A review of the effectiveness of solutions to achieve the good environmental status of the marine environment

Abstract

Europe’s seas are at the nexus of a “triple crisis” of biodiversity and habitat loss, climate change, and pollution, increasingly eroding the ecosystems’ resilience and capacity to provide ecosystem services. Although essential, existing European Union policies, especially the Marine Strategy Framework Directive (MSFD), proved insufficient. The objective of the MSFD to achieve Good Environmental Status (GES) in all EU marine waters by 2020 was not reached, due to gaps in GES definition, a lack of consideration of climate change, uneven ambition, insufficient measures, gaps in monitoring and data comparability, and inadequate integration with other key policies. The aim of this study was to review the management measures and solutions to address the pressures and ecosystem features covered by the 11 MSFD GES Descriptors, assessing their reported effectiveness, co-benefits and trade-offs, and implementation constraints. This review identifies a broad range of solutions contributing to GES, including ecological protection, passive and active restoration, nature-based solutions, pressure reduction, spatial protection and planning, sustainable resource management, and pollution prevention and mitigation. Their effectiveness is often context- and scale-dependent. Also, no single measure is sufficient, and outcomes are enhanced when these are integrated into a coherent framework, adapted to local conditions, and supported by long-term monitoring, stakeholder engagement, and coastal/marine spatial planning. Restoration measures should be preceded by effective pressure/stressor reduction, while pressure-reduction solutions can generate cascading benefits across multiple Descriptors, highlighting opportunities to prioritize interventions. While evidence is abundant for some Descriptors (e.g., non-indigenous species, commercial fish and shellfish, biodiversity, eutrophication), important knowledge gaps remain for food webs, seabed integrity, and hydrographic conditions, as well as on cumulative effects and interactions, cross-Descriptor effects, the status of emerging contaminants, the effectiveness of waste management/circular economy and of marine nature-based solutions against GES objectives, and on climate-change-related measures. Overall, achieving GES will require moving beyond isolated measures towards coordinated, adaptive, and ecosystem-scale management to effectively address the “triple crisis”.