Riparian areas have been well documented as corridors for wildlife species, particularly in fragmented or disturbed areas. However minor drainages, such as intermittent and ephemeral streams and runoff channels are often over-looked as ecologically important features. Nonetheless, these minor drainage features compose a majority of the length of mountainous drainage networks and are highly influential in shaping the topography and vegetation of an area. We evaluated eastern spotted skunk rest site selection in the southern Appalachians of South Carolina, and were the first to investigate the importance of drainage networks for this species. Using a high-resolution (1/9 arc-second) digital elevation model in ArcGIS, we determined a most suitable cell-accumulation threshold to capture minor drainage features in our study area, and then used this drainage layer as a covariate in a discrete choice modelling framework to evaluate if eastern spotted skunk rest site selection may be influenced by drainage channels.
Results/Conclusions
Our results indicate that eastern spotted skunks are selecting rest sites nearer to drainages, and proximity to drainage channel was the most important factor in predicting spotted skunk rest site selection. This effect was only observable when including the numerous minor drainages that do not appear on USGS hydrological layers. Identification of an appropriate cell accumulation threshold was crucial, as very low threshold values depicted false ravines, while very high threshold values failed to identify minor drainages. We suspect that drainage channels may provide multiple beneficial functions to transient mesocarnivores species, particularly in old mountainous terrain where millennia of erosion have created particularly complex drainage networks. Drainage channels may have different functions dependent on size and location, and we suggest that they may provide ecological services such as high-quality foraging habitat, corridors for travel and dispersal, natural hubs for olfactory communication, and natural delineations of home range boundaries. Overall, more research is necessary to understand the different ways in which various species may be using these highly prevalent topographic features. More knowledge regarding the ecology of minor drainages could contribute to our understanding of forest diversity, dispersal, and connectivity within and between naturally occurring drainage networks.