A comparison of herpetofauna and small mammal diversity on black-tailed prairie dog ( Cynomys ludovicianus) colonies and non-colonized grasslands in Colorado

Abstract

Research suggests that prairie dogs play a keystone role in grassland ecosystems. We examined the relationship between black-tailed prairie dogs ( Cynomys ludovicianus) and herptiles and small mammals in eastern Colorado. Using pitfall traps, funnel traps, and ground captures, we captured a total of 152 herptiles representing 10 species. Captures of herptiles and small mammals varied with annual precipitation. As predicted, we captured some species more frequently on colonies and others more commonly off colonies. Bullsnakes ( Pituophis catenifer) and prairie rattlesnakes ( Crotalus v. viridis) comprised 49% of herptiles captured, with significantly more rattlesnakes captured on colonies, but more bullsnakes (not significant) off colonies. We found similar herptile species richness and both Shannon–Wiener and evenness diversity indices on colonies and off-colony sites, but slightly higher diversity when calculated across the two habitat types. We inadvertently caught 134 mammals in traps; 59% on colonies and 41% on off-colony sites. Deer mice ( Peromyscus maniculatus) represented the most frequent mammal caught. Captures of desert cottontail rabbits ( Sylvilagus audubonii) were significantly higher on colonies. Higher species richness and diversity of small mammals was associated with colonies. These results support our hypothesis that the presence of prairie dogs increases diversity between habitats or ecosystems (i.e. beta diversity) on grasslands they inhabit.