Small mammal communities and fire in the Brazilian Cerrado

The Cerrado biome is a complex of open forests, gallery forests and savanna vegetation that harbours about 60 species of small mammals. Despite the fr equent occurrence of fire in this habitat, few studies have analysed its ef fects on the small mammal communities in the Cerrado. The purpose of this s tudy was to compare small mammal communities of two Cerrado areas with diff erent fire frequencies (2-3 years or more than 18 years since the last fire ). Species diversity, species composition, and relative abundance of the mo st common species of these communities were analysed in both areas before a nd after fire. One trapping grid was established in each of the two areas. These areas were sampled monthly or bi-monthly during 1 year before and 1 y ear after prescribed fires. Both areas had communities with similar species composition, but the protected site had more species, before and after fir e (seven and eight, respectively), than the frequently burned site (five an d six species, respectively). Both sites showed significant post-fire chang es for a short time period (3 months), but only the area that had been prot ected against fire for more time showed significant post-fire changes in re lative abundance of the most common species (the murid rodents Bolomys lasi urus, Calomys callosus, C. tener, Oryzomys subflavus, and Thalpomys cerrade nsis) for the 1 year following fire. Overall diversity tended to be greater in the protected site both before and after fire. Species composition and diversity indices of the small mammal communities were relatively unaffecte d by the fires. Thalpomys cerradensis, however, appeared to use only areas that burn frequently and C. callosus showed an immediate post-fire increase in population size in both areas, contrasting with a simultaneous decrease in number of B. lasiurus.