Exploring patterns of beta phylodiversity in the Argentine angiosperm flora through its vegetation units: Insights for its conservation

Abstract

Understanding how biodiversity is distributed is an essential task for prioritizing conservation actions. Phylogenetic diversity metrics have become crucial in conservation studies because they allow us to quantify the evolutionary history harbored within assemblages, as well as their evolutionary uniqueness. The Argentine Flora is especially diverse due to the variety of environments that comprise the country. In this work, we aim to analyze angiosperm phylodiversity patterns for Argentine vegetation units in order to generate assessments for conservation. First, we analyzed the evolutionary uniqueness of units by estimating different metrics of beta phylodiversity, and their contribution to the total beta variance. Second, we examined patterns of alpha phylodiversity and their inclusion in the current protected area network. Our results show that vegetation units with the highest evolutionary uniqueness are distributed in two main biogeographic groups: those distributed along the Andean-Patagonian region, and those distributed in northeastern Argentina, associated with the Humid Chaco and the Southern Cone Mesopotamian Savanna. These units differed in their alpha phylodiversity patterns, showing higher levels of phylogenetic clustering those included in the Altoandina and Patagonia phytogeographic provinces, and lower levels those included in the Chaco and Pampa provinces, consistent with the tropical niche conservatism hypothesis. However, the unit included in the Subantartica province presented higher phylogenetic diversity and divergence than units of the Altoandina and Patagonia provinces, coinciding here with the Austral Niche Conservatism hypothesis. Units also showed a pronounced variation in their protection level, so a priority ranking for conservation was generated.