Assessing Rodent Species Counts and Diversity in the Not-Grazed Montana De Oro State Park and the Rotationally Grazed Pecho Ranch

The available data examining the influence of rotational grazing on rodent responses are limited. This study investigated how rotational livestock grazing practices influence small mammal rodent abundances and species diversity. We looked for evidence of variation in the occurrence and/or numbers of certain rodent species among three plant community types (grassland, shrubland, grass-shrub mix), managed with or without grazing. We used Sherman live traps over a total of eight trapping sessions. We totaled 486 trapnights for each of the six plant community and grazing management combinations. The three plant community types were identified by visual cover. Out of the eight different species we captured, only Peromyscus maniculatus (North American deermouse) and Reithrodontomys megalotis (western harvest mouse) had sufficient captures to be analyzed for differences in abundance. Using all eight species to calculate the Shannon’s diversity index for each plot, we found evidence that rodent species diversity is less in grassland habitats than in shrubland habitats or grassland/shrubland mixed habitats (