EFFECTS OF FOREST FIRE AND DROUGHT-INDUCED TREE MORTALITY ON HABITAT SELECTION BY CALIFORNIA SPOTTED OWLS IN YOSEMITE NATIONAL PARK.
Lynn N. Schofield; The Institute for Bird Populations; PO Box 1346, Point Reyes Station, CA, 94956; (612) 799-8630; lschofield@birdpop.org; Rodney B. Siegel, Stephanie A. Eyes, Sarah L. Stock
Climate change is increasing the frequency and severity of drought in the western United States, contributing to a corresponding increase in "mega-fires" characterized by large areas of high severity burn, and to high tree mortality in unburned stands. We examined habitat characteristics of spotted owl (Strix occidentalis occidentalis) territories found between 2004 and 2017 within Yosemite National Park, including within the footprint of the 2013 Rim fire, to assess how fire and drought may have affected habitat use and selection. Burn severity and tree mortality were not determining factors in territory location, and the proportion of territories within the fire's perimeter did not change after 2013. Prior to the fire, territories were characterized by higher canopy cover, density, and tree height than overall available habitat, but after the fire, territories were not significantly different from random locations, as much of the landscape experienced a reduction in tree cover. Our results suggest short-term resilience of spotted owls to the observed habitat changes, with pre-disturbance characteristics appearing to play a much larger role in driving post-disturbance territory selection, perhaps because of high territory fidelity or the acceptance of a reduction of habitat quality given sufficiently good conditions prior to disturbance.
Wildfire and Wildlife