HomeMy WebLinkAboutAPA2810ALASKA DEPARTMENT OF FISH AND GAME
JUNEAU, ALASKA
STATE OF ALASKA
Bill Sheffield, Governor
DEPARTMENT OF FISH AND GAME
Don w. Collinsworth, Commissioner
DIVISION OF GAME
W. Lewis Pamplin, Jr., Director
Steven R. Peterson, Research Chief
POTENTIAL OF REVILLAGIGEDO ISLAND
FOR A .GOAT TRANSPLANT .
By
Christian A. Smith
Final Report
Federal Aid in Wildlife Restoration
Project W-22-2, Job 12.6R
Persons i ntending ,t:6 . 'cite this material should obtain prior
permission from th'e .. author (s) and/or the Alaska Department of
Fish aj1d Game. BeC'a'li'se ·most reports deal with preliminary
-e sults o f continuing · studies, conclusions are tentative and
:hould be identified as such. Due credit would be appreciated.
(Printed May 1984)
FINAL REPORT (RESEARCH)
State: Alaska
Cooperator: Glen Contreras, Richard Coos, Duane Fisher,
USFS; Tom Meehan and Dave Bramlet, VTN
Consolidated; Kit Kitasaki, u.s. Borax
Project No: W-22-2 Project Title: Big Game Investigations
Job No.: 12. 6R Job Title: Potential of Revillagigedo
Island for a Goat Transplant
Period Covered: 1 July 1982 through 30 June 1983
SUMMARY
Approximately 1, 000 km 2 ( 400 mi 2 ) of the northeast third of
Revillagigedo (Revilla) Island were evaluated as potential moun-
tain goat (Oreamnos americanus) habitat. Point sampling of topo-
graphic and timber type maps provided data for use in frequency
distribution and discriminant function analysis comparisons with
occupied habitat on the adjacent mainland. Results indicate that
the areas are similar with respect to topography and gross vege-
tation communities and that approximately 32% of the sampled area
may be adequate winter habitat for goats. At current densities
on the mainland, this area would support approximately 600 goats.
On-site vegetation sampling was conducted on the mainland and
island to assess similarity of understory composition and browse
availability/utilization. Major species were the same in both
locations, and browse production was comparable. Utilization was
moderate on the mainland and nonexistent on the island. Abundant
forage is present in the transplant area.
Evaluation of interspecific relationships and snow depth patterns
on the island and mainland suggests that neither should adversely
affect transplanted goats. Winter range overlap of introduced
goats with resident deer (Odocoileus hemionus sitkensis) should
be minimal, and wolves (Canis lupus) may even benefit from pre-
sence of a buffer prey species.
It is recommended that a transplant be undertaken to mitigate
anticipated losses associated with development of the u.s. Borax
molybdenum mine at Quartz Hill. State and Federal agencies
should negotiate with private industry to seek an equitable cost
sharing for this project.
Key words: mountain goat, Oreamnos americanus,
habitat assessment.
i
transplant
CONTENTS
Summary . . . . . . • . . . . . . . . . . . . . . . . . . . . i
Background. . . . . . . . . . . . . . . . . . . . . . . . . . 1
Objective .......................... 2
Proposed Transplant Area. • . . . • • . . . • . . • • • • • • 2
Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . 3
Map Analysis . . . . . . . . . . . . . . . . . . . . . . 3
Vegetation Sampling •••••.•...•...••... 3
Interspecific Relationships ..••......••..• 4
Snow Measurements •.....•.....•.••...• 4
Results and Discussion. • • • . • . • • . . • . • . . • • • • 4
Map Analysis . . . . . . . . . . . . . . . . . . . . . . 4
Vegetation Sampling •••..••...•.•..•..• 5
Alpine Meadow . . . • • • . • . • • • • . . • . . • 5
Revilla Island . . . . . . . . . . • . . • . • 5
Quartz Hill. . . . . . . . . . . . . . . . . . 6
Alpine Heath. . . . . • • . . . . • • . • . . . . • 6
Revilla Island . . • • . . . • . . . • • . • . 6
Quartz Hill ••.•..•.••.••.•... 6
Alpine Ridge ..••.••••.••.....•.. 7
Subalpine Forest Zone . • . • . • • . • . . . . • . 7
Revilla Island • • • • . . • • • . . • . . . . 7
Quartz Hill •••.••.•••.•..•.•• 8
Interspecific Relationships •••...•..•••... 9
Deer. . . . . • . . . . . • • • • • . . . . • . . . 9
Wolves •....••..•............. 10
Snow Measurements ••••••••••••.••.•... 10
Conclusion .......................... 11
Recommendations •••.••.••.•.•...•.....• 11
Acknowledgments • • . . . • • . . • • • . • . . •. . . • • . .12
Literature Cited •.•.•••.••••.•..•.••••. 12
Figures ........................... 14
Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
BACKGROUND
Public interest in transplanting mountain goats (Oreamnos
americanus) to Revillagigedo (Revilla) Island from the adjacent
mainland to provide for increased and more readily accessible
recreational use of goats has existed for some time. In response
to public inquiries, the u.s. Forest Service made some prelimi-
nary observations on habitat suitability of part of the island in
1963, but lack of coordination with the Alaska Department of Fish
and Game (ADF&G) and failure to follow up on the idea resulted in
no transplant taking place. Since that time, the concept of a
transplant has been discussed off and on, but ADF&G has generally
opposed this action based on the lack of a clear need to increase
local goat numbers, funding limitations, and a generally
conservative policy toward transplants. Recent events have led
to a reevaluation of the potential benefits of a transplant.
1
Impending development of a major molybdenum mine in the vicinity
of Quartz Hill, 65 km (40 mi) southeast of Ketchikan, is expected
to have a dual effect on the region's goat populations. Direct
impacts resulting from habitat alterations, displacement due to
human activity, and illegal killing of goats may result in a
reduction of the goat herd in the immediate vicinity of the mine
site and access corridors. Indirect effects include increased
competition and/ or higher hunter demand for goats due to the
influx of mine workers and their families to the Ketchikan area.
