Exotic items come through the city gate

Exotic animal and plant species that settle outside their natural range cause biodiversity loss. They can displace native species. In order to do something about it, it is important for researchers to gain insight into how this colonization process works.

For the 24 species of exotic plants that occur in Western Europe, scientists have investigated the climatic zones from which they naturally originate. They have also researched where they mainly appear in our home. This shows that the exotic species you often find in urban areas usually come from warmer and drier areas.

In cities it is often several degrees warmer than outside. This is a result of the so-called heat island effect, which is being created by large amounts of stone and concrete in the city. It’s also often drier there, as the pavement prevents water from seeping into the soil. “So the connection is not surprising, but it has never been thoroughly researched,” explains ecologist and author Charly Géron (UAntwerpen and ULiège).

“Cities can be outposts from which alien species can colonize other areas when it gets warmer and drier there as well,” Geron says. “In addition to the direct negative impact of urbanization on nature, this is an additional negative effect.” Scientists suggest that better monitoring of species emerging in cities could help limit the advancement of alien species in its early infancy..

Source: Charly Géron, University of Antwerp