Range expansion of a declining forest species, the Western Gray Squirrel (Sciurus griseus), into semiarid woodland.

This article focuses on the recent range expansion of the Western Gray Squirrel (Sciurus griseus) into piñon–juniper woodlands of the western Great Basin, a habitat type not historically occupied by the species. Using camera traps across northwestern Nevada and species distribution modeling (SDM) based on historical climate and occurrence data, the study found that warming winter temperatures have increased climatic suitability east of the Sierra Nevada, facilitating this range expansion. Occupancy modeling indicated that Western Gray Squirrels use piñon–juniper woodlands with similar likelihood as their traditional mixed-conifer forest habitats, suggesting habitat flexibility. The findings highlight how climate change can create novel refugia for species declining in their historical ranges, though future persistence may be threatened by factors such as increased wildfire frequency and habitat changes in the Great Basin.