of the layers for open black and white spruce stands
was similar except that white spruce stands contained more over-
story,a reflection of the generally larger size of white spruce
trees (Tables 7 and 8).These units were mapped only on the
1:24,000 and 1:63,360 scale maps.The overstory in open white
spruce stands was less variable among stands than was the overstory
in black spruce stands.Maximum overstory heights of trees in open
black spruce types varied from about 5 to 11 m while white spruce
32
Table 7
Cover percentages for total vegetation,vertical strS;a,and plant
species in open black spruce vegetation/habitat type=in Upper
Susitna River Basin in summer 1980.
Category
Average b
Cover (%)-.1
96
14
13
5
10
4
5
7
8
2
93
34
30
7
14
14
10-
15
12
7
4
Feather moss
Crowberry
Northern Labrador tea
Bog blueberry
Mountain cranberry
Woodland horsetail
Willow
Black spruce
White spruce
Black spruce
White spruce
Black spruce
Understory (2.5 -10 cm dbh)
Picea glauca
Picea mariana
Shrub layer (>0.5 m tall,<2.5 cm dbh)
Picea mariana Black spruce
Salix spp.Willow
Ground layer «0.5 m tall)
Mosses,unidentified
Feather mosses
'Cladonia spp.
Empetrum nigrum
Ledum decumbens
Vacc;nium ul;g;nosum
Vaccinium vitis-idaea
Equ;setum silvaticum
Salix spp.
Picea mariana
Total vegetation
Overstory (>10 cm dbh)
Picea glauca
Picea mariana
~Number of areas sampled was 3.
EI Includes only those species with at least 5%cover in anyone
area sampled.
33
F
I
I
.Table 8
Cover percentages for total vegetation,vertical strsja,and plant
species in open white spruce vegetation/habitat type-in Upper
Susitna River Basin in summer 1980.
<2.5 cm dbh)
White spruce
American green alder
Prickly rose
,~
-
Category
Total vegetation
Overstory (>10 cm dbh)
Picea glauca
Understory (2.5 -10 cm dbh)
Picea glauca
Alnus sinuata
Shrub layer (>0.5 m tall,
Picea glauca
Alnus criSta
Rosa acicuaris
Ground layer (<0.5 m tall)
Feather mosses
Ptilium spp.
Equisetum arvense
Equisetum silvaticum
Linnaea borealis
Betula ~landulosa
Rosa aClcularis
caramagrostis canadensis
White spruce
White spruce
Sitka alder
Feather moss
Meadow horseta i1 t
Woodland horsetail
Twi nfl ower
Resin bi rch
Prickly rose
Bl uejoint
Average
Cover (%)lY'
100
35
35
11
3
6
4
1
4
3
94
30
24
11
6
15
6
5
23
~Number of areas sampled was 5.
lY'Included only those species with at least 5%cover in anyone
area sampled.
34
"""
.-
-
-
stands reached heights of 20 m.Most of the black spruce tree
cover was contained in the shrub layer while the white spruce cover
was concentrated in the overstory layer.Black spruce stands
contained low shrubs such as crowberry,northern Labrador tea,bog
blueberry,and mountain cranberry in the ground layer,while
prickly rose (Rosa acicularis)and bluejoint (Calamagrostis
canadensis)were the most important ground layer species in open
white spruce.Twin-flower (Linnaea borealis)was fairly important
in the white spruce stands,but was not observed in the black
spruce stands,possibly reflecting a preference for better-drained
soils.-Thirty to 35 identified species were encountered in each of
these mapping units.
White spruce sites usually had better-drained soils than black
spruce sites.Viereck (1970)reported that moss developed in white
spruce stands and acted as an insulating layer on the soils.The
soils became colder and permafrost developed.Black spruce was
/better adapted to cold soils than white spruce,so it replaced
white spruce.As the permafrost develops and the soil became more
poorly drained,black.spruce vegetation was replaced by bog vege-
tation.Hence,vegetation in black spruce stands resembled bog or
muskeg vegetation while the associated species in white spruce
stands were more closely related to earlier deciduous successional
stands.Apparently woodland black spruce and bogs alternate in
temporal and spatial succession (Drury 1956).Observations in the
Upper Susitna River Basin,particularly around Fog Lakes and Lake
Louise,seemed to support this.
Viereck (1970)reported northern Labrador tea,Labrador tea (Ledum
groenlandicum),bog blueberry,mountain cranberry,and sphagnum
and feather mosses to be important species in black spruce stands
along the Chena River in interior Alaska.These were also impor-
tant in the Upper Susitna River Basin.However,crowberry,nagoon-
berry,and woodland horsetail were important in black spruce stands
in our study but were not reported along the Chena River by Viereck
(1970).
35
-
-
-
Meadow horsetail (Equisetum arvense)and feather mosses provided
significant amounts of cover in white spruce stands along the Chena
River (Viereck 1970)and in the Upper Susitna River Basin but
bluejoint,twinflower,and ptilium crista-castrensis were appar-
ently more important along the Susitna River than along the Chena.
Hettinger and Janz (1974)reported that feather mosses were impor-
tant in the ground layer of white spruce stands in northeastern
Alaska,which agreed with our results.However,they found crow-
berry to be an important species,but this accounted for less than
2%cover in the Susitna stands.
Among black spruce stands,those occupying significant slopes (8 -
10°)appeared to be more productive of browse species,and in fact,
had noticeably greater use by moose.Browse production was low
relative to other vegetation,but it had incurred heavy use,sug-
gesting such stands may be important areas for cover during severe
weather.Open black spruce stands on the flats were generally very
poor in terms of forage production,but some caribou sign was
present.Skoog (1968)considered this type to represent a good
supply of terrestrial forage lichens for caribou in winter.
Deciduous forest vegetation usually had a greater overstory cover
than spruce stands,possibly because an individual tree had more
foliage cover.These types were restricted mostly to the steep
banks and floodplain along the river.Elevations averaged 582 m
with closed stands occurring at average elevations of 560 m and
open stands at 625 m.They had almost complete vegetation cover
and a well-developed ground layer.The overstory layer in closed
stands covered almost three-fourths of the area but only about
three-eighths in open stands (Tables 9 and 10).Overstory was
sometimes 15 m tall.Neither the shrub layer nor the understory
layer was of major importance.Important woody species in the
ground layer in both types included crowberry,northern Labrador
tea,bog blueberry,and mountain cranberry.Open stands appeared
to have more woody cover in the ground layer than did the closed
36
------_._"""'~~,~----------------------
Table 9
Cover percentages for total vegetation,vertical strata,and plant
species in closed d~7iduous forest (birch and balsam poplar)vege-
tation/habitat typ~in Upper Susitna River Basin in summer 1980.
Category
Average
Cover (%)!Y
99
76
4
54
20
7
3
4
1
5
2
4
1
90
26
5
9
15
20
10 -
5
38
1
19
10
6
White spruce
Paper birch
Ba1 sam poplar
Crowberry
Northern Labrador tea
Bog blueberry
Mountain cranberry
Woodland horsetail
Bunchberry
Balsam poplar
B1 uejoint
Oak-fern
Tall bluebell
White spruce
Paper birch
Balsam poplar
<2.5 cm dbh)
White spruce
Paper birch
Balsam poplar
Ground layer «0.5 m tall)
Pt i 1i um s pp•-
Po1ytrichum spp.
Empetrum nigrum
Ledum decumbens
Vaccinium u1iginosum
Vaccinium vitis-idaea
Equisetum silvaticum
Cornus canadensis
Po tu1US balsamifera
Ca amagrostis canadensis
Gymnocarpium dryopteris
Mertensia panicu1ata
Total vegetation
Overstory (>10 cm dbh)
Picea glauca
Betula papyrifera
Populus balsamifera
Understory (2.5 -10 cm dbh)
Picea glauca
Betula paptrifera
Populus ba samifera
Shrub layer (>0.5 m tall,
Picea glauca
Betula papyrifera
Populus balsamifera
~Number of areas sampled was 4.
!Y Includes only those species with at least 5%cover in anyone
area sampled.
F-
i
37
Table 10
Cover percentages for total vegetation,vertical strata,and pl,nt
species in open birch deciduous forest vegetation/habitat type-
in Upper Susitna River Basin in summer 1980.
Category
Average
Cover (%)Q/
99
38
3
38
6
1
6
5
2
2
95
10
20
12
30
26
11
5
3
White spruce
Paper birch
Northern Labrador tea
Labrador tea
Bog blueberry
Mountain cranberry
Bunchberry
Pri ckly rose
White spruce
White spruce
Paper birch
Shrub layer (>0.5 m tall,<2.5 cm dbh)
Picea glauca White spruce
Betula papYrifera Paper birch
Ground layer «0.5 m tall)
Polytrichum spp.
Ledum decumbens
Ledum ~roenlandicum
Vaccinlum uliginosum
Vaccinium vitis-idaea
Cornus canadensis
Rosa acicularis
P'l"C'ea .9..!au ca
Total vegetation
Overstory (>10 cm dbh)
Picea glauca
Betula papYrifera
Understory (2.5 -10 cm dbh)
Picea glauca
Betula Eapyrifera
~Number of areas sampled was 2.
Q/Includes only those species with at least 5%cover in anyone
area sampled.
r-
I
r-,
38
.-
stands.Closed stands had more herbaceous components such as
bunchberry (Cornus canadensis),bluejoint,and oak-fern (Gymnocarpium
dryopteris).Approximately 16 identified species were encountered
in open deciduous forest types while about 31 were found in closed
deciduous forests.
Closed deciduous stands were further separated on the larger scale
maps according to the dominant species:balsam poplar (PopuluS
balsamifera)and paper birch (Betula papyrifera).Closed balsam
poplar (Populus balsamifera)generally occurred on islands in the
river or flat areas alongside the riv~r.It was usually the first
tree successional stage in vegetation development on alluvial
deposits.The trees provided about three-fourths cover (Table 11).
The ground layer was well developed and included bunchberry,crow-
berry,northern Labrador tea,bog blueberry,and mountain cran-
berry.These areas contained about 14 species which were encoun-
tered and identified.
Closed paper birch (Betula papyrifera)stands occurred on steep,
usually south-facing slopes.The vertical layer structure is
similar to the closed balsam poplar stands:three-fourths over-
story,a well-developed ground layer,and relatively unimportant
shrub and understory layers (Table 12).The most important ground
layer species were bunchberry,bog blueberry,bluejoint,and oak-
fern.Approximately 25 species were encountered and identified.
