Responses of Small Mammals and Vegetation to a Reintroduction of Gunnison's Prairie Dogs

Abstract

This study addressed the initial effects of a reintroduction of Gunnison's prairie dogs (Cynomys gunnisoni) on resident small mammal and plant communities on the Sevilleta National Wildlife Refuge (SNWR), New Mexico. In spring 1997, 60 prairie dogs (36.8 kg live mass) were introduced onto a former prairie dog colony in a desert grassland site. Small mammals and vegetation were sampled on both a treatment (reintroduction site) and a control site (without prairie dogs) before and after the prairie dogs were reintroduced. We tested for differences in small mammal and plant community change during the 1st year of the colony's existence using repeated measures analysis of variance. Although prairie dog biomass was ca. 32 times greater than that of the resident rodent community (1.2 kg), reintroduction of prairie dogs had no significant effect on the resident small mammal and plant communities. Total biomass and abundance of rodents, and percent cover and species richness of plants did not change during the 1st year following reintroduction of prairie dogs. However, two rodent species showed significant differences in abundance between the prairie dog colony and the control site. The banner-tailed kangaroo rat (Dipodomys spectabilis) was significantly more abundant on the treatment site before and after reintroduction of prairie dogs. In contrast, the white-footed mouse (Peromyscus leucopus) was significantly more abundant on the control site following reintroduction of prairie dogs. Habitat modifications made by the former prairie dog colony may be responsible for the habitat preferences observed by D. spectabilis and P. leucopus. Although reintroduction of prairie dogs had no observable influence on the resident small mammal and plant communities in the short-term, their influences may be more evident on a long-term time scale.