Johnny O'Neil Late Successional Reserve Habitat Restoration and ...

Siskiyou Mountain/Scott Bar Salamander (Plethodon stormi / Plethodon asupak)
Environmental Baseline
Siskiyou Mountain salamanders are typically found on forested slopes where rocky soils and
talus outcrops occur. Occupied habitat for the species ranges from small, isolated rock outcrops
to entire hillsides (Clayton et al. 2004). In a review by Ollivier and others (2001), the species is
commonly associated with closed canopy forests on north-facing slopes but can also be
associated with diverse habitat variables including more open canopy, different slope aspects,
slope position, and varying climatic conditions (Clayton et al. 2004, CDFG 2005, DeGross and
Bury 2007). The available data suggest overall that these species are mainly associated with talus
and fissured rock outcrops and are generally associated with moist, cool surface microclimates.
While they may occur in variable conditions, they are likely more common in mature and oldgrowth
forest than in other forest classes. Overall, available moisture and rocky talus appear to
be the two most important habitat conditions for these two species (DeGross and Bury 2007).
Siskiyou Mountain salamanders are lungless salamanders that require moisture in order to respire
through their skin and avoid desiccation (Nussbaum et al. 1983). These traits limit the time the
species can be active at the surface where they forage (Nussbaum et al. 1983, Clayton et al.
1999).
Although these salamanders may occasionally be detected under scattered surface rocks or
woody debris, most detections are within layered rock (talus) with interstitial spaces that
provide underground refugia from unfavorable environmental conditions.
The range of the Siskiyou Mountain Salamander is limited to portions of three counties in
southwestern Oregon and northern California (Clayton & Nauman 2005). On the KNF,
known locations occur on the Oak Knoll and Scott River Districts; three known locations
occur within the project area. Two locations are documented in burn units (UB-N and UB-
R) and one is outside of any treatment unit (USDI Fish and Wildlife Service and Natural
Resources Geospatial 2007). Suitable habitat occurs throughout the project area. The
Maxent Model for Siskiyou Mountain/Scott Bar Salamander was utilized to identify areas
with moderate-high probability of occupancy to assist in determining survey needs in cable
units. This model evaluates the likelihood of occupancy based on biotic and abiotic
variables including soil type, slope position, aspect, elevation, and vegetation (See Survey
and Manage Analysis, Figure 1). The majority of moderate to high probability habitat
occurs within the tractor units which were surveyed in 2009; 56 patches of potentially
suitable habitat were located and mapped in 28 units. Talus patch sizes ranged from 0.06
acre to 3.8 acres, with the mean of about 0.5 acre; the majority of patches were about 0.1
acre (project file).
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