Alien species to increase by 36 percent globally by 2050

Oct. 1 (UPI) -- The number alien species is projected to increase by 36 percent by 2050, according to a new study published Thursday in the journal Global Change Biology.

Species are classified as alien when they colonize habitat outside their native ranges.

To predict how many new species will become aliens in the decades ahead, researchers relied on a mathematical model to analyze current rates of invasion, consider the source pool of possible invaders and produce simulations based on a 'business-as-usual' scenario.

The model predicted that by the middle of the century, there will be 36 percent more alien plant and animal species than there were in 2005.

If current invasion rates continue apace, the data suggests Europe will fare particularly poorly, with the continent expected to welcome 2,500 new alien species over the next 45 years -- a 64 percent increase, double the projected global increase.

"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," study co-author Tim Blackburn said in a news release.

"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," said Blackburn, a professor of invasion biology at the University College London.

Besides Europe, the new simulations showed temperate latitudes in Asia, North America and South America are also likely to welcome a pronounced uptick in alien invaders. Conversely, Australia is expected to see a relatively small number of new alien species.

In Europe, the invaders won't always be obvious.

"These will primarily include rather inconspicuous new arrivals such as insects, molluscs and crustaceans," said lead study author Hanno Seebens.

"In contrast, there will be very few new alien mammal species such as the well-known raccoon," said Seebens, a professor of biodiversity dynamics and climate at Senckenberg Biodiversity and Climate Research Center in Germany.

A similar pattern is expected around the globe, with arthropods, such as arachnids and crustaceans, making up a large percentage of the newest alien species.

"We predict the number of aliens from these groups to increase in every region of the world by the middle of the century -- by almost 120% in the temperate latitudes of Asia," said Franz Essl, study co-author and researcher at the University of Vienna.

Scientists suggest the rate at which new alien species arrive in most parts of the world is likely to accelerate in the coming decades, as global trade and travel continue to increase.

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