AN ASSESSMENT OF HABITAT USED BY REPRODUCTIVE FEMALE FISHERS (PEKANIA PENNANTI) IN THE SOUTHERN SIERRA NEVADA.
Rebecca E. Green; PSW Research Station, USFS; 54325 McKinley Grove Rd, Shaver Lake, CA, 93664; (559) 841-6318; regreen@ucdavis.edu; Kathryn L. Purcell, Douglas A. Kelt, Craig M. Thompson, Heiko U. Wittmer, Nathan M. Hebert, Eric L. McGregor
The fisher (Pekania pennanti) is a forest carnivore of conservation concern in the southern Sierra Nevada. Prior to this study, information on fisher reproductive habitat was extremely limited. Between 2007 and 2012, we documented radio-collared female fishers at reproductive dens (natal = 45, maternal = 95) in spring, then revisited these dens in summer to assess forest conditions. We compared characteristics of habitat used by reproductive females with available habitat at 3 spatial scales. At the structure scale, California black oaks (Quercus kelloggii) and white firs (Abies concolor) were used more than expected, incense cedars (Calocedrus decurrens) were used in proportion to availability, and pines (Pinus sp.) were used less than expected. At the site scale, canopy cover immediately around dens and random trees was relatively high (ca. 72%) as was understory cover (ca. 56%), but these measures did not differ between den and random sites. Finally, when compared to available stands, den stands had higher density and basal area of large California black oaks, higher basal area of large snags, higher stand density indices, denser canopy cover, and steeper slopes. We consider conservation implications of these findings within the context of extensive tree mortality in this region.
Ecology and Conservation of Martens and Fishers