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

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 exist. 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, indicating
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.