Closed trembling aspen (Populus tremuloides)stands were usually
found on the upper portions of dry,south-facing slopes.These
areas were rarely large enough to sample and were not large enough
to map.The general structure was similar to other closed decid-
uous stands in that there were a well-developed overstory and
and ground layer but insignificant shrub and understory layers
(Table 13).
Hettinger and Janz (1974)reported mountain cranberry and bluejoint
as major species in bitch forest stands in northeastern Alaska,
39
Table 11
Cover percentages for total vegetation,vertical strata,and PA?nt
species in closed balsam poplar forest vegetation/habitat type-
in Upper Susitna River Basin in summer 1980.
Category
Average b
Cover (%)J
80
75
5
5
10
5
85
20
5
30
40
40
20
40
1
5
99
Balsam poplar
Crowberry
Northern Labrador tea
Bog blueberry
Mountain cranberry
Bunchberry
Balsam poplar
Beauverd spiraea
White spruce
Balsam poplar
Shrub layer (>0.5 m tall,<2.5 cm dbh)
Populus balsamifera Balsam poplar
Ground layer «0.5 m tall)
Pti1ium spp.-
Po1ytrichum spp.
Empetrum nigrum
Ledum decumbens
Vaccinium uliginosum
Vaccinium vitis-idaea
Cornus canadensis
Populus balsamifera
Spiraea beauverdiana
Total vegetation
Overstory (>10 cm dbh)
Picea glauca
Populus balsamifera
Understory (2.5 -10 cm dbh)
Populus balsamifera-
~Number of areas sampled was 1.
b/Includes only those species with at least 5%cover in anyone
area sampled.
-
40
-
Table 12
Cover percentages for total vegetation,vertical strata,and plan;
species in closed birch deciduous forest vegetation/habitat type~
in Upper Susitna River Basin in summer 1980.
Category
Avera~e
Cover {%)!Y
99
73
8
68
9
5
3
3
1
3
95
15
5
15
5
10
16
38
20
10
Gog blueberry
Mountain cranberry
Woodland horsetail
Bunchberry
Bl uejoint
Oak-fern
Tall bluebell
White spruce
Paper birch
White spruce
Paper birch
Shrub layer (>0.5 m tall,<2.5 cm dbh)
Picea glauca White spruce
Betula papyrifera Paper birch
Ground layer «0.5 m tall)
Ptilium spp.-
Polytrichum spp.
Vaccinium uliginosum
Vaccinium vitis-;daea
Equisetum s;lvat;cum
Cornus canadensis
Calamagrost;s canadensis
Gymnocarpium dryopter;s
Mertensia paniculata
Total vegetation
Overstory (>10 cm dbh)
Piceaglauca
Betula papYrifera
Understory (2.5 -10 cm dbh)
Picea glauca
Betula papyrifera
-
a/Number of areas sampled was 2.
b/Includes only those species with at least 5%cover in anyone
area sampled.
"....
-
41
Table 13
Cover percentages for total vegetation,vertical strata,~?d plant
specles in closed aspen deciduous vegetation/habitat type-in Upper
Susitna River Basin in summer 1980.
<2.5 cm dbh)
White spruce
Paper birch
Resin birch
Prickly rose
Willow
Trembling aspen
-
Category
Total vegetation
Overstory (>10 cm dbh)
Betula papyrifera
Populus tremuloides
Understory (2.5 -10 cm dbh)
Betula papyrifera
Populus tremuloides
Shrub layer (>0.5 m tall,
Picea glauca
Betula papyrifera
Betula glandulosa
Rosa acicularis
saTTx spp.
Populus tremuloides
Ground layer «0.5 m tall)
Ptil ium spp.-
Polytrichum spp.
Ledum decumbens
Vaccinium ulirinosum
Linnaea borea is
Cornus canadensis
Mertensia paniculata
Epilobium angustifolium
Geocaulon lividum
Spiraea beauverdiana
Vaccinium vitis-idaea
Betula nana
Viburnum edulis
Lycopodium annotinum
Lycopodium clavatum
Paper birch
Trembling aspen
Paper birch
Trembling aspen
Northern Labrador tea
Bog blueberry
Twinflower
Bunchberry
Tall bluebell
Fireweed
Sandalwood
Beauverd spiraea
Mountain cranberry
Dwarf arctic birch
Highbush cranberry
Stiff clubmoss
Running clubmoss
Average
Cover (%)EI
99
80
5
80
5
5
5
5
5
5
5
5
5
5
85
5
5
20
10
5
80
5
5
5
5
10
5
5
5
5
-
a/Number of areas sampled was 1.
EI Includes only those species with at least 5%cover in anyone
area sampled.
42
-
-
~,\
...-
which was in agreement with the Susitna results.However,feather-
mosses and alder shrubs which they also found to be important,were
-insignificant in the Susitna area.The undergrowth in the Susitna
stands was taller .than that pictured in Hettinger and Janz's (1974)
publication.The Susitna stands contained bunchberry,northern
Labrador tea,Labrador tea,and bog blueberry as important species
which were not considered important in the other study.Both
studies repo~ted that birch stands occurred on disturbed sites with
southern exposures.
The mixed conifer deciduous vegetation/habitat types had over$tory
cover intermediate between that for spruce stands and that for
deciduous stands.Elevations for mixed conifer deciduous forests
averaged 466 m with closed stands having a mean elevation near 425
m and open stands occurring around·482 m.Most of the larger
stands occurred on slopes downstream from Tsusena Creek.These
were probably successional stands which developed as spruce trees
replaced deciduous trees.All obse~ved stands were mixtures of
paper birch and white spruce,but other types might exist.Cover
in these vegetation/habitat types was almost complete with a well-
developed ground layer containing important amounts of bluejoint,
bunchberry,woodland horsetail,and Ptilium (Tables 14 and 15).
Overstory cover in closed mixed stands was about 60%while that in
open mixed stands was 38%.The height of the overstory was some-
times up to 20 m.The shrub layer was more important in the open
stands,mostly as a result of tall blueberry willow (Salix novae-
angliae).Bog blueberry was an important ground species in the
open mixed stands.About 40 identified vascular plant species were
encountered in 'open mixed stands while about 29 were found in•closed mixed stands.
In general,the deciduous and the mixed conifer and deciduous
forests appeared to represent a relatively poor forage resource for
moose and caribou.This was particularly true in the closed
stands.Steep slopes often associated with these types might be
43
Table 14
Cover percentages for total vegetation,vertical strata,and plant
specA,s in closed mixed conifer deciduous forest vegetation/habitat
typ~in Upper Susitna River Basin in summer 1980.
Category
Average b
Cover (%)J
98
60
33
35
8
3
4
4
3
88
40
3
8
24
13
7
30
White spruce
Paper birch
White spruce
Paper birch
Crowberry
Mountain cranberry
Woodland horsetail
Bunchberry
Nagoon berry
81uejoint
Total vegetation
Overstory (>10 cm dbh)
Picea glauca
Betula papyrifera
Understory (2.5 -10 cm dbh)
Picea glauca
Betula papyrifera
Shrub layer (>0.5 m tall,<2.5 cm dbh)
Picea glauca White spruce
Ground layer «0.5 m tall)
Pti1 ium spp.-:-
Empetrum nigrum
Vaccinium vitis-idaea
Equisetum si1vaticum
Cornus canadensis
Rubus arcticus
Calamagrostis canadensis
a/Number of areas sampled was 3.
'pi Includes only those species with at least 5%cover in anyone
area sampled.
-
44
Table 15
Cover percentages for total vegetation,vertical strata,and plant
spec!7s in open mixed conifer deciduous forest vegetation/habitat
typ~in Upper Susitna River Basin in summer 1980.
~Number of areas sampled was 8•
.Iv'Includes only those species with at least 5%cover in anyone
area sampled.
<2.5 cm dbh)
White spruce
Paper birch
Tall blueberry willow-
-
-.
~.
Category
Total vegetation
Overstory (<10 cm dbh)
Picea glauca
Betula papyrifera
Understory (2.5 -10 cm dbh)
Picea glauca
Betula papyrifera
Shrub layer (>0.5 m tall,
Picea glauca
Betula papyrifera
Salix novae-ang1iae
Ground layer «0.5 m tall)
Feather mosses
Pti1ium spp.
Empetrum nigrum
Ledum decum ens
Vaccinium uli~inosum
Vaccinium vitls-idaea
Equisetum silvaticum
Cornus canadensis
Picea glauca
Calamagrostis canadensis
Gymnocarpium dryopteris
White spruce
Paper birch
Wh ite s pru ce
Paper birch
Feather mosses
Crowberry
Northern Labrador tea
Bog blueberry
Mountain cranberry
Woodland horsetail
Bunchberry
Hhite spruce
B1uejoint
Oak-fern
Average
Cover {%).Iv'
100
38
20
12
7
5
1
17
2
2
11
79
18
34
6
6
16
9
3
13
2
11
8
"
-45
partially responsible for the low preference by ungulates as well.
Natural records of browsing intensity,as indicated by the struc-
ture of paper birch suckers,suggested.these types may incur heavy
use in severe winters.Skoog (1968)stated that these types were
little used by caribou at any time of the year.The frequency of
berry-filled bear scats in this type in spring suggested it might
be an important food resource for black bears as they come out of
winter torpor.However,the open nature of the understory vege-
tation made sighting of fecal piles easier and positively biased
comparison with other types.
Forested communities in the Upper Susitna River Basin were similar
to those described by Viereck (1975).Black spruce generally
occurred in wetter sites than white spruce while deciduous or mixed
forests occurred on warmer sites.Closed forests occurred on
warmer sites also.The drier of these closed sites were usually
deciduous while the moister ones were mixed or dominated by spruce.
Deciduous and mixed forest stands were considered earlier succes-
sional stages of the conifer stands (Viereck 1970,1975,and
Hettinger and Janz 1974).
Prickly rose was reported to be an important species in balsam
poplar stands along the Chena River (Viereck 1970)and in north-
eastern Alaska (Hettinger and Janz 1974)as well as in white spruce
stands along the Chena River (Viereck 1970).However,it accounted
for less than 8%cover in open white spruce stands and less than 5%
cover in the closed balsam poplar stands in the Upper Susitna River
Basin.
