Winter habitat associations of eastern spotted skunks in Virginia

Abstract

Eastern spotted skunk (Spilogale putorius) populations have declined throughout much of their range in the eastern United States over recent decades. Declines have been attributed to habitat loss or change, increased competition with sympatric mesocarnivore species, or disease. To better understand the extant distribution of spotted skunks in the Appalachian Mountains of western Virginia, USA, we used a detection‐non‐detection sampling approach using baited camera traps to evaluate the influence of landscape‐level environmental covariates on spotted skunk detection probability and site occupancy. We conducted camera trap surveys at 91 sites from January to May in 2014 and 2015. Spotted skunk occupancy was associated with young‐aged forest stands at lower elevations and more mature forest stands at higher elevations. Both land cover types in this region can be characterized as having complex forest structure, providing cover that varies with stand age, species composition, elevation, and management regime. Our results provide insight into factors that influence spotted skunk spatial distribution and habitat selection, information that can be used to generate conservation assessments and inform management decisions. © 2017 The Wildlife Society.

Evaluating detection and occupancy probabilities of eastern spotted skunks

“…Between January and April 2016 we surveyed 18 sites continuously for 3 months, and between January and April 2017 we surveyed 27 sites continuously for 3 months. Recent detections of spotted skunks in the Appalachian Mountains have been primarily limited to higher elevation (>350 m) sites (Diggins et al , Wilson et al 2016, Thorne et al ), we therefore selected sites that were stratified by elevation to capture potential differences in topographic or vegetative conditions associated with elevation. We then created random points within our 5 elevational strata such that sampling points were ≥1.5 km from each other.…”

“…Directed investigations of habitat associations of eastern spotted skunks are generally sparse, and strong predictors of occurrence have yet to be identified. One recently completed study from the central Appalachian Mountains in Virginia, USA, indicated that eastern spotted skunk occurrence is influenced by a combination of forest stand age and elevation (Thorne et al ). Specifically, within occupied landscapes, eastern spotted skunks appear to prefer younger pine forests or mature deciduous forests, presumably because of the increased understory complexity these forest types offer at their respective stages of growth (Lesmeister et al , Thorne et al ).…”

“…One recently completed study from the central Appalachian Mountains in Virginia, USA, indicated that eastern spotted skunk occurrence is influenced by a combination of forest stand age and elevation (Thorne et al ). Specifically, within occupied landscapes, eastern spotted skunks appear to prefer younger pine forests or mature deciduous forests, presumably because of the increased understory complexity these forest types offer at their respective stages of growth (Lesmeister et al , Thorne et al ). Historically eastern spotted skunks were common on homestead farms throughout the Midwest (DeSanty ), and the Florida subspecies ( S. p. ambarvalis ) has recently been reported to be abundant in the dry prairie ecosystems of central Florida (Harris ).…”

“…It is likely that a variety of temporal and site‐specific factors influence the detectability of skunks. For example, Thorne et al () reported that moon illumination had a significant negative effect on detection rates of eastern spotted skunks, suggesting that spotted skunks would be less active because of increased susceptibility to predation on nights when moonlight was high. Additionally, eastern spotted skunk detection rates were reported to be greater during the colder winter months (Hackett et al ), a trend that might be related to food availability or behavioral changes during the mating season (Hackett et al , Lesmeister et al ).…”

“…Second, we evaluated landscape‐scale environmental factors that we hypothesized would influence eastern spotted skunk occupancy probability in this southern Appalachian region. Specifically, we hypothesized that detection probability would be influenced by factors associated predation risk (Lesmeister et al , Thorne et al ), seasonal changes in food availability (Hackett et al ), the use of different scent‐based attractants (Schlexer ), and the monitoring station setup (Kays and Slauson ). We hypothesized that occupancy probability would be influenced by topographic features that relate to efficient movement (Fremier et al ), the availability of warmer habitats during the winter to reduce thermoregulatory stress (Lesmeister et al ), and predation risk (Lesmeister et al , Thorne et al ).…”