The project is funded by the State Research Agency (AEI) through the 2021 Knowledge Generation Projects call and is co-funded by the European Union. It is led by researchers Núria Bonada, from the Faculty of Biology and the Biodiversity Research Institute (IRBio) at the University of Barcelona; Núria Cid, from the Institute of Agri-Food Research and Technology (IRTA-La Ràpita); and María del Mar Sánchez-Montoya, from the Complutense University of Madrid.

DRY-Guadalmed will develop new tools to assess the ecological status of Mediterranean temporary rivers and improve their water management, in a context of climate change and increasingly frequent droughts. The ultimate goal is to transfer all this knowledge to public authorities so that they can incorporate new assessment methodologies into their water resource management.

A dry river is still a living ecosystem

“A dry river is not a dead river.” With this powerful statement, Professor Núria Bonada sums up the central idea behind a project that challenges a widely held perception, both among the general public and, historically, within environmental assessment systems.

For decades, environmental assessments of rivers have been carried out almost exclusively when they contain water, but this approach is insufficient for Mediterranean temporary rivers, which alternate between flowing and dry phases that form part of the ecosystem’s cycle. “This is an ecosystem that continues to function. It ceases to be an aquatic ecosystem and becomes a terrestrial ecosystem that is also highly dynamic,” explains Bonada.

This alternation between wet and dry phases makes temporary rivers extraordinarily dynamic systems. As well as harbouring specialized biodiversity, they function as ecological corridors and provide refuge for numerous animal species. The result is an ecosystem that continues to play a vital role in biodiversity. Far from coming to a standstill, the ecosystem is changing the way it functions.

New tools for assessing the health of rivers in the future

DRY-Guadalmed is studying several bioindicators in both isolated pools and dry riverbeds. The team is analysing communities of macroinvertebrates, diatoms, vegetation and terrestrial invertebrates to gain a more comprehensive understanding of the ecological status of these ecosystems.

Another of the project’s innovative contributions involves applying the concept of a metacommunity, a perspective that enables a better understanding of the natural dynamics of these systems and improves environmental monitoring tools.

A natural laboratory for climate change

Temporary rivers are particularly common in Mediterranean regions, and they serve as a natural laboratory for understanding how other European river ecosystems might evolve. “The temporary rivers of the Mediterranean region offer a glimpse into what rivers will be like in the future,” says the researcher. “We have a unique opportunity to understand these ecosystems and learn how to manage them before this situation becomes more common across other regions of Europe.”

Results already pointing to new solutions

One of the findings that has most surprised the team has been the enormous diversity found among the pools scattered across Spain. Some function practically as small lagoons and are home to species not found in other areas, demonstrating the extraordinary complexity of these ecosystems.

In the case of diatoms, the team has found that current methods can be adapted to assess isolated pools more accurately. At the same time, new protocols are being refined to simplify the work of the authorities responsible for environmental monitoring. In dry riverbeds, sediments show different characteristics, and certain terrestrial species could become excellent bioindicators of the river’s ecological status.