CANCELLED - Key habitat characteristics of a threatened ground squirrel and implications for habitat restoration

Background/Question/Methods

The northern Idaho ground squirrel (Urocitellus brunneus brunneus) is a threatened species that is endemic to west-central Idaho. Reductions in habitat are presumably due to fire suppression and subsequent increases in forest density, in particular tree encroachment into historically open meadows and scablands within ponderosa pine forest. Management practices include thinning and burning to open up encroached habitat.  We measured attributes of areas designated as ‘used’ or ‘available’ at four sites: Cap Gun, Summit, Price Valley and OX Ranch.  Used areas were determined via monitoring surveys, visual and audio counts of individuals; available areas were selected 100-300m away from used areas, lacked the presence of squirrels, and could be burned the following fall in efforts to restore habitat. Measured attributes were limited to parameters that can be altered by thinning and burning: canopy cover, ground cover, organic layer depth and soil chemistry. We analyzed variables with ‘used’ nested within site in a nested ANOVA.

Results/Conclusions

Canopy cover was significantly lower (P = 0.01) in used areas regardless of site. There was a significant difference between used and available areas within site for litter, soil, rock, moss/lichen, and understory cover (for all variables P < 0.0001).  Woody debris ground cover was not statistically significant between used and available areas (P = 0.18).  Soil nitrogen levels did not vary between used and available areas (P = 0.66 ); phosphorus and calcium levels varied between used and available within site (P = 0.02, P <0.0001). Soil pH was significantly different (P = 0.001) between used and available areas.  The organic horizon was not significantly different between used and available areas (P = 0.17), but within sites used and available organic material was statistically different (P = 0.03). Our results suggest used areas have less acidic soils, overstory and understory coverage, while having higher levels of bare ground and rocks. Further analysis will be conducted post-fire to determine the effects of prescribed fire on habitat characteristics.