predators

Wind turbines change visitors to tortoise burrows

The design of a wind energy facility can influence the behavior of animal predators and their prey, according to new research on desert tortoises.

Scientists placed motion-activated cameras facing the entrances of 46 active desert tortoise burrows in a wind energy facility near Palm Springs, California. Video recordings show that visits to burrows from five predators—bobcats, gray foxes, coyotes, black bears, and western spotted skunks—increased closer to dirt roads, and decreased closer to wind turbines.

bobcat and desert tortoise
Bobcat approaches desert tortoise. (Credit: USGS)
western spotted skunk gif
Western spotted skunk investigates burrow. (Credit: USGS)

Habitat disturbance from wind energy facilities creates unique challenges and opportunities for wildlife. Although fragmented landscapes may make some large carnivores—like cougars and bears—more vulnerable to population decline, some small- to medium-sized animals—like coyotes and foxes—expand their habitat to include areas that have been changed by humans.

“These findings could be helpful in assisting managers to design future wind energy facilities with species in mind,” says lead author Mickey Agha, a graduate student studying ecology with Professor Brian Todd at the University of California, Davis. “There may be benefits to adding space between turbines and increasing the number of dirt roads, to potentially provide habitat for sensitive terrestrial wildlife.”

Results, published in the Journal of Wildlife Management, suggest that infrastructure associated with wind energy facilities, such as dirt roads or culverts, may create movement corridors through disturbed habitat that some animals prefer. Dirt roads may act as funnels for predators because they are potential corridors through the wind energy facility.

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Earlier research at the study site reported that tortoise burrows were more likely to be closer to roads than random points. Tortoises can move more easily on dirt roads and desert washes than on highly vegetated landscapes.

“There is little information on predator–prey interactions in wind energy landscapes in North America, and this study provides a foundation for learning more,” says coauthor Jeffrey Lovich of the US Geological Survey. “Further investigation of causes that underlie road and wind turbine effects, such as ground vibrations, sound emission, and traffic volume could help provide a better understanding of wildlife responses to wind energy development.”

The cameras did not record any predation on adult desert tortoises close to burrows. This suggests that the predators observed in the study do not often actively prey upon adult desert tortoises, but visit the sites looking for smaller prey that frequently live in desert tortoise burrows.

Funding came from California Desert Managers and the USGS Ecosystems Program.

Source: Jennifer LaVista for UC Davis

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