Species naturally spread beyond their immediate environment and seek to colonize new locations, but the opportunities to do this have been greatly enhanced by the migration of people and by the increasing volume of goods transported around the world. Some species hitch rides to new locations, others are deliberately transported in order to provide food or other services, or simply as reminders of home. Many species exploit opportunities created by the changes humans (often themselves colonizers) have made to terrain. Tens of thousands of species have made these journeys, establishing viable populations in their new homes. The effect on the local environment and indigenous species is only now being fully assessed but, once established, these so-called “exotic” invaders are usually very difficult to eradicate.

Many invasive species are apparently benign additions to the biota of the recipient location, and some may be viewed as positively beneficial. However, many others cause significant environmental and economic damage, and cost perhaps as much as 5% of global GDP through direct economic losses (e.g. of crops), the cost of control, and the necessity for biosecurity measures to prevent further spread. Prominent examples of problematic invasive species include the Ruddy Duck and Grey Squirrel in the UK, West Nile Virus in the USA, avian malaria (and its exotic bird carriers) in Hawaii, and rats (and cats, stoats, ferrets, possums, pigs, and deer) in New Zealand.

Against this background, it is clearly important to understand how a species becomes invasive, and much scientific research has focused on the process by which this occurs. Biological invasions are a consequence of a combination of factors: human actions, species characteristics, and environmental conditions, and so their study weaves together elements of history, biology, and geography. The Atlas of Invasive Species brings together all these elements in a narrative around this increasingly important subject that will both interest and inform the general public.

For a story that is intrinsically involved with movement around the world, across geographic barriers and through new environments, the Atlas is a superb way to present the story of invasions, and also to make sense of it. It presents a well-informed picture of how humans are breaking down natural barriers to the dispersal of species that, over millennia, have helped shaped evolution to produce distinctive varieties of form on every continent and island. We hope to provide an understanding of how the loss of those barriers will make the world a poorer and less interesting place in which to live.