Joachim Claudet Mark Carr Jennifer Caselle Jon Day Alan M. Friedlander Sarah E. Lester Thierry Lison de Loma Brian Tissot Dan Malone Joachim Claudet Kirsten Grorud-Colvert 2011 <p class="do-not-mathjax">As marine ecosystems are plagued by an ever-increasing suite of threats including climate change, pollution, habitat degradation, and fisheries impacts (Roessig <span class="italic do-not-mathjax">et al</span>., 2004; Lotze <span class="italic do-not-mathjax">et al</span>., 2006; Jackson, 2008), there are now no ocean areas that are exempt from anthropogenic impacts (Halpern <span class="italic do-not-mathjax">et al</span>., 2008). In order to preserve marine biodiversity, ecosystem function, and the goods and services provided by resistant and/or resilient systems, marine reserves have been increasingly recommended as part of an ecosystem-based approach to management (Browman and Stergiou, 2004; Levin <span class="italic do-not-mathjax">et al</span>., 2009). Marine reserves are defined as “areas of the ocean completely protected from all extractive and destructive activities” (Lubchenco <span class="italic do-not-mathjax">et al</span>., 2003) and can be experimental controls for evaluating the impact of these activities on marine ecosystems. Growing scientific information has shown consistent increases in species density, biomass, size, and diversity in response to full protection inside reserves of varying sizes and ages located in diverse regions (Claudet <span class="italic do-not-mathjax">et al</span>., 2008; Lester <span class="italic do-not-mathjax">et al</span>., 2009; Molloy <span class="italic do-not-mathjax">et al</span>., 2009). However, most of these data are from individual marine reserves and therefore have inherently limited transferability to networks of marine reserves, which when properly designed can outperform single marine reserves for a variety of ecological, economic, and social management goals (Roberts <span class="italic do-not-mathjax">et al</span>., 2003; Almany <span class="italic do-not-mathjax">et al</span>., 2009; Gaines <span class="italic do-not-mathjax">et al</span>., 2010).</p><p class="do-not-mathjax">The concept of marine reserve networks grew out of a desire to achieve both conservation and fishery management goals by minimizing the potential negative economic, social, and cultural impacts of a single large reserve while still producing similar or even greater ecological and economic returns (Murray <span class="italic do-not-mathjax">et al</span>., 1999; Gaines <span class="italic do-not-mathjax">et al</span>., 2010). In addition, reserves networks can provide insurance by protecting areas across a region and spreading the risk that these sites may be impacted by localized catastrophes such as hurricanes or oil spills (Allison <span class="italic do-not-mathjax">et al</span>., 2003). The World Conservation Union's Marine Programme defines a network as “a collection of individual marine protected areas (MPAs) or reserves operating co-operatively and synergistically, at various spatial scales and with a range of protection levels that are designed to meet objectives that a single reserve cannot achieve” (IUCN–WCPA, 2008). However, general terms such as “co-operatively” and “synergistically” can have myriad meanings. Without a clear definition of a network, it becomes difficult to identify attainable management goals and design a process for evaluating whether the network achieves those goals. Besides, different management goals may in turn result in the need for different types of networks. The use of MPAs with varying protection levels together with no-take zones in multiple-zoning schemes adds another layer of complexity to network design and evaluation; however, partially protected areas are generally used to manage coastal uses and avoid conflicts (rather than for strict ecological purposes) and are therefore a function of the local social, economic, and cultural context. As we are here interested in the ecological effects of networks, for the purposes of this chapter, we focus on marine reserves because these areas are no-take and therefore offer greater ecological benefits than other types of MPAs that allow some forms of extraction (Lester and Halpern, 2008).</p> application/pdf 10.1017/CBO9781139049382.016 en Cambridge University Press Networks - The assessment of marine reserve networks: Guidelines for ecological evaluation chapter