Landscape‐level influences of terrestrial snake occupancy within the southeastern United States

Abstract

Habitat loss and degradation are thought to be the primary drivers of species extirpations, but for many species we have little information regarding specific habitats that influence occupancy. Snakes are of conservation concern throughout North America, but effective management and conservation are hindered by a lack of basic natural history information and the small number of large‐scale studies designed to assess general population trends. To address this information gap, we compiled detection/nondetection data for 13 large terrestrial species from 449 traps located across the southeastern United States, and we characterized the land cover surrounding each trap at multiple spatial scales (250‐, 500‐, and 1000‐m buffers). We used occupancy modeling, while accounting for heterogeneity in detection probability, to identify habitat variables that were influential in determining the presence of a particular species. We evaluated 12 competing models for each species, representing various hypotheses pertaining to important habitat features for terrestrial snakes. Overall, considerable interspecific variation existed in important habitat variables and relevant spatial scales. For example, kingsnakes (Lampropeltis getula) were negatively associated with evergreen forests, whereas Louisiana pinesnake (Pituophis ruthveni) occupancy increased with increasing coverage of this forest type. Some species were positively associated with grassland and scrub/shrub (e.g., Slowinski's cornsnake, Elaphe slowinskii) whereas others, (e.g., copperhead, Agkistrodon contortrix, and eastern diamond‐backed rattlesnake, Crotalus adamanteus) were positively associated with forested habitats. Although the species that we studied may persist in varied landscapes other than those we identified as important, our data were collected in relatively undeveloped areas. Thus, our findings may be relevant when generating conservation plans or restoration goals. Maintaining or restoring landscapes that are most consistent with the ancestral habitat preferences of terrestrial snake assemblages will require a diverse habitat matrix over large spatial scales.

Snake co‐occurrence patterns are best explained by habitat and hypothesized effects of interspecific interactions

“…We based this study on a data set that was previously used to examine how terrestrial snake occupancy was influenced by land cover (Steen et al . ). Data were compiled from 449 passive traps from a number of different sites located across the south‐eastern United States, from North Carolina through eastern Texas.…”

Landscape structure affects distribution of potential disease vectors (Diptera: Culicidae)

“…Consequently, adult mosquitoes are often found in abundance close to their original larval habitats, presence and abundance of which depends on landscape cover, climate and seasonality [14–16]. Landscape elements not only control breeding habitat availability but also govern occurrence and abundance of suitable hosts groups, such as birds [17], amphibians [18] and reptiles [19, 20]. Indeed, effects of landscape factors on mosquito diversity and abundance are increasingly assessed in ecological analyses of mosquito communities [21–23].…”

Pavement and riparian forest shape the bird community along an urban river corridor

“…We also created an ''Urban'' variable (i.e., an index of urbanization) which represented the sum of the area covered by buildings and paved surfaces. All land cover variables were z-transformed before analysis to place all area measurements on the same scale (Bradley et al, 2008;Steen et al, 2012).…”