Evolution of the water quality of a managed natural wetland:: Tablas de Daimiel National Park (Spain)

The Tablas de Daimiel National Park is a Spanish continental wetland which is extremely important for the survival of many migratory birds. However, it is an ecosystem seriously threatened to a point that a Hydric Regeneration Plan was implemented in 1988 to restore this wetland, it has caused a situation of dependence for the use and management of water resources. The aim of this paper was to try to establish how the last years of artificial management have affected this ecosystem. To carry out this study we have analysed the water physico-chemical characteristics during the period 1995-1997 and these data have been compared with those obtained from a survey in 1974-1975, which represent the original situation. Different statistical techniques have been used for this purpose. A serious salinization process, which can affect the life in this wetland, has been pointed out. The present state of pollution, both organic and inorganic, has been evaluated. Trace metals data are reported for the first time. The global quality state has been established by using statistical quality indexes. (C) 2000 Elsevier Science Ltd. All rights reserved.