In a recent study published in Nature Ecology & Evolution, researchers led by Prof. LIU Xuan from the Institute of Zoology of the Chinese Academy of Sciences have shown that extreme weather events may give non-native species advantages over their native counterparts.

Invasive species and extreme weather events (EWEs) have a high impact on global biodiversity, but their combined threat remains unclear, which depends on the responses of invasive species to EWEs. Compared to their native counterparts, invasive species typically exhibit higher phenotypic plasticity, growth rate, and population recovery to rapidly adapt to stressful environments.

It is theoretically predicted that non-native species and native species may exhibit different responses to EWEs, but this has never been tested in terrestrial, freshwater, and marine ecosystems, covering different types of EWEs and response mechanisms across taxonomic groups and biogeographic regions worldwide.

In this study, LIU Xuan and his colleagues built a database of 187 non-native and 1,852 native species that experienced different types of EWEs, including heatwaves, cold spells, storms, floods, and droughts, across seventeen classes in terrestrial, freshwater, and marine ecosystems over the past seventy years.

Based on this comprehensive dataset, their analyses using multilevel mixed-effects meta-regressions showed that, overall, responses to EWEs were more often negative for native than non-native animal populations, but that responses differed by type of EWE and habitat. Both non-native and native marine animals are insensitive to EWEs, although native molluscs, corals and anemones are negatively affected by heatwaves. Non-native terrestrial and freshwater animals were only affected by heatwaves and storms, respectively, while native animals in terrestrial ecosystems respond negatively to heatwaves, cold spells and droughts, and in freshwater habitats are vulnerable to most events except cold spells.

Further spatial overlap analyses between EWE hotspots and existing locations of insensitive non-native species identified several locations including North America, Latin America, East and Southeast Asia, southwest Australia and New Zealand, the west coast and islands of the Pacific Ocean, and the North Atlantic Ocean, where native species may be particularly vulnerable to their combined impacts.

With limited resources available to manage biological invasions and extreme weather events, this study highlights the need to prioritize those biodiversity conservation hotspots where EWE-tolerant non-natives and intensified EWE co-occur, so that timely mitigation strategies can be implemented to mitigate the combined threats of invasive species and climate change.