JWM study: Off-highway vehicles encroaching on kit fox habitat

Come wintertime in the Southwest, a flurry of recreationists hit the desert trails on dirt bikes, in four-wheel-drive vehicles and on all-terrain vehicles. But recent research demonstrates that this popular activity can decrease habitat for the kit fox (Vulpes macrotis), a cat-sized furbearing fox that inhabits the region.

“Correctly managing multiple use landscapes is difficult,” said Andrew Jones, wildlife specialist with the Arizona Game and Fish Department and lead author on the study published in February in The Journal of Wildlife Management. “That’s where research can help, so we can strike balances between conservation and habitat protection and managing for recreational opportunities like off-highway vehicle (OHV) use.”

The biologists focused on OHV routes and the effect they have on how 22 collared kit foxes used two sites in the Sonoran Desert in central Arizona. The study occurred during both periods of low and high OHV use from 2010 to 2013. Because they couldn’t efficiently track and count individual vehicles, Jones and his colleagues measured OHV impacts by looking at the density of OHV roads across their study areas using aerial imagery and GIS and checking their results against OHV activity they observed in aerial surveys.

The study found that OHV road density was the most important predictor of kit fox space use, relative to other environmental features such as topography, prey availability and soil type. Kit foxes avoided areas with OHV trails, particularly from October to March when kit foxes are engaged in breeding, denning, and giving birth to pups. Researchers suggested their avoidance may be due at least in part to higher OHV use occurring at the same time.

“Kit foxes avoid these areas during certain times of the year,” Jones, a TWS member, said. “That can remove habitat available to them in areas where there’s lots of OHV road networks.”

The researchers concluded that the ongoing growth of OHV road networks could compromise habitat for the kit fox, whose population is currently stable in Arizona but at risk in other parts of its range. To balance OHV recreation with the species’ conservation, they recommended restricting road expansion and ensuring that OHVs stay on established trails by educating drivers about existing regulations.