Ebro Delta (Spain)

Abstract

The Ebro Delta is located in the Western Mediterranean (Catalonia, NE Spain), and the delta plain has an area of 320 km². Up to 80% of the delta area has been reclaimed (250 km²), mostly for rice agriculture (210 km²), and there is only 56 km² of wetlands left. At the level of species the delta stands out for its ornithological and ichthyological fauna, as well as for its halophilous vegetation. A significant amount of these habitats and species are very scarce in the European and Mediterranean context. During the last century agriculture became the main human activity of the Delta and nowadays rice fields play a crucial role in its economy and its ecology. The ecological functioning of the Ebro Delta at present is largely dependent on and affected by human activities because of modification of the natural hydrological regime. There have been changes in the temporal and spatial patterns of water salinity, eutrophication, pesticide pollution, and changes in the spatial and temporal patterns of sediment transport and deposition in the deltaic plain. The reduction of sediment transport of the Ebro River is about 99% of that existing prior to the construction of reservoirs in the catchment basin. Under these conditions, the delta has stopped its growth and the coast is being strongly reshaped by waves, with rates of retreat as high as 10 m/year in the mouth area. Additionally, the sediment deficit and the relative sea level rise imply a loss of land elevation of the delta. The main future challenges in terms of conservation and sustainable management of wetlands in the Ebro Delta are:

• A better coordination and stronger involvement of the different administrations and stakeholders in order to plan long-term conservation goals integrating the whole delta.

• A strong program of wetland restoration in order to recover part of the coastal lagoons and marshes which were lost in the past.

• A plan for adaptation to climate change and sediment deficit, in order to reduce coastal retreat and keep pace with sea level rise by means of ecological engineering measures such as wetland restoration and enhancement of vertical accretion through the restoration of the sediment flux in the river.

• A comprehensive monitoring program measuring a set of indicators of ecological status of the main wetland habitats.