Wolves are constantly in the news. Especially because the state of Colorado plans to introduce wolves by the end of 2023, and wolves moving from Wyoming into Colorado have already killed cattle and dogs. Colorado now has an agreement with the state of Oregon to obtain up to 10 wolves to release in Colorado. Wolves are listed under the Endangered Species Act (ESA) and the U.S. Fish and Wildlife Service (USFWS) recently completed an environmental impact statement (EIS) regarding the introduction of wolves to Colorado.
There are many issues regarding the introduction of wolves, including considerable opposition to killing wolves as part of their management. The potential for wolves to move southward from Colorado and impact the Mexican gray wolf subspecies in Arizona and New Mexico is also discussed in the EIS:
“The loss of genetic integrity of Mexican wolves by hybridization with northern wolves would impede recovery efforts of the separately (ESA) listed Mexican wolf … if the ranges of gray wolves and Mexican wolves expanded and eventually overlapped, the Mexican wolf population could be adversely affected by interspecific competition and hybridization … If Mexican wolves disperse northward of their historical range, or if gray wolves disperse southward, competition or interbreeding could occur … the Service will work with states to minimize impacts to Mexican wolf recovery.”
The current policy as expressed in the EIS is to protect the Mexican wolf’s genetics by preventing their mixing with northern wolves by removing wolves that move southward from Colorado. The EIS doesn’t specify a time frame for this, so I assume it’s planned to be permanent. But wolves have spread across western states (Montana, Wyoming, Idaho, Washington, Oregon, California) from the introductions in the 1990s to Yellowstone National Park and Idaho.
A few northern wolves have already been documented traveling into Arizona and New Mexico (see WLJ Aug. 21, 2023). I think it is likely they will continue to spread, and northern wolves will eventually mix with the Mexican wolves; it’s hard for me to imagine a permanent program to prevent wolves from leaving Colorado.
Northern wolves from Colorado interbreeding with Mexican wolves is an issue because Mexican wolves are listed as an endangered species separately from other wolves and are considered a genetically and geographically unique “subspecies.” The northern wolves to be brought to Colorado are considered a different subspecies.
The ESA allows listing of subspecies, which are comparable to livestock breeds. However, subspecies of wild animals are not as distinct as livestock breeds because wild animals move and interbreed between areas over time, and obviously no pedigrees are kept.
Because USFWS, environmental groups and many biologists have spent enormous effort and money to promote the Mexican wolf as genetically different from other wolves to justify an ESA listing, they now must protect its “genetic integrity,” meaning the original genetics of wolves in Mexico and the American Southwest.
At the same time, Mexican wolves have inbreeding problems because the population started with very few animals. There is a conflict in trying to conserve Mexican wolf genetics, while maintaining an inbred wild population.
There are two important scientific points to be considered. The first point, dismissed or ignored by ESA advocates, is that the subspecies category is not definite and largely based on opinion. Second, the Mexican wolf has inbreeding problems which can be corrected with crossbreeding and heterosis, as is done with livestock.
Livestock breeders know that genetics affect the performance and fitness of animals. If there are inbreeding problems with reproduction or health, crossbreeding can correct them. USFWS biologists are probably aware that they could interbreed Mexican wolves with northern wolves and make a more fit population, but they are constrained by the insistence of maintaining the original Mexican wolf genetics, which is based on an indefinite subspecies designation.
Many stockmen justifiably oppose wolves because they kill livestock, dogs and big game. It is common sense that wolf predation on livestock and dogs should not be allowed and wolves preying on livestock should be removed. Wolves also need to be managed with hunting and trapping to maintain big game populations. Montana, Idaho and Wyoming now do this. But wolves are popular with the public, and their spread appears to be unstoppable with current policies. The point is that managing wolves is, and will continue to be, necessary.
Your expertise can help. The issues with Colorado and Mexican wolves provide an opportunity to show USFWS and the public the knowledge of biology and genetics that stockmen have. The livestock industry’s credibility from successful breeding and genetics programs can bring practicality to the wolf issue regarding subspecies, inbreeding and maintaining fit populations. This credibility can be extended to farmers’ and ranchers’ knowledge of wildlife and how to manage them.
Professional managers can’t prioritize one objective (wolves) to the detriment of others (big game and livestock). Your scientist friends with USDA and the state universities can help communicate this to government wildlife biologists: Professional management requires satisfying multiple objectives, not unthinking and emotional focus on one. — Dr. Matthew Cronin
(Matthew A. Cronin is a scientist with Northwest Biology Company LLC in Bozeman, MT. He can be contacted at croninm@aol.com.)
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