The black-tailed prairie dogs, a keystone species, should improve grassland health and animal diversity in their new Sonoita-area home.


A colony of black-tailed prairie dogs moved into new digs Monday as part of an Arizona Game and Fish Department program to re-establish the once-native species to its historic range.

Because the prairie dog is a keystone species, it will provide the added benefit of improving grassland health and animal diversity. A keystone species is one that has a large overall effect on the ecosystem structure and function.

Over the weekend biologists from Game and Fish trapped, examined and released 129 black-tailed prairie dogs from three colonies in Las Cienegas National Conservation Area near Sonoita. Those not previously captured were numbered and tagged, said Mark Hart, spokesman for Game and Fish. A total of 180 prairie dogs live in the colonies.

"The population is doing well and in relative good health," Hart said.

Of the prairie dogs examined, 30 were moved into a newly established fourth colony within the reserve where a burrow had already been created by Game and Fish. All but two, which were captured at the last minute, were fitted with radio collars that will allow biologists to track their movements. It was the first time a population had been moved from one Arizona site to another, Hart said. When reintroduction began in 2008, black-tailed prairie dogs were brought in from other areas, including New Mexico and Sonora, Mexico.

"The animals that were selected for this were on the periphery of a very large colony of 80 individuals and they were a little vulnerable to predators," Hart said of the 30 relocated to the new colony site.

Black-tailed prairie dogs, a species native to Southern Arizona, disappeared from the landscape half a century ago. Their numbers began dwindling in the early 1900s due to extensive extermination efforts by ranchers who considered them pests that competed with their cattle for grass, according to the department website.

Not only are the colonies self-sustaining, but as a keystone species they play a unique role in maintaining a healthy grasslands ecosystem.

Per the Game and Fish website: Prairie dogs clip and eat grasses within their colony. This grazing promotes the growth of certain types of plants and increases the nitrogen concentration and nutritional value of the new growth, making colonized areas favorite foraging land for cattle and antelope and other wildlife.

When prairie dogs dig to find food and to build burrows, the activity allows water to penetrate deeper into the ground and enhances soil structure.

Prairie dogs also have a vested interest in keeping mesquite-tree growth in check because taller shrubs and trees inhibit their ability to see approaching predators. Conversely, prairie dogs are a common prey for raptors, coyotes and other wildlife, which allows those species to thrive. And prairie dog burrows provide homes for other animals, including rattlesnakes, foxes and burrowing owls.

Contact reporter Kimberly Matas at or at 573-4191.