Format: ORAL

Israel Borokini1, Brent Mishler2, Shawn Laffan3

1Montana State University, Bozeman, USA 2University of California, Berkeley, USA 3University of New South Wales, Sydney, Australia.

Mediterranean-type ecosystems (MTEs) are found in five regions (southwestern Australia; the Cape region of South Africa; central Chile; California; and the Mediterranean Basin). These areas are characterized by warm and dry summers, mild and wet winters, and frequent fire, to which resident plants and animals must be adapted. Floristic diversity and endemism are exceptionally high in all five MTEs. Consequently, all five MTEs have been recognized as global biodiversity hotspots. Studies have suggested that biodiversity in the MTEs is influenced by several eco-evolutionary drivers including high net diversification rates, fire, and geological history. As a result, biodiversity in the MTEs is hypothesized to be strongly coupled with plant traits; thus, understanding patterns of functional diversity can increase our understanding of the biodiversity drivers. We integrated spatial occurrence data for native seed plants, four selected traits, and a corresponding phylogeny for plants of the five MTEs, and employed a novel metric based on phylogenetic diversity (PD) called trait diversity (TD), to evaluate and identify areas of significant phylogenetic and/or trait diversity. Areas with different combinations of high or low PD and TD can be used to infer biodiversity drivers and the relative contribution of niche vs neutral processes in these regions. All data used in this analysis were obtained from open access and published empirical studies. The ranges of the plants were restricted to their natural distributions to exclude non-native distributions in other MTEs. We selected four traits that are hypothesized to be associated with the persistence of native flora in the MTEs. Phylogenetic and trait diversity (and spatial randomization hypothesis tests) were computed using Biodiverse software (https://shawnlaffan.github.io/biodiverse/), allowing comparison of these patterns across the five global MTEs. Biodiversity in the MTEs appears to be influenced by an unusually complex mixture of past and current biogeographic, ecological, and evolutionary processes