The net result of this activity will be a reduced supply and
increased demand for goats on the mainland. To some extent, it
may be possible to offset these changes by establishing a new
goat population in vacant habitat on Revilla Island.
The ADF&G has the primary responsibility for wildlife management
in Alaska and is the lead agency in dealing with any proposed
transplants. Policy decisions developed by ADF&G's Game Division
clearly require evaluation of 3 elements before authorizing and
conducting a transplant (ADF&G 1973). First, there must be a
recognized public demand and benefit from the transplant.
Second, studies must demonstrate that sufficient habitat exists
at the proposed transplant site to support the introduced
species. Third, it must be demonstrated that the proposed
introduction will not have detrimental effects on resident
wildlife species.
The initial requirement of identification of public support and
potential benefit appears to have been fulfilled. (Yet to be
resolved, however, is how the public benefits and need for the
transplant to offset mine development impacts relate to sharing
the anticipated costs of a transplant.) The purpose of this
study was to evaluate the latter 2 points, habitat suitability
and potential interspecific relations on Revilla Island.
OBJECTIVE
To evaluate potential transplant locations for mountain goats and
to assess feasibility and possible impacts of establishing an
introduced population on Revillagigedo Island.
PROPOSED TRANSPLANT AREA
The northeast third of Revilla Island was selected as a potzntial
tr~nsplant site (Fig. 1). This area of roughly 1,000 km (400
mi ) is part of the coastal foothills formation (Jaques 1973)
with peaks reaching elevations over 1,200 m (4,000 ft). It
appears similar in bio-geo-physical characteristics to the
adjacent mainland which supports healthy goat herds (Wood 1981).
The area is separated from the mainland by Behm Canal, which
averages about 3 km (2 mi) wide.
2
PROCEDURES
Map Analysis
A grid overlay with 6.4-acre cells was superimposed onto 2-inch
to 2 the mile ~opographic and timber type maps of approximately 600
km ( 230 mi ) in the proposed transplant area between Marble
Creek and Orchard Creek (Fig. 1). Every other row of cells in
alternating columns was sampled for physical and biological
parameters: elevation, aspect, slope, distance to the nearest
Cliff (i.e., area With SlOpe greater than 50°) 1 vegetation type,
and timber volume as described by Fox et al. (1982). Similar
data were available from the adjacent Upper Cleveland Peninsula
(UCP) where Smith (1983) has been conducting radio telemetry
~tudies of mountain goat habitat use.
Frequency distributions of selected habitat traits were analyzed
to quantify similarity of the island to the mainland, and
discriminant function analysis (DFA) was used to predict
locations of winter range on Revilla Island. For the DFA, the
1,527 sampled cells on the UCP were divided into subsets of cells
used by radio-collared goats monitored by Smith (1983) between
November 1981 and April 1982 and cells unused by those goats.
DFA was used to determine the optimal method of classifying these
cells into their respective categories. The resulting function
was then used to predict whether or not each of the 5,690 cells
sampled on Revilla most resembled a used (hence winter habitat)
or unused (nonhabitat) cell on the UCP.
Vegetation Sampling
To evaluate floristic similarity within habitat types and to
compare forage availability for goats on Revilla versus the
mainland, vegetation sampling was undertaken on ridges within the
proposed transplant area and in the vicinity of Quartz Hill.
Rectangular plots 5 by 25 m were ran9omly located in alpine and
subalpine habitat types. Fifty 0.1-m microplots were located at
1 m intervals along the long axis of the plot to determine
forb-subshrub canopy cover values (Daubenmire 21959). Basal
diameters of shrub stems rooted in the 0.1-m frames were
measured with calipers and recorded. Shrub stems were counted in
10, 1 x 5 m subplots along the long axis of the plots to
determine mean stem density. Stem diameter and density were used
to calculate estimates of available forage biomass of selected
shrub species (Alaback 1980). Arboreal species within the plot
were classified as seedlings (less than 1 m high) , saplings (dbh
less than 2. 5 em) , or trees. Counts were made for the 1st 2
classes, while dbh was measured and height estimated for each
tree. Abundance of arboreal lichens was determined subjectively
in 3 classes (abundant, moderate, rare) in each plot. Sampling
was conducted on Revilla Island by ADF&G and at Quartz Hill by
VTN Consolidated under contract with u.s. Borax.
3
Interspecific Relationships
Aerial surveys were flown in a PA-18-150 Super Cub during early
morning and evening hours in August 19 8 2 to determine
distribution of deer using open subalpine and alpine habitats.
No standardized routes were flown, but the main ridge complexes
between Marble Creek and Mt. Reid were surveyed on each flight.
Additional observations on distribution and activity of deer and
wolves were made during vegetation sampling and by searching for
tracks in the snow during winter months.
Snow Measurements
Snow measurement poles were distributed at 150, 460, and 760 rn
(500, 1,500, and 2,500 ft) elevations in the transplant area and
·in the vicinity of Quartz Hill on the mainland to rnoni tor snow----
depth. As weather permitted, we recorded snow depth in fixed-
wing aircraft and helicopters from November 1982 through February
1983.
RESULTS AND DISCUSSION
Map Analysis
A total of 5, 690 points was systematically sampled on Revilla
Island maps. Results of frequency analysi::; o;f these .data in corn.,..
parison with UCP data (1,527 random points sampled by Smith 1983)
are presented in Table 1.
Distribution of elevational classes is similar, particularly in
the areas above 460 rn (1,500 ft). This is not surprising as the
ridges in both areas are part of the same major geological
formation. Aspects in the 2 areas are more dissimilar, as the
UCP has more flat ground than Revilla and the general east-west
orientation on the mainland results in varying exposures. The
relatively low amount of flat ground on Revilla is to some extent
due to the drawing of the sample area boundary; in other words,
lowlands on the edge of the proposed transplant region were
excluded from sampling to a greater extent than on the previously
sampled UCP. Although the distribution of south-facing slopes
differs between the 2 areas, when southeast, south, and southwest
slopes are lumped together, the island and mainland have similar
amounts (36% vs. 37%, respectively) of these heavily used
aspects.
