The effects of climate change on aquatic ecosystems are a growing concern for both the scientific community and water management authorities. Rising temperatures, changes in river flow regimes, and the increasing frequency of droughts are altering river conditions worldwide. In this context, a recent study published in Ecological Indicators proposes new indicators based on river habitat time series that enable a more accurate assessment of climate change impacts and support the definition of environmental flows.
Fish are among the groups most sensitive to hydrological alterations. Each species requires specific conditions of water depth, flow velocity, temperature, and shelter availability to feed, reproduce, and complete its life cycle. When these conditions change, the quality of available habitat also changes, with direct consequences for the biodiversity of river ecosystems.
Traditionally, fish habitat assessments have relied on snapshots in time or relatively short study periods. However, the effects of climate change unfold over decades and are characterized by high temporal variability. Understanding how habitats evolve over time is therefore essential to anticipate risks and design effective adaptation strategies.
The study was carried out by the Ecology Research Group at the Gandia Campus of the Universitat Politècnica de València (UPV), led by researcher Francisco Martínez Capel, in close collaboration with the Hydroeconomic Models Group of the Institute of Water and Environmental Engineering (IIAMA-UPV).
From Flow to Habitat: A New Way of Understanding Rivers
This shift in perspective is particularly important because two flow scenarios with similar discharge levels may provide very different conditions for aquatic fauna. Channel geometry, flow velocity, water depth, and the physical characteristics of the river all play a decisive role in determining habitat quality.
The new indicators make it possible to better identify future trends, detect critical periods, and assess in greater detail the capacity of river ecosystems to sustain healthy fish populations under different environmental and climate change scenarios. As a result, these tools provide a more ecological understanding of how rivers function and respond to climatic disturbances.
Applications for Sustainable Water Management
One of the most notable aspects of the study is its potential application in water resources planning and management. The results can contribute to improving the definition of environmental flows, that is, the water regimes required to maintain aquatic ecosystems and the environmental services they provide.
Determining these flows is a key challenge in regions particularly vulnerable to water scarcity, such as the Mediterranean basin. Increasing competition among urban water supply, agriculture, industry, and environmental conservation requires robust scientific tools to support balanced, evidence-based decision-making.
The proposed indicators make it possible to quantify not only the amount of water available but also its capacity to generate functional habitats for aquatic species. This can help identify ecological thresholds, prioritize restoration actions, and evaluate the consequences of different future management and climate change scenarios.
Science to Anticipate the Future of Our Rivers
The research highlights the importance of incorporating advanced ecological indicators into water management. In a context of increasing climatic uncertainty, having tools capable of directly linking hydrological dynamics with habitat availability for aquatic fauna is essential for protecting river biodiversity.
This work is closely linked to the WATER4CAST 2.0 project, led by Manuel Pulido and Félix Francés (IIAMA-UPV) and funded by the PROMETEO programme of the Generalitat Valenciana. Within this project, an open-access platform has been developed to assess the effects of climate change using a range of indicators related to river flows, agricultural activity, river habitat status, and other key aspects of water resource management.
Ultimately, these studies represent an important step forward in developing methodologies that improve our understanding of how aquatic ecosystems will respond to future environmental changes and how they can be managed more sustainably to ensure the conservation of rivers and the species that depend on them.
Further information:
Frank Santiago-Bazan, Francisco Martínez-Capel, Héctor Macian-Sorribes, Manuel Pulido-Velázquez, Indicators from fish habitat time series for climate change and environmental flows assessment, Ecological Indicators, Volume 191, 2026, 115606, ISSN 1470-160X, https://doi.org/10.1016/j.ecolind.2026.115606.