| Affiliation: | 1. Institute of Marine Biological Resources and Inland Waters, Hellenic Centre for Marine Research, Ag. Kosmas, Greece;2. ARC Centre of Excellence for Environmental Decisions, School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia;3. Bren School of Environmental Science and Management, University of California, Santa Barbara, CA, U.S.A.;4. Imperial College London, Silwood Park Campus, Ascot, United Kingdom;5. STARESO Research Station, Revellata Cape, Calvi, France;6. Oceanologie Laboratory of Oceanology, B6c Bat Chimie, University of Liege, Sart Tilman, MARE and AFFishCentres, Liege, Belgium;7. Department of Marine Sciences, University of the Aegean, University Hill, Mytilene, Lesvos Island, Greece;8. Mediterranean Institute of Oceanography (MIO), Aix‐Marseille University and Toulon University, CNRS/IRD, Marseille Cedex 9, France;9. Stazione Zoologica Anton Dohrn, Napoli – Laboratory of Functional and Evolutionary Ecology, Villa Comunale, Napoli, Italy;10. European Commission, Joint Research Centre, Institute for Environment and Sustainability, Ispra, Italy;11. DiSTAV, Department of Earth, Environment and Life Sciences, University of Genoa, Genoa, Italy;12. EqEL, FRES 3041, University of Corsica, Corte, France;13. Department of Marine Science and Applied Biology, University of Alicante, Spain;14. Center of Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria;15. Department of Earth and Marine Sciences, University of Palermo, Palermo, Italy;16. Institut de Recherche pour le Développement, UMR MARBEC (IRD, Ifremer, UM, CNRS), Sète Cedex, France;17. Université Nice Sophia Antipolis, Faculté des Sciences, Nice, France;18. Hopkins Marine Station, Stanford University, Pacific Grove, CA, U.S.A |
| Abstract: | Effective ecosystem‐based management requires understanding ecosystem responses to multiple human threats, rather than focusing on single threats. To understand ecosystem responses to anthropogenic threats holistically, it is necessary to know how threats affect different components within ecosystems and ultimately alter ecosystem functioning. We used a case study of a Mediterranean seagrass (Posidonia oceanica) food web and expert knowledge elicitation in an application of the initial steps of a framework for assessment of cumulative human impacts on food webs. We produced a conceptual seagrass food web model, determined the main trophic relationships, identified the main threats to the food web components, and assessed the components’ vulnerability to those threats. Some threats had high (e.g., coastal infrastructure) or low impacts (e.g., agricultural runoff) on all food web components, whereas others (e.g., introduced carnivores) had very different impacts on each component. Partitioning the ecosystem into its components enabled us to identify threats previously overlooked and to reevaluate the importance of threats commonly perceived as major. By incorporating this understanding of system vulnerability with data on changes in the state of each threat (e.g., decreasing domestic pollution and increasing fishing) into a food web model, managers may be better able to estimate and predict cumulative human impacts on ecosystems and to prioritize conservation actions. |
