Effectiveness of combined management interventions in European Seas to face cumulative impact of multiple human activities and climate change trajectories

Conclusive knowledge about the likely consequences of multiple management interventions to overcome the negative impacts of global change on the biodiversity, ecosystem functioning and service provisioning of European seas remains scarce. We developed a comparative study to assess different management interventions in various European marine regions subjected to the cumulative impacts (of fishing, shipping, windfarms development and climate change). Specifically, we used seven spatial-temporal ecological models representing both regional seas (North Sea, Central Baltic Sea, Bay of Biscay and Western Mediterranean Sea) and sub-regions (Coastal Baltic Sea, North-western Mediterranean Sea, and the Portuguese Shelf) to mechanistically simulate contrasting scenarios. These scenarios were based on three global narratives of alternative futures (“Global Sustainability”, “National Enterprise”, “World Markets”) that account for contrasting SSP/RCP scenarios, translated to regional and sub-regional relevance. Management interventions under different Nature-Based Solutions (NBSs) options included spatial protection, restoration and sustainable fisheries management and were translated to regional contexts, legislations and legal frameworks. The cumulative impacts of fishing, shipping and windfarms development were considered, in addition to contrasting climate change trajectories. The effect of multiple management interventions to overcome the impacts of climate and cumulative human activities was then assessed quantifying the spatiotemporal trajectories of key commercial and vulnerable species, and selected ecological and economic indicators. Trade-offs between management strategies were compared given impacts on species diversity, ecosystem function and service delivery, and resilience to CC.

Our collective results projected distinct ecological and socioeconomic realities on the mid- (2050) and long- (2100) term, suggesting that NBSs (e.g., restoration of habitat forming species and protection of key areas, nutrient loading reduction, and reaching conservation targets regarding MPAs - 30%) combined with fishing sustainability actions (e.g., reduction of fishing effort and reduction of discards and bycatch, establishment of fisheries restricted areas) and mitigation measures for shipping activity (e.g. reducing vessels’ speed) and wind farms (e.g., reducing mortality due to collision) could play a vital role in mitigating the future impact of cumulative changes. Results showed divergent trajectories for many species and indicators between the scenarios and their baseline analogues. With expected increases in climate change impacts and human activities in the future, our results highlight that ecosystem-based management interventions are crucial to shape the future ecological and socioeconomic status of European seas, and underpin the significance of proactive management of European Regional Seas at present.