3.5.2 -Tundra Types
Tundra communities usually occurred above the present limit of tree
growth.Most of the well-vegetated communities occurred on flat to
gently sloping areas while sparser vegetation occurred on steep or
rocky terrain.Approximately 70 identified vascular plant species
46
were encountered in these types.Four distinct subtypes occurred
in areas large enough to map:wet sedge-grass tundra,mesic sedge-
grass tundra,herbaceous alpine tundra,and closed mat and cushion
tundra communities.Aspects of tundra vegetation/habitat types
were variable.
Wet sedge-grass tundra communities occurred in wet,depressed areas
with poor drainage at an average elevation of 587 m.They had
almost complete total vegetation cover with most of it occurring in
the ground layer (Table 16).Nineteen identified species were
encountered.The most important herbaceous species were two
species of sedge,especially water sedge (Carex aquatilis),blue-
joint,and sphagnum as well as several other unidentified mosses~
The shrub layer,when it was present,contained scattered indi-
viduals of willow (Salix spp.).Wet sedge-grass communities could
potentially contain up to 10%cover of erect shrubs.There was
usually a large amount of organic matter in these soils and some-
times there was a thick organic layer on top of mineral soil.
Mesic sedge-grass tundra generally occurred on rolling uplands with
well-drained soils at an average elevation of 1372 m.In some
areas the soils were well-developed,but in other areas the soil
occurred as patches alternating with rocks.Nine identified
species were encountered.Total vegetation cover was between half
and three-fourths of the area (Table 17).All vegetation was low
in the ground layer and usually less than 30 cm tall.Bigelow
sedge (Carex bige10wii)was the most common species and accounted
for almost half of the total vegetation cover.
Two types of herbaceous alpine tundra occurred in the Upper Susitna
River Basin,although only one occurred in areas sufficiently large
to map.The herb-sedge communities occurred at higher elevations
near the glaciers,particularly the West Fork Glacier at an ele-
vation of 1295 m,where there were gentle slopes of fairly we11-
drained soils which were relatively well developed.They were
47
Table 16
Cover percentages for total vegetation,vertical strata,S?d plant
species in wet sedge-grass tundra vegetation/habitat type-in
Upper Susitna River Basin in summer 1980.
Sphagnum moss
Alaska bog willow
Bl uejoint
Water sedge
Bigelow sedge
Sedge
Category
Total vegetation
Shrub layer (>0.5 m tall,<2.5 cm dbh)
.Salix pulchra Diamondleaf willow
Salix spp.Willow
Ground layer «0.5 m tall)
Mosses,unidentified
Sphagnum spp.
Salix fuscescens
Calamagrostis canadensis
Carex aquatilis
Carex bigelowii
Carex spp.
Average
Cover {%)b/
99
13
8
5
86
20
22
5
14
38
23
-
~Number of areas sampled was 3.
~Includes only those species with at least 5%cover in anyone
area sampled.
48
Tab1 e 17
Cover percentages for total vegetation,vertical strata,anR/p1ant
species in mesic sedge-grass tundra vegetation/habitat type-in
Upper Susitna River Basin in summer 1980.
,~
Category
Total vegetation
Ground layer «0.5 m tall)
Po1ytrichum spp.
Salix spp.
Carex bige10wii
Carex spp.
Willow
Bigelow sedge
Sedge
Average
Cover (%).!Y
65
65
5
13
30
4
~Number of areas sampled was 2.
b/Includes only those species with at least 5%cover in anyone
area sampled.
49
basically a mineral soil but contained about 5%organic matter.
Some of the soil may have developed from loess blown from the
glacier surface.Approximately 42 identified species were en-
countered in the one area that was visited.Vegetation cover was
almost complete,but cover was dispersed evenly among the many
species present so that no group of species dominated the area
(Table 18).No estimates were made of cover because of the com-
plexity of the vegetation.All vegetation occurred in the ground
layer.The other type of herbaceous alpine community was found in
small,isolated rocky areas that were too small to map or to
sample.Small forbs and sometimes shrubs grew in the pockets of
mineral soil imbedded between th~rocks.
The fourth type of tundra community was the mat and cushion tundra
which was found at higher elevations (1013 m)on dry,windy ridges.
Vegetation covered about three-fourths of the area and was usually
less than 20 to 30 cm tall (Table 19).Vegetation consisted pre-
dominantly of lichens and low mat-forming shrubs.Soils were
shallow and coarse.
Diverse wildlife occupied the high elevation tundra communities in
summer.Most obvious were caribou,black and brown bears,ptarmigan,
hoary marmots,and arctic ground squirrels.Whimbrel pairs were
frequently spotted here in early summer.Bear scats indicated
over-wintered berries were the major attractant of bears in June
although many squirrel dens were found which had been excavated by
bears.Caribou were more frequently sighted in the sedge-grass
tundra than in any other type.Skoog (1968)considered sedge-grass
tundra to be important year-round range for caribou in this region.
He considered mat and cushion tundra to be more important as a
winter forage supply,since its wind swept condition generally kept
it relatively snow-free.
Wet sedge-grass communities,more common below tree line,showed use
by moose where browse was available.Otherwise,its importance was
50
......
.-.
Table 18
Plant species list in herbaceous alpine tundra in Upper Susitna River
Basin in summer 1980.~
Category
Lycopodium alpinum
Polytrichum spp.
Salix polaris
Salix reticulata
Petasites frigidus
Rumex arcticus
Sanguisorba stipulata
Sedum rosea
Calamagrostis purpurascens
Carex bigelowii
Eriophorum angustifolium
Anemone narcissiflora
Diapensia lapponica
Luzula confusa
Luzula tundricola
Valeriana capitata
Aster sibiricus
Senecio atropurpeus
Saxifragatricuseidata
Aconitum delphinlfolium
Sibbaldia procumbens
Deschampsia caespitosa
Polygonum bistorta
Salix rotundifolia
Campanula lasiocarpa
Artemisia arctica
Myosotis alpestris
Cassiope tetragona
Lycopodium annotinum
Lycopodium selago
Boykinia richardsonii
Festuca rubra
Silene acaulis
Epilobium latifolium
Veronica wormskjoldii
Carex filifolia
Polemonium acutiflorum
Salix phlebophylla
Juncus sp.
Caltha leptosepala
Phleum commutatum
Equisetum sp.
~Number of areas sampled was 1.
51
Table 19
Cover percentages for total vegetation,vertical strata,and plaR;
species in closed mat and cushion tundra vegetation/habitat type-
in Upper Susitna River Basin in summer 1980.
Category
Total vegetation
Ground layer «0.5 m tall)
Lichens,unidentified
C1adonia spp.
Empetrum nigrum
Ledulll decumbens
Vaccinium uliginosum
Arctostaphylos spp.
Betula glandu10sa
Betula nana
Crowberry
Northern Labrador tea
Bog blueberry
Bearberry
Resin birch
Dwarf arctic birch
Average
Cover (%).!Y
78
78
14
8
8
7
8
7
6
10
~Number of areas sampled was 8.
.!Y Includes only those species with at least 5%cover in anyone
area sampled.
52
r""
I
more closely associated with wading birds and beaver,where topo-
graphy allowed dam building.In many cases,the wet sedge-grass
vegetation was likely the result of beaver activity.
3.5.3 -Shrubland Types
Shrubland vegetation/habitat types were the most prevalent types in
the Upper Susitna River Basin.They generally occurred at higher
elevations than forest communities but at lower elevations than
tundra types.Most areas,particularly the low shrub,were found
on extensive,fairly level benches at mid-elevations throughout the
upper basin.Less extensive areas,usually tall shrub,were found
on steep slopes above the river.Two main types were found:tall
and low shrub with each being further divided into closed and open
types by the percentage shrub cover.Approximately 65 identified
species were encountered in this overall type.Aspects of the
shrubland vegetation/habitat types were variable.
Tall shrub communities were dominated by alder (Alnus sinuata)and
were found mostly on steep slopes above the river or sometimes
above the flat benches with an average elevation of 573 m.~Many of
these stands were 2 to 4 m tall.Approximately 25 identified
species were encountered in either the closed or open alder stands.
Alder stands frequently occurred as stringers through other vege-
tation/habitat types along the slopes by the river.Many areas
also contained alder as a ring around a mountain at a certain
elevation or a strip alonQ a river drainage as at Portage Creek.
The closed stands had almost complete vegetation cover with the
ground layer and understory each accounting for most of the cover
(Table 20).Portions of some of these stands were like thickets.
Alder provided the most cover with bluejoint and woodland horsetail
accounting for most of the ground layer cover.
Only one open alder stand was visited,but it had less vegetation
cover than the closed alder sites with most of the vegetation being
53
Table 20
Cover percentages for total vegetation,vertical str~;a,and plant
specles in closed tall alder vegetation/habitat type-in Upper
Susitna River Basin in summer 1980.
<2.5 cm dbh)
Sitka alder
American green alder
Currant
~
,
Category
Total vegetation
Understory (2.5 -10 cm dbh)
Alnus sinuata
Alnus crispa
Shrub layer {>0.5 m tall,
Alnus sinuata
Alnus crispa
Ribes spp.
Ground layer (<0.5 m tall)
Equisetum siTvaticum
Ribes spp.
Alnus sinuata
CalamagrQstis canadensis
Sitka alder
American green alder
Woodland horsetail
Currant
Sitka alder
Bluejoint
Average b
Cover {%)...1
96
57
25
32
38
28
10
8
62
31
8
7
35
""'"I
~Number of areas sampled was 3.
~Includes only those species with at least 5%cover in anyone
area sampled.
54
.....
in the understory layer (Table 21).Bluejoint was the most im-
portant ground layer species.White spruce was !Jresent in the
overstory and understory.A mixture of alder with white spruce
probably indicated that this was a successional stand.
Hanson's (1953)description of alder types was similar to those
found in the Upper Susitna River Basin in that these thickets
occurred on well-drained slopes and·varied from 1-to 4-m tall.
Bluejoint was a dominant ground layer species in many cases.
Beauverd spiraea (Spiraea beauverdiana)and bog blueberry were also
mentioned as important species.Hanson (1953)observed birch
shrubs (Betula spp.)as an important species in alder stands,but
the areas encountered along the Upper Susitna River Basin did not
contain any observed birch shrubs.In contrast,the Susitna stands
contained important quantities of woodland horsetail.Hettinger
and Janz (1974)similarly observed that alder stands occurred on
steeper slopes and older riparian sites.
