November 2004 / Vol. 54 No. 11 • BioScience 1003ArticlesMarine fisheries are failing (Pauly et al. 1998,2002), and species from invertebrates to charismaticmegafauna are threatened by fishing pressures and other en-vironmental changes. The remedies are not simple, but clearlymarine reserves have a fundamental role to play (Lubchencoet al. 2003). The design of reserve systems requires a soundtheoretical foundation, which has led to the beginning of ascience of reserve design, both in marine (Gerber et al. 2003)and terrestrial systems (ReVelle et al. 2002). The problem ofdesigning successful reserves, which would be difficult evenif there were only a single goal, is further complicated bygoals related to the preservation of biodiversity, to the ex-traction of renewable natural resources (e.g., fisheries; Hast-ings and Botsford 2003), and more generally to themaintenance of a range of services that humans derive fromecosystems.The criteria that are used to select protected sites are an important part of marine reserve design (Leslie et al. 2003,Roberts et al. 2003). Recent studies suggest that the variousgoals motivating the establishment of marine reserves can sig-nificantly overlap when the selection criteria are based on anecosystem approach, in which the main goal is the mainte-nance of the highest possible biodiversity and the protectionof underlying ecological processes (Roberts et al. 2003). Theecosystem approach thus recognizes that the viability both ofsingle species and of whole communities ultimately dependson ecological processes involving many species. Althoughthe ecosystem approach to marine reserve design seems to pro-vide the greatest potential for generalization (Lubchenco etal. 2003), it is limited by researchers’understanding of the eco-logical and physical processes that influence the distributionof species across spatial and temporal scales.Complexity in the design of marine reserves results fromthe large number of species involved and from the underlyingphysical and biological heterogeneity of the landscape.Single reserves present one set of problems, but the design ofreserve networks places additional emphasis on understandingpatterns of dispersal. In marine systems, dispersal is the result of a complex interaction between physical factors (themovement of water) and biological factors (organisms’ be-havior), making its description even more difficult (Flierl etal. 1999). Because it is impossible to describe the dynamics ofmarine ecosystems in all their biological and physical com-plexity, simplifying assumptions are needed to develop prin-ciples for the design of marine protected areas.Frédéric Guichard (e-mail: [email protected]) is an assistant professor in the Department of Biology, McGill University, Montreal, QuebecH3A1B1, Canada. Simon A. Levin is director of the Center for Biocomplex-ity and George M. Moffett Professor of Biology in the Department of Ecologyand Evolutionary Biology, Princeton University, Princeton, NJ 08544. AlanHastings is a professor in the Department of Environmental Science and Policy and member of the Center for Population Biology, University ofCalifornia, Davis, CA 95616. David Siegel is a professor in the Departmentof Geography, University of California, Santa Barbara, CA 93106. © 2004American Institute of Biological Sciences.Toward a DynamicMetacommunity Approach toMarine Reserve TheoryFRÉDÉRIC GUICHARD, SIMON A. LEVIN, ALAN HASTINGS, AND DAVID SIEGELCoastal habitats have recently received much attention from policymakers, but marine reserve theory still needs to integrate across scales, from localdynamics of communities to biogeographic patterns of species distribution, recognizing coastal ecosystems as complex adaptive systems in which localprocesses and anthropogenic disturbances can result in large-scale biological changes. We present a theoretical framework that provides a new per-spective on the science underlying the design of marine reserve networks. Coastal marine systems may be usefully considered as metacommunities inwhich propagules are exchanged among components, and in which the persistence of one species depends on that of others. Our results suggest thatthe large-scale distribution of marine species can be dynamic and can result from local ecological processes. We discuss the potential implications ofthese findings for marine reserve design and the need for long-term monitoring programs to validate predictions from metacommunity models.Only through an integrated and dynamic global perspective can scientists and managers achieve the underlying goals of marine conservation.Keywords: complex adaptive systems, self-organization, marine conservation, larval dispersal, spatially explicit ecological modelsTwo very different approaches are typically used in de-signing marine reserves. In the static approach, the dynamiccomplexity and connectivity of the system are ignored, andthe focus is on making sure that different habitats and speciesare sufficiently represented within the network of reserves(Roberts et al. 2003). By contrast, the other main approachemphasizes the importance of connectivity and the inclusionof dynamics. However, in most cases, only single-species dy-namics and idealized connections based on simple aspects ofconnectivity have been included. Real systems include mul-tiple species, complex physics, heterogeneous habitats, andtemporal variability. In developing principles for the designof reserves, it is essential to understand the role of system com-plexity. Recent advances in ecological theory have begun toaddress this complexity, at least in conceptual models that helpto develop an understanding of how different features influ-ence the dynamics of real systems. Our goal here is to beginbridging the gap between the two most common approachesto marine reserve design by exploring a simple metacom-munity model. A metacommunity can be defined as a set ofpotentially interacting species coupled through dispersal(Wilson 1992). Metacommunity theory has been developedto elucidate the maintenance of biodiversity in fragmentedhabitats (Klausmeier 2001, Mouquet and Loreau 2002). Herewe use metacommunities to explore the interacting roles oflarval dispersal and species interactions in generating large-scale patterns of species distribution.We begin by reviewing recent work that illustrates thegeneral importance of connectivity in marine reserve design. Next, we discuss how to move beyond