Tallgrass prairie restoration often seeks to re-establish prairie flora with relatively minor efforts directed to research or restore prairie fauna. Reinstating fire and grazing disturbance regimes is often a critical component to maintaining prairie communities, with a particular focus on ecosystem-engineering bison. Grazing and fire impacts have been well-studied in remnant – never plowed – prairies, but little is known about how bison grazing and fire will impact flora and fauna in recently-restored or even old prairie restorations. Small mammals play an important role in the tallgrass prairie communities through their omnivorous diet and by acting as prey for larger predators. The goal of this research was to quantify small mammal community (diversity, abundance, and composition) responses to bison and prescribed fire in a chronosequence of 13 prairie sites restored 3-30 years ago, two remnant prairies, and one agricultural field. Bison were reintroduced to half the prairie sites and remnants in 2014-2015, and prescribed fires were set as management dictated. We used capture-mark-recapture data to identify and track small mammal individuals in each study site and used generalized linear models to test for the impacts of prescribed fire, grazing, and time since restoration on small mammal communities.
We trapped over 700 unique individuals of nine species from 2013-2016. We recaptured ~40% of tagged individuals. The species most frequently encountered were deer mice (Peromyscus maniculatus), prairie voles (Microtus ochrogaster), white-footed mice (Peromyscus leucopus), and 13-lined ground squirrels (Ictidomys tridecemlineatus), accounting for 94.5% of all captured individuals. Deer mice alone comprised 82.4% of all recapture events.
Small mammal diversity increased with time since restoration as a more heterogeneous ecosystem later in restoration increased the occurrence of habitat specialists. Small mammal abundance increased with prescribed fire but diversity was not impacted. Diversity decreased following bison introduction, though that impact was only marginally significant; abundance was not impacted by bison. Overall, two years post-bison reintroduction, there were minor to no impacts to small mammal communities, though we detected a pronounced increase in abundance with prescribed fire. We found no interactions between fire and grazing, which was surprising because we expected to see impacts of pyric herbivory – bison preferring to graze in recently burned sites – translate to different habitat quality for small mammals. More research is necessary to track responses over the long term and to tease out whether differently-aged prairie communities will have different responses to bison reintroduction and fire.