Current marine pressures and mechanisms driving changes in marine habitats. Deliverable 1.2, MERCES Project.

Human activities and the resultant pressures they place on the marine environment have beenwidely demonstrated to contribute to habitat degradation, therefore, their identification andquantification is an essential step towards any meaningful restoration effort. The overall scope ofMERCES Deliverable 1.2 is to review current knowledge regarding the major marine pressuresplaced upon marine ecosystems in EU waters and the mechanisms by which they impact habitatsin order to determine potential restoration pathways. An understanding of their geographicaldistribution is critical for any local assessment of degradation, as well as for planningconservation and restoration actions. This information would ideally be in the form of maps,which: (a) compile single or multiple activities and pressures over broad scales, integrating andvisualizing available data and allowing direct identification of aggregations as well as gaps and(b) may be overlaid with habitat maps (or any other map layer containing additionalinformation), thus combining different data levels and producing new information to be used forexample when implementing EU policies. The deliverable also documents typical examplehabitat case studies, the prominent impacts and consequences of activities and pressures towardsthe identification of possible restoration or mitigation actions. Finally the deliverable discussespressures, assessments, marine spatial planning and blue growth potential.

Activities and pressures are used in a strict sense, where marine activities are undertaken tosatisfy the needs of societal drivers (e.g. aquaculture or tourism) and pressures are considered tobe the mechanism through which an activity has an actual or potential effect on any part of theecosystem (e.g. for demersal trawling activity, one pressure would be abrasion of the seabed).Habitats are addressed using a nested approach from large-scale geological features (e.g. shallowsoft bottoms) to species-characterised habitats (e.g. Posidonia meadows) because of the waythey are referred to in current policy documents which lack standard and precise definitions.