Alien versus native: The fight for free space


  • Mary Catherine Gallagher School of Biological, Earth and Environmental Sciecnes, University College Cork, Ireland.



It is easy to forget that we live on an island. Even though we have recently become a lot more aware of where our food comes from, we don’t really think about how it gets to us. In Ireland, 95% of our imports and exports are transported by ships, but it is not just cargo that these vessels can move. Plants and animals can grow on the outside of ships, or survive in ballast water, which keeps ships steady, but is almost like a travelling aquarium. It has been estimated that there are up to 10,000 species being moved around the world every day – Just in the ballast water of ships! Only some of these species will survive the journey to a new region, and not all of those will be able to become established in their new environment. However, for those alien species that can survive in a ...