Security fences prevent jaguars coming home

Until recently jaguars were rarely seen in the United States. Photo / Reuters

The jaguars are coming home. Until recently the big cats, which evolved in North America, then spread south, were rarely seen in the United States.

The last known female was shot in 1963. But over the past decade at least four jaguars, probably males and identified from photographs by the unique rosette patterns on their fur, have padded north via a wildlife corridor of "sky islands," mountains that straddle the border, into southern Arizona and New Mexico.

But the cats, protected by the US Endangered Species Act, may become victims of America's paranoia about illegal immigration and national security, as the Department of Homeland Security moves to seal the US-Mexico border.

"It's potentially catastrophic for the species' recovery prospects in the northern part of its range," explains Michael Robinson, who monitors jaguars for the Centre for Biological Diversity.

Steel fences, which have begun to appear along part of the 3138km border, would strand existing jaguars in the US, prevent others from increasing the nascent population, and limit the cat's gene pool.

Last June, the American Society of Mammalogists said jaguars could survive in the US only if they could roam across the border. This charismatic animal is one of 30 species - including pronghorn antelope, ocelots, bears and wolves - environmentalists say would suffer from a solid fence.

This barrier would also devastate ecosystems, repaired in schemes costing millions of dollars, and wreck bustling eco-tourism in struggling communities.

The sky islands, where the Chihuahua and Sonoran deserts intersect with the Rocky Mountains and Mexico's Sierra Madre Occidental, are a vital link in a chain of wildlife corridors, stretching from the Arctic into Latin America.

Conservationists hope corridors will protect species, from iconic predators to reptiles, plants and insects, reeling from climate change and habitat loss.

"If there's any place we can point to on this continent to show how fragmentation of habitat can destroy species, this is it," says Kim Vacariu, western director of the Wildlands Project.

The border fence would effectively cut this unique area in two. So far the Bush Administration has been deaf to environmental pleas to substitute "virtual wall" technologies, such as motion sensors, laser barriers and infrared cameras, for impenetrable steel fences.

In 2005 Congress passed the Real ID Act to fight terrorism. It contained a waiver from environmental laws. Proponents claimed it was needed to fast-track 22km of border fence in San Diego, California.