Groundwater extraction poses extreme threat to Doñana World Heritage Site

To the editor — Climate change threatens migratory waterbirds, which are projected to decline drastically by 2050, but protected areas have a critical role in counteracting these effects1. Natural marshes and temporary ponds in Doñana, Spain, are a global hotspot for biodiversity and support thousands of breeding birds and millions of migratory birds2 (Fig. 1). The area supports more wintering wildfowl than anywhere else in Europe and is home to many globally threatened species, including the marbled duck (Marmaronetta angustirostris) and common pochard (Aythya ferina). Doñana is also famous for its apex predators, including the Iberian endemic Spanish imperial eagle (Aquila adalberti) and the endangered Iberian lynx (Lynx pardinus). Even abundant birds of prey are dependent on the productive aquatic systems3. This iconic wetland is representative of the threats that face inland waters around the world, and the conservation challenge that they pose4. Doñana became internationally famous in the 1950s, when its spectacular bird concentrations were threatened by development plans (for example, drainage and the planting of exotic Eucalyptus for pulp). A pioneering campaign in the early days of the World Wide Fund for Nature (WWF) led to the initial declaration of a scientific reserve of about 7,000 ha in 1964, primarily to save birds. The reserve was founded along with the Doñana Biological Station (arguably the most prestigious ecological and evolutionary research institution in Spain today), testimony to the immense value of Doñana for science in general and for training conservation biologists in particular. The original protected area was later expanded and declared a national park, and then a UNESCO (United Nations Educational, Scientific and Cultural Organization) World Heritage Site, which lies within a larger ‘Natural Space’ protected within the Natura 2000 Network and the Ramsar Convention2. Despite the hugely important biodiversity of Doñana, its existence remains threatened by local anthropogenic stressors — particularly the expansion of intensive agriculture, and resulting groundwater extraction and pollution5. Protected areas are key elements for biodiversity conservation and the maintenance of ecosystem services for future generations, but degradation of protected areas is an increasingly common phenomenon in many countries6. Doñana National Park is no exception, as it experiences major threats to water quality and quantity5,7. Groundwater that naturally supports the marshes and ponds in Doñana has fuelled rapid greenhouse expansion surrounding the park, in Europe’s biggest strawberry production area7. Despite the repeated requests by UNESCO to stop illegal groundwater extraction, the cataloguing of over 1,000 illegal boreholes by the WWF, and the risk of European Court fines for inaction against aquifer degradation, little has been done to address the problem. The effect of aquifer exploitation is most obvious in the disappearing dune ponds, which directly depend on the water table and hold endemic plankton species and rich communities of amphibians and dragonflies8. However, when the aquifer recharges it also overflows into the marsh system that supports the waterbirds, and this flow has been greatly reduced by the boreholes5. Migratory songbirds are also in decline, probably owing to agricultural intensification9. To add insult to injury, on 9 February 2022 the Andalusian regional parliament voted to support a plan to legalize 1,500 ha of irrigated land and thus legitimize the operations of illegal farmers — despite open opposition from the Spanish central government, EU, UNESCO and several nongovernmental organizations. This policy is diametrically opposed to the reductions in groundwater extraction that are required to provide climate change resilience (by creating a safe operating space), pushing the ecosystem towards collapse4,5. This winter (2021–2022), with rainfall well below average, only 5% of the marsh area flooded, and waterbird numbers were exceedingly low compared to previous years. Such dry winters are not unknown in Doñana,