Species Reintroduction Programs

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Species Reintroduction Programs


The reintroduction of species to the wild is the latest step in the effort to preserve animals, birds, insects, and plants that are endangered or extinct in the wild. Although captive breeding programs increase populations, they do not restore wild environments. Species reintroduction plans attempt to create biodiversity.

Historical Background and Scientific Foundations

Species reintroduction programs are an important feature of global conservation efforts. The reintroduction of native species is essential to the long-term environmental health of a region. In Canada, the Karner Blue butterfly is being reintroduced because the species supports the Prairie thistle, the Blue racer, the Frosted elfin, and the Antenna-waving wasp. The restoration of oak savanna is dependent upon the restoration of the Karner Blue. Each level in the food chain is critical, with the removal of one level resulting in environmental damage or chaos.

Many of the species restoration programs are not controversial. In 2007, the U.S. Fish and Wildlife Service (USFWS) began to restore 21 threatened and endangered species to the Tennessee River system as part of a broader campaign to reverse more than 75 years of damage caused by dams and dredging for navigation. The reintroduced species included fifteen types of mussels, five fish, and a river snail.

In contrast, reintroductions of some predators have proved enormously controversial. The Mexican gray wolf, one of the first species to be reintroduced to the wild, is the southernmost and smallest subspecies of the North American gray wolf. From prehistoric times into the mid-nineteenth century, it ranged from central and northern Mexico to western Texas, southern New Mexico, and central Arizona. When the numbers of native prey species, such as deer and elk, dropped because of human predation, these wolves turned for food to the large numbers of cattle that had newly arrived in the West. The increased predation on livestock by the wolves led to their demise. Wolves were trapped, shot, and poisoned by both private individuals and government agents. Bounties were paid for the corpses of wolves.

By the 1970s, there were few, if any, Mexican gray wolves left in the United States. In 1976, they were listed as endangered under the Endangered Species Act (1973). Such a listing indicates that the peril of extinction is greater and more imminent than for a “threatened” species. In 1977, Mexico teamed with the United States to create a breeding program with five wolves in captivity. According to the USFWS, the 1982 Mexican Gray Wolf Recovery “recommended maintenance of the captive breeding program and re-establishment of a viable self-sustaining population of at least 100 wolves in the wild within the Mexican wolf’s historic range.” In 1998 wolves that were raised in captivity were reintroduced by release into designated recovery areas within Arizona and New Mexico. By 2007, population estimates indicated that approximately 60 wolves lived in the recovery areas.

Impacts and Issues

When high-level predators, such as Mexican gray wolves or African wild dogs, are reintroduced to an area, human residents typically fear the loss of their livestock. In New Mexico in 2007, Grant County Commissioners sent a resolution to the USFWS calling for the federal government to pay ranchers for livestock losses due to wolves. Later in 2007, the USFWS removed two adult femaleSpecies Reintroduction Programs


CAPTIVE BREEDING: A wildlife conservation method in which rare or endangered species are bred in restricted environments such as zoos or wildlife preserves.

FOOD CHAIN: A sequence of organisms, each of which uses the next lower member of the sequence as a food source.

REWILDING: The restoration of a plant or animal to its historic habitat.

ZOONOSIS (ZOONOTIC DISEASE): Any disease that can be transmitted from animals to humans.

Mexican gray wolves from the Gila Forest in New Mexico because of multiple cow depredations by the animals. Some humans attacked the introduced predators. In 2007, USFWS law enforcement officials issued a reward for the person responsible for the disappearance of three members of another wolf pack. The success of the Mexican wolf reintroduction is in doubt.

Additionally, the reintroduction of large mammals after decades of absence may favor the spread of zoonotic diseases and may put ecological communities at risk. The reintroduction of the wild boar to Denmark is possible, but the animal may act as a reservoir of diseases, such as leptospirosis. Failure to prevent the disease consequences of species restoration can negate the conservation benefits and may limit public cooperation with other species reintroduction efforts.

See Also Biodiversity; Extinction and Extirpation; Genetic Diversity; Natural Resource Management; Wildlife Population Management; Wildlife Protection Policies and Legislation



Akcakaya, H. Resit. Species Conservation and Management: Case Studies. New York: Oxford University Press, 2004.

Klyza, Christopher McGrory. Wilderness Comes Home: Rewilding the Northeast. Hanover, NH: University Press of New England, 2001.

Norton, Bryan G. et al. Ethics on the Ark: Zoos, Animal Welfare, and Wildlife Conservation. Washington, DC: Smithsonian Institution Press, 1995.

Web Sites

U.S. Fish and Wildlife Service. “The Mexican Wolf Recovery Program.” March 11, 2008. http://www.fws.gov/southwest/es/mexicanwolf/ (accessed March 15, 2008).

Caryn E. Neumann