SAN FRANCISCO, May 29 (APP/Xinhua): An analysis of the
relationship between top predators on three different continents
and the next-in-line predators they eat and compete with indicates
that wolves and other top predators need large ranges to be able
to control smaller predators whose populations have expanded to
the detriment of a balanced ecosystem.
The findings, published in Nature Communications, were similar
across continents, showing that as top predators’ ranges were cut
back and fragmented, they were no longer able to control smaller
predators.
“Our paper suggests it will require managing for top predator
persistence across large landscapes, rather than just in protected
areas, in order to restore natural predator-predator interactions,” co-author Aaron Wirsing, an associate professor at the University of Washington’s School of Environmental and Forest Sciences, was quoted
as saying in a news release from the university.
In places like Yellowstone and eastern Washington and Oregon in
the United States, smaller wolf populations are too far removed from
the remaining core of the species’ distribution to really make a
difference in controlling coyote numbers. Fewer wolves aren’t the only reason coyotes have proliferated everywhere in North America.
Coyotes are generalists that can live almost anywhere and have
basically followed humans, eating human food and, in some cases,
household pets.
“Coyotes have essentially hitched a ride with people,” Wirsing
noted. “Not only do we subsidize coyotes, but we also helped them by
wiping out their predators — wolves.”
Gray wolves historically lived across vast swaths of North
America, particularly in the western U.S. states and Canadian
provinces. Coyotes, a smaller predator kept in check by wolves,
appear to have been scarce in areas once dominated by wolves. As
human development shrank territories for wolves, however, the wolf populations became fragmented and wolves no longer had the numbers
or space to control coyotes, whose populations in turn grew.