The Biogeographic Network of Birds in the Brazilian Cerrado May Guide Conservation Efforts

Abstract

The Brazilian Cerrado, characterized by grasslands, savannahs and riverine forests, is a biodiversity hotspot, threatened by the expansion of the agricultural frontier, and therefore, needs effective conservation actions. At the national level, the Cerrado core-region has received more conservation efforts than the marginal (non-core) areas, being considered more biodiverse. However, many marginal areas are also home to high species richness and endemism. Birds represent a highly diverse and widely distributed biological group, whose variety of functions gives them important roles in the maintenance of ecosystem services. In this study the authors analysed the distribution patterns of bird biodiversity in the Brazilian Cerrado and verified whether a separation into core and marginal Cerrado zones would make sense for birds’ distribution, as this is an important issue concerning resources allocation for biodiversity conservation. The authors developed a biogeographic network analysis considering 42 sites with savannah vegetation distributed throughout the country and built two presence-absence matrices for birds – with and without species typical of the woodland Cerrado and forest physiognomies – and generated two biogeographic networks. The network without woodland/forest bird species showed no modularity, whereas the complete network produced three modules: Northwest, Centre-South and Centre-North. Network modularity was mainly determined by forest/woodland bird species. The Northwest region was richer and had a greater number of regional species compared to the other two modules; lower richness of bird species was found in the Centre-South region, which had more widespread species. The biogeographic pattern for the Cerrado birds perceived in this study did not evidence a clear dichotomy between core versus marginal regions. Therefore, the same conservation effort should be implemented throughout the Cerrado.