Beaver Library

Climate change will diminish the quality and connectivity of stream and riparian habitats and threaten native stream-associated species across western North America. Ecological restoration that mitigates these impacts and supports processes that confer adaptability is urgently needed. The ecosystem engineering capabilities of beaver (Castor canadensis) are increasingly applied (through beaver reintroductions and beaver mimicry) in ecological restoration to reestablish ecosystem processes. However, there are no systematic syntheses on the impacts of beaver-related restoration (BRR) at the regional scale that incorporate both beaver and beaver mimicry or highlight key climatic and ecological contexts where BRR may be most impactful. We conducted a comprehensive literature review focused on BRR’s influence on habitat and biodiversity attributes that confer climate resilience in western North America. Using 161 sources, we assigned confidence scores for specific outcomes and identified climatic and hydrogeomorphic contexts where BRR may be most impactful at building climate resiliency. There is substantial evidence that BRR increases climate resiliency of stream and riparian ecosystems by reducing summer water temperatures, increasing water storage, and enhancing floodplain connectivity. BRR can ameliorate negative impacts of high-flow events, create fire-resistant habitat patches, and foster heterogeneous habitat mosaics that enhance watershed-level biodiversity of aquatic and riparian ecosystems. However, these benefits are only likely to accrue under certain climatic and hydrogeomorphic conditions, and we highlight the deficit of peer-reviewed literature at the spatial and temporal scope necessary to bridge our understanding of the expected potential and the realized benefits of BRR.

Beavers, Castor canadensis in North America and Castor fiber in Eurasia, are widely referred to as nature’s engineers due to their ability to rapidly transform diverse landscapes into dynamic wetland ecosystems. Few other organisms exhibit the same level of control over local geomorphic, hydrologic, and ecological conditions. Though freshwater ecosystems are particularly vulnerable to changing climate, beavers and their wetland homes have persisted throughout the Northern Hemisphere during numerous prior periods of climatic change. Some research suggests that the need to create stable, climate-buffered habitats at high latitudes during the Miocene directly led to the evolution of dam construction. As we follow an unprecedented trajectory of anthropogenic warming, we have the unique opportunity to describe how beaver ecosystem engineering ameliorates climate change today. Here, we review how beavers create and maintain local hydroclimatic stability and influence larger-scale biophysical ecosystem processes in the context of past, present, and future climate change.

Rivers and streams, when fully connected to their floodplains, are naturally resilient systems that are increasingly part of the conversation on nature-based climate solutions. Reconnecting waterways to their floodplains improves water quality and quantity, supports biodiversity and sensitive species conservation, increases flood, drought and fire resiliency, and bolsters carbon sequestration. But, while the importance of river restoration is clear, beaver-based restoration—for example, strategic coexistence, relocation, and mimicry—remains an underutilized strategy despite ample data demonstrating its efficacy. Climate-driven disturbances are actively pushing streams into increasingly degraded states, and the window of opportunity for restoration will not stay open forever. Therefore, now is the perfect time to apply the science of beaver-based low-tech process-based stream restoration to support building climate resilience across the landscape. Not every stream will be a good candidate for beaver-based restoration, but we have the tools to know which ones are. Let us use them.

Low-tech stream restoration gains using beaver dam mimicry gains popularity as an effective fix for ailing waterways in the American West.

A new study concludes that, by building dams, forming ponds, and digging canals, beavers irrigate vast stream corridors and create fireproof refuges in which plants and animals can shelter. In some cases, the rodents’ engineering can even stop fire in its tracks.

The final webinar in the ASWM-BLM Beaver Restoration Webinar Series showcases research which indicates that beavers are able to create and maintain wetlands resistant to both seasonal and multiyear droughts and that this landscape wetting and drought buffering goes on to reduce or prevent burning in wildfire. Perhaps instead of relying solely on human engineering and management to create and maintain fire?resistant landscape patches, we could benefit from beaver’s ecosystem engineering to achieve the same goals at a lower cost.

This study found that prescribed fires negatively affected beaver lodge occupancy, an effect compounded with frequent burns. Though prescribed fire is considered an important landscape restoration process, the frequency of prescribed burning should be mitigated to ensure that flooding by beavers can continue as a key process that maintains wetlands on the landscape.

This publication, guided by the inseparable nature of streams and riparian ecosystems, emphasizes the interrelationships and continuity of riparian areas along with dependent wildlife and human services.

The potential role of beavers in mitigating wildfire impacts on stream ecosystems

Impact of beavers regarding drought and wildfire in the Methow River Watershed

Study of how beaver ponds make nearby vegetation more resilient towards wildfires