AUTHORS: Nadine Pershyn, Southern Illinois University Carbondale; Clay Nielsen, Southern Illinois University Carbondale; Nicole Gorman, Southern Illinois University Carbondale; Abby Weber, Southern Illinois University Carbondale; and Guillaume Bastille-Rousseau, Southern Illinois University Carbondale
ABSTRACT: Gray fox (Urocyon cinereoargenteus) populations have declined throughout the midwestern U.S. without clear causation. Despite this decline, until recently minimal research has been conducted in the region to gain insight into the ecological needs of a vulnerable population. We evaluated gray fox second order habitat selection to determine which habitats are best suited to supporting gray foxes in southern Illinois and similar landscapes throughout the region. Gray foxes were trapped during November-March 2022-2024 using padded foothold traps and fitted with GPS collars programmed to take locations every 2 hr. Using more than 11,000 GPS locations from 10 gray foxes (5 ad F, 4 ad M, 1 ju M), we used a 2nd order resource selection function (RSF) to analyze habitat selection relative to vegetation cover (e.g., forest, grassland, crop, shrub, barren), distance to forest-grassland edges, distance to forest-crop edges, human development, distance to secondary roads, and elevation. We also investigated the impact of relative probability of use (RPU) across the landscape of coyotes (Canis latrans) and bobcats (Lynx rufus), using GPS locations also collected across southern Illinois. Gray foxes selected most strongly for developed areas, grasslands, and forest, and preferred areas closer to forest-grassland edge and farther from forest-crop edges and secondary roads. Our results support previous research that shows interspersed forest and grassland is important gray fox habitat. Gray foxes avoided areas with high coyote RPU but were not impacted by bobcat RPU. Coyotes are intraguild predators of gray foxes, and may contribute to mortality, which could be why gray foxes avoided them. Bobcats have similar habitat requirements and prey as gray foxes, which could explain the lack of response. Our study provides novel insight into habitat selection of a species of concern and sheds light on intraguild carnivore interactions.
