Another Milestone in Conservation Literature


Connectivity and Conservation. Crooks , K. R. , and M. Sanjayan , editors . 2006 . Conservation Biology Series No. 14 , Cambridge University Press , New York . 728 (xvi + 712) pp . $160.00 (hardcover) . ISBN 0-521-85706-6 . $80.00 (paperback) . ISBN 0-521-67381-X .

Enhancing ecological connectivity in the context of protected-area networks and land- and waterscapes may be the greatest challenge and possibly the most important task facing conservationists today. This book is a milestone in conservation biology not only because of the importance of the subject matter but also because of the numerous excellent and authoritative summaries.

Connectivity refers to the movement of organisms or processes. Ecologists recognize 2 broad forms of connectivity: structural, which refers to the spatial arrangement of habitats, and functional, which defines the behavioral response of an organism to physical structure. In fragmented landscapes connectivity is essential for the maintenance of many ecological and evolutionary processes and the population viability of many species—thus the centrality of connectivity to conservation.

The book is divided into 3 major sections: part 1 examines the importance of ecological connectivity in the context of terrestrial, freshwater, and marine systems; part 2 reviews approaches for assessing connectivity; and part 3 discusses challenges and approaches for implementing connectivity. Of the 26 chapters contained within this volume, I found 5 chapters particularly important because of their subject matter: chapter 1 by Crooks and Sanjayan, which reviews the importance, historical development, and interest in ecological connectivity particularly in relation to wildlife corridors; chapter 3 by Moilanen and Hanski, which discusses measurements of connectivity in the context of metapopulation biology; chapter 12 by Fagan and Calabrese, which provides a comprehensive overview and discussion of approaches for quantifying connectivity; chapter 16 by Haddad and Tewksbury, which examines wildlife corridors in the context of enhancing population viability; and chapter 22 by Beier and colleagues, which describes the experience and process of implementing a connectivity plan for southern California.

Several important concepts are emphasized in various chapters throughout the book that proponents and critics of connectivity often ignore. First, connectivity is scale- and species-specific. Thus, strategies to enhance connectivity for species A may not be effective at alternative temporal or spatial scales or for species B and C. Second, if a primary objective is to enhance species viability, questions about population persistence can only be addressed through studies that examine population dynamics and more than movement or connectivity studies are required. Third, the implementation of broad-scale connectivity plans on the ground is and will almost certainly remain the primary obstacle to enhancing connectivity in fragmented landscapes in most regions of the world. If there is any weakness in the book, it is the absence of any rigorous evaluation of the implementation of broad-scale connectivity plans particularly in the poorer but more biologically rich nations so that conditions, approaches, and policies essential for the successful implementation of such plans can be identified.

This book provides, as described on its cover, a summary of the current status and literature on connectivity and will certainly become one of the classic texts in conservation biology. As with other books in this series, it should be required reading in all advanced courses in conservation biology.