Forest heterogeneity influences habitat selection by fishers (Pekania pennanti) within home ranges

Habitat selection by animals occurs across a wide range of spatial and temporal scales. Information about habitat requirements across scales is needed to develop effective habitat management strategies that promote wildlife conservation. The fisher (Pekania pennanti) is a wide ranging mesocarnivore that occurs at low population densities, uses large tracts of forested land, and has been repeatedly petitioned for listing under the Endangered Species Act, primarily due to habitat loss. Although habitat selection by fishers at fine and broad spatial scales has been studied, selection at scales between these extremes is poorly reported in the literature. We used data from 18 fishers fitted with Argos satellite telemetry collars to evaluate two competing hypotheses about habitat selection by fishers within home ranges: fishers select core use areas based on (1) abundant and contiguous mature forest, or (2) heterogeneity and diversity of habitats. We identified core and peripheral use areas within home ranges using an optimal isopleth analysis, and we evaluated a suite of a priori models that described how forest composition and configuration might influence habitat selection within home ranges. Results indicated that core use areas were composed of intermediate amounts of both landscape edge and high canopy cover forest. Such selection potentially facilitates access to a diverse array of resources. Overall, our results supported the hypothesis that fishers select core use areas within home ranges based on habitat heterogeneity and diversity. Because most forest management occurs at a scale similar to our analysis, these results contribute to a better understanding about how forest management strategies can facilitate persistence of fishers in managed forest landscapes.