EL: DO YOU SEE, CURRENTLY OR POTENTIALLY, ANY EFFECTS ON JAGUAR HABITAT WITH THE ONGOING EFFORTS TO CURB ILLEGAL IMMIGRATION FROM MEXICO?
EM: Yes. The Border Patrol policy right now is to completely cut off all traffic in the lowlands, forcing all illegal traffic (both migrant workers and narcotic traffickers) into the mountain ranges that span or approach the international border. Those mountains also happen to be the only existing habitat in the U.S. for a species that is very sensitive to human disturbance. The 14-18 foot steel pedestrian fences that have recently been built were said to not likely affect jaguars because they could just walk around the end of the wall. (It took awhile for border patrol to figure out that the human border crossers could do the same thing.) Because jaguars are sensitive to human disturbance, the remaining unfenced areas are likely no longer suitable habitat for jaguars since the level of human activity from border crossers has greatly increased. Jaguars need cross border connectivity with populations in Mexico to sustain/recover in the U.S. There has not been any known reproduction [in the U.S.] since 1910 and the last female was killed in 1963. Therefore, jaguars in the U.S. are completely dependent on dispersal from a reproducing population in Mexico. Maintaining habitat connectivity across the border is essential. http://www.switzernetwork.org/viewArticle.taf?id=106
Although there is no evidence of a female in Arizona—the last breeding female on the U.S. side of the border was documented in 1963—McCain figures that if only one were present in those 13 years since Macho B's been here and she had cubs every two to three years, if half survived, she would've had three to five young in the borderlands area in the last 10 years. "If one of those was a female cub, there could be more," he says.
With 30 percent of the land in Arizona suitable habitat for jaguars and only 12 percent surveyed, the idea of a resident female isn't that farfetched. But either way, the survival of a U.S. jaguar population is absolutely dependent on the Mexico population, says McCain. The 700-mile border fence being erected to stop Mexican immigrants from illegally entering the United States will dash any hopes of establishing a larger population in the cat's historic northern range. "Without cohesive habitat spanning the border, there can be no gene flow and no dispersing cats," he sayshttp://www.defenders.org/newsroom/defenders_magazine/winter_2008/wildlife_the_comeback_cat.php