The Ebro Delta Natural Park (in Catalan, and officially, parc natural del Delta de l’Ebre) is a protected natural area located at the mouth of the Ebro River, in the province of Tarragona, Catalonia, Spain, between the regions of Baix Ebre and Montsiá. It was declared a natural park in August 1983 and extended in 1986. It currently covers an area of 7736 ha (3979 ha on the right hemidelta and 3757 ha on the left).It is a ZEPA area (Bird protection Zone), a Ramsar Convention (international convention to protect wetlands) site and forms part of the Tierras del Ebro biosphere reserve. The Ebro delta is the largest wetland area in Catalonia and one of the most important in Western Europe.
All the lagoons of the Ebro delta are surrounded by a belt of very characteristic helophytic vegetation, composed mainly of reed beds and reed beds that make up the Typho-Schoenoplectetum glauci community.These are freshwater lagoons, mainly due to the contribution of water from the rice fields.
The Ebro delta wetland is of international importance for hundreds of species of vertebrate fauna, the majority of which are birds. Here 95 species nest, winter, rest and feed during the migrations of many other species. The Ebro delta is home to 316 common bird species and some 360 of the 600 recorded bird species in Europe.
The rice cultivation system in the Ebro Delta is cyclical. From April to September (rice harvesting season), fresh water flows from the river, through canals and irrigation channels, to the fields and into the coastal lagoons and from there to the sea. By December, the intake gates are closed and the water remains stagnant in the fields and canals, where it evaporates during the winter until it becomes almost completely dry at the end of February.
During the month of March the fields are worked and prepared for sowing, and then they are completely dry, until they are flooded again in April and the cycle begins again. Thus, the hydrological dynamics together with certain natural phenomena place the Ebro Delta in an atypical situation, since the salinity of the lakes is higher in winter than in summer, whereas it should be the other way round, since summer evaporation should concentrate the salts, but the contribution of fresh water at this time means that the opposite is the case.
This extremely singular phenomenon, together with the rice productivity cycle, means that the biological rhythms are altered, so that it has been seen that the real regulator, the biological clock that sets the tone in the population fluctuations of the fauna, is rice cultivation. One example is the delay in the nesting of many birds compared to populations in other places of similar latitude, thus adapting the birth of the young to the ripening period of the rice field, which allows better feeding of the offspring, a phenomenon that has been verified in both ducks and passerines.
