Marine protected area networks: assessing whether the whole is greater than the sum of its parts

Abstract

Anthropogenic impacts are increasingly affecting the world's oceans. Networks of marine protected areas (MPAs) provide an option for increasing the ecological and economic benefits often provided by single MPAs. It is vital to empirically assess the effects of MPA networks and to prioritize the monitoring data necessary to explain those effects. We summarize the types of MPA networks based on their intended management outcomes and illustrate a framework for evaluating whether a connectivity network is providing an outcome greater than the sum of individual MPA effects. We use an analysis of an MPA network in Hawai'i to compare networked MPAs to non-networked MPAs to demonstrate results consistent with a network effect. We assert that planning processes for MPA networks should identify their intended outcomes while also employing coupled field monitoring-simulation modeling approaches, a powerful way to prioritize the most relevant monitoring data for empirically assessing MPA network performance.

Figure 1. Map of study sites inside and outside protected areas in West Hawai'i and Maui.

Figure 2. The mean percent change (±1 SE SE) in density of yellow tang (Zebrasoma flavescens) before versus after MPA network establishment in West Hawai'i within limited-take and no-take MPAs and control (open to fishing) sites on West Hawai'i and Maui.