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Moderate levels of exotic species invasions may help maintain biodiversity, study suggests

Globally, more than 13,000 plant species, equivalent to the entire native flora of Europe, have been naturalized outside their native ranges. A study, jointly conducted by scientists from China and the U.S., provides new insights about biodiversity, exotic invasion, and their relationship to climate change.

in Nature Plants, the research uncovers the climatic niche mechanisms that shape both the vulnerability of native ecosystems and the invasiveness of exotic species in a warming world.

A long-standing debate exists over the impact of exotic species on native ecosystems and how to manage it. Some researchers argue that exotic species are simply "hitchhiking" on environmental change rather than driving ecosystem transformation. Understanding whether climate change drives both the loss of native biodiversity and the increase in exotic invasions is critical to addressing this debate.

Researchers from Wuhan Botanical Garden, the Chinese Academy of Sciences, and Rice University analyzed global distribution records of 142 plant species in the Yangtze River Valley and found substantial differences between the climatic niches of exotic and native species.

Compared to native species, exotic species tend to thrive in warmer, drier, and more isothermal climates. These climatic preferences, particularly temperature, were key predictors of invasion intensity in the Yangtze River Valley.

The study also predicted that global warming would intensify exotic species invasions over the next century, especially in colder regions.

The findings suggest that the loss of native biodiversity and the increase in exotic species invasions are both driven by climate change. As a result, researchers caution against oversimplifying the relationship between exotic species and native biodiversity. The decline in native biodiversity is more strongly influenced by rising temperatures and, to a lesser extent, human activity, according to the research.

Intriguingly, the study also reveals that moderate levels of exotic species invasion may help maintain high biodiversity within ecosystems. This suggests that exotic species invasions could be part of a broader ecological response to climate change, representing a form of natural species turnover.