On 26 January 1998, federal wildlife officials drove three Mexican wolves to a remote corner of southeastern Arizona, where they soon became the first wild wolves to roam the U.S. Southwest in nearly 30 years. Mike Phillips, a biologist who had helped reintroduce wolves to the southeastern United States and Yellowstone National Park, said that day that reestablishing the Mexican wolf was going to be "the biggest wolf conservation challenge" yet. The captive-bred wolves would have to survive in a landscape grazed heavily by livestock, increasing the potential for deadly conflicts with ranchers.
Still, Phillips never thought it would be this hard.
Nineteen years after the U.S. Fish and Wildlife Service (FWS) released those animals, the agency has announced its draft plan for reestablishing a viable population. The recovery plan, released this June, will guide the agency's actions as it tries to boost the Mexican wolf population enough to justify removing it from Endangered Species Act (ESA) protection.
Southwestern states believe the plan appropriately balances the concerns of ranchers and local communities with conservation goals. But Phillips and some other wildlife scientists say it will leave the Mexican wolf in peril, despite decades of effort to save it. They charge that FWS designed the plan primarily to appease the states, putting politics before science-based conservation.
"The plan is an absolute waste of time," says Phillips, director of the Turner Endangered Species Fund in Bozeman, Montana, a private organization that has long contributed to Mexican wolf conservation. "They've given the states everything they wanted." FWS officials acknowledge that the plan was developed with state input in a series of closed-door workshops that Phillips also participated in, an approach they say is consistent with the ESA's mandate that the agency partner with states.
The Mexican wolf is a subspecies of gray wolf, a smaller cousin of the wolves that were reintroduced to Yellowstone in 1996. Those wolves have gone on to flourish throughout the northern Rocky Mountains and are gaining a foothold in the Pacific Northwest, with the total population estimated at nearly 2000 animals. Mexican wolves, meanwhile, have limped along. Their numbers surpassed 100 only recently, and the population is highly inbred.
At the heart of the current controversy is a debate over where federal biologists should release more wolves, outside their current range in southeastern Arizona and southwestern New Mexico, to create a larger and more resilient population.
In 2011, Phillips was one of nine scientists recruited by FWS to come up with a science-based definition of "recovery" for Mexican wolves. The team eventually recommended establishing two additional populations, one around the Grand Canyon in northern Arizona, and another in southern Colorado and northern New Mexico. Recovery would be achieved, they suggested, when the wolves in the three areas totaled 750, with at least 200 animals in each population and movement between them. The team also supported restoration in Mexico, but concluded the habitat there was too marginal to support a sizable population.
In 2012, FWS incorporated the science team's recommendations into a rough draft of a recovery plan. A copy of the draft obtained by Science said the Mexican wolf was "not recoverable" unless its range included the northern sites. But the agency never finished the draft or released it to the public. Sherry Barrett, FWS's Mexican wolf recovery coordinator in Albuquerque, New Mexico, says the process was put on hold for administrative reasons, including an environmental lawsuit that forced the agency to prioritize revising its regulations for the release and management of wild wolves. Phillips and others, however, believe the agency buried the plan because of pressure from Arizona, New Mexico, Colorado, and Utah, which objected to expanding wolf territory.
The draft recovery plan released this summer departs dramatically from the science team's earlier recommendations. It concludes that expanding the current Arizona-New Mexico population to just over 300 wolves and establishing a population of 170 wolves in Mexico will be enough to ensure recovery. "Our focus," Barrett says, "was to see if there was enough habitat in Mexico and south of Interstate 40 [I-40]," the eastwest highway that bisects both states.
Barrett explains that Mexican wolves historically occupied these areas, whereas the states argue that the northern sites fall outside the historic range. After running models on habitat potential and population viability, FWS concluded that populations south of I-40 and in Mexico could have at least a 90% chance of persisting for 100 years, the threshold it set for recovery. "That's what the science showed us," Barrett says.
Carlos Carroll, a biologist with the Klamath Center for Conservation Research in Orleans, California, questions the FWS population modeling. He argues that it included an incomplete "sensitivity analysis"—an examination of how small changes in, say, mortality or reproduction affect the outcome. Such analyses can tell managers how much confidence to invest in a model's results. One factor missing from the analysis, Carroll says, was potential variation in the proportion of female wolves that breed every year. Small fecundity changes can lead to significantly worse outcomes, he notes, suggesting the populations FWS envisions may be much more vulnerable to extinction than the agency estimates.
Phillips is also skeptical about the plan to build a wolf population in Mexico, where most habitat is on private land, cattle are plentiful, and data on natural prey are unreliable. "Wolf recovery has gone forward because of large tracts of public land," where the animals are less likely to be shot for threatening livestock, he says. "It's also critical that those public lands support large numbers of native prey." But Barrett says FWS has good partners in the Mexican government, which is not voicing concern that private lands are a barrier to recovery. "Our intent is to see if it's possible down there," she says.
Jim Heffelfinger, wildlife science coordinator at the Arizona Game and Fish Department in Phoenix, thinks that's the right course. The 2011 science team, he says, put "too much focus on what would be the gold standard if we didn't need to consider stakeholders." He believes the new plan can get enough buy-in to work on the ground.
FWS is reviewing more than 100,000 public comments on the draft plan. A final version is due in November.
Phillips concedes that focusing on Mexico and the existing U.S. wolf population is the path of least political resistance. But biologically, he says, it's a dead end. "I think the world of the U.S. Fish and Wildlife Service. But in this case, they let the Mexican wolf down."