Ecologists are being forced to reevaluate green energy’s footprint after a new study published in The Journal of Wildlife Management.
Wind farms are designed to supply renewable power. This large-scale function often overshadows their smaller-scale effects.
Altered hunting and movement behaviors of local carnivores are some of these factors.
Researchers focusing on sensitive desert ecosystems recently captured unexpected footage of predators investigating the ground around wind turbines.
What were they doing there?
How researchers track wildlife behavior changes in response to energy installations
A research team from the University of California, Davis, and the United States Geological Survey set out to understand these animal interactions. A monitoring network was set up around the Mesa wind farm’s 460 turbines near Palm Springs.
It is a key location at an intersection where the coastal scrub, Mojave Desert, and montane ecosystem meet. This collision of environments is unique because species that normally live in separate elevation zones are drawn closer together.
The desert tortoise (Gopherus agassizii) was the scientific team’s target. It is a threatened species with engineering skills enabling it to dig deep, stable burrows to escape the desert heat. It may seem like an unlikely meal, considering the shell to get through, but it has a number of natural predators.
The researchers set up motion-activated cameras at the entrances of 46 active tortoise burrows in a wind farm. This way, every animal that approached the critical shelters could be documented.
An increase in carnivore sightings to be explained
It turns out that the tortoise burrows were attracting a surprisingly high number of mammals. The motion cameras showed that activity centered around the tortoise homes, and it was not random.
The footage showed a steady parade of carnivores patrolling the entrances rather than occasional bypassers.
Five distinct predatory species were identified visiting the site: coyotes, bobcats, gray foxes, western spotted skunks, and bears.
Mapping of the encounters against the wind farm infrastructure revealed a clear geographic pattern. The carnivore visits were not spread uniformly across the site. Predator activity was lower in the areas directly around the turbines themselves.
But it was different closer to the dirt roads running through the facility.
The presence of man-made infrastructure had a clear impact on wildlife activity, but there was still an exact ecological instigator to be explained.
Man-made roads crossing wildlife paths
Among the most surprising footage captured was a mother black bear and her cub descending from the high-elevation montane habitat to investigate a tortoise burrow.
The cameras revealed that hunting desert tortoises had nothing to do with the changes in predator behavior. Not even one case of predation on an adult tortoise was recorded. Instead, there was a dual mechanism behind the attraction to the wind power infrastructure.
The mammals reacted to the low resistance to movement along the wind farm’s unpaved roads and culverts alongside. Essentially, it meant free-flowing corridors through the dense scrub where none existed before.
When the predators reached the tortoise homes, they realized that many more species of smaller prey use the same burrows. Different kinds of rodents, lizards, and insects set up their own safe zones thanks to the tortoises’ endeavors. The burrows essentially become hubs for hunting.
Energy planners need to think about so much more than just turbine placement
Wind farm developers are learning how important it is to plan beyond the placement of infrastructure. It is vital to consider how infrastructure influences wildlife behavior like hunting and navigating.
One way to preserve natural predator-prey dynamics is to build fewer roads in future facilities. In some cases, the addition of infrastructure can help with conservation, such as protecting foxes from coyotes.
To learn more about how infrastructure affects local ecosystems, read this article on how the construction of modern roads interferes with historic migratory pathways for desert mule deer.
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