NETFRESH: Networking the response of freshwater ecosystems to environmental change

Biodiversity in freshwaters is declining at a rate far greater than marine or terrestrial biomes, yet we lack a mechanistic understanding. A key to elucidating the mechanisms driving these losses is the study of ecological interactions (e.g., predation, competition, parasitism, mutualism), which translate environmental change into alterations in the structure and function of biological communities. Our knowledge of ecological networks in freshwaters, however, remains limited due to technological constraints associated with identifying and quantifying ecological interactions in underwater environments.

Here, we propose an ambitious project developing our ability to quantify ecological interactions in running freshwater environments with the aim of understanding ecosystem responses to environmental change. We will combine established (gut content analysis, stable isotopes, production estimates) and novel techniques (metabarcoding, video footage combined with machine learning/artificial intelligence, macronutrients) to explore ecological interactions in real time. Using these methods, we will construct the first multilayer ecological networks (networks including multiple interaction types, e.g., competition, predation, facilitation) in running waters, and test the ability of the framework to detect changes in ecosystems using micro- and meso-cosms. For the latter, we focus on low flows as a pivotal component of environmental change in freshwater ecosystems - with existing mechanistic understanding surrounding the individual-level responses of different species (i.e., increased metabolic demand) and clear hypotheses surrounding the potential responses of ecological interactions (i.e., reduced habitat size leads to increased resource competition).

The project will support the generation of: (i) novel methods for identifying and quantifying ecological interactions in freshwaters; and (ii) fundamental knowledge on ecological interactions in running waters. Furthermore, findings from this work will also help to inform national monitoring strategies to better detect the response of ecosystems to environmental change and methods could be developed further to potentially provide an early warning system for species loss and ecosystem collapse in freshwater ecosystems.