Deadly fish, exotic ladybirds and huge jellyfish are just some of the invasive species which threaten the environment and economy in Europe. So warn researchers who have compiled the first comprehensive database of Europe’s invaders and alien species.

The database for the "DAISIE" project is the first of its kind, as it not only logs all current invaders, but also possible invaders of the future. It was launched at a meeting in Portoroz, Slovenia on 23 January.

"Not all alien species in Europe are invaders," explains David Roy at the Centre for Ecology and Hydrology, UK and an expert for DAISIE. To be classified as an "invader", a species must cause economic damage or threaten local biodiversity. There are 10,677 alien species on DAISIE, of which roughly 10% are invasive.