The greater amount of flat ground on the UCP contributes to the
higher percentage of cells with 0-15° and 16-20° slope there than
on Revilla. Correspondingly, the island has a higher percentage
of the moderate to steep (e.g., 26-50°) slopes than the UCP.
Cliff areas (slopes greater than 50°) are slightly more common on
the UCP; however, overall, nearly 50% of Revilla is in the slope
categories over 30° which are preferred by goats (Smith 1983).
4
Distribution of cells based on their distance from the nearest
cliff also indicates relatively more extreme terrain on the UCP,
but fully 75% of the sample area on Revilla is on or within 0.8
km (0.5 mi) of a cliff. In absolute terms, this means there is
substantially more of the preferred terrain on the island than
the mainland sample areas.
Both areas have similar proportions of commercial volume old-
growth forest, cliff and slide forest, muskeg, and muskeg forest.
Of the other vegetation types, Revilla has more subalpine forest,
brush, and alpine than the UCP. The latter area has less soil
and vegetation development above 600 m (2,000 ft) than the
island, resulting in relatively greater amounts of bare rock and
other (primarily lake) areas. This distribution of vegetation
types accounts for the variation in timber volumes. Revilla has
less nonforested and more noncommercial timber than the UCP, and
although distribution by volume class varies, the total
commercial volume forest land is virtually equal on the 2 sites.
DFA identified 1, 827 cells, or 32% of the area, as potential
winter habitat (Large-scale maps of the identified winter habitat
are on file in the K~tchikan o~fice of ADF&G.) This implie~that
of 2 the total 600 km (230 mi ) area, an estimated 191 km (74
mi ) could be suitable winter habitat for goats. If winter range
density of an introduced goat population reached the levels cur-
rently susta~ned i~ the vicinity of Quartz Hill (about 8
goats/2.59 km [1 mi ]) (ADF&G, unpubl. data), the estimated win-
ter range on Revilla could support over 600 animals.
Vegetation Sampling
The nonforested plant communities above tree line were divided
for sampling into alpine meadows dominated by forbs and herbs,
alpine heaths dominated by sub-shrubs, and xeric alpine ridges.
Alpine Meadow:
Revilla Island. The alpine. meadow plots were located in a
forb-sedge community on a ridge complex 5 km (3 mi) northwest of
Lake Grace at 760 m (2, 500 ft) elevation on moderately steep
( 35-45 °) southerly aspects (Fig. 2) • Fauria crista-galli and
Carex spp. dominated this moist type with 68 and 18% ground
cover, respectively (Table 2). Other major species include
Erigeron sp., Geum calthifolium, Luetkea pectinata, Pedicularis
ornithorhyncha, Sanguisorba sp., Valeriana sitchensis, and an
unknown Compositae. The species-area curve (Fig. 3a) indicates
that sampling was adequate to identify most species present 1
although several other species, such as Gentiana platypetala 1
were noted to be present but not located in the sample plots.
The site was extremely moist with surface drainage apparent at
the time of sampling.
5
Quartz Hill. The alpine meadow plots were located on ridge tops
(slope 10°) near Bakewell Head and north of Tunnel Creek at
approximately 915 m (3,000 ft) in elevation. Fauria crista-galli
and Carex were abundant, but Cassiope mertensiana and Cassiope
stelleriana were codominant. Empetrum nigrum, Geum calthifolium,
Luetkea pectinata, Vaccinium caespitosum, and Vaccinium
ulig1nosum were other major vascular species; the lichen Cladonia
sp. was common (Table 2). Although the species-area curve (Fig.
3a) has more or less leveled off, its lower slope and asymptote
than the Revilla curve indicate reduced floral diversity in the
area sampled.
Major summer forage species such as Fauria crista-galli, Carex
spp. , Luetkea pectinata, and Geum cal thifolium were found to be
abundant in both areas. Numerous other forb species, which goats
probably utilize, also occur. The major differences between the
2 locations are the greater abundance of forbs and sedges on
Revilla versus higher sub-shrub and lichen densities at Quartz
Hill. To some extent, these differences may simply be due to
site moisture and exposure characteristics; the presence of
Cladonia sp. at Quartz Hill indicates these sites may be more
like the exposed ridge site on Revilla. In addition, it is
possible that the lower forb density at Quartz Hill may reflect
grazing by goats.
Alpine Heath:
Revilla Island. The alpine heath plots were located in Cassiope-
forb communities on moderate slopes (15-20°) and south and east
aspects at about 670 m (2,200 ft) elevation. These communities
overlaid old scree or rock slopes with relatively limited soil
development and were well drained relative to the alpine meadows.
Cassiope mertensiana, Cassiope stelleriana, and Luetkea pectinata
clearly dominate this community (Table 2). Fauria crista-galli,
Carex spp., grasses, and several species of Compositae are also
common, as are young, stunted yellow cedar Chamaecyparis
nootkatensis and mountain hemlock Tsuga mertensiana. Floral
diversity is lower here than in the alpine meadows as evident
from the species-area curve· (Fig. 3b) . This type is the most
extensive in the alpine zone on Revilla and the adjacent
mainland.
Quartz Hill. One heath plot was located on a ridge at 1,070 m
(3,500 ft) near the head of Falsegate Creek, the other at the 915
m (~000 ft) level on East Ridge. Both sites were relatively flat
and near the top of the ridge. Goats and/or sign were observed
in the immediate vicinity of the plots. As on Revilla, the heath
type at Quartz Hill is dominated by Cassiope mertensiana and
Cassiope stelleriana (Table 2); Carex spp., Fauria cr1sta-galli,
Luetkea pectinata, and Phyllodoce aleutica are also relatively
common and/or abundant. The high level of occurrence of Cladonia
sp. and Vaccinium caespitosum indicates the sites were dry, as
would be expected for ridge tops. The species-area curve (Fig.
3b) reveals that sampling was adequate.
