Researchers at Harvard University have compiled a dataset of over
200,000 plant species worldwide to illustrate the extent to which
species extinctions and non-native invasive plants reorganize plant
communities in the Anthropocene, the current geological age dominated by
human activity.

Led by Barnabas H. Daru, a former postdoctoral fellow at the Harvard
University Herbaria and in the Department of Organismic and Evolutionary
Biology, the project began several years ago with mapping North American
biomes. Daru expanded it to include the biomes ofAustralia, South
Africa, Europe, and China. The study examined how plant landscapes and
communities change, especially after the bridging of the eastern and
western hemispheres 500 years ago.

Daru noted that extinction and the naturalization of non-native species
cause biotic homogenization or the gradual replacement of native species
by locally spreading non-native species. This leads to species reduction
and evolutionary differences and cal also have negative impacts on key
ecosystem functions.

The study showed that regardless of the extinction scenario, the
strongest contributor to biotic homogenizations resulted from non-native
plants naturalized by humans. These changes occurred over a short
evolutionary span of approximately 500 years and were facilitated â??
intentionally or unintentionally â?? by humans moving organisms around the
landscape. Daru developed the GreenMaps database from globalized
Herbaria collections. The global map helped in closing the knowledge gap
in global distributions of plant occurrence records by generating
predicted distributions for more than 200,000 species worldwide.

Global database of plants reveals human activity biggest driver of
homogenization of plant communities | Department of Organismic and
Evolutionary Biology (harvard.edu)
[oeb.harvard.edu]