Ecology: Lasting legacy of European colonialism on global plant distribution

In colonizing other lands, European empires left lasting legacies on the global distribution of plants, according to a study published in Nature Ecology & Evolution.

When people move, plants move with them — whether intentionally or unintentionally. The distances that plants travel are known to have increased dramatically since European colonization of other continents began in the 15th century.

Focusing on four European powers (Britain, Spain, Portugal and The Netherlands), Bernd Lenzner and colleagues investigated the distribution of 19,250 plant taxa from 1,183 formerly colonized regions worldwide. Applying an ecological measure known as zeta diversity, the team reveal that the number of shared plant species in regions that were once occupied by the same empire (for example, South Africa and regions of North America that were both colonized by The Netherlands) is greater than would have been expected by chance. The authors also find that changes in these regional groups of species over time are affected not only by climate and geographical distance, but also by the length of time that a region was occupied by a given empire. The team were also able to identify key economic and strategic hubs within empires. For example, within the former British Empire, Australia and India share more plant species than other regions.

These findings provide insight into the impacts of human socioeconomic behaviour on biodiversity over very long timescales, something the authors conclude is only likely to increase in the future with the continued expansion of globalization and connectivity.