6
As with the alpine meadow type, the sites on Revilla were
floristically more diverse than those on Quartz Hill, and forbs
(specifically Fauria crista-galli and Luetkea pectinata) are more
abundant on the island. Reduced available moisture and grazing
by goats at the Quartz Hill sites probably account for most of
the differences. The abundance of forbs in the alpine heath of
Revilla Island indicates that this extensive community would
provide large quantities of summer forage for goats.
Alpine Ridge:
This type was sampled separately on Revilla Island because it was
felt that it was different from either the meadow or heath type.
Due to limited development of soil and extreme wind, this site
was the most xeric on the island. Although relatively limited in
extent, it is expected to receive extensive use by goats during
the summer months due to the proximity of steep, broken terrain.
Fauria crista-galli, Carex spp., and Cassiope mertensiana are the
dominant vascular plants, but the abundance of Cladonia sp. and
the presence of Empetrum nigrum, Loiseleuria procumbens,
Vaccinium caespitosum, and Vaccinium uliginosum reveal the
difference between this site and the forb-sedge meadows (Table
2). These sites are similar to the "alpine meadow" plots from
Quartz Hill (as might be expected since those sites were located
closer to the ridge-top than the meadow plots on Revilla) , and
confirm the presence of several additional species on both the
island and mainland.
Subalpine Forest Zone:
Revilla Island. Open and closed canopy stands were sampled in
the subalpine zone on a tributary of Carroll River (Fig 2) . The
open stands were located on a moderately steep (25-40°) south
slope at 760 m (2,500 ft) elevation. Average canopy closure was
33%, composed primarily of mountain hemlock and yellow cedar with
a well-developed intermediate layer of seedlings and saplings
(Table 3). The closed canopy sites were on the same south slope
but were much steeper (60-70°) and averaged 73% canopy cover.
Hemlock dominated the stands~ and though seedlings were common,
saplings were not found in the plots (Table 4). Arboreal
lichens, including Alectoria spp. and Lobaria sp. were found at
intermediate to abundant levels in the open stands and
intermediate levels in closed forests, while Cetraria sp. , and
Parmelia sp. occurred on some trees in the closed canopy forest.
The understory shrub layer was well developed in both stands.
Vaccinium spp. (ovalifolium and alaskensis) dominated and were
estimated to produce 158 and 55 kg/ha of leaf and twig biomass
per year in open and closed stands, respectively (Table 5).
The forb layer in the open stands was lush and dominated by
Fauria crista-galli, Streptopus sp., Rubus pedatus, Cornus
canadensis, Coptis aspleniifolia, and Blechnum spicant (Table 2).
In closed stands, species composition was sim1lar, except for the
7
lack of Fauria, but the combination of steeper slopes and reduced
light resulted in lower ground cover of forbs and much higher
moss and lichen cover.
Quartz Hill. Open and closed canopy subalpine sites were sampled
at a variety of locations. The open stands were on moderate
(17-25°) slopes at 640-790 m (2,100-2,600 ft) elevation and aver-
aged 25% canopy closure (Table 3). The overstory was dominated
by hemlock with some mature yellow cedar, while the seedling and
sapling layers contained an abundance of young and/or stunted
yellow cedar with less hemlock. The closed canopy stands were
slightly steeper ( 17-34 o) and had a mean canopy cover of 69%
(Table 4). Hemlock was the only tree species found in the plots;
seedlings were abundant but saplings were relatively rare. Arbo-
real lichens, including Alectoria spp. and Lobaria sp. , were
found in low to abundant density throughout subalpine stands;
Cetraria sp., Parmelia sp., and Bryoria sp. occurred
occasionally.
The understory shrub layer was again dominated by Vaccinium spp.
(Table 5), which showed signs of past browsing by goats in both
open and closed stands. Although stem densities were lower than
on the island, mean diameters were larger and forage biomass was
estimated to be 108 and 71 kg/ha for Vaccinium in open and closed
stands, respectively.
The forb layer in the open stands was somewhat heath-like with an
abundance of Cassiope spp., Phyllodoce aleutica, and the fern
Polypodium vulgare were well represented (Table 2). Cover values
for most of the common species were lower in the closed canopy
stands, but a greater total number of species was found.
Recent evidence of grazing by goats on Fauria was noted in some
plots.
The presence of tracks, trails, and fecal pellets as well as
evidence of grazing and browsing in the subalpine forests at
Quartz Hill demonstrate that this habitat is intensively utilized
by goats. The areas sampled on Revilla Island indicate that the
vegetation is very similar with at least comparable quantities of
major winter forage in the form of Vaccinium spp. and conifer
browse. The larger mean diameter and reduced stem density of
Vaccinium at Quartz Hill may be due to the noted browsing by
goats. Basal diameters may increase due to "hedging" effect, and
these plants may have fewer resources to put into berries due to
the need to replace vegetative tissue annually. On Revilla,
where the shrubs are virtually untouched, growth may be more
equitably shared between vegetative and propagative growth,
resulting in relatively abundant new young plants. Within the
areas sampled on Revilla Island, it is apparent that sufficient
forage is available to support goat population densities similar
to those at Quartz Hill.
8
Interspecific Relationships
A major consideration in judging the possible effects of a
transplant is how the introduced species will interact with, and
affect populations of, resident species in the area. In the case
of this proposed transplant, concern is minimal inasmuch as goats
are endemic to the local area and most species with which goats
-would coinhabit the island are also found on the mainland; no
adverse interspecific relationships are known to exist there.
Nevertheless, Game Division policy requires an evaluation of this
potential. The main species of concern on the island are deer
and wolves.
Deer:
Two fixed-wing surveys were flown in August 1982 to assess deer
use of the alpine and open subalpine areas. Flight routes are
illustrated in Fig. 4. On 4 August, a total of 11 deer (9 bucks
and 2 does) was seen in 1.5 hours, yielding a rate of 7.3 deer
per hour of survey time. On 28 August, 6 deer (4 bucks, 1 doe,
and 1 fawn) were observed in 1.1 hours for a rate of 5.5 deer per
hour.
