Alien invasion: how species are globetrotting and setting up home in unnatural habitats

Biologists believe nature’s migration is down to increasing world trade and travel

Eastern grey squirrel originally from North America and now found in Europe. Credit: Tim Blackburn, UCL

Box tree moth, native to east Asia and now found across Europe. Credit: Tim Blackburn, UCL

Egyptian goose (Alopochen aegyptiaca) originally from Africa and now established in Central and Western Europe. Credit: Tim Blackburn, UCL

Aedes koreicus, a mosquito species from east Asia that has been found in Europe since 2008. Credit: Dorian Dörge, Senckenberg

Globalisation could see the number of ‘invasive’ species setting up home in an unnatural habitat rise by more than a third by 2050, experts have predicted.

The number of non-native or 'alien' species is expected to increase 36 per cent by 2050 compared to 2005 when the most recent comprehensive catalogue of such migration was recorded.
The term alien species refers to an animal living in an ecosystem that it does not inhabit naturally.

Around 2,500 alien species new to Europe are expected to arrive over the same time period – an increase of 64 per cent, according to research published in Global Change Biology, which was led by the German Senckenberg Biodiversity and Climate Research Centre.

Global trade and long-haul transport are largely responsible for the spread with many species able to move across borders as stowaways, and an increasingly globalised world suggests a reversal of the trend is unlikely.

Alien species can be damaging to local habitats and economies, and are a key driver in the extinction of other animals and plants, according to researchers.

“Our study predicts that alien species will continue to be added to ecosystems at high rates through the next few decades, which is concerning as this could contribute to harmful biodiversity change – and extinction,” said the report’s co-author Tim Blackburn, professor of invasion biology at University College London.

“But we are not helpless bystanders: with a concerted global effort to combat this, it should be possible to slow down or reverse this trend.”

While Europe is deemed most likely to witness the largest increase in new alien species, temperate latitudes in Asia and the Americas mean those areas are also predicted to become hotspots.

Lead author Dr Hanno Seebens, from the Senckenberg Biodiversity and Climate Research Centre, said new arrivals were more likely to be inconspicuous arrivals such as insects, molluscs and crustaceans rather than mammals.

“We will not be able to entirely prevent the introduction of alien species, as this would mean severe restrictions in international trade,” he said.

“However, stricter regulations and their rigorous enforcement could greatly slow the flow of new species. The benefits of such measures have been shown in some parts of the world. "Regulations are still comparatively lax in Europe, and so there is great potential here for new measures to curtail the arrival of new aliens.”