Beavers can turn streams into carbon stores – we measured how much Across Europe, beaver populations are rebounding after years of decline, and their return is reshaping river ecosystems. As these animals rebuild wetlands by damming streams, they are creating environments that could significantly influence carbon storage in river systems. A recent study reveals that beaver-created wetlands can lock away carbon at rates up to ten times higher than undisturbed river and floodplain areas. The research team focused on a wetland in northern Switzerland, where beavers had been active for over a decade. By monitoring the site intensively for a full year, they tracked water flow, dissolved carbon levels, greenhouse gas emissions, and plant growth. Sediment and dead wood samples were also collected to analyze long-term carbon accumulation. The findings suggest that the wetland acted as a strong carbon sink, storing approximately 98 tonnes of carbon annually. Over 13 years, the site sequestered more than 1,100 tonnes of carbon—equivalent to two Olympic swimming pools filled with charcoal. The study highlights how beaver dams slow water flow, allowing sediments rich in organic material to settle. These sediments, containing leaves, soil, and plant fragments, become buried in wetland soils rather than being carried downstream. Flooding caused by dams also leads to the death of trees, which sink into the water and store carbon over decades. Meanwhile, new wetland plants and algae absorb atmospheric carbon, creating a layered natural storage system. Despite seasonal methane emissions, which are a potent greenhouse gas, the study found that these emissions accounted for less than 0.1% of the wetland’s total carbon balance.#climate_change #beavers #northern_switzerland #carbon_storage #river_ecosystems
