Posted on February, 02 2024

On World Wetlands Day, WWF presents a comprehensive review of scientific evidence on the current deterioration of Doñana - a World Heritage site and one of Europe's most important wetlands.

Produced in collaboration with 30 scientists from leading research organisations, including CSIC-EBD, IGME and CSIC-IEO, and several universities, the report warns that current pressures have triggered a "domino effect" of biodiversity loss that is leading Doñana to a point of no return.

All the scientific evidence points to overexploitation of water, together with the irrational growth of legal and illegal irrigation, aggravated by unsustainable urban development in Matalascañas, as the reasons for the deterioration of this unique wetland, causing its biodiversity to plummet.

After carrying out an exhaustive analysis of all the scientific information available to date, and thanks to the participation of nearly 30 experts from different disciplines, WWF has published a new report “Science to save Doñana” which indisputably demonstrates the main scientific evidence of the ecological collapse Doñana is facing as a result of agricultural overexploitation and unsustainable urban development.

The wetland is receiving less water
The river network around Doñana, with the exception of the upper basin of the Guadiamar, is in a poor ecological state, as evidenced by the current hydrological plan for the Guadalquivir. One of the most alarming figures is the decrease in the surrounding flows of the Rocina stream, which feeds directly into the marshland, and which have fallen by more than 60% (from 775 l/s to 292 l/s), partly due to a lack of surface inflows, the decrease in rainfall associated with climate change, and the lack of natural underground inflows from the overexploited aquifer.

Very little water and it is heavily polluted by fertilisers, herbicides, pharmaceuticals and urban runoff.
Urban-industrial discharges and fertilisers and other chemicals used in industrial agriculture are polluting Doñana's surface and groundwater. As a result, 14 bodies of water are in poor chemical status, according to the Guadalquivir Hydrological Plan. The eutrophication and concentration of pharmaceutical compounds in tributaries and marshes has accelerated in recent decades, often reaching levels incompatible with biodiversity conservation.

Although these problems should have been solved decades ago, and despite the construction of treatment plants for discharges since 2002 and the declaration of the nitrate vulnerable zone in 2008, the data show that these pollution problems have increased and affect species and all ecosystems. Neither have the treatment plants been properly maintained and updated, nor have ambitious programmes been implemented against pollution from agricultural sources, despite having a budget of approximately EUR 1 billion for actions in the entire Guadalquivir basin since 2010.

The Arroyo del Partido is the tributary most heavily polluted by nutrients, particularly by high concentrations of ammonium and nitrites, and there are wide stretches of the Rocina and Partido rivers that have levels of some pollutants that are considered toxic for fish.

Other scientific studies indicate that the concentration of nitrates in the Guadalquivir Estuary were 40-50% above the permitted threshold, while the permitted thresholds for the herbicides terbuthylazine and simazine were exceeded by 60-80% during the study period (1981-2009).

The Almonte-Marismas aquifer is on red alert and overexploited
To date, and despite the seriousness of the situation in Doñana, it is still unknown how much water is actually extracted from the aquifer. However, according to all the existing scientific evidence, it can be concluded that more water is extracted than is recharged and that underground contributions to the streams that feed the marshes have declined alarmingly.

Decades of overexploitation, mainly linked to the expansion of industrial agricultural production for export, have caused groundwater levels in the Almonte-Marismas aquifer to fall to historic lows or values close to these in more than half of the monitoring piezometers. Of the 16 sectors into which the CHG subdivides the aquifer, not a single one is in a normal situation, and this year a new sector has entered the maximum alarm level, bringing the total to 10.

More than half of the temporary ponds have been wiped off the map
The growth of the tourist area of Matalascañas has also contributed to the deterioration of the dune ecosystem, one of the best studied of the entire protected area. In the entire enclave where the temporary ponds are located, whose waters depend to a large extent on the discharge of the aquifer, there has been a downward trend from 1995 to the present day of some two to three meters, aggravated by the effects of the increase in evaporation due to the rise in air temperature.

In years of heavy rainfall, more than 3,000 temporary ponds have been estimated and mapped in the wind mantle of the Doñana National Park. However, remote sensing has confirmed the loss of flooding since 2013 of 60% of the ponds detected by satellite images (larger than 900 m2).

All the lagoons - both temporary and permanent, including the Santa Olalla lagoon - dried up completely during the summers of 2022 and 2023.

Doñana's biodiversity is in "free fall"
All these impacts are causing a progressive and alarming decline in biodiversity in Doñana, as not enough water -  neither groundwater nor surface water - is reaching the aquatic and terrestrial ecosystems that need it to survive.

The consequence of this is the dramatic reduction of key indicators, such as the death of century-old cork oaks, which need high water tables to feed their roots, the loss of amphibian species due to the disappearance of lagoons and the reduction in the surface area of the marsh, which has gone from an average of 4.3 species per km² in 2003 to 2.5 species/km² in 2021; and the disappearance in 40 years of 28 species of dragonflies and damselflies, species that act as indicators and depend on aquatic ecosystems to develop their larvae.

"We have reviewed all the available scientific information and have relied on the best experts to demonstrate irrefutably how the pollution of its waters, the overexploitation of the aquifer for strawberry cultivation or unsustainable tourism have significantly deteriorated the habitats and species of Doñana," said Teresa Gil, Head of the Water Programme of WWF Spain.

"The science is clear and political will is needed to implement courageous and comprehensive actions to attack the root of the problem and reduce the pressure of industrial agriculture that dries Doñana".