Squirrel,hare,and moose signs were relatively prevalent in these
stands.One alder stand located on a slope of the Susitna Canyon
(RllE,T29N)\'Ias very heavily used by moose.Currant (Ribes spp.)
appeared to be highly preferred browse in this stand.Willow was
important browse in all stands,and certain individuals of American
green alder (Alnus crispa)were heavily browsed.
Low shrub communities were found on the extensive relatively flat
benches where soils were frequently wet and gleyed but usually
lacking standing water (except for willow types).Average ele-
vation was about 781 m.Over 40 identified species were encoun-
tered in this vegetation/habitat type.Subtypes included birch,
willow,and a mixture of the two.Because of the gradations
between the subtypes,descriptions were very general.Both open
and closed stands had almost complete vegetation cover (Tables 22
and 23).The ground and shrub layers contributed similar amount of
cover in closed stands while the ground layer provided most of the
cover in the open communities.Shrub layer cover estimates might
55
Table 21
Cover percentages for total vegetation,vertical s£yata,and plant
species in open tall alder vegetation/habitat typ~in Upper
Susitna River Basin in summer 1980.
~Nurnber of areas sampled was 1.
~Includes only those species with at least 5%cover in anyone
area sampled.
Shrub layer (>0.5 III tall,<2.5 Clll dbh)
Alnus sinuata Sitka alder
,~-
-
-
Category
Total vegetation
Overstory (>10 cm dbh)
Picea glauca
Understory (2.5 -10 cm dbh)
Picea glauca
Alnus sinuata
Ground layer «0.5 m tall)
Linnaea borealis
Alnus sinuata
Calamagrostis canadensis
White spruce
White spruce
Sitka alder
Twi nfl ower
Sitka alder
Bluejoint
Average b
Cover {%)J
85
10
10
45
5
40
10
10
25
5
5
10
56
-
--I
Table 22
Cove~percentages for total vegetation,vertical sta7 ta,and plant
specles in closed low shrub vegetation/habitat type-in Upper
Susitna River Basin in summer 1980.
Feather moss
Crowberry
Northern Labrador tea
Labrador tea
Bog blueberry
Mountain cranberr}{
Red-fruit bearberry
Resin birch
Dwarf arctic birch
-
Category
Total vegetation
Shrub layer (>0.5 m tall,<2.5 cm dbh)
Betula glandulosa Resin birch
Salix pulchra Diamondleaf willow
Ground layer «0.5 m tall)
Mosses,unidentified
Feather mosses
Empetrum nigrum
Ledum decumbens
Ledum groenlandicum
Vaccinium uliginosum
Vaccinium vitis-idaea
Arctostaphylos rubra
Betula glandulosa
Betula nana
Average b
Cover (%)-.1
93
42
10
8
52
17
6
7
18
4
8
8
6
34
9
-
~Number of areas sampled was 10.
~Includes only those species with at least 5%cover in anyone
area sampled.
57
Table 23
Cover percentages for total vegetation,vertical ~;rata,and plant
species in open low shrub vegetation/habitat type-in Upper Susitna
River Basin in summer 1980.
Feather moss
Labrador tea
Bog blueberry
Resin birch
Water sedge
Category
Total vegetation
Shrub layer (>0.5 m tall,<2.5 cm dbh)
Betula glandulosa Resin birch
Ground layer «0.5 m tall)
Feather mosses
Ledum groenlandicum
Vaccinium uliginosum
Betula glandulosa
Carex aquatilis
Average b
Cover (%)-1
100
17
5
83
13
5
15
15
43
-
~Number of areas sampled was 2.
QI Includes only those species with at least 5%cover in anyone
area sampled.
58
I~
-
be high because of problems in estimating cover from the ground,
the same problem encountered in the forest types.
Birch shrub stands were usually dominated by resin birch (Betula
glandu10sa)about 1.0 m tall and contained several other species of
low shrubs,especially northern Labrador tea.Mosses contributed
an important amount of cover.In some stands,there was a buildup
of soil and debris around the bases of each birch shrub clump
creating a large amount of microrelief.Sometimes the stands were
dense like a thicket while others had large openings between
individual birch shrubs.Scattered black spruce occurred in some
stands contributing almost 10%cover.Hence,low shrub and wood-
land black spruce stands were difficult to distinguish on the
ground and on the aerial photography.The two species of birch
shrub,resin (Betula glandu10sa)and dwarf arctic birch (~.nana),
were sometimes difficult to distinguish based on leaf shape and
plant height.Viereck (1966)commented on this problem,also.
Willow stands were usually found in wetter areas,frequently with
standing water.Water sedge was the important herbaceous species
in these stands.Because of the wetness,these communities were
usually less diverse than birch shrub stands.Willows frequently
had soil and debris built up at their bases also with standing or
running water in the troughs.
t
Birch shrub communities apparently received moderate use by moose
most of the year.However,it was obvious that stands with more
willow were preferred.Indeed,willow stands received greater use
than any other vegetation type.Fe1t1eaf willow (Salix a1axensis)
and diamond1 eaf wi 11 ow C~..planifo1 ia)\l/ere heavi 1y uti1 i zed in
most areas.
Caribou sign were also frequent in birch communities.Skoog (1968)
found that leaves of resin birch were important food for caribou in
summer,and in winter,lichens were important.He found that
59
,."..
caribou feed on willows in spring and fall and considered willow
stands important to the ecology of caribou.We agree with this,
but specify that this is apparently true only for stands found
above the rim of the river canyon.
Low shrub vegetation/habitat types were common in northwestern
(Hanson 1953)and northeastern Alaska (Hettinger and Janz 1974)as
well as in the Upper Susitna River Basin.The 80st important
associated species in the birch shrub stands was bog blueberry
while mosses and lichens contributed large amounts of cover.
Crowberry was also common in all three studies as well as Viereck's
(1966)study on the Muldrow Glacier.The birch-willow type which
Hanson (1953)described is 2 to 3 m or more tall,while Susitna
birch-willow stands were usually less than 1.5 m tall.Birch shrub
stands near the Muldrow Glacier in the Interior were 1.0 to 1.5 m
tall (Viereck 1966),which was similar to the Susitna stands.
Similar associated species included northern Labrador tea and bog
blueberry (Hanson 1953 and Hettinger and Janz 1974).Mountain
cranberry was important in northeastern Alaska and the Susitna
area,but not in the northwestern part of the state.
3.5.4 -Herbaceous Types
Two herbaceous types also existed but were not described on field
reconnaissance sheets.Grasslands dominated by b1uejoint were
present on level to sloping areas at lower elevations along the
river and along the Portage Creek drainage.Herbaceous pioneer
communities were present on gravel and sand bars that had recently
become vegetated.These soils had little organic matter and often
had a large amount of cobbles.Pioneer species included horsetails
(Eguisetum spp.),lupines (Lupinus spp.),and alpine sweetvetch
(Hedysarum a1pinum).
60
-'
-
.-
-
3.5.5 -Unvegetated Types
There are three classes of unvegetated areas depicted on the
maps:water,rock,and snow and ice.Lakes and streams were
included in the water category.Lakes were generally found along
flat benches and ranged in size from small ponds to large lakes
such as Big Lake.Rock was those areas of bedrock or deposited
geologic materials which had little or no vascular vegetation
growing on or in them.Rock occurred as outcroppings at high
elevations or along steep cliffs along the river or as unconsoli-
dated gravel in newly deposited river bars.Snow and ice include
permanent snowfields and glaciers.Glaciers and permanent snow-
fields were most common at the northern end of the study area in
the Alaska Range although some did occur near the southern boundary
in the Talkeetna Mountains.
3.6 -Wetlands
3.6.1 -Identification and mapping of wetlands
Recently,the U.S.Fish and Wildlife Service adopted (USF&WS 1980)
the wetland classification system described by Cowardin et ~.
(1979).The primary purpose of this classification is to provide a
basis for conducting inventory and evaluation of wetland portions
of ecosystems,so they can be managed more logically.The classi-
fication was not designed to define the jurisdiction of government
agencies (USF&WS 1980).As Cowardin et~.(1979)state,"There is
no single,correct,indisputable,ecologically sound definition of
wetlands,primarily because of the diversity of wetlands and be-
cause the demarcation between dry and wet environments lies along a
conti nuum".
61
-
With the above in mind,we attempted to use the classification of
Cowardin et~.(1979)to map and classify the wetlands within the
proposed impoundment areas and floodplain below the Devil Canyon
dam site to Talkeetna.However,it was apparent that many of the
wetland classes given by this classification could not be identi-
fied solely from aerial photography.Specifically,we could not
classify riverine or most lacustrine systems without on-ground
sampling of bottom and shore materials.Consequently,these were
classified simply as lake,pond,river,or stream.Table 24 lists
the vretland classes and corresponding vegetation types (from
Viereck and Dyrness 1980)by the landscape that was actually mapped.
The map of wetlands (Figure 5,see accompanying maps)does not
delineate all the wetlands occurring in the area,nor are the
boundaries precise which are given.This is in part due to re-
strictions imposed by scale (many wetlands are smaller than what
can be legibly mapped),but is also due to the fact that boundaries
are graded and obscure,even when viewed from the ground.The
Alaska District Corps of Engineers (1979)encountered the same
problems when they attempted to map much of the wetlands of the
same area in 1979.They concluded that detailed maps would have
been lI ex tremely difficult"to produce,because the wetlands are
highly integrated with non-wetlands,and because plant species
composition in wet and non-wetlands is similar,differing only
in the quantities of individuals.Additionally,they,as we,
found that many non-wetland areas can contain free water.This
was especially true during the unusually wet summer of 1980.
3.6.2 -Vascular Aquatic Plants
3.6.2.1 -Introduction
The objective of this study was to assess the aquatic vascular
plants growing within the adjacent to ponds and lakes in the area
62
Table 24
Vegetation and wetland classes found in the proposed Susitna impoundment
and borrow areas.
63
,....
,~
.-
of study.The area of study extended from Devil Canyon to the
confluence of the Oshetna River.Selected ponds and lakes within
the impoundment area as 'Ilell as on the adjacent upl and plateau
areas were evaluated.Twenty-four lakes and ponds were assessed
from the ground (Figure 6).Helicopter overflights were made of
many of the remaining lakes and ponds in the area to ensure simi-
larity among ponds and to search for new species.
