Fire disturbance and severity shape Canada lynx behavior: fine-scale movements and unburned island refugia

Abstract Context Increased fire frequency and severity in subalpine forests causes uncertainty regarding how forest-dependent species may respond to fire-disturbed landscapes relative to burn heterogeneity and severity. Objectives We tested individual-level habitat-use response of Canada lynx to fire severity, heterogeneity, patch characteristics, and unburned island refugia. Methods We instrumented 22 Canada lynx (27 lynx years, 2018–2020) in the Northern Rocky Mountains, U.S.A. to investigate selection behavior in recent (≤ 3 yrs) fire-impacted landscapes using resource selection (RSF) and integrated step selection models (iSSF), functional response analyses, and hurdle models. Results Canada lynx increasingly avoided burned landscapes as disturbance became more prevalent within home ranges. At a finer scale (iSSF), lynx traversing burns selected high post-fire normalized burn ratio (NBR; i.e., low severity), high heterogeneity of severity, and near fire perimeters. Lynx exhibited strong selection for unburned islands, with 22.8% of random locations in islands compared to 42.5% of lynx locations. Lynx traveled an average of 720 m (range: 42–2293 m) inside fire perimeters to access unburned islands. Islands with higher post-fire NBR, lower perimeter to area ratio (simpler shape), and greater surrounding fire heterogeneity were more likely to be used. Snowshoe hares were more abundant in unburned islands in fires compared to controls outside fires. Conclusions Canada lynx were sensitive to the extent of fire-impacted landscapes in home ranges and to patterns of fire severity and heterogeneity, including their use of unburned islands of fire refugia. Trends of increased fire severity in subalpine forests may reduce habitat suitability for Canada lynx.