United States border fence threatens wildlife

from Nature News:



United States border fence threatens wildlife
Barrier between the United States and Mexico divides habitats and puts species at risk.

Melissa Gaskill


The 1,000 kilometres of impenetrable barrier constructed along the Mexico–United States border, with the aim of stemming illegal human immigration, is also hampering the movements of animals, including several endangered species, a recent study finds.

The species most at risk are those with smaller populations and specialized habitats, says Jesse Lasky, a graduate student at the University of Texas, Austin, and an author on the study, published in Diversity and Distributions1. Small range size is associated with a higher risk of extinction, and for some species, the barriers reduce range by as much as 75%. According to the study, species most at risk include four listed by the International Union for Conservation of Nature as endangered or threatened — the Arroyo toad (Anaxyrus californicus), the California red-legged frog (Rana draytonii), the black-spotted newt (_Notophthalmus meridionalis_) and the Pacific pond turtle (Clemmys marmorata) – together with the jaguarundi (Puma yagouaroundi), which is endangered in the United States and threatened in Mexico.

The study also identified three border regions where wildlife is most at risk from the barrier: coastal California, coastal Texas and southeastern Arizona's Madrean Sky Island Archipelago.

Fragmented communities

The Rio Grande Valley, in coastal Texas, contains one of two remaining stands of native Mexican sabal palms. The solid metal and concrete fence, around 5.5 metres high, with an 18-metre-wide strip of open land on either side, runs through a preserve created to protect the trees. Rare animals in the valley include the ocelot, of which fewer than 50 remain in the United States. The fence further fragments their habitat and separates the population in Texas from the larger and more genetically diverse population in northern Mexico. ............(more)

The complete piece is at: http://www.nature.com/news/2011/110802/full/news.2011.452.html