Efficacy of Deferred Grazing in Reducing Prairie Dog Reinfestation Rates

Population growth of black-tailed prairie dogs (Cynomys ludovicianus) was studied in 1985 and 1986 at 20 prairie dog towns on short- and mixed-grass rangeland in western Nebraska, to determine the efficacy of 2 years deferred (May 1 - Sept. 1) grazing in reducing population growth rates following population reduction. In 1985, population growth measures on deferred sites were not significantly different from grazed sites, perhaps due to drought conditions. In 1986, natality and population growth (% increase in animals) were significantly lower on deferred sites than on sites grazed by livestock. Deferred sites studied both years showed significant reductions in 1986 active area: 4 of 5 deferred sites decreased in size; 6 of 8 grazed sites increased in size. Results of this study suggest that deferred grazing may be effective in reducing reinfestation rates of prairie dogs following control, given favorable vegetative growth conditions