During each ground stop the species growing within and adjacent to
the body of \'/ater were recorded.Notes were kept on the types of
species encountered (floating,submergent,etc.)and where the
species commonly occurred (bank,shallows,deep water,etc.).
The species were divided into "true"aquatics and II bank II species.
Although there is no good definition of aquatic plants,"true"
aquatic plants are defined here as those growing directly in water
or immediately adjacent to water.Species that dominated the banks
or periphery of the ponds or that frequently occurred on floating
mats were considered 11bank"species.All the species recorded are
considered hydrophytes.
For each species a subjective evaluation was made as to whether it
was dominant,common,or sparse in each area in which it was found.
Total estimated cover of aquatic vegetation (relative to the total
amount of water),surrounding wetland width,and elevation were
also recorded for each water body assessed.
The wetland area,as defined here,is primarily restricted to the
wet sedge-grass tundra type presented in the vegetation/habitat
cover maps,or the Lacustrine-Limnetic-Emergent Wetland-Vascular
wetland class of Cowardin et al.(1979).
The Susitna River itself and its tributaries were not specifically
assessed for aquatic plants.Because of the high velocity of the
tributaries and the velocity and sediment load of the mainstream
Susitna,they are nearly devoid of aquatic vascular plants.
64
>~-J l 1 )1 1 }1 j ]J J j
Lo._,
10
15510
I<ILOMETER5
MILES
_...-.-SUSITNA BASIN BOUNDARY
o~----
5 0
--"('d \I C It~/~-:.~~_}~/;.~"'"~.'"""''-_/./(Jv ';,.'...d .....•//'.C":>I:?'\.r---.~..l",~•,'.""\"~...I\..I .r----.,.....J'"',~!~~"y'\......-.J \I I -'.....-t ~\.'""..'.'......,~A~·.\./j.l.").~y '.J.?r"'C--.-.\"-..)i]o.•)~II_~.,,,T
/'d.__t1 J ~~)-'-f {.?-[.~""r:'::"t.¢~~~.''.'\'-l ------.
(~",,\.\\~6W_~
Figure 6
Locations of lakes and ponds surveyed for vascular aquatic plants in August 1980.
-
.-
3.6.2.2 -Results and Discussion
There are very few ponds and lakes within the impoundment areas.
Most of the water bodies occur on the upland plateau between the
edge of the river canyon and the surrounding mountain.There are a
countless number of lakes in the large flats of the Upper Susitna
Basin,such as those in the southeastern portion of the upper basin
in the Lake Louise area.Most of the lakes and ponds immediately
adjacent to the impoundment area are classified according to
Cowardin et~.(1979)as:Lacustrine-Limnetic-Unconsolidated
Bottom or Aquatic bed;or Lacustrine-Littoral-Aquatic Bed or Uncon-
solidated Bottom.
The dominant Ittrue"aquatic species of the water bodies were:
horsetail (Equisetum fluviatile),bur reed (Sparganium angustifolium),
sedge (Carex aguatilis),yellow pond lily (Nuphar polysepalum),
mare's tail (Hippuris vulgaris),and bladderwort (Utricularia
vulgaris)(Table 25).
Bur reed and yellow pond lily probably contributed more to total
cover than all other species combined.Yellow pond lily,which is
a submerged species with large floating leaves,was particularly
prominent and formed vast beds in several water bodies.It did not
occur along the edges of ponds,but appeared to grow best at depths
ranging from 0.6 to 2.1 m.As a result,a band of yellow pond lily
frequently occurred around the lake away from the shore in the area
between the shallows and deep water.Bur"reed,on the other hand,
frequently dominated the shallows of the ponds which were about
0.15 to 0.60 m in depth.Horsetail,mare1s tail,and bladderwort
were also common in these shallows.Horsetail was common on rocky
bottoms where little other vegetation occurred.Bladderwort
appeared to be more prominent in shallows with a mud bottom or a
bottom of organic matter.
Dominant "bank"or edge species included:horsetail,reed bent
grass (Calamagrostis canadensis),cotton grass (Eriophorum spp.),
66
}1 )}1 )}}]})}1 j )i
Table 25
Jlquatic Plant Survey,Susitna Hydroelectric Project.llLl!1JSt 1980
SPECIES Pond or Lcte (#)
"'TRUE"JlQ.U\TICS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Cl imaciun sp.--M:lss d(a)c
Isoetes lIlJricata --Quilll'tlJrt s
Equisetun fllNiatile --Horsetail d d d c d s s
Sparganiun angustifoliun --Bur rem c d d d d d d c d c c d s s c c c
Potamgeton sp.--Pond.o.eed
(narlU'l-leaved)c c s
Potamgeton sp.--Pond.o.ea:l
(broad-leaved)s s c d
Potamgeton Robb ins ii --Ponck!a:l d
Potamgeton fil ifonnis --Pona.-.eect s s
Eriophorun spp.--Cotton grass s
Carex aquat j 1is --Sed~d d c c d d c d
NUJt1ar IXllysepahm --Yellcw IXlnd 1ily c d d d d d c d d d d c d d d d d
Ranuncu 1us confervo ides --Buttercup c d d s s s s
Potentilla palustris --Marsh fivefin~r s
Ca 11 itriche vema --Water starl'tlJrt d
HipPUris vulgaris --Mare's tail c c s d c c s s s
~yanthes trifol iata --Buckbean s
utricularia vulgaris --Bladderl'tlJrt c d c c d d s s d
a.d=dJninant.c=ccrmnn.s=sparse
1 1 )1 })1 )l }')J j 1 -~
Tible 25 (Cont')
SPECIES Pool or Lc*e (#)
IB1W<"SPECIES 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
(a)
Spha~spp.--Sphagrun nnss c d d
Equisetun fluviatile --Horsetail d d d s
\tlods ia sp.--W:lods ia s
Ca lanagrostis canadensis --Reed
bent !Tass d d d c c s
ErioJitorun spp.--Cottoo grass d d c d d d c s d c
Carex sp.--Sedge d d d
Carex aquat i 1is --Sedge d d d d d d d d d d s d d d d d d d d d
Carex rhyncop,y.;a --Sedge s c
Iris setosa --Iris s---
Sal ix sp.--WillCM c s s
Potentilla palustris --Marsh fivefinger c d c c d c c d c s s c d c
JllldrarEda pol ifo 1ia --Andrareda c
M:nyanthes trifo1i ata --Buckbean s c c d s c
a.d=daninant,c=eamon,s=sparse
}}1 1 )1 -)')I ;1 1 1 -1 1
'.Cill.e 25 (ll:nt.')
RIrl cr late (J)
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
(6)
Total Cover (%)<1 <5 -0-1 --10-20 <5 -0-5 0-1 1-5 1-2 ID-9O 80-100 50-60 1-5 0-1 5-10 40-50 15 2o-:Jl 20-35 10-20
Surrounding Wetland
0 2-3 3-6 &'J 3-6 3-6 2-9 15-:Jl 0-3 15-25 3-5 15-:Jl 15-25 30-45 3-15 1-2 2-3 0 &'J 12-15 3-6 2-3width(Meters)--
Elevation (Feet)1950 1700 2m 2m 2180 2180 2llOO 1950 1950 1975 2m mel 2410 2J4O 1850 2m Dill 2750 1800 :m:l 2250 2560 2575 2560
b.data rot recorded
-
F'.
sedge (Carex aguatilis),marsh fivefinger (Potentilla palustris)
and buckbean (Menyanthes trifoliata).Sedge probably contributed
more to total cover than all other edge species combined.It was
the prevalent species of the pond shallows from about 0 -0.3 m in
depth,along the pond periphery,and,also on floating mats,which
were sometimes present.
The same species'were encountered in many of the water bodies of
the area.The one exception was the aquatic vegetation of Watana
Lake.This lake was dominated solely by pondweed (Potamogeton
Robbinsii).This pondweed is a submerged rooted aquatic species
that grew in water from about 1.2 to 2.4 m in depth.Hulten (1968)
reports that this species is known from his area of study,but it
has only been collected once at Summit.Welsh (1974)indicates
that it is known from southcentral Alaska,but evidently rare.The
reason for the lack of other vascular plants in Watana Lake and the
presence of Potamogeton Robbinsii is not understood;although at
914 m elevation,this lake had the highest elevation of any water
body assessed.
Total cover of aquatic vegetation and the width of the surrounding
emergent wetland area varied from pond to pond (Table 25).Total
cover appeared to vary depending upon the proportionate amount of
open water (i n general,more than 2.1 m in depth)to shallow water
present in each pond.The higher the percent of shallow water the
greater the area that sufficient light could penetrate to the
bottom and,as a result,the higher the cover of aquatic plants.
This trend is valid in general,although lakes and ponds above 945.
m in elevation usually had sparse aquatic vegetation cover regard-
less of the bottom morphology.Rocky substrate and rock ledges
also appeared to limit the amount of aquatic vegetation cover.
The amount of associated emergent wetland area,which was dominated
by sedge and other common bank species,appeared to be related to
surrounding topography,bottom morphology and the age of the water
70
.....
body.Steep slopes or topographic relief around the water body
limited the amount of associated emergent wetland.Ponds in de-
pressions in relatively flat terrain had a well developed asso-
ciated wetland around them.Organic matter developed as the water
bodies became older and probably increased the periphery area
dominated by emergent wetlands.A floating mat of vegetation was
sometimes a'part of the associated emergent wetland.These mats
developed over a layer of water and were dominated by sedge,
sphagnum moss,and common bank species.
A summary of the dominant aquatic species and factors influencing
their location in and around many of the water bodies in the Upper
Susitna Basin is presented in Figure 7.The existence and size of
each zone indi~ated varies from pond to pond,although the general
trends of the area are presented.
3.7 -Endangered,Threatened,Rare,and Noteworthy Species
3.7.1 -Endangered,Threatened,and Rare Species
No plant species are presently officially listed for Alaska by
federal or state authorities as endangered or threatened,however
37 species are currently under review by the U.S.Fish and Wild-
life Service (USF&WS 1980)for possible protection under the
Endangered Sped es Act of 1973.A recent pub 1i cati on by Murray
(1980)discusses the h~bitat,distribution,and key traits of most
of these species.
