title: An ecosystem-based approach to assess the status of a Mediterranean ecosystem, the Posidonia oceanica seagrass meadow.
abstract: Biotic indices, which reflect the quality of the environment, are widely used in the marine realm. Sometimes, key species or ecosystem engineers are selected for this purpose. This is the case of the Mediterranean seagrass Posidonia oceanica, widely used as a biological quality element in the context of the European Union Water Framework Directive (WFD). The good quality of a water body and the apparent health of a species, whether or not an ecosystem engineer such as P. oceanica, is not always indicative of the good structure and functioning of the whole ecosystem. A key point of the recent Marine Strategy Framework Directive (MSFD) is the ecosystem-based approach. Here, on the basis of a simplified conceptual model of the P. oceanica ecosystem, we have proposed an ecosystem-based index of the quality of its functioning, compliant with the MSFD requirements. This index (EBQI) is based upon a set of representative functional compartments, the weighting of these compartments and the assessment of the quality of each compartment by comparison of a supposed baseline. The index well discriminated 17 sites in the north-western Mediterranean (French Riviera, Provence, Corsica, Catalonia and Balearic Islands) covering a wide range of human pressure levels. The strong points of the EBQI are that it is easy to implement, non-destructive, relatively robust, according to the selection of the compartments and to their weighting, and associated with confidence indices that indicate possible weakness and biases and therefore the need for further field data acquisition.
authors.affiliation: Aix-Marseille University, Mediterranean Institute of Oceanography (MIO), Université de Toulon, CNRS/INSU, IRD, UM 110, Marseille, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Personnic
authors.affiliation: Aix-Marseille University, Mediterranean Institute of Oceanography (MIO), Université de Toulon, CNRS/INSU, IRD, UM 110, Marseille, France.
authors.forename: Charles F
authors.initials: CF
authors.lastname: Boudouresque
authors.affiliation: GIS Posidonie, Pytheas Institute, Aix-Marseille University, Marseille, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Astruch
authors.affiliation: Centre d'Estudis Avançats de Blanes - CSIC, Blanes, Spain.
authors.forename: Enric
authors.initials: E
authors.lastname: Ballesteros
authors.affiliation: Aire marine protégée de la côte Agathoise, site natura 2000, Agde, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Blouet
authors.affiliation: Aix-Marseille University, Institut Méditerranéen de Biodiversité et d'Ecologie (IMBE), UMR 7263, Station Marine d'Endoume, Marseille, France.
authors.forename: Denise
authors.initials: D
authors.lastname: Bellan-Santini
authors.affiliation: GIS Posidonie, Pytheas Institute, Aix-Marseille University, Marseille, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Bonhomme
authors.affiliation: Aix-Marseille University, Mediterranean Institute of Oceanography (MIO), Université de Toulon, CNRS/INSU, IRD, UM 110, Marseille, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Thibault-Botha
authors.affiliation: Museum National d'Histoire Naturelle, UMR 7208, Station Marine de Dinard, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Feunteun
authors.affiliation: Aix-Marseille University, Mediterranean Institute of Oceanography (MIO), Université de Toulon, CNRS/INSU, IRD, UM 110, Marseille, France.
authors.forename: Mireille
authors.initials: M
authors.lastname: Harmelin-Vivien
authors.affiliation: Equipe Ecosystèmes Littoraux, FRES 3041, University of Corsica, Corte, France.
authors.forename: Gérard
authors.initials: G
authors.lastname: Pergent
authors.affiliation: Equipe Ecosystèmes Littoraux, FRES 3041, University of Corsica, Corte, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Pergent-Martini
authors.affiliation: Université de Perpignan, Via Domitia, Centre de Formation et de Recherche sur les Environnements Méditerranéens, UMR 5110, Perpignan, France.
authors.forename: Jérémy
authors.initials: J
authors.lastname: Pastor
authors.affiliation: Aix-Marseille University, Mediterranean Institute of Oceanography (MIO), Université de Toulon, CNRS/INSU, IRD, UM 110, Marseille, France.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Poggiale
authors.affiliation: Aix-Marseille University, Institut Méditerranéen de Biodiversité et d'Ecologie (IMBE), UMR 7263, Station Marine d'Endoume, Marseille, France.
authors.forename: Florent
authors.initials: F
authors.lastname: Renaud
authors.affiliation: Aix-Marseille University, Mediterranean Institute of Oceanography (MIO), Université de Toulon, CNRS/INSU, IRD, UM 110, Marseille, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Thibaut
authors.affiliation: Aix-Marseille University, Mediterranean Institute of Oceanography (MIO), Université de Toulon, CNRS/INSU, IRD, UM 110, Marseille, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Ruitton
mesh_terms: D035961:Alismatales / Q000254:growth & development*; D058448:Biota; D064308:Ecological Parameter Monitoring / Q000379:methods*; D006801:Humans; D008522:Mediterranean Sea; D014873:Water Pollutants / Q000032:analysis*; D060753:Water Quality
chemical_list: D014873:Water Pollutants