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Climate change, resulting from both natural and anthropogenic factors, is expected to affect virtually every aspect of marine ecosystem structure and function, from community composition and biogeochemical cycling, to the prevalence of diseases. Climate can affect all life-history stages through direct and indirect processes. The possible impacts of climate change on marine populations include changes in population dynamics (body size, reproduction), community composition and geographical distributions. Climate change can be expected to affect populations, habitats and ecosystems differently, depending on their underlying characteristics (ICES 2011a, ICES 2011b). Climate change can potentially alter connectivity patterns by changing larval duration times, adult movement patterns and species distributions, for example. Given the importance of connectivity to MPA network design, understanding the influences of climate change on different components of connectivity remains a key research need. Although there are many uncertainties about the rates and spatial structure of future climate change, the probable and potential changes need to be considered in ecosystem management planning.

MPA networks must be designed to be integrated, mutually supportive and focused on sustaining key ecological functions, services and resources. As such, they can provide a mechanism to adapt to and mitigate climate change effects on ecosystems. MPA networks are especially suited to addressing spatial issues of connectivity (e.g., connecting critical places for life stages of key species), habitat heterogeneity and the spatial arrangement and composition of constituent habitats, all of which can contribute to ecosystem resilience. Some of these properties can be supported through the size and placement of protected areas (e.g., abundance and size structure of upper trophic levels, species richness), and the reduction of other stressors such as fishing pressure. Some ecosystem properties may not be amenable to MPAs but can be used to predict their vulnerability to climate change (e.g., phenological matches, flexibility of migration routes, dependence on critical habitats, functional redundancy, response diversity and community evenness) (ICES 2011a).

Ocean governance will need to adjust to reflect a new imperative: maintaining structure, function, processes and biodiversity of ecosystems to enhance resilience to change. A highly coordinated, integrated and adaptive approach to oceans governance will clearly be central to implementing this new imperative, necessitating some mechanism to enhance consistency and coherence across sectors and regions. This will be particularly important with regard to establishing and operating transboundary MPA networks.