Beaver Library

Hydrologic extremes dominate chemical exports from riparian zones and dictate water quality in major river systems. Yet, changes in land use and ecosystem services alongside growing climate variability are altering hydrologic extremes and their coupled impacts on riverine water quality. In the western U.S., warming temperatures and intensified aridification are increasingly paired with the expanding range of the American beaver—and their dams, which transform hydrologic and biogeochemical cycles in riparian systems. Here, we show that beaver dams overshadow climatic hydrologic extremes in their effects on water residence time and oxygen and nitrogen fluxes in the riparian subsurface. In a mountainous watershed in Colorado, U.S.A., we find that the increase in riparian hydraulic gradients imposed by a beaver dam is 10.7–13.3 times greater than seasonal hydrologic extremes. The massive hydraulic gradient increases hyporheic nitrate removal by 44.2% relative to seasonal extremes alone. A drier, hotter climate in the western U.S. will further expand the range of beavers and magnify their impacts on watershed hydrology and biogeochemistry, illustrating that ecosystem feedbacks to climate change will alter water quality in river systems.

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.

Reducing nutrient runoff in streams is an important task to reduce algae blooms and associated environmental damage in large waterbodies. Beaver Dam Analogs (WTBDA) are an means to address this problem. These Water Tight Beaver Dam Analogs (WTBDA) present a novel approach to this technique that also aim to restore eroded seasonal creeks to perennial wetlands.

Published in Chesapeake Bay Magazine in March 2021, the article highlights various industry professionals who attended BeaverCON 2020. Professionals in stream restoration, water control devices, and environmental journalism were interviewed for this article, discussing successes related to coexisting with beavers. Several important beaver-related studies are mentioned.

A synthesis of scientific literature and our current level of: 1) understanding of the relationship between habitat quantity and quality and salmon production, 2) quantify the improvements in salmon production and survival that can be expected with different restoration actions, and 3) use models to help identify habitat factors limiting production and quantify population-level responses to restoration.

Study on how beavers alter freshwater ecosystems and increase aquatic production to determine how these changes influence the magnitude and lateral dispersal of aquatic nutrients into terrestrial ecosystems

Beaver activity (i.e., damming of streamflow) holds significant potential to impact water quality, specifically in-stream nutrient processing.

A review by the University of Southampton of how the reintroduction of beaver will affect fish in Scotalnd

Review of research about the positive and negative effects of beaver towards fish

Study on how beaver dams affect coastal marshes and their Phosphorus and pH levels

This study quantifies the impacts of beaver on stream hydrologic and temperature regimes, and highlights the importance of understanding the spatial and temporal scales of those impacts.  We explored the impacts of beaver dams on hydrologic and temperature regimes at different spatial and temporal scales within a mountain stream in northern Utah over a 3-year period spanning pre- and post-beaver colonization.

The presence of beaver ponds in Taylor Creek could improve water quality by reducing the phosphorus load entering Lake Tahoe.

In-depth report on how beaver could provide benefits to local residents and visitors well into the millions of dollars per year in Utah.

A 44 minute Baltimore Sun podcast by Dan Rodricks on beavers and their impact. He interviews beaver experts Frances Backhouse, Mike Callahan, and Scott McGill on the history, present management and future of beavers in North America. Recorded in Feb. 2, 2018

A Finnish study of beaver wetland effects on dissolved carbon and oxygen.

A well-researched video on the intestinal parasite Giardia. It is the most common waterborne pathogen in the world. It impacts 200,000,000 people annually, and beavers have gotten a bum rap.

How beavers affect the biodiversity in their ecosystem

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

This review summarizes how beaver impact ecosystem structure and geomorphology, hydrology and water resources, water quality, freshwater ecology, and humans and society.

Summary of the benefits of beavers, their conflicts with humans, and the policies and conditions that affect their survival