Richness pattern and phytogeography of the Cerrado herb-shrub flora and implications for conservation

Aims: The herb-shrub flora has been widely neglected in science and conservation policy throughout the world, so that this biodiversity component remains largely unknown. The objective of this study was to elucidate the spatial patterns of species richness and phytogeographic regions of the Cerrado herb-shrub flora, and to estimate the percentage of areas with high species richness that is still covered by natural vegetation and is located in protected areas or priority areas for conservation. Location: Central Brazil and surrounding territories. Methods: To estimate the pattern of species richness we produced species distribution models (SDMs) for 5362 species using botanical records combined with 17 least correlated environmental variables. All SDMs were tested against a bias-corrected null model and the 5039 significant SDMs were stacked to generate the pattern of botanical richness. The resulting presence-absence matrix was subjected to a partitioning around medoids (PAM) cluster analysis to delineate phytogeographic regions. Results: The pattern of species richness indicated that highest levels of richness are in the central-south and west parts of the Cerrado. The study recognized two floristically distinct clusters at the core of the Cerrado region, and seven additional regions that share floristic elements with the two core clusters. Many areas with high levels of modelled species richness are located outside protected and priority areas for conservation. Conclusions: We recognized patterns of regional variation, reflected in the phytogeographic division. Furthermore, we show that the current protected areas in Brazil do not effectively protect high richness areas of the herb-shrub flora.