Mountain meadows inhabited by beavers have an important role in mitigating climate change. As carbon sinks, they store remarkably large amounts of greenhouse gases for the long term. However, degradation from livestock grazing and conversion to dry grasslands has greatly diminished the carbon-storing capacity and biodiversity of meadows in the Cascade Range and Sierra Nevada of California.
Launched in 2015 and concluded in late 2019, this experimental project was designed to test whether artificial and natural beaver dams are effective meadow restoration tools for reducing climate-warming gases and increasing biodiversity. Beaver dams increase carbon storage by trapping sediment high in carbon and raising the locally adjacent water table, which expands the growth of riparian and aquatic vegetation.
The research sites are located on conservation easement land within Childs Meadow, near Lassen Volcanic National Park. Portions of the 520-acre meadow complex support one of the few remaining strongholds for the highly imperiled Cascades frog and willow flycatcher.
The project tested the effects of two meadow restoration treatments on carbon sequestration, hydrology, and sensitive species — one section of meadow fenced from cattle grazing with the beaver dam analogues (BDAs) and the other fenced from cattle grazing without the structures. Results from the two treatments were compared with measurements in an unrestored section of the meadow as well as a section of the meadow with natural beaver dams from resident beavers. We found that the cattle exclusion had the largest positive impact on carbon sequestration and the BDAs supported locally higher groundwater levels when maintained, similar to effects from natural beaver dams.
Following the success of this demonstration project (see final project report below), we are seeking to expand the restoration efforts to the full Childs Meadow complex with local restoration partners in the near future.