Comparable survey data are extremely limited, but 2 areas of
Prince of Wales Island were flown under similar conditions on 20
August 1980 and 9 August 1982 by R. Wood. Estimated sighting
rate for the Cholmondeley Sound-Craig portion of Prince of Wales
Island in 1980 was 25-30 deer per hour, while the Coffman
Cove-Thorne Bay area yielded approximately 50 deer per hour in
1982 (ADF&G, unpubl. data). Sighting rates for many areas of
Admiralty and Baranof Islands exceed 100 deer per hour
(L. Johnson, pers. commun.).
During other nonsurvey fixed-wing flights over the transplant
area, as well as on helicopter flights to and from the vegetation
sampling plots, no deer were observed in the alpine. While on
the ground to complete the vegetation sampling on Revilla, 1-2
sets of tracks were observed and an occasional pellet group was
located, but no browsing was·evident on plants within the plots.
A single set of tracks was observed in the snow at 760 m (2,500
ft) on 8 November 1982 during the helicopter flight to place the
snow poles on the island, but no other tracks were observed in
the snow in the course of checking the poles through late
February 1983.
General opinion and hunter success statistics indicate that the
deer population on northeast Revilla Island is significantly
reduced from levels of the mid to late 1960's (Wood 1982~). The
low numbers seen from the air combined with the lack of sign
observed on the ground also suggest that relatively few deer are
currently using the mid-to high-elevation areas northeast of
Carroll Inlet.
9
Radio telemetry studies of deer (Schoen et al. 1979) and goats
(Smith 1983) in Southeast Alaska indicate that winter range areas
for these species are relatively distinct. Although both deer
and goats utilize medium to high volume old-growth forests on
southerly aspects when snow cover is present, deer generally
exploit· lower elevations, gentler slopes, and smoother terrain
than goats (Table 6) . Given this inherent separation and low
deer numbers, it is unlikely that these species will compete for
limited resources, and the introduction of goats to Revilla
Island should not adversely affect deer.
Wolves:
Snow cover was not adequate during the winter of 1982-83 to
permit effective monitoring of wolf activity at low elevations in
the proposed transplant area. Limited observations made during
flights to set and check snow poles resulted in no wolf track
sightings.
The current wolf population on Revilla Island is significantly
reduced from the higher levels of the late 1960's and early
1970's (Wood 1982b) presumably as a result of the decline in
their major prey species, deer. Although the possibility exists
that the residual wolf packs in the area may locate and prey upon
some of the introduced goats, wolves are not expected to
eliminate the initial stocking. As the goat population expands,
wolves may begin to prey upon the species regularly--as they must
on the adjacent mainland--but, once established, goats should be
able to sustain these losses.
Regardless of the predator-prey outcome, introducing goats should
not have an adverse effect on the wolves. In fact, by increasing
prey diversity, the transplant may benefit wolves in the long
run. (It remains to be seen how, or if, providing a buffer
species will affect the island's deer-wolf relationship.)
Snow Measurements
A combination of poor weather and unavailability of sui table
aircraft limited acquisition of snow depth data on Revilla.
Destruction of snow poles (presumably by bears) at Quartz Hill
had the same effect in that area. Still, the available data are
adequate to determine the general similarity of snow depths on
the island and mainland.
Fig. 5 illustrates progression of snow depth on Revilla and at
Quartz Hill from early November 1982 through February 1983. Snow
depth was generally greater at Quartz Hill than on Revilla at any
given elevation. In both locations, snow cover was inconsistent
and/or incomplete on timbered slopes up to nearly 2, 000 ft on
southerly exposures.
10
CONCLUSION
The proposed transplant location on northeast Revilla Island
closely resembles areas of the adjacent mainland currently used
by goats in many bio-geo-physical and environmental features. In
fact, the failure of goats to colonize the island naturally may
simply be a consequence of their arrival in the region from a
southern glacial refugium after post-pleistocene sea levels rose
and flooded Behm Canal, isolating this segment of the coastal
foothills (Klein 1965). Based on the results of this study,
introduced goats should find adequate forage, shelter, and escape
cover to support a population of from several hundred to as many
as 1,000 goats.
Establishing goats on Revilla is not expected to have significant
direct effects on resident species. Competition with deer should
be minimal, even if currently depressed populations increase in
future years. Although wolves may prey on goats on the island,
current wolf-goat relationships on the mainland indicate that
goat populations can increase in the presence of existing wolf
densities there. Once the introduced goats have surpassed a
threshold level, it is expected that they could withstand
predation on the island as well.
If an introduced population of 500-1,000 goats developed on the
island, a human harvest of 25-50 goats per year could be
sustained under the current 5% harvest guidelines. Although
accessibility may restrict actual kill to lower numbers, this
would represent a potential increase of approximately 50% over
current hunter yield in Subunit 1A. Given the persistence of low
deer numbers in spite of mild winters during the past 6 years,
this could represent a significant enhancement of opportunity for
subsistence and recreational hunting. Opportunities for non-
consumptive use would also be increased by providing a more
accessible population for recreationists based in Ketchikan.
RECOMMENDATIONS
1. In view of the suitability of habitat, public interest, and
availability of "surplus" goats on the adjacent mainland, ADF&G
should pursue the option of transplanting goats to Revilla
Island.
2. A detailed proposal covering timing, logistics, number of
animals to be moved, and monitoring of introduced goats should be
developed.
3. ADF&G should confer with the U.S. Forest
authorization for the transplant under terms
Memorandum of Understanding.
11
Service to seek
of their Master
4. ADF&G should meet with representatives of the U.S. Forest
Service, u.s. Borax, and interested members of the public to
explore options for cost and personnel sharing to accomplish the
introduction.
ACKNOWLEDGMENTS
Several persons in the Ketchikan Ranger District and Area
Supervisor's office of the U.S. Forest Service were helpful in
providing logistic and financial support for this project. In
particular, thanks are due to Win Green, Glen Contreras,
Dick Coos, and Duane Fisher. Kit Ki tasaki of U.S. Borax and
Tom Meehan and Dave Bramlet of VTN supported work at Quartz Hill
and provided data on plant communities on the mainland.
