This book presents proceedings of a biology seminar held in the Royal Irish Academy in 2003. The contributors consider ecosystems as diverse in location, type and scale as the Mediterranean, hedgerows, Galapagos, bridges, the Antarctic, roadside verges and Bermuda, to illustrate the profound impact that the transport of people has had on the environment. The fragmentation of habitats, pollution, the introduction of alien species and the spread of disease are among the topics discussed by these leading scientists from Ireland, the United Kingdom, Israel and Bermuda.