GUNNISON, Colo. – Work to protect the Gunnison’s prairie dog by Colorado Parks and Wildlife has proven successful during the last four years and biologists are continuing with more research to improve methods to sustain populations.
“In some situations prairie dogs can be seen as pests, but they are critical in the environment and help to promote survival of numerous other species such as burrowing owls, badgers and raptors,” said Dan Tripp, a wildlife disease researcher with Colorado Parks and Wildlife.
In Colorado there are three species of prairie dogs. The Gunnison’s prairie dog resides primarily in the southwest portion of the state. The others are the white-tailed prairie dog which lives mainly in northwestern Colorado, and the black-tailed prairie dog which inhabits areas along the Front Range and eastern plains.
Plague, caused by a non-native bacteria carried by fleas, has been identified as a threat to the stability of Gunnison’s prairie dog populations in Colorado. Outbreaks of plague frequently kill every prairie dog in a colony. To combat the disease, agency biologists are dusting prairie dog burrows with an insecticide powder that kills fleas. Researchers are also evaluating the efficacy of oral vaccine baits which may prevent plague in the animals.
The bacteria that causes plague was transported to North America around 1900 and was subsequently found in Colorado around 1940. Because prairie dogs did not evolve with the bacteria, they carry little immunity to fight off the disease.
“The plague bacteria is a non-native invasive species that devastates prairie dogs and other wildlife species. We’re not attempting to upset nature’s balance with these treatments. We are working to restore balance in the environment and reduce the risk of major plague outbreaks in prairie dog colonies,” Tripp said. “We lose a lot of resilience in the environment when we lose prairie dogs.”
Controlling plague in prairie dogs may also help limit potential exposure to people and their pets.
In 2010, CPW biologists started dusting some burrows in the Gunnison Basin with an insecticide that kills fleas. The experiment has worked. In some cases, nearby colonies that were not dusted were wiped out by plague while colonies that were dusted remain healthy. Biologists also said that they’re seeing many more prairie dogs in more areas in the basin this year compared to five years ago.
Although the insecticide is not harmful to other species, applying it is labor intensive and expensive. For dusting to be effective every burrow in a colony must receive an application annually.
A potentially promising treatment is the oral sylvatic plague vaccine, Tripp said. Developed by the U.S. Geological Survey’s National Wildlife Health Center, the vaccine—still in the experimental stage—works well in the laboratory. It is administered in a cube flavored with peanut butter. The baits also contain a red dye that adheres to animals’ coats which helps researchers track the prairie dogs that eat the bait. This is only the second year that the vaccine has been tested in the field in Colorado. Longer term monitoring will be needed to determine its efficacy.
“So far, we’re encouraged by the results and we are optimistic that the vaccine will be effective in limiting future plague outbreaks,” Tripp said.
In the Gunnison area, four prairie dog colonies are being used for vaccine testing. Two colonies are receiving the vaccine bait, two are receiving no treatment. In Teller County the test is being conducted with two colonies.
The vaccine is also being tested in Arizona, Montana, South Dakota, Texas, Utah, and Wyoming. The experiment will continue for another two years and is a collaborative effort among more than 30 federal, state and tribal agencies and nongovernmental organizations.
In Colorado, the vaccine research in Gunnison’s prairie dogs is occurring on public land—state wildlife areas, BLM and National Park Service property.
Contrary to public perception, prairie dogs don’t reproduce prolifically. Females have only one litter of 3-5 pups each year and the natural mortality rate of the young is about 50 percent. Consequently, the colonies generally do not spread rapidly over wide areas. Tripp explained that few connections between colonies across a landscape exist; so when a colony is wiped out it may have little chance of being re-colonized.
“By preventing plague we can have healthy, stable prairie dog colonies that we can manage on public lands,” Tripp said.
The conservation work is aimed at preserving the ecological niche of prairie dogs and preventing a listing of the Gunnison’s prairie dog under the federal Endangered Species Act. If the animal is listed it could lead to various land-use restrictions.
J Wenum, area wildlife manager in Gunnison, explained that when landscapes are restored to a more natural condition, more uses can be accommodated.
“If you have healthy, functioning landscapes you don’t have to be focused on limiting uses,” Wenum said. “A healthy landscape will accommodate agriculture, recreation and wildlife.”
The testing of the oral vaccine will continue for a few more years, and biologists are cautiously optimistic that the vaccine will prove to be effective at limiting plague.
“We won’t be able to prevent plague in every colony. But this work will help to stabilize the overall population at its current distribution and benefit this important species,” Tripp said.
For more information about prairie dogs and other wildlife species, see cpw.state.co.us.