22 spatial datasets of human activities and stressors and 19 eco- system types were assembled and used in the analyses and maps (NCEAS 2008).
The analysis concluded that pressures that exert the greatest im- pacts on Mediterranean marine ecosystems are climate change, demersal fishing, ship traffic, and, in coastal areas, run-off from land and invasive non-indigenous species. The lowest estimated impacts are associated with oil spills and oil rigs, due to a combi- nation of the limited spatial extent of these pressures and their overlap with habitats with relatively low vulnerability to these potential threats. The analysis shows distinct spatial patterns in the distribution of cumulative human impacts.
Supporting the findings of the Initial Integrated Assessment done in support to the Ecosystem Approach process, the NCEAS model- ling suggests that the Adriatic and Alboran seas are the most im- pacted by multiple human pressures, while the Western Mediter- ranean and the Tunisian Plateau/Gulf of Sidra are the least. Coastal areas within the territorial waters of nations, particularly Spain,
France, Italy, Tunisia and Egypt suffer the greatest cumulative im- pact from multiple pressures, with estimated cumulative impact scores up to ten times greater than in the high seas.
It must be noted that the modelling of cumulative impacts only suggests areas for further study. Ground-truthing is needed to see if the models accurately reflect the extent to which multiple human pressures are causing ecological impacts and potentially undermin- ing the delivery of ecosystem services. In addition to establishing a systematic monitoring regime to derive needed information on condition and trends, future research will have to elucidate cause and effect relationships, not just correlations. The milestones recent- ly achieved in the application of the Ecosystem Approach roadmap, namely the setting of ecological objectives and operational objec- tives, together with indicators, form the basis for such a rationalised approach to deriving information for all future assessments. Estab- lishing targets, and analysing trend information to know when tar- gets are being approached, will provide the kind of robust scientific information needed to allow management priorities to be deter- mined and to guide effective ecosystem-based management.
HUMAN PRESSURE, STATE AND IMPACTS ON MEDITERRANEAN ECOSYSTEMS