The sources of the Mediterranean region are drying up. This is indicated by a recent scientific review published in Global Change Biology and led by CREAF. The matter is worrying, experts say, since these natural sources are points of biodiversity and host a multitude of species, such as some mosses, amphibians and crustaceans. The publication includes the results of an investigation that reveals that 46.2% of 31 sources in Catalonia have dried up since they began monitoring in 2013.
Among the main causes of why the sources dry up, the authors point out continued heat waves and drought episodes, to which are added problems such as water pollution caused by intensive agriculture and livestock, microplastics or pharmaceuticals.
The situation described in Catalonia “gives us clues about what may be happening in other places,” warns Marcos Fernández-Martínez, ERC researcher at CREAF, first author of the publication and coordinator of the case study.
“The Mediterranean climate is characterized by being arid and with little rainfall. Therefore, the fountains represent small humid oases that are normally dispersed in the landscape and isolated from each other,” explains Fernández-Martínez, who is also a researcher at the Faculty of Biology of the University of Barcelona.
This precisely facilitates the existence of a high number of endemic species – unique from one or a few sources. Typical examples are the pumice-forming moss Palustriella commutata, the midwife toad Alytes obstetricans, the liverwort Apopelia endiviifolia or various species of microscopic crustaceans. “The problem is that when they dry out, these communities disappear with them. In Catalonia, for example, we have already observed that the fountain ecosystems have disappeared in the Montseny, among others, the Font de las Nàiades (Montseny) or in the Maresme, such as the Font del Ferro,” explains Fernández-Martínez.
In addition to the wealth that inhabits them, the sources constitute climatic refuges where animals come to protect themselves from the heat, drink water or reproduce.
In its surroundings, you can see everything from deer or birds that hydrate themselves, to salamanders, which seek a cool environment, or toad larvae that need water to grow. “With climate change this function is increasingly necessary,” says Fernández-Martínez.
The case study data belong to the Fonts project coordinated by the ICHN in collaboration with the CREAF. Since 2013, both entities have been analyzing the state of the sources located in the Catalan Coastal Cordillera.
In 2023, they found that, counting the 31 sources that they had begun to study in 2013, there had been a 92% reduction in water flow and practically half were already dry.
The team that has carried out the monitoring identifies three factors. On the one hand, the drought episodes of 2021-2022, since during these years it rained 30% less compared to the 2011-2012 period.
Another important factor is that the temperature has increased on average by 0.6 °C in the last decade, which causes water to evaporate more.
In addition, some of them are abandoned, so the pipes become clogged and water from the aquifer cannot reach them.
“To this we have to add pollution. Intensive crops use fertilizers, herbicides and insecticides, some of them pass through the soil to the aquifers, which are what provide water to the sources,” explains Estela Romero, researcher at CREAF and the UB and co-author of the article.
“In the spring of 2023 we began a new investigation to carry out long-term monitoring of another 32 sources in Catalonia,” adds Fernández-Martínez.
To recover the sources and the life they host, the research includes several proposals. One of the solutions is to restore and maintain the water flow of those that still work; for example, removing the roots that colonize the conduits to facilitate water re-emergence.
Another measure is to return the source to its natural state; This involves promoting vegetation in the surrounding area, allowing water to filter through pipes to create small puddles, or creating stone walls so that amphibians can protect themselves from the heat.
“In this restoration process it is also important not to remove plants and mosses, but rather to let them develop freely,” explains Fernández-Martínez. Finally, the team claims that measures that protect the source ecosystem by state and regional administrations should also be included.
