In peninsular Spain, the Temporary gaps are disappearing at an alarming rateExtensive scientific work has confirmed that, in just over two decades, practically one in four has ceased to exist or has had its natural functioning drastically altered.
This silent, but very significant, setback It directly affects a type of wetland considered a priority by the European Union due to its enormous biodiversity and its fragility in the face of environmental changes. Spain, which is home to one of the highest concentrations of these ecosystems in Europe, risks losing a significant part of its natural heritage in this accelerated transformation of the landscape.
A pioneering study that X-rays the loss of temporary gaps
A team from the Doñana Biological Station (EBD-CSIC) and the Autonomous University of Madrid (UAM) has documented that Around 22% of temporary gaps in peninsular Spain have disappeared between 2000 and 2022This figure comes from the detailed analysis of 1.303 lagoons spread throughout the peninsular territory.
The work, published in the scientific journal Journal of Environmental ManagementThis is considered the first large-scale assessment to quantify the loss and degradation of these wetlands across the Iberian Peninsula. Until now, data were fragmented and, in many cases, limited to specific areas such as Doñana or certain protected spaces.
To reach these conclusions, the team used high-resolution images from Google Earth Pro corresponding to the period 2000-2022, with the collaboration of the Remote Sensing and GIS Laboratory of the Doñana Biological Station (LAST-EBD). The resolution of up to about 30 centimeters made it possible to detect both the presence of water and the visible traces of human activity on the basins and their surroundings.
Through a systematically applied visual interpretation protocol, the researchers were able to Identify the condition of each lagoon, its flooding frequency, and the associated physical impacts. for agricultural, livestock, urban, or infrastructure uses. This approach offered a level of detail difficult to achieve with other, lower-resolution satellite sources.
The most striking result is that, of the more than 1.300 gaps analyzed, Almost 22% have disappeared completely in just two decadesIn many others, severe degradation has been observed, although they still maintain a certain level of flooding.
What are temporal gaps and why are they so valuable?
Temporary gaps are small bodies of water that flood and dry up irregularlyThey follow cycles linked to rainfall, evaporation, and soil and aquifer dynamics. Unlike permanent lakes or reservoirs, they can remain dry for part of the year, especially in Mediterranean climates.
This alternation between wet and dry phases, which might seem like a disadvantage, is actually the key to its enormous biological richness. They harbor highly specialized communities of fauna and flora, with species that have developed surprising strategies to survive prolonged desiccation.
The sediments in the basin accumulate resistant eggs, cysts, and seeds capable of remaining dormant for long periods without water. When the lagoon is flooded again, these resistant structures "awaken" and give rise to explosions of life: aquatic invertebrates, amphibians, submerged or emergent plants, and a long list of organisms that depend on these cycles to complete their development.
In addition, many aquatic insects possess a great capacity for flight, which allows them to move between different bodies of water in search of favorable conditionsOther organisms adjust the duration of their larval stages to the time the lagoon remains flooded, a clear example of adaptation to a highly variable environment.
Beyond their ecological value, temporary lagoons provide essential ecosystem servicesThey help regulate the climate at a local scale, store carbon, contribute to nutrient control and the maintenance of fertile soils, and shape landscapes with significant cultural and aesthetic value. For all these reasons, the European Union considers them priority habitats for conservation.
The main causes of their disappearance: intensive agriculture and climate change
The study concludes that the combination of agricultural pressure and climate change It is behind the accelerated decline of these lagoons. Intensive agriculture appears to be the main driver of their physical disappearance.
Among the impacts most frequently detected in the analyzed images, the following stand out: the plowing of the edges and the troughsThe opening of channels to divert or drain water and the artificial deepening that modifies the original morphology of the basin. These actions fundamentally transform the hydrological and ecological functioning of the wetland.
In addition to these direct effects, there are other threats, sometimes more difficult to observe from the air, such as the colonization of the basins by terrestrial vegetation In the prolonged absence of flooding, progressive urbanization in its immediate surroundings, intensive use of floodable areas by livestock, and vehicle traffic on depressed surfaces.
