Towards a framework for assessment and management of cumulative human impacts on marine food webs

Understanding ecosystem responses to multiple human stressors, rather than focusing on single stressors, is necessary for effective ecosystem-based management. Management actions aimed at stressor mitigation will be most effective if prioritized based on their expected ecological benefits and associated costs. However, establishing direct links between actions and their ecosystem benefits is hindered by the diversity and complexity of ways in which human stressors interact with ecosystem components. To address this issue, we propose a framework for guiding conservation practitioners on the selection of conservation actions that accounts for cumulative human impacts on food web components. We used the case study of the Mediterranean seagrass Posidonia oceanica food web and expert knowledge elicitation to apply the initial steps of this framework. We produced a conceptual seagrass food web model, determined main trophic relationships, identified main stressors to the food web components, and assessed the components’ vulnerability to stressors. Some stressors appeared to have high impacts on all food web components (e.g. coastal infrastructure) whereas others (e.g. introduced herbivores) had lower and often highly variable impacts across components . Partitioning the ecosystem to its components facilitated the identification of main stressors previously disregarded (e.g. fishing practices other than trawling), and reconsideration of the importance of stressors commonly perceived as major threats (e.g. agricultural runoff and climate change related stressors). Incorporating the obtained vulnerability values along with data on the change of the stressors’ state (e.g. decrease of domestic pollution and increased fishing) into a dynamic food web model will facilitate the estimation of cumulative human impacts and guide decision-making on action prioritization. The suggested framework is transferable to any ecosystem and location.

GIAKOUMI Sylvain;  HALPERN Benjamin;  MICHEL Loic;  GOBERT S.;  SINI Maria;  BOUDOURESQUE C.F.;  GAMBI M.C.;  KATSANEVAKIS Stylianos Marios;  LEJEUNE P.;  MONTEFALCONE Monica;  PERGENT Gerard;  PERGENT-MARTINI C.;  SANCHEZ-JEREZ P.;  VELIMIROV Bruno;  VIZZINI S.;  ABADIE A;  COLL Marta;  GUIDETTI P.;  MICHELI Fiorenza;  POSSINGHAM Hugh; 

2017-04-06

WILEY-BLACKWELL

JRC90561

0888-8892,   

http://onlinelibrary.wiley.com/doi/10.1111/cobi.12468/abstract,    https://publications.jrc.ec.europa.eu/repository/handle/JRC90561,   

10.1111/cobi.12468,