The impact of invasive organisms is second only to habitat loss as a threat to biodiversity and yet, despite increasing ecological awareness, people remain largely unaware of these plants and animals and their potentially devastating impact. Although most biological introductions fail, many prove successful and these can prove disastrous for native fauna and flora. This field guide will enable the identification of a range of invasive plants and animals now found in Britain. Though these species are of particular concern to conservationists there has previously been no unified guide devoted to their recognition. This book will act both as an ID guide, appealing to the amateur naturalist, and as an important tool for ecologists and land managers attempting to tackle the problem posed by invasive species.