Las praderas de Posidonia oceanica y la regeneración de playas

The meadows of the seagrass posidonia oceanica are essential for the protection of the marine environment on the Spanish Mediterranean coasts. The presence of these meadows demands that maximum attention be paid to the development of projects and sea works and in the planning and management of the Mediterranean coast. Posidonia oceanica is a Mediterranean endemic phanerogam or flowering plant which has special characteristics which must be known at the outset in order to prevent serious environmental damage through the construction of harbour works. These characteristics include a millenary life span, a need for light and clear water, very slow growth and reproduction rate, a need for sandy beds, a shedding of leaves in Autumn and the fact that they form meadows over a very long period which stabilise the shoreline by preventing the impact of the sea. While very intense sedimentation processes may kill this plant, it is also particularly sensitive to a build up in the turbidity of the sea water caused by waste and spillages and is similarly affected by the persistent erosion of the sea bed which can rip out its roots and rhizomes. This article describes the main aspects to be considered with regards to this "seagrass" in the planning and administration of harbour and sea works on the Mediterranean coast. The article goes on to analyse the problem of shore protection and the suitability of using shore regeneration to guarantee the stability of the same over the medium and long term.