Global patterns and determinants of multiple facets of plant diversity

Aim

Combining different biodiversity dimensions can reveal new diversity patterns disclosing the relative roles of historical, environmental and anthropogenic factors in shaping global seed plant diversity.

Location

Global.

Time period

Present.

Major taxa studied

Vascular plants.

Methods

We collated a database encompassing taxonomic (249,000 species), functional and phylogenetic information (34,694 species) of seed plants across different regions of the world. Species richness in each region was weighted accounting for their phylogenetic and functional distinctiveness, obtaining a new metric—μ-diversity—which was modelled to disentangle the relative roles of historical factors such as climate variability since the Last Glacial Maximum (LGM), environmental features (e.g. actual evapotranspiration—AET) and anthropogenic factors (past and current).

Results

Higher μ-diversity was observed in Papuasia, South East Asia, Australia and Central America, whereas the lowest values were primarily located in the Northern Hemisphere. Climate variability and AET were the most important determinants of μ-diversity and individual diversity facets, whereas the importance of past human impacts (i.e. the onset of pastoralism) equated or exceeded those of the present ones.

Main conclusions

Our integrative approach proved more sensitive in describing species diversity patterns. Few areas on Earth host high and unique proportions of multiple diversity facets and individual diversity facets contribute differently to μ-diversity across continents. Historical climate stability and water-energy dynamics strongly affect species diversity, but we also observed that past land-use legacy may have influenced current plant diversity, which is under intense anthropogenic pressure, especially in Asia as well as in Central and South America.