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U.S.-Mexico border fence isolates wildlife

July 7, 2009 |  8:55 pm


Walls built along the U.S.-Mexico border don't just keep human families apart.

Biologists say the barriers also threaten such wildlife species as bighorn sheep and pygmy owls, isolating populations and narrowing the gene pool. Pygmy owls, who sometimes fly low to the ground, may find their flight patterns disrupted by high fences or walls.

"This has happened so fast, there was no time for a pre-fence study," said Clinton Epps, a wildlife biologist at Oregon State University and a co-author of the study. A break in the fence in key places could allow for greater genetic diversity among bighorn sheep, Epps said.

Constructing poles for owls to perch on and maintaining brush and tall trees around the border could support pygmy owls, according to Aaron D. Flesch, a biologist from the University of Arizona and the lead author of the study.

"Movement of pygmy owls from Mexico to Arizona may be necessary for the persistence of the Arizona population," Flesch said.

The results of the study were published in the journal Conservation Biology.

-- Amy Littlefield

Photo: A bighorn sheep and her lamb in the Rocky Mountains in Wyoming. Credit: Anacleto Rapping/Los Angeles Times