More diverse gene pool key to Mexican wolves

Officials in the wolf reintroduction program say most of the wolves in the wild are too closely related to one another to ensure the survival of the species. (U.S. Fish & Wildlife Service)

 

By Lauren Villagran / Journal Staff Writer - Las Cruces Bureau
PUBLISHED: Monday, June 1, 2015 a

 

Janess Vartanian, left, and Maggie Dwire process a Mexican gray wolf pup born in captivity before placing it in a den of wild wolves last year in southwestern New Mexico. (U.S. Fish and Wildlife Service)

Last month, the U.S. Fish and Wildlife Service shot the last captive-born Mexican gray wolf in the wild for “escalating nuisance behavior” after it came too close to Catron County neighborhoods.

It was a fairly routine kill, but the take of Mexican gray wolf No. 1130 marked a shift in the program to recuperate the endangered species: Today all 110 wolves roaming the wild of eastern Arizona and southwestern New Mexico were born in the wild.

On the surface, that sounds like a milestone.

Just crossing the 100 mark for wild wolves sounds significant, especially for a program that began with just seven known wolves left in the species. The authors of the original 1982 Mexican gray wolf recovery plan – which badly needs an update – set 100 as a goal but could hardly imagine ever reaching such numbers.

Shouldn’t wolf advocates be celebrating, then? Shouldn’t ranchers, many of whom oppose the reintroduction of a top predator, be able to say enough is enough?

New Mexico Game Commissioner Ralph Ramos posed a question to the federal Fish and Wildlife Service at a recent commission meeting in Farmington. With more than 100 wolves successfully reproducing and surviving in the wild, he asked, “Why don’t we support their natural breeding? Why do we want to keep adding more?”

Here’s why: Because the Mexican gray wolf population isn’t nearly as strong as its numbers suggest.

Maggie Dwire, the Fish and Wildlife Service’s assistant wolf recovery coordinator, said most of the animals in the wild are related to one another – too closely related to ensure the survival of the species, the goal of the reintroduction program.

The Fish and Wildlife Service can’t get there without diversifying the gene pool, and right now many of the most genetically valuable animals are in captivity. Again, why?

When the Fish and Wildlife Service began releasing wolves into the wild in 1998 after a decades-long breeding program, it released wolves from the bottom of the genetic barrel, so to speak. “We weren’t sure that releasing wolves after generations in captivity would even work,” Dwire told me. “As those wolves started becoming more and more successful, we started releasing from the middle of the barrel.” 

Those wolves did well, too. So the Fish and Wildlife Service hedged its bets by releasing one wolf from the top of the genetic barrel 13 years ago: Female No. 521. She was so successful – a “super mom,” as Dwire put it, who wouldn’t stop breeding – “that almost every single wolf in the wild is somehow related to her.”

Today, when a wolf leaves his native pack he has a slim chance of finding a mate that is not somehow related to him, Dwire said. Inbreeding hurts the Mexican gray wolf’s chance of long-term survival.

The reproductive success of the super mom wolf is one part of that equation. The other is the lack of releases from captivity.

All told, the Fish and Wildlife Service has released seven captive-bred wolves over the past decade – all in Arizona. During six of the past 10 years, no wolves were released at all.

That has less to do with the sensitive politics that plague the program and more to do with biology and the limits of the previous rule governing management of the species: Releases of captive-bred wolves were restricted to one small area of the Apache National Forest in Arizona, where wolves had already claimed territory.

The new management rule published this year allows the Fish and Wildlife Service to release captive wolves into the Gila National Forest in New Mexico. The state’s Game and Fish Department is reviewing the Fish and Wildlife Service’s request for permits to do so.

The Fish and Wildlife Service believes it has found a way to improve the gene pool in the wild with wolf releases and simultaneously temper the risks to ranchers’ herds with a practice called cross-fostering. It has requested permits to release up to 10 pups into existing wolf dens in New Mexico.

Adult wolves that are released after living their entire lives in captivity tend to display more “nuisance behavior,” going after cattle instead of wild game. With cross-fostering, the Fish and Wildlife Service places pups born in captivity in a wild den before they are 2 weeks old. If the wild mother adopts them – and it’s worked with at least one mother wolf in Arizona – then the wolves are raised as wild wolves from the start and are less likely to go after domestic animals, Dwire says.

How large and diverse the wolf population eventually should be is a question to be answered by a new recovery plan; the Fish and Wildlife Service says it will begin work again this summer after disbanding two previous planning teams and pausing the work of a third. The latest management rule sets a current population objective of 300 to 325 wolves in the wild – not the final recovery goal.

The federal government’s end game is to build up the population of Mexican gray wolves to the point that management of the species could be turned over to the states. Then New Mexico could manage the wolf as hunted game – a goal the New Mexico Wildlife Federation of sportsmen supports.

It remains to be seen whether New Mexico’s Game and Fish Department will give the Fish and Wildlife Service a better chance at reaching that goal and the Mexican gray wolf a better shot at survival.

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