Allee effects are (broadly) defined as a decline in individual fitness at low population size or density. They can result in critical population thresholds below which populations crash to extinction. As such, they are very relevant to many conservation programmes, where scientists and managers are often working with populations that have been reduced to low densities or small numbers. There are a variety of mechanisms that can create Allee effects including mating systems, predation, environmental modification, and social interactions. The abrupt and unpredicted collapses of many exploited populations is just one illustration of the need to bring Allee effects to the forefront of conservation and management strategies. Allee Effects in Ecology and Conservation provides a concise yet authoritative overview of the topic, collating and integrating a widely dispersed literature from various fields - marine and terrestrial, plant and animal, theoretical and empirical, academic and applied. This accessible text, with its clear and simple explanations of both empirical observations and theoretical predications is particularly suitable for professional and academic ecologists requiring an overview of the state-of-the-art in Allee effect research, as well as for graduate students in population ecology and conservation biology. It will also be of relevance to a wide readership of professionals in conservation and management requiring a concise summary of the topic.

Franck Courchamp is a CNRS researcher in population dynamics at the University of Paris Sud, France. His research covers two connected areas: biological invasions and Allee effects, both carried out mostly from a conservation biology perspective. He focuses mainly on theoretical work, but his prolonged stays at the Scripps Institute of Oceanography San Diego, CA, and at the Department of Zoology of Cambridge University, UK have involved him in a wide range of studies and approaches, including field work on remote islands, isotopic analyses of trophic webs and analyses of African wild dog populations. Luděk Berec is a researcher in theoretical ecology at the Biology Centre of the Academy of Sciences of the Czech Republic. His interests move between development and analysis of general population models aimed at understanding fundamental ecological processes, and of more focused, species-specific models addressing more applied issues. His two key interests are two-sex population dynamics and Allee effects. Jo Gascoigne is an empirical ecologist, and a research lecturer in marine biology at the University of Wales Bangor. Her research covers two different areas, Allee effects in conservation biology and the role of physical processes in structuring marine ecosystems. Before going to North Wales, she did her PhD on Allee effects in marine invertebrates at the Virginia Institute of Marine Science in the USA.