14/05/2026
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Beavers act as remarkable ecosystem engineers by constructing dams that fundamentally transform river systems into effective carbon sinks.
According to a recent international study led by the University of Birmingham and published in Communications Earth & Environment, these industrious rodents slow water flow, trap sediments, and expand wetlands in headwater streams.
In a 13-year-old beaver wetland in northern Switzerland, researchers measured a net annual carbon sink of about 98 tonnes, primarily through subsurface retention of dissolved inorganic carbon.
While carbon dioxide emissions occur seasonally, especially in summer, overall storage dominates. Projecting long-term sediment and deadwood accumulation, the site sequestered up to 1,194 tonnes of carbon—roughly 10.1 tonnes per hectare yearly—nearly ten times more than unmodified river sections.
By flooding margins and altering groundwater paths, beaver dams bury organic material, preventing its decomposition and release as greenhouse gases. This creates persistent carbon stores lasting decades, as long as dams remain intact.
The findings highlight beavers' role in climate mitigation, enhancing biodiversity and water retention while turning streams into natural buffers against atmospheric CO2. Reintroducing beavers could amplify these benefits across restored habitats, offering a low-cost, nature-based solution to carbon management.