Prairie Dogs & the Ecosystem

Prairie Dogs & the Ecosystem

Prairie dogs are inextricably linked with the entire prairie grassland ecosystem. Prairie dogs are a keystone species in grassland ecosystems in that they have far-reaching ecological effects upon the landscapes where they live. Prairie dog towns provide an abundant prey base for predators such as ferruginous hawks, golden eagles, coyotes, mountain plovers, burrowing owls, bobcats, badgers and, historically, the black-footed ferret.

Prairie dog activities increase both plant and vertebrate diversity. The digging actions of prairie dogs contribute to enhancing soil structure, water filtration, and forb growth in a natural grassland. There is a significantly higher diversity of birds and mammals and greater avian species richness on prairie dog colonies than on adjacent prairies. Burrowing and feeding by prairie dogs affect prairie ecosystems by:

• modifying the physical structure and nutrient composition of the soil;
  
• causing changes in plant species composition and density by clipping of foliage and roots; and
  
• providing breeding or resting sites for a variety of other species.

Why are prairie dogs in jeopardy?

Habitat destruction

America's grasslands have shrunk to less than 1 percent of their historic range. What was once 100 - 250 million acres has been reduced to 700,000 in the last 150 years. The North Dakota dog population has declined 65 percent from 1970 to 1990, for example, and a 50 percent decline occurred in the Montana prairie dog population during that same time period. Colonies are often too small and widespread to support viable populations or allow for critical movement between populations.

Poison

The control of prairie dogs with chemical toxins is still a threat to the long-term survival of prairie dogs. During the period of 1982-92, chemical control was used on 1.2 million acres in South Dakota, Wyoming and Montana. In 1991 alone, APHIS/Animal Damage Control and the South Dakota Department of Agriculture produced 150,000 pounds of poisoned oats. Even small, isolated prairie dog colonies are chemically controlled by ranchers. This repeated poisoning results in the slow but progressive erosion of the range distribution of prairie dogs.

Unlimited, unregulated shooting

Throughout the American West, "gopher hunters" use prairie dogs as targets. Some public agencies actually promote shooting by providing guides that identify locations of prairie dog towns, while a few rural communities host prairie dog shooting contests with cash prizes for those who kill the most animals in a day.

Sylvatic plague

Prairie dogs carry sylvatic plague (or bubonic plague in humans). Sylvatic plague is a foreign disease, first found in California ground squirrels in 1904. Prairie dogs are host to a flea species that carries the causative bacterium (Yersinia pestis). These fleas do not infest other animals unless their natural hosts are unavailable.

The bacterium can be transmitted to people through fleabites and direct contact with infected animals. Domesticated cats and dogs can contract plague by catching and eating infected rodents and rabbits or by being bitten by infected fleas. Pets may carry infected fleas home to their owner, or especially with cats, serve as a direct source of infection. Although cases of human infection from prairie dogs have been documented, it is extremely rare. Plague can be treated successfully and cured if it is diagnosed early in its course. If precautions are taken, the probability of an individual contracting plague, even in an active plague area, is quite low. Only 395 cases of plague have occurred in humans in the U.S. since 1946, according to the Center for Disease Control and Prevention. Of those, only 23 cases, or under 6 percent, were linked to contact with prairie dogs.

The plague has diffused across the West, and prairie dogs appear to have little or no immunity. South Dakota is the only state that has shown no evidence of sylvatic plague so far. Once the disease appears in a colony, the entire prairie dog population is often lost.

Learn more about prairie dogs

Last Updated on Monday, 27 March 2006 08:08