Letter to feds points out dangers of ‘genetic bottleneck’
Political resistance at the state level shouldn’t deter federal biologists from releasing more Mexican gray wolves into the wild, according to conservation activists, who say that such releases are needed to prevent the wild population from becoming genetically crippled.
In a letter to federal officials, biologists and wildlife advocates urged Secretary of the Interior Sally Jewell to release at least five more packs of wolves into the Gila National Forest in New Mexico through the end of this year and into 2016.
The “perilously low” number of breeding pairs makes the wolf population vulnerable to inbreeding depression that could send the population into a downward spiral, more than 40 biologists and conservation groups warned in the Oct. 8 letter.
“Federal biologists know they must release more Mexican wolves from captivity, but the Obama administration has permitted the release of just four,” said Michael Robinson of the Center for Biological Diversity. “Then the government recaptured one and shot another, and the remaining two also died, which argues not only for stricter protections but also for many more releases to ensure that some wolves actually add to the gene pool.”
Conservation advocates said in the letter that the U.S. Fish and Wildlife Service is underestimating the number of wolf releases needed to nudge wolf populations toward recovery and long-term stability:
“What worries us, in addition to the absence of releases in the seven and a half months since the rule went into effect, is that the Service’s final numbers –– 35 to 50 wolves to be released over the course of 20 years, with more at the outset and fewer later on – seem not to take into account evidence that far more releases will be required to address the crisis of inbreeding.”
“The longer we delay in introducing new wolves to increase genetic variation in the wild Mexican gray wolf populations, the greater our future challenge will be to ensure that this distinctive wolf survives,” said Joseph Cook, of the American Society of Mammalogists. “Small populations with limited genetic variability often suffer from the consequences of inbreeding depression, Small populations with limited genetic variability also are generally less resilient to changing environmental conditions and less resistant to the introduction of novel pathogens.”
According to the latest census number, 110 wolves, including just eight breeding pairs, live in the combined Gila National Forest in New Mexico and Apache National Forest and Fort Apache Indian Reservation in Arizona. Fewer than 15 wolves live in the wild in Mexico.
“Mexican wolves are part of the natural heritage of all Americans,” said Mary Katherine Ray of the Sierra Club’s Rio Grande chapter. “The Endangered Species Act, which requires the protection and recovery of imperiled animals, continues to be a very popular national law. Though a vocal minority at the state level is attempting to obstruct the return of wolves to the Southwest, the Fish and Wildlife Service should proceed to release more wolves to safeguard their still fragile population.”
Conservation activists say there’s plenty of room for wolves to roam in the Gila Wilderness, and that more hesitation will simply delay the targeted recovery of the species.
The U.S. Fish and Wildlife early this year expanded the area where captive-bred wolves could be released to include the 3.3-million-acre Gila National Forest. The Gila is the fourth-largest national forest in the country and encompasses the world’s first official wilderness area, designated in 1924, that was protected from construction of roads. The Gila also supports thousands of deer, elk and other animals on which wolves prey, thereby overall strengthening such animals’ herds and preventing overgrazing. Yet more than half of this national forest has no wolves.