Criteria for assessing ecological coherence of MPA networks: a review

Identifying and protecting marine features through the establishment of marine protected areas (MPAs) is an important step towards conserving biodiversity, yet it is insufficient from an ecological perspective. An ecologically coherent network of well-managed MPAs is now a requirement of a number of international, regional and national directives to effectively protect biodiversity. This means having a network of well-conserved MPAs representing the full variety of a region’s ecosystems, with sites close enough together to allow movement of individuals among them. Historically, MPAs have been established on an ad-hoc basis over varying timescales and with different conservation objectives. Thus, a range of MPA characteristics and a number of ecological processes need to be evaluated to determine if a collection of MPAs within a given region forms an ecologically coherent network. Several criteria have been proposed to further improve the assessment and design of ecologically coherent MPA networks and ensure consistency across regions. Six of these criteria are reviewed here: representativity, replication, adequacy, connectivity, level of protection and resilience. Four case studies are then discussed, providing examples of how these criteria have been used in the establishment of ecologically coherent MPA networks.