Arizona Game and Fish Department

Mexican wolf.

After 30-plus years of wrangling, wildlife managers have yet to agree on a revised recovery plan for the endangered Mexican wolf. As a November deadline looms, a study in the journal Biological Conservation offers guidance for finding common ground.

A successful recovery plan means restoring Mexican wolves enough to maintain genetic diversity, but not so much that they spread out and prey on nearby livestock.

“The number one thing impeding Mexican wolf recovery right now is not their lack of genetic diversity, it’s the lack of human social tolerance,” said Jim Heffelfinger, a wildlife science coordinator for Arizona Game and Fish Department, who worked on the study.

“Illegal killing is the No. 1 source of mortality. So, we can’t charge ahead focusing only on maximizing genetic diversity and leave behind stakeholders and the public, and their tolerance for wolf recovery," Heffelfinger said.

The ideal number is, for now, unknown. While scientists work to find it — and to establish a threshold at which the wolf numbers would be considered stable enough to remove from the Endangered Species Act — the debate is complicated by misconceptions and mistrust.

On one side, said Heffelfinger, some conservation groups rely too heavily on a particular number — three populations of 250 wolves each — that is based on a population genetics rule of thumb, not research focused on this species.

“People have relied on that too much and treated that like it was some kind of magic threshold, below which the population would fail, and above which it would be OK, and that’s not true,” he said.

On the other side, some livestock owners, mindful of missteps that occurred during gray wolf reintroduction in the northern Rockies, mistrust the process. While an ecological triumph, that restoration — which led to cattle predation, lawsuits and congressional intervention — harmed conservation efforts overall, and interfered with the process of delisting that species.

“It’s that experience there that I think has a lot of people worried that the Mexican wolf won’t ever be delisted — that, whatever number we pick, we’ll be five times that and we still won’t have them delisted."

Meanwhile, some eco-groups, fearing that Mexican wolves lack the numbers they need to maintain genetic diversity, have called for a large-scale release of captive wolves to the wild. Heffelfinger said fostering captive-bred pups with wild litters offers a better solution.

“When they’re raised as wild wolves, they don’t have that human habituation — that human connection of captivity. They get into much less trouble; they act like wild wolves should.”

Conversely, captive wolves are more likely to attack livestock, which makes them targets of illegal killings. Heffelfinger said any recovery plan for the wolves will fail if it ignores the people who share the land with them.

“We don’t have the advantage of Yellowstone National Park. We’ve got to recover wolves in areas where people live, and so we had better be paying attention to human tolerance and to bringing stakeholders along with us.”