Kent Bovee was a patient and competent assistant in gathering
field data and miraculously maintained his enthusiasm throughout
the map sampling. Don McKnight and Bob Wood provided support and
encouragement for this study and the proposed transplant which is
greatly appreciated.
LITERATURE CITED
Alaback, P. B. 1980. Biomass and production of understory
vegetation in seral Sitka spruce-western hemlock forests of
southeast Alaska. Ph.D. Diss. Oregon State Univ., Corval-
lis.
Alaska Department of Fish and Game.
ment Policies. Juneau, Alaska.
1973. Alaska Game Manage-
65pp.
Daubenmire, R.
analysis.
1959. A canopy cover method of vegetation
Northwest Sci. 33:43-64.
Fox, J. L., K. J. Raedeke, and C. A. Smith. 1982. Mountain goat
ecology on Cleveland Peninsula, Alaska, 1980-1982. Final
Rep. Pacific Northwest For. Range Exp. Sta. Contract
PNW-82-197. For. Sci. Lab. USFS. Juneau, Alaska. 40pp.
Jaques, D. R. 1973. Reconnaissance botany of alpine ecosystems
of Prince of Wales Island, southeast Alaska. M.S. Thesis.
Oregon State Univ., Corvallis. 133pp.
Klein, D. R. 1965. Post-glacial distribution patterns of
mammals in the southern coastal regions of Alaska. Arctic.
18(1):7-20.
Schoen, J. W., 0. C. Wallmo, and M. D. Kirchhoff. 1979.
Seasonal distribution and habitat use by Sitka black-tailed
deer on southeastern Alaska. Alaska Dep. Fish and Game. Fed
Aid in Wildl. Rest. Prog. Rep. Proj W-17-11, Job 2.6R.
Juneau. 64pp.
12
Smith, c. A. 1983. Habitat use by mountain goats in south-
eastern Alaska. Alaska Dep. Fish and Game. Fed. Aid in
Wildl. Rest. Prog. Rep. Proj. W-22-1, Job 12.4R. Juneau.
88pp.
Wood, R. E. 1981. Unit 1A mountain goat survey-inventory
progress report. Pages 185-190 in R. A. Hinman, ed. Annual
Report of Survey-Inventory Activities. Part II. Caribou,
Moose,and Mountain Goats. Vol. XII. Alaska Dep. Fish and
Game. Fed Aid in Wildl. Rest. Prog. Rep. Proj. W-19-1 and
W-19-2. Job 3.0, 1.0, and 12.0. Juneau.
1982a. Unit lA and 2 deer survey-inventory progress
report. Pages 1-2 in R. A. Hinman, ed. Annual Report of
Survey-Inventory Activities. Part VI. Deer, Bison, Small
Game, Elk, Musk-oxen, and Walrus. Vol. XIII. Alaska Dep.
Fish and Game. Fed Aid in Wildl. Rest. Prog. Rep. Proj.
W-22-1. Job 2.0, 9.0, 10.0, 13.0, and 16.0. Juneau.
1982b. Unit 1A and 2 furbearers survey-inventory
progress report. Pages 12-13 in R. A. Hinman, ed. Annual
Report of Survey-Inventory Activities. Part VII. Beaver,
Furbearers, Lynx, Wolf, and Wolverine. Vol. XIII. Alaska
Dep. Fish and Game. Fed. Aid in Wildl. Rest. Prog. Rep.
Proj. W-22-1. Job 7.0, 14.0, and 15.0. Juneau.
PREPARED BY:
Christian A. Smith
Game Biologist III
SUBMITTED BY:
Donald E. McKnight
Regional Supervisor
APPROVED BY:
(<-'. t'eua=,;,e (fqwtJf ~ 0.. I cfrl ''iii n Director, bivr
Research Chief',''vivis1.on o!: Game
13
tN
BKm
~5 ;-f ffil.
Fig. 1. Revillagigedo Island. Stippled portion is the
proposed transplant area.
14
St
•pu-etSI
au-rdt-eqns pu-e
opao-rfi-eTT"FAaH 1 s~otd
(CJ) au-rdTV ·z ·o-rd
30-3.a Revilla
Number of
Species
20
10
20
Number of
Species
Revilla
Alpine Ridge A-A. A-6. Quartz Hill
Alpine Me.a.«d:Pw ... ._-'
~
l
I
I
.... •-··
,.....o-o-o-o
I. o-o-o ,.o
I
1 I
I o I
I r,
3.b
25
/ ;·
./ .,...o
5
/
/
./
"'
7
--o------
Number of Plots
Revilla
Alpine Heath
100
10
5 '0
Quartz Hill
Alpine Heath
7
Number of Plots
100
Fig. 3. Species-area curves for Daubenmire (1954)
plot samples, Revillagigedo Island and Quartz Hill.
16
20
Number of
Species
20
10
Quartz Hill
3.c Open Subalpine Forest
--0
3.d
o"
/
o .... o
,I
I
~
Fig. 3.
/
o-o -·--·--o--
5
Revilla
Open Subalpine
Forest
7
Number of Plots
100
o-----0 Quartz Hill
Closed Subalpine
Forest ..... .... ,..
o,...o-o-o-o,......,.......
Revilla
Closed Subalpine Forest
25 so 7 100
Number of Plots
Continued.
17
Fig. 4. Alpine deer survey flight routes, Revillagigedo
Island./'"""-../= 4 August 1983;-·-·-= 28 August 1983.
18
Feet of
Snow
Feet of
Snow
10~ Revillagigedo Island
-t. -. -Jr • - . - . - . -. -. -. -. -·-. -. -. -.... ---<>------------o-----_o
_____.
s_
..
!720 -T/17 11/8 11/20
1982
10 Quartz Hill
5
/
-
.-·-·-A ___ ........
_A_.-·-·-· -
ll/8 11/20 1/20
1982
/
1983
/
/
.-A ......