A list of species (Table 26)extracted from Murray (1980)was
believed to be the most likely plants of this category to be found in
the Susitna River drainage,and in the landscape modified by the
construction of the proposed dams and hydroelectric power plants .
Since the upper reaches of the drainage were expected to be the
least impacted,the major portion of the survey was devoted to the
71
1 1 -,]B -»J )l l )1 ,
...J
N
OPEN WATER ZONE
-usually greater than 2.)m in depth
-little to no aquatic vegetation
FIGURE 7
DEEP WATER ZONE
-water from 0.6 to 2.)m in depth
-usually dominated by yellow pond lily
-size variable depending on bottom morphology
SHALLOW WATER ZONE
-water 0.)5 to 0.6 m in depth
-usually dominated by bur reed,
horsetail,mare's tail,and
bladderwort
-size variable depending on bottom
morphology
-species composition influenced by
\substrate~EMERGENT WETLAND PERIPHERY
-water from ground surface to Oo3m
in depth
-may contain a floating mat of
vegetation
-dominants include sedge,cotton grass,
reed bent grass,marsh fivefinger,
buckbean,and sphagnum moss
-size influenced by bottom morphology
and surrounding topography
A SCHEMATIC REPRESENTATION OF THE DOMINANT VEGETATION ASSOCIATED WITH MANY OF THE LAKES AND PONDS
OF THE UPPER SUSITNA BASIN.
Table 26
List of endangered and threatened plant species~sought in the August
1980 survey.
Species and Habitat Unofficial Status b/
Smelowskia pyriformis Drury &Rollins Threatened species
North American endemic
calcareous scree,talus,in upper Kuskikwim R.drainage
Aster yukonensis Cronq.Endangered species
North American endemic
river banks,dry streambeds,river delta sands and gravels
Kluane Lake,Koyukuk River.
Montia bostockii (A.E.Porsild)S.L.Welsh Endangered species
North American endemic
wet,alpine meadows,St.Elias Mtns.,~Jrangell Mtns.
Papaver alboroseum Hult.Endangered species
Amphi-Beringian
well-drained alpine tundra,Wrangell Mtns.,St.Elias Mtns.
Cook Inlet lowlands,Alaska Range
Podistera yukonensis Math &Const.Endangered species
North American endemic
S.facing rocky slopes,grasslands at low elevations,
Eagle area,Yukon border
Smelowskia borealis (Greene)Drury &Rollins Endangered species
var.villosa
North American endemic
alpine calcareous scree,Mt.McKinley Park,Alaska Range
Taraxacum carneocoloratum Nels.Endangered species
North American endemic
alpine rocky slopes,Alaska Range,Yukon Olgilvie Mtns.
Other Endangered Species Possibilities:
Cryptantha shackletteana
Eriogonum flavum var.aquilinum
Erysimum asperum var.angus tatum
Upper Yukon River
Eagle,Alaska
Upper Yukon River
a/Species information and status from Murray (1980).
b/All species,except Papaver alboroseum,are under review by the U.S.
Fish &Wildlife Service for possible protection under the Endangered
Species Act of 1973.
73
-
study of potential habitats in and around the impoundments.The
general habitat requirements and occurrence of these plant species
were known from a previous taxonomic and ecological study in
Alaska,and from information given by Hulten (1968).
Field searches were made in potential habitats in August 1980.The
late date of the survey may have made the detection of the spectes
difficult although all are perennials,and the late vegetative stages
should have still been present in the phytomass.
The field survey was conducted in three main areas:1)the upper
drainage basin,alpine areas near the Susitna and West Fork Glaciers,
2)the lowlands of the upper drainage basin,Maclaren and Tyone
Rivers,ridges,terraces,and periglacial features,and 3)the
lower drainage,outcrops,and promontories along the Susitna River
near Watana Creek,Kosina Creek;and gravel bars in the river bed.
As several of the-endangered species and the only threatened
species (Sme10wskia pyriformis)favored well-drained,rocky or
scree slopes,this habitat was surveyed in the steep valleys
adjacent to the Susitna and West Fork Glaciers,Figure 8.Typical
alpine tundra vegetation prevailed on most of the sc~ee slopes
studied.
A helicopter and foot survey was made of the upper basin of the
Susitna drainage and its tributaries.These rivers meander widely
in this area and are re-working glacial-fluvial deposits.There
are numerous lakes and ox-bow ponds,and periglacial features are
abundant.Well-drained,sandy and gravelly ridges and terraces in
this area would provide suitable habitat for several of the species
being sought (Table 24).None of the endangered and threatened
plant species were found in the upper basin lowland survey which
was not exhaustive in extent considering the large area involved.
Additional field work may be justified in this area.
74
-
....
Figure 8
Areas surveyed for threatened and endangered
species in the Susitna-West Fork Glacier area.
The major portion of the endangered and threatened plant survey was
conducted in the Susitna River drainage adjacent to and upstream
from the Watana Camp site to the confluence of the Susitna River
and the Oshetna River.A trip was made downstream as far as Devil
Canyon and two large gravel bars within the river bed were surveyed.
These gravel bars are rather vigorously eroded and the vegetation
is primarily confined to the dense growth of spruce,hardwoods,
shrubs,and grasses on the stable,elevated portion of the bar.
Few invader species were observed on bare gravel and silt.
Since several of the species being sought were recognized calci-
philes,calcareous rock materials were surveyed from geologic maps
of the area.Field tests were made with 10%hydrochloric acid
which indicates by effervescence the presence of free carbonates.
The included maps (Figures 8 and 9)show the locations of the
outcrops surveyed in the Watana Creek-Oshetna River area with
calcareous outcrops being indicated,and the alpine areas surveyed.
Three calcareous areas were found in the survey,one of which was
indicated on the geologic maps consulted.The first calcareous
area encountered was on the northwest slopes of Mt.Watana at an
altitude of approximately 1128 m.An outlier ridge with light
colored rock outcrops in this area and a report of marine fossils
in the area made it a likely habitat for calciphilic species.The
light gray rocks on this ridge gave a positive test for carbonates
and two recognized calciphiles were found in the area,Saxifraga
oppositifolia and Rhododendron lapponicum.None of the plant
species on the endangered or threatened list were found.
The second calcareous outcrop encountered in the survey of poten-
tial habitats in which the endangered and threatened species might
be found was located on the south side of the Susitna River,just
east of the confluence of Kosina Creek and the Susitna River.A
series of low,grey domes occur on the westfacing slope of an
unnamed prominence at an elevation of 1006 m (Figure 9).These
76
1 1 J 1 1 1 1 1 1 1 j 1 ]1
-
--
~,
-
domes of calcareous rock were apparently distinct from the main
mass of rocks composing the main peak which was acidic by test.
The Kosina Creek calcareous area had several calciphilic species
such as Saxifraga oppositifolia and Rhododendron lapponiculll.A
sterile collection of Taraxacum was collected adjacent to the
largest calcareous dome and it is the only potential representative
of the threatened and endangered species group encountered in the
1980 survey.A third calcareous prominence was encountered in the
survey of peaks in the middle Susitna River drainage.This area is
on the north side of the Susitna River,on the west side of Watana
Creek,approximately 7.24 km west of the creek at an altitude of
671 m.No threatened species were observed on the gravelly domes
in this area.
In summary,the only plant species observed and collected during
1980 which could have belonged to any of the endangered or threat-
ened taxa was a collection of Taraxacum made near Kosina Creek on
calcareous rocks and soils.This site was at an elevation of 1006
m,and is far above any possible impact from the impoundments.
3.7.2 -Noteworthy Species
Twenty-one vascular plant species were encountered during the
summer of 1980 in the Upper Susitna Riv~r basin which were outside
the ranges indicated by Hulten (1968)(Table 27).Some of these
species may have been reported in the area in the 12 years since
Hulten1s publication.Some of these range extensions are the
result of more intensive botanical surveys in the area while some
may represent an actual enlargement of the range for some species.
Because the Upper Susitna River drainage is not extremely well-
represented in existing plant collections,range extensions,and
some new records may be expected from any botanical surveys in the
area.The Upper Susitna River drainage may represent a unique
78
r-
,
-
-,
-
".",
-
Table 27
Vascular plant species in the Upper Susitna River Basin which are
outside their range as reported by Hulten (1968).
Equisetum fluviatile
Lycopodium selago ssp.selago
a/L~copodiu~complanatum
-Plcea manana
Carex filifolia
Danthonia intermedia
Luzula wahlenbergii
Veratrum viride
Plantanthera convallariaefolia
Plantanthera hyperborea
Echinopanax horridum
a/Senecio sheldonensis
-Myrica ~
Ranuncu~occidentalis
a/Potentilla biflora
-Rubus idaeus .
Rubus pedatus
Galium triflorum
Pedicularis kanei kanei
Pedicu1aris parviflorus
Potamogeton robbinsii
~Viereck and Little (1972)include the Upper Susitna River Basin
in the range of this species.
79
-
-
phytogeographic region in that the lowlands habitats of the Cook
Inlet and Talkeetna River valley extend into the upper basin of the
Susitna drainage and make contact with the arctic-alpine habitats
and flora of the Alaska Range.Alpine habitats close to maritime
locations in central Alaska have unique assemblages of plant
species,especially those called the amphi-Beringian floristic
element.A representative example of this floristic type may be
seen at Hatcher Pass in the Talkeetna Mountains.
Two of these species represent significant range extensions:
Senecio she1donensis and Danthonia intermedia.S.she1donensis had
not previously been reported in the state except possibly in the
Skagway area (Hulten 1968).Our specimen was collected in a mesic
midgrass community in August near upper Portage Creek,but has not
yet been verified.There is at least one other informal report of
the species occurring in the study area.Welsh (1974)reports that
the species occurs in the southern Yukon and northern British
Columbia.
Danthonia intermedia was found in August in the grass portion of a
mosaic of low birch and grass communities in the low shrub areas
between the Maclaren River and the Denali Highway.Previous re-
cordings of the species occurred near the upper end of Cook Inlet
and the Skagway area (Hu1ten 1968).Moreover,the only other
representative of the genus in the state,Q.spicata,has only been
reported from near Ketchikan.This would represent a significant
extension of the genus although Q.intermedia was found in only the
one location in our study area.Welsh (1974),on the other hand,
reports the occurrence of Q.intermedia in southcentra1 Alaska with
no specific locations mentioned.
