"Biodiversity and conservation of tree species of a megadiverse South American region. "

Abstract

Plant biodiversity is under increasing threat due to habitat loss, land-use change, and climate pressures, particularly in megadiverse regions such as the La Plata Basin (LPB). Here, we present a spatially explicit analysis integrating taxonomic and phylogenetic diversity metrics to identify biodiversity hotspots and conservation gaps for tree species across the LPB. Using occurrence data for woody species and metrics including species richness (SR), phylogenetic diversity (PD), standardized effect size of PD (ses.PD), evolutionary distinctiveness (ED), and biogeographically weighted ED (BED), we mapped patterns of evolutionary value and evaluated their alignment with existing protected areas. Our results reveal marked geographic disparities among the metrics, with eastern LPB regions—highly impacted by agriculture and urbanization—still retaining significant evolutionary heritage. Additionally, the Andes, Cerrado, and Pantanal also emerged as key areas for phylogenetic conservation. However, current protected areas fail to adequately represent these hotspots, highlighting urgent conservation gaps. We emphasize the need for targeted spatial strategies that integrate evolutionary history and land-use planning to enhance the effectiveness of conservation networks. This approach provides a comprehensive framework to guide biodiversity protection in tropical landscapes under rapid anthropogenic change.