Bobcats (Lynx rufus) as a Model Organism to Investigate the Effects of Roads on Wide-Ranging Carnivores

Abstract

We are using bobcats (Lynx rufus) as a model organism to examine how roads affect the abundance, distribution, and genetic structure of a wide-ranging carnivore. First, we compared the distribution of bobcat-vehicle collisions to road density and then estimated collision probabilities for specific landscapes using a moving window with road-specific traffic volume. Next, we obtained incidental observations of bobcats from the public, camera-trap detections, and locations of bobcats equipped with GPS collars to examine habitat selection. These data were used to generate a cost-surface map to investigate potential barrier effects of roads. Finally, we have begun an examination of genetic structure of bobcat populations in relation to major road networks. Distribution of vehicle-killed bobcats was correlated with road density, especially state and interstate highways. Collision models suggested that some regions may function as demographic sinks. Simulated movements in the context of the cost-surface map indicated that some major roads may be barriers. These patterns were supported by the genetic structure of bobcats. The sharpest divisions among genetically distinct demes occurred along natural barriers (mountains and large lakes) and in road-dense regions. In conclusion, our study has demonstrated the utility of using bobcats as a model organism to understand the variety of threats that roads pose to a wide-ranging species. Bobcats may also be useful as one of a group of focal species while developing approaches to maintain existing connectivity or mitigate the negative effects of roads.

An evaluation of hunter surveys to monitor relative abundance of bobcats

“…Briefly, raster rank at a coarse resolution was influenced by the locations of 665 incidental sightings of bobcats by the general public (collected Dec 2007 through Jan 2013) in relation to mean monthly snow depth. That pattern of bobcat distribution was corroborated by trail cameras (Litvaitis et al ). At a fine resolution, raster rank was influenced by habitat selection by GPS‐collared bobcats in relation to environmental variables expected to influence probability of bobcat use of established home ranges (Litvaitis et al ).…”

“…That pattern of bobcat distribution was corroborated by trail cameras (Litvaitis et al ). At a fine resolution, raster rank was influenced by habitat selection by GPS‐collared bobcats in relation to environmental variables expected to influence probability of bobcat use of established home ranges (Litvaitis et al ). The habitat‐suitability index value for each WMU was taken as the average of all raster cells coincident with potential bobcat habitat.…”

“…A model of habitat suitability for bobcats in New Hampshire ranked 30‐m raster cells covering the state on a scale of increasing suitability from 0 to 1 (Litvaitis et al ). Briefly, raster rank at a coarse resolution was influenced by the locations of 665 incidental sightings of bobcats by the general public (collected Dec 2007 through Jan 2013) in relation to mean monthly snow depth.…”

“…First, along with coyotes, bobcats have functioned as an apex predator since the extirpation of wolves ( C. lupus ) and cougars ( Puma concolor ) throughout much of eastern North America (Roemer et al ). As a wide‐ranging carnivore, bobcats require large areas of available habitat and are often selected as a focal or umbrella species in large‐scale conservation efforts (Crooks , Rubino and Hess , Litvaitis et al ). In northern New England, The Nature Conservancy's “Staying Connected” initiative recently identified bobcats as a focal species for maintaining landscape linkages (The Nature Conservancy ).…”

“…With these limitations in mind, we decided to compare hunter surveys and a recently completed model of bobcat habitat suitability in New Hampshire (Litvaitis et al ). Our goal was to evaluate the use of hunter observations as an efficient index for monitoring the abundance of bobcats at regional and statewide scales.…”