Arthropod Consumption by Small Mammals on Prairie Dog Colonies and Adjacent Ungrazed Mixed Grass Prairie in Western South Dakota

The percentage of arthropods and plants in the diets of seven small rodents captured on prairie dog colonies and adjacent mixed grasslands were estimated by microhistological techniques. Arthropod composition over the two year study averaged 51% and 37% on prairie dog colonies and mixed grasslands, respectively. Composition of arthropods on prairie dog colonies was greater during the summer than in late spring or late summer. Conversely, arthropods made up a considerably smaller percentage of small mammal diets in the summer on mixed grasslands. Nearly twice as many small mammals, excluding prairie dogs, were trapped on prairie dog colonies than on the adjacent mixed grasslands. Prairie dog colonies favor insectivorous rodent species. Prairie dogs, in creating habitat for insectivorous small mammals, may indirectly reduce localized arthropod outbreaks