Habitat mapping of Portugal’s north-western continental shelf and its application to implement the European Marine Strategy Framework Directive

Abstract

Seafloor habitat maps allow to integrate various data layers and compare areas, being valuable tools for assessing environmental quality. Although the European Nature Information System (EUNIS) was created to catalogue habitats throughout Europe, its use in ecological assessment is relatively uncommon. This work proposes a EUNIS, level 5, benthic habitats map for the Portuguese continental shelf North of Nazaré canyon. Seven EUNIS level 5 habitats were identified, of which six were new to EUNIS, as this catalogue is less complete for southern Europe. Hereafter this map was used to assess the environmental status (ES) within the Marine Strategy Framework Directive (MSFD), which was developed to help European Union countries achieve a good environmental status (GES) in their marine ecosystems. In this sense, eleven quality descriptors (and respective criteria) were set to assess the environmental status (ES), which can be performed using diverse indicators. In this study, the ES status was assessed for two of such descriptors, namely D1, Biodiversity, which was assessed using the Marine Biological Value (MBV); and D6, Seafloor Integrity, which was assessed through the AZTI Marine Biotic Index (AMBI) and Multivariate-AMBI (M-AMBI). For both descriptors, an overall GES (or higher) was determined for this study area. These results set a baseline for future ES assessments within the MSFD, while the use of the EUNIS habitat maps can be expanded to assess the ES of other descriptors, namely D2, non-indigenous species, D3, commercially exploited fish and shellfish and D4, food webs.