The research team warns that many of these visible impacts are often accompanied by processes not detectable with the methodology usedsuch as the overexploitation of underground aquifers and exposure to agrochemicals. This indicates that the true extent of the degradation could be even greater than estimated from the images.
In parallel, the work detects a clear reduction in the frequency and duration of flooding of many lagoons, especially in autumn. This change is linked to climatic factors such as the increase in maximum temperatures and the alteration of precipitation patterns, in a context of global climate change, but also to intensive agricultural practices that accelerate runoff or reduce the natural recharge of aquifers.
In some key locations, such as the Doñana areaScientists have been warning for years about a critical situation in the wetlands as a wholewith a high number of lagoons that no longer flood as they used to or that have disappeared completely. The new statewide analysis confirms that this problem is not isolated, but rather part of a widespread trend across the peninsula.
Insufficient protection: limits of the Natura 2000 Network and differences between figures
One of the most relevant aspects of the study is that It tests the effectiveness of existing protection mechanisms.The results indicate that, although the Natura 2000 Network is the largest network of protected areas in the European Union, it has significant limitations in reducing the impact on temporary lagoons.
According to the comparative analysis, Lagoons located within Natural Parks or National Parks generally show a lower degree of impact than those that only have the designation within Natura 2000 or that lack formal protection. In other words, stricter levels of protection make a clear difference in the state of conservation.
However, a very significant part of these gaps It has no kind of protective figure. Or it is located in areas where management is lax and oversight insufficient. In these circumstances, changes in land use, agricultural intensification, or urban sprawl advance with virtually no effective checks.
The scientific team raises the need to Complete the Natura 2000 Network with additional layers of protectionadapted to the specific fragility of these wetlands. It also proposes integrating modern monitoring tools, such as periodic remote sensing and on-site validation, to detect degradation processes early.
In conclusion, the work suggests that It is not enough to be listed in a protected areaClear rules, management resources, effective controls, and planning that takes into account the role of these small wetlands within the overall landscape are needed.
What can be done: restoration, incentives for agriculture and citizen science
Despite the worrying diagnosis, the EBD-CSIC and UAM team emphasizes that A significant portion of the impacts resulting from human activity are avoidable. if appropriate measures are taken. It is not an inevitable process, but a trend that can be slowed and, in some cases, reversed.
Among the priorities, researchers highlight the expansion of conservation to lagoons that currently lack formal protectionwith particular attention to the most degraded habitats and areas where agricultural or urban development pressure is greatest. This would involve incorporating more lagoons into networks of protected areas and developing specific management plans for them.
The study also emphasizes the need to establish financial incentives for the agricultural sectorThese measures could be directed towards keeping the lagoons unplowed, preventing the use of heavy machinery on the basins, and creating belts of natural vegetation at least five meters wide around the maximum flood zone. This would reduce erosion, the runoff of fertilizers and pesticides, and trampling by livestock.
Another key line is the ecological restoration of the disappeared or severely altered lagoonsThe scientific team proposes prioritizing the restoration of the original hydrological function, eliminating channels, covering artificial depressions, and returning the basin to its natural shape and depth.
In this process, the following can play a very important role: use of the original sediment from the lagoonsThis material contains stored eggs, cysts, and seeds of the organisms that lived in the wetland before its degradation, facilitating the regeneration of biological communities when suitable flooding conditions are restored.
The study also focuses on the citizen participationMany temporary ponds, especially smaller ones, go unnoticed even in aerial photographs or some satellite images. To locate them and monitor them more thoroughly, the team encourages the use of tools like the PondMapp app, which allows users to record small bodies of water, share information, and improve the inventory of these habitats.
This citizen collaboration is considered another piece of the puzzle, alongside public policies, government management, and agricultural sector practices. The sum of all these efforts can make a difference for to preserve these authentic oases of life in the peninsular landscape.
Scientific data shows that the decline of seasonal lagoons in peninsular Spain is neither a minor nor an isolated issue, but rather a clear symptom of the impact of climate change and the intensification of land use on aquatic ecosystems. Their disappearance implies a loss of biodiversity, ecosystem services, and part of the cultural identity of numerous territories, making the strengthening of their protection and the promotion of their restoration an essential task if we are to ensure their continued existence for future generations.
