Spring is in the air, and that means that black-footed ferret captive breeding programs, like the ones in Wellington and Colorado Springs will soon have litters of ferret kits. Believed to be extinct in 1979, 18 ferrets were discovered in the last surviving wild population and were taken into captivity to repopulate the species. Since this original captive breeding program, more than 7,000 kits have been born in captivity, and over 3,000 have been released in the wild.
Despite this success, black-footed ferrets have been listed as Endangered under the Endangered Species Act (ESA) for 38 years. Of the 19 attempts to reintroduce ferrets in the last 20 years, only four of the released populations are self sustaining. What is holding back the recovery of this species? To fully recover ferrets in the wild, the ESA needs to shift focus from single species protection to conserving the ecosystem on which that species relies.
Prairie dogs are the main prey of ferrets, and their burrows provide ferrets with shelter for security and denning. The critical factors for a successful ferret reintroduction site are large areas of suitable habitat with a high density of prairie dogs. The conversion of their native grassland habitat to crop fields and urban development, and the extermination of prairie dogs by poisoning and shooting, have made it less likely that these ferrets will survive when released into the wild.
Since the late 1800s, prairie dogs have been viewed as pests and extensively controlled, resulting in a 98 percent reduction of their historic range. This pervasive prejudice was unwarranted and based on misconceptions that prairie dogs were degrading habitat and competing with livestock for forage. The prairie dog is now understood to be a keystone species and an ecosystem engineer that helps provide suitable habitat for over 200 vertebrate species. Other Colorado threatened species and species of concern, including the burrowing owl, ferruginous hawk, swift fox, and mountain plover, depend on prairie dogs for shelter, food, or breeding habitat. Should prairie dog populations continue their decline into nonviable population levels, we can expect to see a wave of secondary extinctions.
Black-footed ferret recovery can only be achieved by a change in the public’s attitude towards prairie dogs. It is time to let go of the myth that prairie dogs are pests, and recognize their key importance in the prairie ecosystem. Policy makers should control the use of poison, and the recreational shooting on prairie dog towns. Landowner incentives and partnership programs are necessary on private lands to conserve large areas of suitable habitat and prevent prairie dog declines. Restoration efforts can also help to convert degraded land back into native prairie.
Our best hope for prairie dog conservation is on public land. Managers should focus on increasing the size and density of current prairie dog populations, as conservation of this prey species is essential for the recovery of the ferret. Prairie dogs should be managed as an umbrella species to conserve the entire ecosystem efficiently and effectively. Efforts are also needed to manage plague epidemics which affect both ferrets and prairie dogs by dusting colonies and creating vaccines.
According to the U.S. Fish and Wildlife Service, all wild ferrets exist in “nonessential, experimental populations” that are not afforded the same level of protection as other endangered species. In 1978, Congress amended the ESA to make critical habitat designations mandatory for all threatened and endangered species. Because the black-footed ferret was listed under the ESA before the 1978 amendment there is no critical habitat designated for ferrets despite the fact that it has been found to assist species recovery. The ESA’s single-species focus has left the ferret without a functioning ecosystem, habitat, or prey. Considering the resources that have been spent on the captive breeding program, shouldn’t an effort be made to ensure that these ferrets have a suitable home when released?
Samantha Tolve lives in Boulder. EDITOR’S NOTE: This is an online-only column and has not been edited.
