US-Mexico border wall could threaten wildli...( CORVALLIS Ore. A 700-mile security ...)

CORVALLIS, Ore. A 700-mile security wall under construction along the United States' border with Mexico could significantly alter the movement and "connectivity" of wildlife, biologists say, and the animals' potential isolation is a threat to populations of some species.

However, technology and alterations to the design could dramatically improve the potential for animals to move more freely between the two countries, the scientists added.

Results of their study are being published in the journal Conservation Biology.

"The biggest concern is that this barrier will break small populations of animals into even smaller pieces that will result in fewer animals interacting," said Clinton Epps, a wildlife biologist at Oregon State University and co-author on the study. "A major barrier such as this could lead to significant degradation of connectivity for many different species, ultimately threatening their populations."

In their study, the authors looked at the potential effects of the security wall on two species the pygmy owl and bighorn sheep primarily because they already had studied those animals in that region. They found that the low-flying pygmy owl made three-fourths of its flights below the height of the security wall, which is approximately four meters high, and that juvenile owls had lower colonization in areas of disturbance or areas with less vegetation.

"Some of the potential damage to pygmy owls could be mitigated with a few tweaks to the system," Epps added. "Putting in poles near the fence could allow the owls to swoop down from a perch, and planting brush to provide better cover could help them avoid predation by larger avian species and improve their chances for colonization."

Maintaining or augmenting trees that are taller than the fence, and that are associated with patches of dense, low vegetation should not only promote permeability, agreed lead author Aaron D. Flesch, a biolog
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