Oregon State University
The return of wolves in some areas has reduced coyote populations by 50 percent. Researchers at Oregon State University say that could mean there will be more showshoe hares for the threatened Canada lynx to eat – a key to their recovery.
Look out, coyotes. Wolves are coming back.
A new study from Oregon State University has found that restoring wolf populations not only helps restore balance in broader ecosystems, it can also help save threatened species such as the Canada lynx … by shrinking the number of coyote “mesopredators” and leaving more showshoe hares for the lynx to eat.
In the absence of wolves, research shows, coyote populations have expanded across the U.S. Where wolves have recovered – in Yellowstone National Park, for example – coyote numbers initially shrank by 50 percent.
Fewer coyotes means more showshoe hares for other species like the Canada lynx, which has been in decline for decades and was listed as threatened in 2000.
This is what scientists call a “trophic cascade” of impacts. And as wolves return to the Northwest, it doesn’t stop with coyotes and hares. Other studies have found trickle-down impacts on birds, lizards, rodents, marsupials, rabbits, scallops, insects, and ranch animals such as sheep.
Oregon State University
The ecosystem links wolves, coyotes, lynx, lizards, birds and insects. As wolves return, researchers are finding a trophic cascade of effects on other species.
Canada lynx suffer from a decline in their food supply and possibly from an increase in coyote attacks, though there are other factors threatening their populations, too, including habitat alteration and climate change because they rely on snow-covered mountain turf.
Coyotes in this scenario are considered “mesopredators” – the second in nature’s chain of command. William Ripple, a professor in OSU’s Department of Forest Ecosystems and Society, has studied the role of predators in ecosystems and the relationship between the decline in wolves and the rise of coyotes:
“The increase in mesopredators such as coyotes is a serious issue; their populations are now much higher than they used to be when wolves were common in most areas of the United States. Before they were largely extirpated, wolves used to kill coyotes and also disrupt their behavior through what we call the ‘ecology of fear. Coyotes have a flexible, wide-ranging diet, but they really prefer rabbits and hares, and they may also be killing lynx directly.”
Ripple has studied the ecosystem value of predators and documented how the wolves and other large predators helps control populations of grazing ungulates including deer and elk. That, in turn, is changing forests where deer and elk forage and bringing plants back alongside streams. Here’s a video where Ripple explains how removing predators affects the ecosystem: