Widespread homogenization of plant communities in the Anthropocene.

Native biodiversity decline and non-native species spread are major features of the Anthropocene. Both processes can drive biotic homogenization by reducing trait and phylogenetic differences in species assemblages between regions, thus diminishing the regional distinctiveness of biotas and likely have negative impacts on key ecosystem functions. However, a global assessment of this phenomenon is lacking. Here, using a dataset of >200,000 plant species, we demonstrate widespread and temporal decreases in species and phylogenetic turnover across grain sizes and spatial extents. The extent of homogenization within major biomes is pronounced and is overwhelmingly explained by non-native species naturalizations. Asia and North America are major sources of non-native species; however, the species they export tend to be phylogenetically close to recipient floras. Australia, the Pacific and Europe, in contrast, contribute fewer species to the global pool of non-natives, but represent a disproportionate amount of phylogenetic diversity. The timeline of most naturalisations coincides with widespread human migration within the last ~500 years, and demonstrates the profound influence humans exert on regional biotas beyond changes in species richness.

Funder

Funder name	Awards
Texas A&M University-Corpus Christi, United States
Harvard University, United States
National Science Foundation, United States	Award 2031928 - Awards 2113424 - Award 1208835 - Award 1802209, and 1754584 - Award 1754584
Texas Parks and Wildlife Department, United States	Award F21AF03049-00
Tartu Ülikool, Estonia	PLTOM20903
Eesti Teadusagentuur, Estonia	PRG609 - PRG1065
European Regional Development Fund	Centre of Excellence EcolChange