Many wetlands started as beaver-dammed streams. As the beaver pond grows, it provides for an increasing number of plants and animals. Frogs splash at the edges, fish dart beneath the surface, and many species of birds find refuge in these lush habitats. But there's an invisible benefit too – these waterlogged areas are amazing at trapping air pollution. Studies show beaver-made wetlands contribute to clean air and water worth, providing services worth hundreds of millions of dollars. Though to the beavers, it’s all in a day’s work.
During a heavy rainstorm, some streams and rivers overflow their banks, but a beaver-engineered stream system handles floodwaters with ease. Their dams work like aquatic speed bumps, creating winding paths that slow rushing water. This prevents soil washing away and allows rich nutrients to settle to the bottom. Over time, this activity gradually raises the stream beds and reconnects them to surrounding land that used to flood naturally. And during dry spells, beaver dams release stored water slowly, keeping streams flowing when they might otherwise dry up. Perhaps most impressively, these structures function like a free water treatment plant, cleaning water by trapping dirt and filtering out pollutants like nitrogen and phosphorus.
Recent studies have also found that areas with beaver activity burn much less severely during wildfires – suffering only one-third the damage compared to similar areas without beavers. In the western United States, where landscapes are subject to drought and wildfires, fires often burn everything except areas surrounding beaver complexes. There, even during dry spells, water continues to soak into the ground, refilling underground water supplies and keeping plants moist.
