Supporting results and data for assessing impacts of the Grassy Ridge Fire on greater sage-grouse space use in eastern Idaho, USA

Global change has altered the nature of disturbance regimes and megafire
events are increasingly common. Megafires result in immediate changes to
habitat available to terrestrial wildlife over broad landscapes, yet we
know surprisingly little about how such changes shape space use of
sensitive species in habitat that remains. Functional responses provide a
framework for understanding and predicting changes in space use following
habitat alteration, but no previous studies have assessed functional
responses as a consequence of megafire. We studied space use and tested
for functional responses in habitat use by breeding greater sage-grouse
(Centrocercus urophasianus) before and after landscape-level changes
induced by a >40,000 ha, high-intensity megafire that burned
sagebrush-steppe in eastern Idaho, USA. We also incorporated functional
responses into predictive resource selection functions (RSFs) to map
breeding habitat before and after the fire. Megafire had strong effects on
the distribution of available resources and resulted in context-dependent
habitat use that was heterogeneous across different components of habitat.
We observed functional responses in use and selection of a variety of
resources (shrubs and herbaceous vegetation) for both nesting and brood
rearing. Functional responses in use of nesting habitat were influenced by
the overarching effect of megafire on vegetation, whereas responses during
brood rearing appeared to be driven by individual variation in available
resources that was conditional on nest locations. Importantly, RSFs built
using data collected prior to the burn also had poor transferability for
predicting space use in a post-megafire landscape. These results have
strong implications for understanding and predicting how animals respond
to a rapidly changing environment, given that increased severity,
frequency, and extent of wildfire are consequences of global change with
the capacity to reshape ecosystems. We therefore demonstrate a conceptual
framework to better understand space use and aid habitat conservation for
wildlife in a rapidly changing world.