In a study published December 6 in Nature Communications researchers, including Professor Charles C. Davis, Curator of Vascular Plants, and former HUH Research Fellow, Barnabas Daru, compiled a dataset of over 200,000 plant species worldwide revealing human activity, be it intentional or unintentional, is the biggest driver of homogenization of plant communities. “The study’s results highlight yet another imprint of the Anthropocene and demonstrate the profound influence humans exert on regional biotas beyond changes in species richness,” said co-author Professor T. Jonathan Davies, The University of British Columbia.
Abstract: 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.
Funding was provided by the Harvard University Herbaria and Natural Science Foundation grants #2101884, 1802209, 1902078, and Texas A&M University-Corpus Christi NSF #2113424 and #2031928, where Daru is now Assistant Professor.