Beaver dams mitigate the impacts of whiplash weather in a fragmented habitat: A Salinas River case study

Abstract Beaver Castor canadensis create ecological refugia against drought, heat stress, and fire, and policies to support beaver conservation and recolonization in regions where they have been historically extirpated are increasingly common. Between prolonged periods of drought, arid regions are increasingly challenged by extreme precipitation events that promote flash floods, debris flows, and mudslides—a phenomenon known as whiplash weather. Understanding how beaver wetlands respond to whiplash weather will help inform the development of restoration policies targeting the species as a natural climate solution. We used remotely sensed normalized difference vegetation index data to characterize the influence of beaver complexes on riparian greenness dynamics under whiplash weather by comparing three complexes and five nearby reference areas along the Salinas River, California. Our study region is within a remanent patch of the historical range of beaver and is highly impacted by agricultural and urban uses. Despite these limitations to expansion and their low density due to historical extirpation, the Salinas River beaver complexes demonstrated greater riparian greenness resistance to drought and resilience to flood disturbance than the watershed reference areas. Thus, policies supporting beaver re‐colonization—even within highly fragmented and anthropogenically impacted habitats—may confer both riparian resistance and resilience to increasingly erratic climatic conditions.