Margins have long provided key questions for ecological investigation. Today with climatic warming becoming ever more apparent margins as regions of ecological change invite an assessment of their responses to environmental alteration. The purpose of this book is therefore to examine how marginal plant communities in different parts of the world are responding to climate change. Practically every aspect of modern biological enquiry can be used to address the nature of margins. Biogeography, demography, reproductive biology, physiology and genetics all provide cogent explanations as to why limits occur where they do. The aim of this book is to bring together, wherever possible, different avenues of enquiry in relation to explaining the existence of limits to plant distribution. Each of these disciplines can contribute to our understanding of the biological consequences of climatic warming.

Marginal areas have a number of features in common. These can be seen in demographic limits to population renewal, in adaptations to shortness of the growing season, in problems of access to resources, and impediments to reproduction. To avoid repetition an attempt is made therefore to discuss these common features before moving on to individual case studies.

Part I examines the nature of margins and their effects on biodiversity. Part II is functional, and explores how plants in marginal areas overcome the shortness of the growing season and other physical limitations in acquiring resources and reproducing. The remaining chapters look at individual examples of marginal areas which have been selected on the supposition that they may be sensitive to climatic change.