Influence of land use on the diversity of pond-breeding anurans in South Brazilian grasslands

The degradation of natural ecosystems due to land use changes has been increasing, altering ecosystem composition, structure and processes, which negatively affects biodiversity. Herein, we explored how the diversity patterns of anurans respond to the scenario of extensive replacement of grasslands with agriculture in southernmost Brazil. We determined possible changes in the species richness, taxonomic composition, and structure of pond-breeding anuran communities in the grassland ecosystems of the South Brazilian Grasslands (SBG). Using the survey at breeding sites method, we sampled a total of 238 ponds, 153 from extensive livestock grazing on grasslands and 85 from agricultural areas. The higher species richness was found in the livestock areas on grasslands. There was a significant nestedness pattern associated with agricultural areas, indicating a non-random process of community simplification by species loss. Seven anuran species were considered land use indicators, of which five were considered indicators of grasslands with livestock, and two as indicators of agricultural areas. Generalist species were persistent and dominant in agricultural areas, while habitat specialists disappeared from these areas. Land use was a significant factor explaining the community structure segregation between land uses regardless of the natural variation reported at the local and regional levels. We highlight the importance of grasslands for the conservation of pond-breeding anurans in non-forest landscapes of the subtropical region, and we discuss the view that extensive livestock production needs strategic incentives to help the conservation of SBG biodiversity, such as multi-institutional measures.