Potamogeton robbinsii,a submerged rooted aquatic was found in
Watana Lake.There has been limited collection of this species in
Alaska.Hulten (1968)reports it from his area of study,but it
has only been collected once at Summit.Welsh (1974)indicates
that it is known from southcentra1 Alaska,but evidently rare.
80
-
.....
The distribution of Picea mariana should also be noted since Hu1ten
(1968)includes areas north and ,south of the Upper Susitna River in
the range,but does not include the study area.Viereck and Little
(1972),however,do include the Susitna drainage in their distri-
bution map.This tree is one of the most common species in the
study area.
Most other species on the list represent only slight range exten-
sions.Most of these are extensions to the north (more inland)
from their previous observations.P1antanthera hyperborea and
Myrica ~extensions include sites between areas that were
previously included in the range.Potenti11a bif10ra and Pedicu1aris
kanei Durand kanei extensions were south of the previously reported
range.Both of these species were found on calcareous outcroppings
(Kosina Creek and Mt.Watana,respectively)while looking for
endangered species.These species are probably more adapted to the
drier environment associated with the interior or with calcareous
outcroppings in the Upper Susitna River Basin.
81
-
-
-
4 -IMPACT ASSESSMENT
4.1 -Construction Impacts
Assuming the plan developed by the U.S.Army Corps of Engineers (1978),
it is obvious that the major impact of the Susitna Hydroelectric Project
on vegetation will be the elimination of area from different vegeta-
tion/habitat types.The hectares of each vegetation/habitat type to be
impacted are presented in comparison with the total hectares of those
types in the entire Upper Susitna River Basin (Table 4).
If proposed maximum pool elevations are required,the Devil Canyon (1500
ft elevation)and Watana (2200 ft elevation)reservoirs will inundate
/'
3603 and 15,885 ha of area respectively;2753 and 13,669 ha,respectively,
are vegetated (Table 4).A total of 18,109 ha of vegetation will be
lost if all borrow areas (outside the impoundment areas)are also
totally utilized.Borrow sites may eventually be revegetated,however.
The 18,109 ha of impacted vegetation .represents roughly 1.2%of the
total vegetated area in the Upper Susitna River Basin.
Assuming maximum impact in the impoundment and borrow areas,the vege-
tation/habitat types which will be lost (and the apparent %each is of
the total available in the entire basin)are presented in Table 4.As
discussed in Section 3.4 Preliminary Vegetation/Habitat Type Maps,
problems created by comparing maps of two different scales resulted in
apparent percentages of overlap which are highly inflated for the com-
parison of birch forests in the impact areas with that of their avail-
ability in the overall basin.However,it can safely be said that birch
forests will be substantially impacted by the project,relatively more
so than any other vegetation/habitat type.The only other types which
would receive relatively substantial impact are open and closed coni-
fer-deciduous forests and open and closed balsam poplar stands.
The access road or railroad will destroy an additional 150-300 ha of
vegetation,depending on the route selected,and assuming access is from
82
-I
one direction only and 30 m wide roadbed.Three-hundred hectares is
roughly equal to 0.02%of the vegetation in the entire basin.The
primary vegetation types to be affected are mat and cushion tundra,
sedge-grass tundra,birch shrub1and and woodland spruce.Preliminary
observations indicate that the alternative routes are well below the
elevation where potential threatened or endangered species might occur.
The impact these losses of vegetation will have on the food supply for
wildlife can only be hypothesized or extrapolated from the literature.
The principal losses of vegetation impactment for large mammals will
likely be in terms of reduced berry supply for black bears and reduced
browse for moose.Skoog (l968)did not consider vegetation/habitat
types to be of much value for caribou when located on the steep sides or
bottoms of the Susitna River canyon.
Our own observations suggest that the berry resources which will be
inundated may be of primary importance to the black bears in early
spring.South-facing slopes of the canyon are the first to become free
of snow,at which time,much of the previous year's berry crop is
available to bears coming out of winter torpor.
The impact of the Devil Canyon reservoir on moose browse supply would
probably be minimal since the topography is steep and receives rela-
tively light use by moose.The impact of the Watana reservoir could be
more substantial,not only because it is larger,but because it also
receives at least moderate use by moose.It is not yet clear whether or
not this area is critical to overwintering moose.Ballard (1980)states
that moose use of the Watana Creek area occurred prior to March in
winter (1979-1980).In early November 1980,willow stands along Watana
Creek and porti ons of the Susitna Ri ver vl/i thi n the Watana impoundment
area had already been heavily browsed by moose.In both years,temper-
atures were higher than normal in November,and in early November 1980
snow accumulations were light.Consequently,it appears that browse
supplies in the bottoms of the Susitna River Canyon and its tributaries
may already be depleted before they would have much value as a browse
83
-
-
reserve in late winter or during severe winters.Additional information
on moose populations and impact is provided in the annual reports pro-
duced by ADF&G and Dr.Richard Taber.
4.2 -Operation Impacts
4.2.1 -Impoundment Areas
The Susitna Hydroelectric Project is located in a region of dis-
continuous permafrost.Consequently,we believe there is potential
for large earthflows and slumps,especially on north-facing slopes,
as the relatively warm reservoirs thaw adjacent permafrost.This
type of disturbance will most likely occur on black spruce sites
and may lead to their replacement,in places,by alder stands and
possibly open paper birch stands.Bank erosion may also result
from wave action and altered subsurface drainage.
4.2.2 -Downstream Floodplain
Impacts on the downstream floodplain have not been adequately
considered since vegetation studies are not planned for that area
until summer 1981.Preliminary thoughts are that the impacts on
vegetation will be relatively slight in the reach from Devil Canyon
to the Chulitna River,because this portion of the river is chan-
nelized most of its length,and aerial photography indicates rela-
tively little variations in area affected by fluctuating water
levels.Comparisons of 1951 aerial photography (1 :4000 scale)with
1980 photographs (1:4000 scale)indicates very little shifting of
banks or islands during the past 30 years.
Downstream from the Chulitna River to Delta Islands,considerably
more shifting of the river has occurred.In this reach plant
84
--
-
communities are in more varied stages of succession;the effects of
fluctuating water levels are apparently greater.However,the
extent to which moderated flows of the Susitna River,above the
Chulitna River,affect the periodicity and intensity of flooding in
the lower portion will need to be determined before we can appro-
priately predict impacts on the vegetation.
85
f~,
-
-
.-
5 -tHTIGATION
5.1 -Avoidance
Some vegetation in the vicinity of access roads,ancillary facilities
and reservoir facilities could likely be protected from damage during
the environmental studies and construction.This will require planning
and regulation of unnecessary activities,especially those involving
heavy machinery and ATV use during summer and fall.
5.2 -Compensation
Vegetation in the impoundment areas will obviously be erased.However,
some access-road cuts,borrow areas,or other ancillary facilities may
be revegetated upon completion of construction.Natural revegetation
may be adequate in most cases.Indeed,the current philosophy of those
connected with pipeline development in Alaska is that natural revege-
tation is desirable,providing soils with suitable physical and chemical
properties are in place where revegetation is to occur.Often,ferti-
lization is all that is needed before good natural revegetation will
occur.The apparent utility of this approach,coupled with the fact
that Native ownership of part of the lands prefers revegetation to be
natural,makes this approach most desirable.However,there may be some
sites where potential wind or water erosion or aesthetic considerations
would require more intensive revegetation practices,involving mulching
and/or reseeding with native or introduced species.
There appears to be good potential for increasing forage supplies in
areas adjacent to Watana Creek.We found considerable evidence sug-
gesting that past wildfires had stimulated growth of willow and birch
species.These areas have since received heavy use by moose.
86
-
-
Of all the vegetation types in the Watana Creek area,we believe that
woodland and open spruce stands hold the greatest potential for moose
habitat development,because,in their climax condition,they are rela-
tively unproductive of most kinds of wildlife habitat.Black spruce
stands reverted to an early successional stage would not necessarily be
the most valuable habitat of those already existing,but they would
represent the type with the least tradeoff in type conversion.
Much more work is needed to determine which kinds of sites would show
the best response to manipulation.If fire should be the tool used to
bring about a type conversion,then conditions should be determined
which result in the greatest removal of overlying moss and provide for
good establishment of desirable plant species.
Compensation for moose browse which may be lost along the floodplain
downstream from the Devil Canyon dam site appears to have the greatest
potential of any compensatory action.There,removal of later suc-
cessional vegetation (i.e.mature balsam poplar and spruce stands)might
effectively be accomplished through logging and/or fire.Indeed,we
suspect that more moose browse could be produced than is currently
growing there.Winter timber harvest and burning of slash could likely
pay its own way.
These types of habitat manipulation have not been studied on forest
lands in southcentral Alaska other than to document the effects of
wildfires.Consequently,a number of small test burns and clearings
would be highly advantageous for establishing which techniques and
conditions are most effective.Also,it will be important to determine
the extent to which other animal species might be displaced through this
type of habitat manipulation.
87
-
6 -REFERENCES
Floristic/Botanical Works:
Argus,G.W.1973.The genus Salix in Alaska and the Yukon.National
Museum of Natural Sciences Publications in Bota~y,No.2.Ottawa.
279 p.
Batten,A.R.,D.F.Murray,and J.C.Dawe.1979.Threatened and
endangered plants in selected areas of the BLM Fortymile planning
unit,Alaska.BLM-Alaska Tech.Rep.3.127 p.
Conard,H.A.1979.How to know the mosses and liverworts.Wm.C.
Brown Co.,Philadelphia.302 pp.
Crum,H.1976.Mosses of the Great Lakes forest.University Herbarium,
U.of Michigan,Ann Arbor.104 pp.
*Hulten,E.1968.Flora of Alaska and neighboring territories.Sanford
University Press.1008 p.
*Murray,D.F.1980.Threatened and endangered plants of Alaska.USDA
For.Serv~Pub.59 p.
Thomson,J.W.1979.Lichens of the Alaskan arctic slope.U.of Toronto
Press.314 pp.
*Viereck,L.A.and E.L.Little,Jr.1972.Alaska trees and shrubs.
Agric.Handbook No.410.USDA For.Servo 265 p.
*Welsh,S.L.1974.Anderson's flora of Alaska and adjacent parts of
Canada.Brigham Young University Press,Provo,Utah.724 p.
Plant Ecology/Succession:
Auclair,A.N.and F.G.Goff.1975.Intraspecific diameter differenti-
ation as a measure of species replacement potential.Can.J.For.
