Coastal Ecosystems and Landscapes

Coastal landscapes Many centuries of interactions between natural and human- induced processes have created a complex landscape mosaic in the Mediterranean Basin (Bratina-Jurkovič 2011). This evo- lution has been shaped by major historical developments. In recent times, the period of population growth, industrialisa- tion and technical and technological advances following the Second World War precipitated major land-use changes, es- pecially increased urbanisation and agricultural intensifica- tion. New pressures on Mediterranean ecosystems came with these changes, including increased need for arable land and fresh water and increased demand for land and sea transpor- tation. The expansion of urbanised and cultivated land and marine traffic caused multiple impacts, including habitat loss, reductions in freshwater and sediment discharges by rivers, salinisation of coastal aquifers, soil and coastline erosion and eutrophication of some coastal waters. These continuing pres- sures and their associated impacts now threaten natural and cultural landscape integrity and diversity in the region, altering the fine-grained and multifunctional landscape and limiting options for sustainable development.

In the Mediterranean Basin, the areas that have experienced the most human-induced change are those most intensively ex- ploited due to ready availability of the natural resources needed for settlement. Deltas are good examples, with low-lying terrain suitable for construction of dwellings, arable land, freshwater re- sources and easy access to the sea.

Coastline stability and erosion

The Mediterranean coastline is approximately 46.000 km long, with nearly 19.000 km of island coastline. 54 % of the coastline is rocky and 46 % is sandy coast that includes important and fragile habitats and ecosystems such as beaches, dunes, reefs, lagoons, swamps, estuaries and deltas. Low-lying sedimentary coasts are more dynamic than rocky coasts. The balance between sea-level rise, sediment supply and wave and coastal current regimes will determine whether the coastline advances (accretes), remains stable, or retreats (erodes).

Model predictions for the extent of sea-level increase in the Mediterranean for the 21st century range up to 61 cm (in a worst-case scenario) for the Eastern Mediterranean (Marcos and Tsimplis 2008). Satellite altimetry data on variations in the level of the Mediterranean Sea between January 1993 and June 2006 indicate that sea level will rise more in the Eastern Mediterrane- an than in the Western Mediterranean. Delta areas, due to their topography and sensitive dynamics, are most vulnerable to im- pacts from sea-level rise.

Coastline stability is also affected by the increase in artificial structures, both within the drainage basin (especially reser- voirs) and along the coastline (the proliferation of marinas and other urban and tourist-industry infrastructure). About 45 % of the sediments that would be delivered by rivers to the Mediter- ranean annually are either retained behind dams or extracted from river beds for sand and gravel, leading to an overall deficit

HUMAN PRESSURE, STATE AND IMPACTS ON MEDITERRANEAN ECOSYSTEMS

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