Using a holistic ecosystem-integrated approach to assess the environmental status of Saronikos Gulf, Eastern Mediterranean

Abstract

The holistic Nested Environmental status Assessment Tool (NEAT), developed for the integrated assessment of the status of marine waters, was applied to Saronikos Gulf, in the Eastern Mediterranean. We used different spatial and decadal time series data covering 9 biological and chemical ecosystem components, 24 indicators and 8 descriptors of the Marine Strategy Framework Directive (MSFD), to test its performance under different ecosystem approaches. The results were evaluated in relation to the anthropogenic pressures affecting the study area as well as the management measures taken, and compared to the results from previous studies. NEAT has shown clear spatial gradients differentiating the impacted and slightly-impacted areas, as well as the response of the ecosystem towards the management measures taken, demonstrating the most responsive and early warning ecosystem components. The application of NEAT to Saronikos Gulf classified the whole basin into good status, with the pelagic habitat components (fish, water column and phytoplankton ecosystem components) contributing strongly to the overall environmental status of the gulf. Sediment, benthic fauna and vegetation, mammals and alien species were the most impacted ecological components in Saronikos Gulf. The most affected areas, Elefsis Bay and Psittalia (wastewater submarine outfall), were assessed as in poor and moderate status, respectively. We conclude that: (i) it is possible to integrate data from different sources, spatial and temporal scales; (ii) this integration has permitted to undertake a real ecosystem assessment; (iii) there is no loss of information, allowing full tracking of problems and cases in no good status that should be addressed at lower levels (e.g. species or species groups); (iv) the results are related with the pressures identified; (v) the assessment demonstrates the recovery of the system and the time needed to recovery; and (vi) these results could be very useful for managers, policy makers and scientists when deciding the method to use in assessing the environmental status under the MSFD.