Res.4(4):424-434.
Bliss,L.C.and J.E.Cantlon.1957.Succession on river alluvium in
northern Alaska.Am.Midland Naturalist 58(2):452-469.
Clements,F.E.1934.The relict method in dynamic ecology.J.Ecol.
22:1-68.
*Drury,W.H.,Jr.1956.Bog flats and physiographic processes in the
Upper Kuskokwim River regions,Alaska.Contrib.Gray Herb.Harvard
Univ.130 p..
Dyksterhuis,E.J.1958.Ecological principles in range evaluation.
Bot Review 24:253-272.
88
*Gatto,L.W.,C.J.1~1erry,H.L.McKim,and D.E.Lawson.1980.Environ-
mental analysis of the Upper Susitna River Basin using LANDSAT
imagery.U.S.Army Cold Regions Research and Engineering Lab.,
Report CRREL 80-4,Hanover,N.H.,56 p.
Goff,F.G.1968.Use of size stratification and differential weighting
to measure forest trends.Am.Midland Naturalist 79(2):402-418.
*Hanson,H.C.1953.Vegetation types in northwestern Alaska and
comparisons with communities in other arctic regions.Ecology
34:111-140.
Haug,P.T.and G.M.Van Dyne.1968.Secondary succession in abandoned
cultivated fields:An annotated bibliography.ORNL-TM-2104.p.1-70.
(Oak Ridge National Laboratory,Oak Ridge,Tenn.)
Hegg,K.M.1970.Forest resources of the Susitna Valley,Alaska.USDA
For.Servo Pub.PNW-32.
Henry,J.D.and J.M.A.Swan.1974.Reconstructing forest history from
live and dead plant material:An approach to the study of forest
succession in southwest New Hampshire.Ecology 55(4):772-783.
*Hettinger,L.R.and A.J.Janz~1974.Vegetation and soils of north-
eastern Alaska.Arctic Gas Biol.Rep.Ser.21.North Eng.Serv.,
Co.,Ltd,Edmonton,Canada.206 p.
Itow,S.1963.Grassland vegetation ;n uplands of western Honshu,Japan.
Part II.Succession and Grazing Indicators.Japanese J.of Bot.
18(2):133-167.
Leeuwen,G.G.1966.A relation theoretical approach to pattern and
process in vegetation.Wentia 15:25-46.
*Mue11er-Dubois,D.and H.Ellenberg.1974.Aims and methods of vegetation
ecology.John Wiley and Sons,New York.547 p.
.Pichi-Sermolli,R.E.1948.An index for establishing the degree of
maturity in plant communities.J.Ecol.36:85-90.
Spenceley,A.P.1973.The effect of the stratification of vegetation on
the analysis of successional data.J.Ecol.61(3):767-773.
*Viereck,L.A.1966.Plant succession and soil development on gravel
outwash of the Muldrow Glacier,Alaska.Ecol.Monogr.36:181-199.
*Viereck,L.A.1970.Forest succession and soil development adjacent
to the Chena River in interior Alaska.Arctic and Alpine Research
2(1):1-26.
*Viereck,L.A..1975.Forest ecology of the Alaska Taiga.Proc.Circum-
polar Conf.on Northern Ecology,1975.
89
,~
....
*Viereck,L.A.,J.Foote,C.T.Dyrness,K.Van Cleve,D.Kane,and
R.Seifert.1979.Preliminary results of experimental fires in the
black spruce type of interior Alaska.USDA For.Servo Pub.PNW-332.
Whitford,P.B.1949.Distribution of woodland plants in relation to
succession and clonal growth.Ecology 30:199-208.
Zedler,P.H.and F.G.Goff.1973.Size association analysis of forest
successional trends in Wisconsin.Ecol.Monogr.43(1):79-94.
Remote Sensing:
Hironaka,M.,E.W.Tisdale,and M.A.Fosberg.1976.Use of satellite
imagery for classifying and monitoring rangelands in southern Idaho.
Forest,Wildlife,and Range Exp.Sta.Bull.No.9.University of
Idaho.
McKendrick,J.D.and P.C.Scorup.1974.A super bird's eye view of
Alaska.Agroborealis 6(1):26-30.
*Payne,D.P.1975.Introduction to aerial photography for natural resource
management.Oregon State University Press.324 p.
Poulton,C.E.1971.Inventory and analysis of natural vegetation and
related resources from space and high altitude photography annual
progress report.Calif.Univ.,Berkeley Forestry Remote Sensing
Laboratory,U.S.Forest Service.
Vegetation Classification/Mapping:
*Alaska District Corps of Engineers.1979.Wetlands survey of the Watana
and Devil Canyon dam sites.Dept.of the Army,Anchorage,Alaska.
Cowardin,L.M.,V.Carter,F.C.Golet,and E.T.LaRoe.1979.Classifi-
cation of wetlands and deepwater habitats of the United States.
USF&WS Pub.FWS/BS-79/3l.
*Joint Federal-State Land Use Planning Commission of Alaska.1973.Major
ecosystems of Alaska (map).
Kuchler,A.W.1967.Vegetation mapping.Ronald Press,,New York .
Kuchler,A.W.1964.Where is what?Bio-Science 14(7):39-41.
McCormick,J.1978.Ecology and regulation of freshwater wetlands.
IN:Freshwater Wetlands:Ecological Processes and Management PotentialTR.E.Good,D.F.Whigham,and R.L.Simpson,eds.),p.341-355.
Academic Press,New York.
*Mueller-Dubois,D.and H.Ellenberg.1974.Aims and methods of vegetation
ecology.John Wiley and Sons,New York.547 p.
90
,.,..
-
*Payne,D.P.1975.Introduction to aerial photography for natural
resource management.Oregon State University Press.324 p.
Sochava,V.1975.The content of vegetation maps and how to enrich it.
XII International Botanical Congress,Section 8,Ecological Botany.
Paper for Presentation at Symposium:Logical Principles of Construction
and Improvement of Information Content of Vegetation Maps.
*Spetzman,L.A.1963.Terrain study of Alaska,Part V:Vegetation.Engineer
Intelligence Study.Office,Chief of Engineers,Dept.of the Army,
Washi ngton,D.C.(map).
*U.S.Fish and Wildlife Service,1980.Notice.Federal Register,Vol.
45,No.193.
*Viereck,L.A.and C.T.Dyrness.1980.A preliminary classification
for vegetation of Alaska.Pacific N.W.Forest and Range Exp.
Sta.,Gen.Tech.Rep.PNW-106.38 p.
*Walker,D.A.,P.J.Webber,and V.Komarkova.1979.A large scale
(1:6000)vegetation mapping method for northern taiga.Institute
of Arctic and Alpine Research.Unpublished manuscript.48 p.
Other:
*Ballard,W.1980.Upstream moose studies.Quarterly Report,Susitna
Hydroelectric Project,Environmental Studies.
*Rost,G.R.and J.A.Bailey.1979.Distribution of mule deer and elk
in relation to roads.J.Wildl.Manage.43(3):634-641.
Skoog,R.O.1968.Ecology of the caribou in Alaska.Ph.D.Dissertation.
University of California,Berkeley.
*U.S.Army Corps of Engineers.1978.Plan of study for Susitna hydro
power feasibility analysis.U.S.Army Corps of Engineers,Alaska
District.
*Wallmo,O.C.,D.F.Reed,and L.H.Carpenter.1976.Alteration of
mule deer habitat by wildfire,logging,highways,agriculture,and
housing developments,p.37-47.IN:Mule deer decline in the
West --a symposium.Utah Agric.-rxp.Sta.Pub.134 p.
*Ward,A.L.1979.Dispersed recreation impact on big game resource.
IN:Dispersed recreation and natural resource management --a
symposium.College of Natural Resources,Utah State University,
Logan.(in press).
*References actually cited in this report.
91
7 -AUTHORITIES CONTACTED
Federal Agencies:
Bureau of Land Management
Anchorage,Alaska
Steve Talbot,Ecologist
-Letter from B.Collins 29 Sept.1980;request of plant
species list of Watana Mtn.area."
Paula Krebs,Remote Sensing Specialist
-Telephone call from B.Collins 9 July 1980;request for
preliminary vegetation map of the Denali study.
Forest Service (Forest and Range Exp.Station)
Anchorage,Alaska
Fred Larson,Research Forester
-Visit from B.Collins and P.Scorup 8 May 1980;requesting
cooperative agreement for inventory and analysis of plant
communities in the upper Susitna basin.
Forest Service (Forest and Range Exp.Station)
Fairbanks,Alaska
Leslie Viereck,Plant Ecologist
-21 May 1980;met with B.Collins (in Anchorage at ALMCTF
meeting)to discuss need for a hierarchical classification
of Alaska vegetation.
Soil Conservation Service
Weymeth Long,Director of State Office
-15 May 1980;hand delivered letter of cooperative agree-
ment to obtain approval for cooperative st~dy of vegetation
in upper Susitna basin.
Agricultural Stabilization and Conservation Service
Salt Lake City,Utah
Lola Britton, File Manager
- 6 May 1980,21 July 1980;orders for CIR imagery of th~
upper Susitna basin.
-19 Feb 1980;telephone call from J.McKendrick to discuss
availability of CIR imagery covering upper Susitna basin.
-10,11,18 June 1980;telephone calls from B.Collins
arranging for CIR imagery.
92
Fish and Wildlife Service
Kenai,Alaska
Wayne Regelin,Research Biologist
-27 May 1980;visit from B.Collins and J.McKendrick
discussing techniques for assessment of moose browse
production and utilization.
State Agencies:
Alaska Dept.of Fish and Game
Paul Arneson,Biologist
Suzanne Miller,Statistician
-13 May 1980;met with B.Collins to discuss needs of
lower Susitna moose habitat study.
- 6 June 1980;met in the field with B.Collins to test
techniques for sampling moose browse production/
utilization.
Charles Swartz,Biologist
-27 May 1980;met with B.Collins and J.McKendrick to
discuss methods for evaluating moose habitat and
nutritional value of browse species.
Loca 1 Agenci es :
Matanuska-Susitna Borough
Lee Wyatt,Acting Borough Manager
- 8 May 1980;letter from B.Collins to request cooperative
purchase of 1:63,360 scale CIR photography of upper
Susitna basin ..
93