Invasive species spread much faster than native species

The failure of flora and fauna distribution areas to adapt to the pace of global climate change is a major problem as it increases the likelihood of species extinction. This problem is compounded by the fact that non-native species, many of them invasive, are gaining advantages over native species, which shows that they may also have advantages in the face of climate change. To investigate this, a group of specialists from Spain and the United States has reviewed studies of more than 6,000 native and non-native species of flora and fauna, including observed (682 study species) and modelled (5,571 study species) changes in their range expansion.

This study, which involves the participation of two institutes of the Spanish National Research Council (CSIC), has led to the conclusion that non-native species, on average, are expanding their distribution areas much faster than native species. Invasive species may have traits that allow them to spread more quickly than native species. But human intervention indirectly also tends to help invasive species spread.

The research team, led by Bethany A. Bradley of the University of Massachusetts at Amherst, also showed that nonnative species have larger potential ranges and faster range expansions under climate change, likely due to a combination of multiple foci of introduction and broader climate tolerances. The study also found that under climate change, the zones of contraction will be larger for native species than for nonnative species, confirming that nonnative species gain more and lose less space than native species.

The Lymantria dispar moth is an invasive species in North America. (Photo: NPS / Catoctin Mountain Park)

Clearly, with faster rates of spread and greater potential to persist or expand, populations of non-native species have a decisive advantage in a changing climate. This is an environmental alarm, as many of these species cause environmental and socio-economic problems in the recipient ecosystems. Belinda Gallardo, a senior scientist at the CSIC’s Instituto Pirenaico de Ecología (IPE), says: “As a society, we often resist the risks associated with moving native species beyond their ranges in response to climate change, while we recklessly move non-native species around the world.”

“A greater focus on propagation mechanisms would help us identify vulnerable native species and non-native species at high risk of expansion with climate change,” concludes Montserrat Vilà, research professor at the CSIC’s Doñana Biological Station (EBD).

The study is titled “Observed and potential range shifts of native and nonnative species with climate change.” It has been published in the academic journal Annual Review of Ecology, Evolution, and Systematics. (Source: CSIC)