An ecosystem-based approach to assess the status of a Mediterranean ecosystem, the Posidonia oceanica seagrass meadow

PLoS One. 2014 Jun 16;9(6):e98994. doi: 10.1371/journal.pone.0098994. eCollection 2014.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alismatales / growth & development*
  • Biota
  • Ecological Parameter Monitoring / methods*
  • Humans
  • Mediterranean Sea
  • Water Pollutants / analysis*
  • Water Quality

Substances

  • Water Pollutants

Grants and funding

This study has been funded by the French Centre National de la Recherche Scientifique (CNRS), the French Réseau des Stations et Observatoires Marins (RESOMAR), the Muséum National d'Histoire Naturelle (MNHN, Paris), the French Agence de l'eau Rhône Méditerranée Corse through the French part of the European MSFD project (in French: Directive Cadre Stratégie pour le Milieu Marin, DCSMM). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.