It happened again. Santa Olalla, the largest permanent lagoon in Doñana, has completely dried up. The Singular Scientific and Technical Infrastructure (ICTS) – Doñana Biological Reserve, dependent on the Higher Council for Scientific Research (CSIC) Doñana Biological Station (EBD-CSIC), updated its surveillance camera of the lagoon a few weeks ago to see its development .
Finally, Complete drying out was noted yesterday. Since the research center began collecting data on the natural space half a century ago, this picture had never repeated itself for two years, testifying to the serious situation in which the Doñana Lagoon system finds itself and with it all the biodiversity that comes with it at.
The Doñana National Park was declared a World Heritage Site in 1994 for its diversity of ecosystems and the great diversity of species that inhabit it, making it a unique enclave in Europe.
One of these ecosystems is the lagoon system, which is home to a great diversity of species Sanctuary for various endemic and endangered species. However, in recent years, the Doñana Lagoons have experienced a significant deterioration, their flooding period is becoming shorter and many of them no longer flood, seriously affecting the biodiversity they support. The summer drying up of Santa Olalla is one of the greatest evidence of the degradation of the lagoon system and indicates the lack of summer water conservation areas for the Doñana wind coat aquatic fauna and flora.
What the latest scientific data reveal
The ICTS – Doñana Biological Reserve has confirmed through the monitoring program that the hydrological cycle in 2021-2022 was the year with the lowest rainfall in the last decade (283 mm), which has not improved significantly in the current year, with rainfall being similar (337 mm to August). In addition, they register in both years very high maximum temperatures and the highest recorded mean annual temperature (18.53 °C).
However, these factors are not the only causes of the deterioration of the lagoon system. A study published earlier this year by the Doñana Biological Station, using data collected over a 40-year period, found that 59% of Doñana’s largest lagoons have already disappeared.
This phenomenon is largely related to the high temperatures and long periods of low rainfall that Doñana suffers from. but also with the overexploitation of the aquifer that feeds this lagoon system. 80% of these gaps they dried up earlier than expected With recorded temperature and precipitation levels, 84% less flooding occurred than expected, showing that human activities are altering the natural balance of the lagoons and exacerbating the problem.
It is also worrying that 19% of the surviving lagoons have scrub and pine trees covering more than half of their basins and only 10% are in good condition, mostly on the banks.
In another recently published study, the Doñana Biological Station concludes that the invasion of the lagoon basins by terrestrial vegetation is a good indicator of their progressive deterioration and imminent disappearance. These symptoms are particularly noted in the north-western area of the National Park and in the lagoons closest to Matalascañas, including Santa Olalla, where they are already observed. dense reeds in the middle of the floodplain and lots of bushes who populated today’s coasts and islets.
An ecosystem in danger
Most of the lagoons in Doñana are temporary in nature and are flooded by the water from the aquifer which, when recharged by the rain, reaches the surface, filling its pools and flooding the reserve with life.
In the last decade there have been years of absence of heavy rainfall, which has reduced the recharge of the aquifer, insufficient to counteract the excessive water withdrawal for summer consumption in the tourist town of Matalascañas and for intensive strawberry cultivation. located in the vicinity of the park, the area of which has increased by more than 30% in the last 10 years. All of this helped lower groundwater levelsThis prevents many lagoons from being flooded or shortens the length of time they remain flooded, affecting the life cycles of the species living in these waters.
Permanent lagoons that carry water all year round are very rare in the park and serve as a haven for many species in this temporary system. Until a few years ago, only three lagoons were considered permanent: Santa Olalla, the Dulce Lagoon and the Sopetón Lagoon. The only one that could still be considered permanent was Santa Olalla, although there were few flood plains and high salt concentrations in summer. Its complete drying out prevents the presence of fish, for example. When it dried up in 2022, we saw the remaining eels, one of the currently threatened species, die off. We are also seeing population decline in the Galapagos Islands.
The recommendations of the scientific community
The Doñana Biological Station requests the urgent reduction of the total amount of water withdrawn from the aquifer to a level that allows the restoration of the lagoon system and halts the deterioration of the natural space. also suggests Update of the aquifer status assessment system And conduct annual water availability assessments to determine maximum allowable withdrawals and conservation actions to be taken.
Another of his proposals is to urgently restore the administration of water management and spatial planning in the Doñana region so that they are within the framework of current legality and natural protect the agricultural sector working under the legality They face loss of brand value for their products, unfair competition from illegal manufacturers and the uncertainty that threatens them for the future.
They also keep setting up the Working Committee Doñana 2030approved by the Doñana Participation Council, in order to act quickly and in a coordinated manner in resolving all the problems that Doñana is facing, not only related to the aquifer but also, among others, to the water pollution or the severe overgrazing that also affects the natural enclave .