Effects of pasture-burning management on anuran communities in subtropical Brazilian grasslands

Anthropogenic fire is a worldwide event that affects many ecosystems and organisms. In Southern Brazil, grassland management with fire has been highly employed since the mid-18th century. Although the practice is regulated by federal law (prescribed fire), there is no detailed information about the impacts of this practice on the small, non-volant fauna. We evaluated the effect of fire management on anuran species richness and community composition in Brazilian grassland areas that have adopted this practice for more than 15 years. Our results show that burning practices lead to a reduction of anuran richness. About 37% of the species occur exclusively in sites free of fire. Sites with fire management have low densities of taller grass and shrubs, which could reduce habitat availability for some anuran species. Nestedness and turnover components of beta diversity did not differ within and between treatments, but there was a tendency for a nestedness organization of the community in burned sites, suggesting that sites with fire management are a subsample of sites where fire is absent. Our results pointed out that prescribed fire practices have potentially negative effects on the anuran diversity. These results suggest that the changes in vegetation, in particular percentages of shrub cover, affect habitat suitability for some species. Therefore, anuran communities tend to become less diverse and lack arboreal species where fire occurs.

Abstract in Portuguese is available with online material.