Response of plant and rodent communities to removal of prairie dogs ( Cynomys gunnisoni) in Arizona

Abstract

We conducted a natural removal experiment, utilizing a local outbreak of sylvatic plague ( Yersinia pestis) as the removal agent, to test the effects of removal of Gunnison's prairie dogs ( Cynomys gunnisoni) on plant and nocturnal rodent assemblages in three grassland habitats (ponderosa, pinyon-juniper, and desert grasslands) in northern Arizona. We measured plant cover, rodent abundance, plant and rodent species richness, and plant and rodent composition at three treatment locations: active prairie dog colonies ( n = 15 ), inactive colonies ( n = 15 ), and control locations ( n = 15 ). Only the amount of plant cover differed significantly among treatments. As landscape level heterogeneity among habitat types increased, rodent abundance and species diversity increased, suggesting that intrinsic habitat characteristics are stronger drivers of plant and rodent assemblages than presence or removal of Gunnison's prairie dogs. We conclude that Gunnison's prairie dogs are not functioning as a keystone species in grasslands of northern Arizona.