2/8 2/17
1983
Fig. 5. Snow depth at 500 feet (-) , 1, 500 feet (o---o) ,
and 2, 500 feet (A..,_..t) on Revillagigedo Island and Quartz
Hill, 8 November 1982-17 February 1983.
19
Table 1. Frequency distribution (%) of habitat characteristics on Revilla Island and the
Upper Cleveland Peninsula (UCP) based on point sampling of topographic and timber type
maps, summer 1982.
Area Habitat characteristic
Elevation in feet (thousands)
0-0.5 o. 6-1.0 1.0-1.5 1.5-2.0 2.0-2.5 2.5-3.0 3.0-3.5 3.5-4.0 >4.0
Revilla 13.3 18.4 17.9 17.5 14.8 10.7 5.7 1.7 0.1
UCP 13.9 14.9 19.7 16.3 16.0 11.9 5.1 1.8 0.3
Aspect
Flat North NE & NW E & W SE & SW South Ridge top
1\J
0 Revilla 5.8 12.6 21.0 24.6 21.8 14.2 0.1
UCP 14.0 6.4 19.8 20.6 17.6 9.8 1.8
Slope (degrees)
0-15 16-20 21-25 26-30 31-37 38-50 51-65 66-90
Revilla 14.9 11.5 8.2 15.6 19.2 26.3 4.3 0.1
UCP 29.7 4.7 8.5 21.7 17.2 11.3 5.3 1.6
Distance to cliffs (mi)
0.00 0.25 .25-.50 .51-.75 .76-1.00 1.01-1.25 1. 26-1.50 1. 50-2.25 --
Revilla 4.4 42.1 32.9 12.7 2.1 0.6 0.1 0.0
UCP 6.9 49.6 20.0 9.4 3.3 2.0 2.0 0.5
Table 1. Continued.
Vegetation type
Old-growth Cliff/slide Muskeg and Subalpine Rock and
Area forest forest muskeg forest forest Brush Alpine cliff Other --
Revilla 34.0 7.0 9.1 26.7 5.4 9.2 5.8 2.8
UCP 32.4 5.7 11.3 20.4 2.7 5.8 14.8 7.0
Timber volume (board feet/acre)
None 8,000 8-20,000 20-30,000 30-50,000
Revilla 24.1 42.6 11.0 19.6 2.7
N UCP 30.3 36.9 16.6 14.7 1.4
.....
N
N
Table 2. Results of 0.1 m2 micro-plot sampling for canopy cover of herb-su};)shrub layer plants on Revilla
Island and Quartz Hill, summer 1982.
Plant species
Arnica latifolia
Athyrium filix-
femina
Blechnum spicant
Caltha biflora
Carex spp.
Cassiope
mertensiana
Cassippe
stelleriana
Castilleja.
parviflora
Chamaecyparis
nootkatensis
Cladonia spp.
Cladothamnus
pyrolaeflorus
Compositae spp.
Copt.is aspleniifolia
Cornus canadensis
Dryopteris dilatat~
Empetrum nig:rum
Epilobium
hornemannii
Er.i,geron sp.
Eriophorl,llll
angustifolium
Fauria crista:-galli
Galium sp.
. Alpine meadows
Revilla Quartz
Island Hill
10/Tra
5/Tr
3/Tr
85/17.8 47/11.0
12/2. <? 41/11. 7
7/Tr
10/2.8
27/2.4
11/2.2
18/2.4
94/68.5
36/3.2
34/9.1
22/1.9
7/Tr
12/4.4
62/11.8
5/Tr
Alpine heath
Revilla Quartz
Island Hill
26/3.3 24/3.9
99/74.1 88/33.5
96/13.9 87/18.1
1/Tr
28/1.2 62/18.9
14/1.0
1/Tr
44'/5.1 27/1.2
5/Tr
Alpine ridge
Revilla
Island
80/15.7
48/10.6
30/1.5
2/Tr
88/13.6
26/Tr
22/2.8
66/19.4
Open subalpine
fore !;it
Revilla Quartz
Island Hill
20/2.2 2/Tr
3/1.4
36/2.6
27/Tr
Tr/Tr
14/1.2 4/Tr
6/2.1
34/1.1
14/1.8
14/2'. 8
19/6.1
21/Tr
50/3.0
3/Tr
50/25.0 52/11.6
Closed subalpine
forest
Revilla Quartz
Island Hill
24/2.6
18/2.4
2/Tr
58/7.0
16/2.3
7/1.7
Tr/Tr
29/10.7
10/Tr
2/Tr
15/5.0
14/2.0
15/2.2
18/2.1
2/Tr
Table 2. Continued.
Open subalpine Closed subalpine
Alpine meadows Alpine heath Alpine ridge forest forest
Revilla Quartz Revilla Quartz Revilla Revilla Quartz Revilla Quartz
Plant species Island Hill Island Hill Island Island Hill Island Hill
Gentiana douglasiana Tr/Tr
Geum calthifolium 20/2.6 22/1.1 30/1.3
Grasses 12/1.0 8/Tr 52/1.9 38/2.2 8/Tr 1/Tr
Kalmia polifolia 7/Tr
Leptarrhena
pyrolifolia 1/Tr
Listera cordata 6/Tr 4/Tr 22/1.6 1.3/Tr
Lob aria spp. 2/Tr 9/Tr 2/Tr 16/3.1 11/Tr 86/21.0 12/Tr
Loise leur a
;erocumbens 48/4.6
IV Luetkea pectinata 18/4.2 24/1.5 92/19.0 63/5.9 28/2.0 17/2.0 w Lupinus nootkatensis 3/Tr 20/1.4 Tr/Tr
Lysichi tort
americanum Tr/Tr
Menziesia ferruginea 12/3.2 29/7.9 10/2.9 10/3.0
Mosses 12/1.8 58/17.8 33/5.3 48/5.2 88/26.3 98/52.6 79/32.3 100/30.4 59/24.9
Echinopanax horridum 5/1.9
Pedicular is
ornithorhyncha 24/1.1 5/Tr 3/Tr 12/Tr
Phy11odoce aleutica 6/1.5 10/Tr 5/Tr 29/3.5 6/Tr 33/3.7 14/2.3
Pinguicula vulgaris 2/Tr
Platanthera dilatata 9/Tr
Polypodium vulgare 23/3.0 1. 3/Tr
Pyrola spp. 2/Tr
Ribes laxiflorum Tr/Tr
Rubus pedatus 90/15.0 47/2.0 96/15.6 43/4.1
Rubus spectabilis Tr/Tr
Sanguisorba sp. 12/2.2
Saxifraga tolmiei 10/1.5 3/Tr
Senecio triangularis 3/Tr
Table 2. Continued.
