This volume is the first in a series entitled Conservation Ecology: Principles, Practices and Management, a theme which Elsevier's pioneer­ ing journal Biological Conservation has promoted since its foundation thirty-three years ago. The science of conservation ecology is now widely acknowledged as an essential component in the planning and develop­ ment of activities which change or modify our natural environment. Nevertheless in spite of much research and publicity, there is still a wide gap between theory and practice. Today it is especially important to try to bridge this gap by interpreting the results of ecological research so that they are understandable and relevant to a wide range of land managers, agriculturalists, foresters, and those working in the many categories of protected areas. The volumes in this series are designed to fulfil this purpose, and also to play an important educational role for students of the environmental sciences in schools, universities and other institutions.