Measurements, mechanisms, and management recommendations for how marine protected areas can provide climate resilience

The number of marine protected areas (MPAs) implemented globally is rising, with calls to protect 30 % of the ocean by 2030. One potential benefit of MPAs is increased resilience to anthropogenic climate change impacts. However, realistic ecological expectations are needed to identify the conditions that may yield resilience benefits and determine effective evaluation methods. To date, global meta-analyses have consistently shown positive ecological effects of protection, yet assessing resilience effects has been more complex. 'Resilience' is challenging to define and measure and may manifest at various spatiotemporal scales. Additionally, identifying an appropriate reference point to quantify resilience is challenging. Robust assessments require long time series to estimate variability or opportunistic observation of disturbance and recovery. Such data are not always available. We suggest an alternative, complementary approach. First, it is crucial to define the ecological and socioeconomic mechanisms by which an MPA could provide any resilience benefit to the human-natural system; these mechanisms are both limited and context-dependent. Then, we can measure indicators of resilience to assess the contribution of such mechanisms inside MPAs. This provides a pathway to assess how conservation influences adaptive capacity, overcoming the challenge of directly measuring resilience itself. Finally, it is critical to recognize that MPAs are only one tool in a portfolio of management actions that could improve resilience. They should not be misconstrued as standalone solutions, but rather as integral parts of a comprehensive approach to ecosystem-based sustainability management.