Recreational trail traffic counts and trail proximity as a driver of ungulate landscape utilization

Abstract

With continual growth in recreational trail use, it is becoming increasingly complicated to balance demands for outdoor recreation opportunities with wildlife conservation. To better understand how mule deer (Odocoileus hemionus) and Rocky Mountain elk (Cervus canadensis) respond to trail-based recreation, we deployed remote cameras in a paired study design to assess ungulate encounter rates relative to recreation traffic counts and distance from trails. Our methodology allowed us to estimate the magnitude of human activity on public land trails, which can be challenging, but is a key step in understanding recreational effects on animal utilization, especially if any interaction in trail proximity and human traffic rates exists. Paired cameras provided a comparison of animal encounter rates on- and off-trail at varying trail proximities, and the on-trail camera also yielded daily recreation traffic counts to assess how animals respond to varying traffic for each camera pair. Elk avoided busier trails and showed a strong positive response to distance from trails, while mule deer exhibited a positive response to higher traffic counts and no measurable effect of trail proximity. We identified a distance to trail threshold of 600–655 m, where elk utilization shifted from lower-than-expected utilization to higher-than-expected utilization, indicating that this elk population was redistributed to some degree within 57.5% of the study area's extent. Quantifying recreation traffic counts was key to understanding species' responses to recreation, highlighting the need for managers to consider both trail placement and human traffic regulation to mitigate recreation impacts.