Hydro-sedimentary imbalance, biophysical responses, and recovery potential in Mediterranean rivers. I. Microbial processes and fluvial metabolism.

RIVHS investigates the impacts of reduced hydrological and sedimentary dynamism on fluvial ecosystems, a common issue in many Mediterranean watercourses. This reduction, caused by persistently low flows and a lack of sediment, is exacerbated by climate change and water scarcity. RIVHS is based on the hypothesis that the absence of competent flood events disrupts morpho-sedimentary balance, compromising the resistance and resilience of biological communities and ecosystem functions, potentially leading to irreversible losses.

The project focuses on the responses of key trophic components—microbes, invertebrates, and fish—and essential ecosystem functions such as primary production, organic matter decomposition, and respiration, which are fundamental to services like water purification. It assesses effects on biological diversity and abundance, as well as on ecosystem functions, through field monitoring, experimental rehabilitation, and laboratory experiments. These efforts aim to understand specific responses and mechanisms related to the loss of dynamism and the influence of contaminants.

RIVHS evaluates adaptive rehabilitation measures, such as gravel augmentation and the generation of flood events, to improve hydro-sedimentary dynamics and thereby enhance habitat conditions and ecosystem functions. The project’s conclusions will guide strategies to mitigate the impacts of global change on fluvial ecosystems, improving understanding of their resilience and the effectiveness of rehabilitation interventions, and providing valuable knowledge for water authorities.