125
GENERAL NOTES
WINTER 2001
PEACOCK RL, NUSSBAUM RA. 1973. Reproductive biology and population structure of the western
red-backed salamander, Plethodon vehiculum
(Cooper). Journal of Herpetology 7:215-224.
PETRANKA JW. 1998. Salamanders of the United
States and Canada. Washington DC: Smithsonian
Institution. 587 p.
ROLLMANN SM, HOUCK LD, FELDHOFF RC. 1999. Proteinaceous pheromone affecting female receptivity
in a terrestrial salamander. Science 1999:1907-1909.
USDA Forest Service, Pacific Northwest Research
Station, 3625 93rd Ave SW, Olympia, Washington
98512 USA (LLCJ, MGR); Biolinx Environmental
Research Lt., 4180 Clinton Place, Victoria, British
Columbia V8Z 6M1 Canada, and Department of
Forest Sciences, University of British Columbia,
Vancouver, British Columbia V6T 1Z4 Canada
(KO). Submitted 19 March 2001, accepted 10 July
2001. Corresponding Editor: M. Adams.
82:125-126
WINTER 2001
NORTHWESTERN NATURALIST
OCCURRENCES OF THE WESTERN SKINK (EUMECES
SKILTON/ANUS) IN GRASSLANDS OF WESTERN MONTANA
YVETTE K. ORTEGA AND DEAN
Key Words: Eumeces skiltonianus, western
skink, Montana, Lolo National Forest, Calf
Creek Wildlife Management Area, distribution,
records
The western skink (Eumeces skiltonianus) was
recently classified as a Montana Species of Special Concern due to its restricted range in the
state (D. P. Hendricks, Montana Natural Heritage Program, Helena, MT, pers. comm.). Records of the western skink in Montana are limited to a few, scattered locations on the western
edge of the state (Tanner 1988; Reichel and
Flath 1995). Skinks have been documented in
the Bitterroot Valley in Ravalli County (Rodgers and Jellison 1942) and on the Kootenai National Forest in Lincoln County (Werner and
others 1998). In addition, there have been unconfirmed reports of their presence on islands
of Flathead Lake in Lake County (Franz 1971),
and Werner and others (1998) discuss unconfirmed records from the Flathead Indian Reservation within Lake and Missoula counties.
We caught 65 skinks in pitfall traps at 8 grassland sites within Missoula, Mineral, and Ravalli counties in west-central Montana during a
study of arthropod and small mammal communities. Except for 2 individuals, skinks died
in traps and were collected, and species identification was confirmed in the lab (P. S. Corn,
E. PEARSON
US Geological Survey, Missoula, MT, pers.
comm.). These records represent a significant
addition to information on the western skink in
Montana, confirming their presence in Missoula County, documenting their occurrence in
Mineral County, adding locations to Ravalli
County, and providing evidence of local abundance within some grasslands.
During 116,480 trap nights tallied May
through September in 1999 and 2000, we captured 59 skinks at 6 of 8 study sites located
within the Lolo National Forest. Each site consisted of four 250-m transects, 50 m apart, with
a total of 52 pitfall traps spaced at 20-m intervals. We caught 8 skinks at a site approximately
4.8 km SW of Clinton in Missoula County
(Tl2N R17W S19SE) which represents the eastern-most record reported for the state. At 3
sites approximately 6.4 km SE of Alberton in
Missoula County, we caught 48 skinks (1, 19,
and 28 skinks, respectively, from T14N R22W
S16NE, S20NW, and S30NE). In Mineral County approximately 4 km NE of Alberton, we captured 3 skinks at 2 sites (1 and 2 skinks, respectively, at Tl5N R22W S31SE and S31SW).
The above study sites are classified as Agropyron spicatum-Faa sandbergii grasslands (Mueggler and Stewart 1980) and occurred on southwest aspects at elevations between 1310 and
1707 m. These were steep, rocky slopes (averThis file was created by scanning the printed publication.
Errors identified by the software have been corrected;
however, some errors may remain.
126
82(3)
NORTHWESTERN NATURALIST
age slope of 30%) that had scatterings of ponderosa pine (Pinus ponderosa; 60% of trees) and
Douglas-fir (Pseudotsuga menziesii; 40% of
trees), and were located within a matrix of
montane coniferous forest. Four of 6 sites
where skinks were captured had been invaded
by the exotic forb, spotted knapweed (Centaurea
maculosa), which occurred in patches at low to
moderate densities. The remaining sites were
relatively pristine with only trace amounts of
knapweed.
As part of a 2nd study, we caught an additional 6 skinks at 2 of 4 sites within Calf Creek
Wildlife Management Area, approximately 16
km E of Hamilton in Ravalli County (1 and 5
skinks, respectively, at T6N R19W SSSE and
SSNW). Captures resulted from 13,824 trap
nights tallied between 6 April and 15 October,
2000. Each of these study sites consisted of
three 180-m transects, 50 m apart, with a total
of 18 pitfall traps spaced at 30-m intervals. Sites
were located within expansive Agropyron spicatum I Poa sandbergii grasslands (Mueggler and
Stewart 1980) with rolling topography and
gentle slopes ( < 20% slope). Spotted knapweed
was ubiquitous at Calf Creek. Sites where
skinks were captured were rocky areas with
moderate to high densities of knapweed,
southwest aspects, and elevations of 1400 and
1450 m.
Although little information is available for
the species in Montana, western skinks are believed to inhabit open habitats as well as dry
sites within forested areas (Tanner 1988; Reichel and Flath 1995). Given that we found
skinks at 8 of 12 grassland study sites, selected
originally for study of other taxa and located
up to 96 km apart at a range of elevations within 2 landscape contexts, we suggest that this
species may be widespread and sometimes locally abundant within west-central Montana.
However, the eastern and southern extent of
their range remains nebulous. Furthermore,
those habitat types where skinks are thought to
reside are rapidly being overtaken by spotted
knapweed (Porcella and Harvey 1983; Sheley
and others 1998), and it is unclear how associated habitat changes may affect their popula-
tions. Much research into the distribution and
ecology of the western skink in Montana is
needed to understand their status and associated implications of knapweed invasion.
ACKNOWLEDGMENTS
We thank S. Connolly, S. Hayden, J. Roberts, and
R. Palmer for their work in the field; Lolo National
Forest staff and M. Thompson of Montana Fish Wildlife and Parks for logistical assistance; and B. Maxell
for comments on a draft of the manuscript. The Lolo
National Forest study is sponsored by the Bitterroot
Ecosystem Management Research Project, a partnership among the Rocky Mountain Research Station,
the Bitterroot National Forest, and the University of
Montana. The Calf Creek study is financed by the
Wildlife Ecology Research Unit of the Rocky Mountain Research Station.
LITERATURE CITED
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FRANZ R. 1971. Notes on the distribution and ecology
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Bulletin of the Maryland Herpetological Society
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MUEGGLER WF, STEWART WL. 1980. Grassland and
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USDA Forest Service, Rocky Mountain Research
Station, PO Box 8089, Missoula, Montana 59807
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