Species on the move

Flowers, trees, insects, mammals, fish and birds can all find themselves living in environments for which nature did not necessarily intend or equip them. Certain species are imported to their new homes with a view to solving problems such as pest plagues, while others inadvertently hitch a ride on logs or in the trunk of a car.

Since ships and planes have started taking large quantities of goods to all corners of the world, animals and plants have conquered new environments at a staggering pace. Experts view the discovery of the Americas by Christopher Columbus in 1492 and the intense trade between Europe and America that followed, as so significant that they use that date as a reference: All the species that migrated after Columbus’ historic voyage are considered non-native species in their new home.

In many cases, these species take to their unfamiliar surroundings like ducks to water. In others, they are more like bulls in proverbial china shops. Species that cause damage in their new environment are called "invasive species." Those with no natural predators in their adopted home can be particularly devastating for existing biodiversity. The International Union for Conservation of Nature (IUCN) describes their impact as "immense, insidious, and usually irreversible." These interlopers are responsible for hundreds of extinctions around the world, say experts. And they can also cause extreme economic problems.

According to the BUND conservation group in Germany, the EU currently spends between 9.6 and 12.7 billion euros every year to put right the damage caused by invasive species. But not all newcomers are bad. Honestly. Click through the graphic to find out more about about animals and plants that have created a home away from home.