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Biological responses in marine no-take reserves versus partially protected areas

S. E. Lester and B. S. Halpern

Marine Protected Areas (MPAs) are a common tool for conserving and managing marine and coastal ecosystems. MPAs encompass a range of protection levels, from fully protected no-take reserves to restriction of only particular activities, gear types, user groups, target species, or extraction periods. There is a growing body of scientific evidence supporting the ecological benefits of full reserve protection, but it is more difficult to generalize about the effects of other types of MPAs, in part because they include a range of actual protection levels. However, it is critical to determine whether partial protection and no-take reserves provide similar ecological benefits given potential economic costs of lost fishing grounds in no-take areas, common sociopolitical opposition to full protection, and promotion of partially protected areas as a compromise solution in ocean zoning disputes. Here we synthesize all empirical studies comparing biological measures (biomass, density, species richness, and size of organisms) in no-take marine reserves and adjacent partially protected and unprotected areas across a range of geographic locations worldwide. We demonstrate that while partially protected areas may confer some benefits over open access areas, no-take reserves generally show greater benefits and yield significantly higher densities of organisms within their boundaries relative to partially protected sites nearby.