Assessing cumulative risks to coastal and marine habitats under management and climate change scenarios: The case of northern Portugal

Managing the risks associated with human activities and uses in marine and coastal regions is crucial in a time of maritime activity expansion promoted by Blue Growth, especially with the increasing effects of climate change. Effective management of the cumulative risks is essential to safeguard ecosystems from potential further degradation, maintaining their resistance and resilience and ability to provide ecosystem services (ES) and societal goods and benefits (SGB). Here, we adopt a cumulative risk-based approach to assess risk to habitats and ecosystems, considering human activities and two climate-derived pressures for three management narratives, across three IPCC Shared Socioeconomic Pathways in the northern marine and coastal region of Portugal. Our findings highlight high ecosystem risk in some marine areas and coastal segments, particularly affecting beaches, aphotic soft and rock bottoms, and estuarine areas. Across the management and climate scenarios, the most important contributors to risk included rising sea surface temperatures, increased coastal exposure to relative sea-level rise (SLR) and storminess, fishing, tourism, artificial areas, and maritime transport. Overall spatial risk patterns varied more with changes in management scenarios than between climate scenarios, with climate pressures having an additive effect on habitat and ecosystem risk. The inclusion of the climate-derived exogenous pressures (i.e. those whose causes emanate from outside the management system) altered the high-risk zone spatial patterns at the land-sea interface, while in marine areas, it increased the overall risk scores without changing the observed overall risk patterns. It is recommended that policymakers and managers should adopt a precautionary approach, using cumulative assessments integrated into decision-support systems and ecosystem-based management plans to anticipate and adapt to or mitigate future changes. Thereby, ensuring the maintenance of the ecosystem resilience to change, to avoid reaching tipping points that would disrupt the resource-provisioning capacity of these ecosystems and the provision of ES and SGB.