Open subalpine Closed subalpine
Alpine meadows Alpine heath Alpine ridge forest forest
Revilla Quartz Revilla Quartz Revilla Revilla Quartz Revilla Quartz
Plant species Island Hill Island Hill Island Island Hill Island Hill
Sorbus sitchensis 1/Tr 1.4/Tr
Streptopus spp. 5/Tr 58/10.2 Tr/Tr 34/3.1 12/1.7
Thuja plicata 8/1.9
Tiarella unifolia·ta 3/Tr
Tofieldia glutinosa 1/Tr
Trientalis europaea 4/Tr
Tsuga mertensiana 2/Tr 24/4.3 14/2.5 28/11.9 28/1.5 6/1.3
Vaccinium
alaskensis/
ovalifolium 8/1.3 5/Tr 92/49.8 69/24.7 76/24.4 51/19.5
1\.) Vaccinium
,j:>. caespitosum 17/2.6 11/2.3 28/2.9 25/5.0 34/1.1 6.0/Tr
Vaccinium uliginosum 18/4.1 14/4.2
Vaccinium
vitis-idaea 7/Tr
Valeriana sitchensis 41/8.3
Veratrum viride 5/1.2 8/2.6 2/Tr
Unknown spp. 4/Tr 14/1.2
No. of plots sampled 100 100 100 100 50 50 150 50 150
No. of species
with 25/x.x 3 4 6 5 10 6 9 5 3
No. of species
with x.x/20.0 1 0 1 1 0 2 1 1 0
Total no. of species
by area 28 18 13 11 17 14 23 13 27
Total no. of species
for both areas 38 17 N/A 27 32
% floral species
overlap 21 41 N/A 37 25
.
N
Ul
•
Table 2. Continued.
Plant species
No. of species
with 25/x.x
Alpine meadows
Revilla Quartz
Island Hill
6
% overlap of Species
with 25/x.x 30
No. of species
with x.x/20.0 1
% overlap of species
with x.x/20.0 0
-
Alpine heath
Revilla Quartz
Island Hill
7
57
1
100
a % frequency of occurrence/% ground canopy; Tr <1.0%.
Alpine ridge
Revilla
Island
N/A
N/A
N/A
N/A
Open subalpine
forest
Revilla Quartz
Island Hill
12
25
2
50
Closed subalpine
forest
Revilla Quartz
Island Hill
7
29
1
0
N
0"1
Table 3. Overstory composition of open canopy subalpine sample plots, .summer 1982.
Average
Average % a Average no. Average no. no. trees/ha
canopy closure seedlings/ha saplings/ha and (MBF/ha)
Revilla Quartz Revilla Quartz Revilla Quartz Revilla Quartz
Plant species Island Hill Island Hill Island Hill Island Hill
Chamaecyparis
nootkatensis 1,320 2,347 400 3,653 360(19) 133(4)
Tsuga spp. 1,120 320 480 453 520(72) 293 (14)
Picea sitchensis 200 0 120 0 0(0) 0 (O)
Totals 33 25 2,640 2,667 1,000 4,106 880(92) 426(17)
a Canopy closure not determined for individual species.
I\.)
-....)
•
Table 4. OVerstory composition of closed canopy subalpine sample plot~, summer 1982.
Average
Average % a Average no. Average no. no. trees/ha
canopy closure seedlings/ha saplings/ha and ( MBF /ha)
Revilla Quartz Revilla Quartz Revilla Quartz Revilla Quartz
Plant species Island Hill Island Hill Island Hill Island Hill
Chamaecyparis
nootl<atensj s 0 0 0 0 200(100) 0 (0)
Tsuga spp. 520 4,613 0 187 520(139) 1,147(76)
Picea sitchensis 0 0 0 0 40 (29) 0(0)
Totals 73 69 520 4,613 0 187 760(268) 1,147(76)
a Canopy closure not determined for individual species.
N co
Table 5. Mean density, stem diameter at ground level, and estimated twig an~ leaf biomass of selected shrub
species in subalpine forests on Revilla Island and Quartz Hill, summer 1982.
Habitat type
Open subalpine
forest
Closed sub-
alpine forest
Shrub species
Vaccinium spp.
Menziesia sp.
Total
Vaccinium spp.
Menziesia sp.
Total
Stem density
Revilla Quartz
Island Hill
b 87.4(6.7)
3.4(0.9)
46.0(6.0)
2.3(0.6)
23.9(1.6)
7.5(1.8)
33.0(4.2)
2.6(1.0)
a Based on regression formulas in Alaback (1980).
b Mean (SE).
Stem diameter
Revilla Quartz
Island Hill
5.2(0.3) 8.3(0.5)
c 11.5(0.8)
4.2(1.0) 5.7(0.3)
c 9.1(1.7)
Forage biomass a (kg/ha )
Revilla Quartz
Island Hill
157.9 107.6
c 104.7
c 212.3
55.3 71.2
c 20.8
c 92.0
c Menziesia stems were not located within micro-plots and hence were not measured. Biomass cannot
be estimated without mean stem diameter values.
•
Table 6. Comparison of habitat characteristics at winter deer
and goat relocations.
Habitat characteristic
Mean elevation of relocations (ft)
Mean slope at relocations (0 )
% use of smooth terrain
a
b Schoen et al. 1979.
Smith 1983 •
29
Species
a Deer
188
8
99
b Goat
2,003
39
5