Guardians of our Rivers: transforming river health assessment through macroinvertebrate monitoring with citizen scientists
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Freshwater ecosystems in Scotland are increasingly threatened by multiple interacting stressors, including pollution, hydrological alteration, land use change, and climate-driven pressures. Scotland’s rivers are amongst the most physically diverse and dynamic in the UK, contributing significantly to the country’s economy and natural heritage. Monitoring 125,000 km of waterways presents an issue, with limited funding and capacity of environmental agencies creating an environmental monitoring deficit at a time when robust data are essential for delivering national and global biodiversity targets. Citizen science offers a scalable, community driven approach to strengthening environmental evidence. This study evaluates the development, implementation, and outcomes of Guardians of our Rivers (GooR), a nationwide citizen science programme using macroinvertebrate-based river health assessments based on the Anglers’ Riverfly Monitoring Initiative (RMI) established by the Riverfly Partnership. Between 2022 and 2025, GooR trained more than 850 volunteers, established 123 monitoring sites across Scotland, and generated over 860 surveys—surpassing the previous 16 years of aquatic invertebrate monitoring efforts. Standardised field training, full equipment provision, and structured support enabled high-quality data collection across diverse catchments. The establishment of nationally applied trigger and target thresholds created a consistent mechanism for detecting ecological deterioration and ensured that verified trigger breaches (n = 39 in 2025) resulted in formal investigation or follow-up. Analysis of national abundance patterns revealed ecological and biogeographic trends across the eight RMI taxa, confirming data sensitivity to habitat differences, water quality, and regional pressures. A detailed case study of the Lothian Esk catchment demonstrated the programme’s capacity to detect seasonal macroinvertebrate dynamics and site level ecological trajectories over time. Overall, GooR illustrates how well-designed and well-supported citizen science can deliver high resolution spatiotemporal datasets, enhance early warning systems, empower communities, and make a meaningful contribution to promoting river health. Importantly, GooR forged a working partnership with Scottish Environmental Protection Agency (SEPA) that allowed communities to not only gather data but also transformed the way citizen science is recognized as contributing to freshwater conservation. Continued investment and long-term support will be essential to sustain these gains and realise the full potential of citizen-driven freshwater stewardship.
Author Summary
In this study, we explore how communities across Scotland can help protect the health of their rivers at a time when freshwater ecosystems are under increasing pressure from a range of threats. Scotland has an extensive network of rivers and streams, creating a challenge for environment agencies to provide comprehensive monitoring coverage that delivers the level of preventative care needed to keep our water courses in optimal health. To address this, we created a national citizen science monitoring programme, ‘ Guardians of our Rivers ’, and showed that by harnessing local knowledge and with training and support, local communities can collect robust reliable data about river health, contribute meaningfully to local environmental stewardship, and successfully engage with the relevant statutory body, SEPA.
Between 2022 and 2025 more than 850 volunteers learned how to assess river health by counting freshwater macroinvertebrates that are known to be sensitive to changes in water quality. Over 860 surveys were carried out at 123 monitoring sites, creating a level of coverage not possible with professional monitoring alone. Working together with SEPA, we established protocols to increase robustness and consistency in data collection and empower citizen scientists to share information, which can form the basis for further actions. Our work demonstrates how citizen science can produce robust data, strengthen existing monitoring efforts, and build stronger connections between communities and their rivers. Our works highlights a scalable model that could be implemented widely in the UK and beyond.
