Topic Results: Stream RestorationBack to Currated List of Topics
Comparing translocated beavers used as passive restoration tools to resident beavers in degraded desert rivers
Wildlife translocation facilitates conservation efforts, including recovering imperiled species, reducing human–wildlife conflict, and restoring degraded ecosystems. Beaver (American, Castor canadensis; Eurasian, C. fiber) translocation may mitigate human–wildlife conflict and facilitate ecosystem restoration. However, few projects measure outcomes of translocations by monitoring beaver postrelease, and translocation to desert streams is relatively rare. We captured, tagged, and monitored 47 American beavers (hereafter, beavers) which we then translocated to two desert rivers in Utah, USA, to assist in passive river restoration. We compared translocated beaver site fidelity, survival, and dam-building behavior to 24 resident beavers. We observed high apparent survival (i.e., survived and stayed in the study site) for eight weeks postrelease of resident adult beavers (0.88 ± 0.08; standard error) and lower but similar apparent survival rates between resident subadult (0.15 ± 0.15), translocated adult (0.26 ± 0.12), and translocated subadult beavers (0.09 ± 0.08). Neither the pre- nor the post-translocation count of river reaches with beaver dams were predicted well by the Beaver Restoration Assessment Tool, which estimates maximum beaver dam capacity by river reach, suggesting beaver-related restoration is not maximized in these rivers. Translocated beavers exhibited similar characteristics as resident subadult beavers during dispersal; they were more vulnerable to predation and many emigrated from the study sites. High mortality and low site fidelity should be anticipated when translocating beavers, but even so, translocation may have contributed to additional beaver dams in the restoration sites, which is the common goal of beaver-assisted river restoration. Multiple releases at targeted restoration sites may eventually result in establishment and meet conservation objectives for desert rivers.
EEAGER: a model that detects beaver-created wetlands in satellite and aerial imagery
Beavers are ecosystem engineers that can dramatically change the shape of the landscape and how water moves through it. They create and maintain wetland environments across North America and Eurasia in a wide variety of places, including mountains, deserts, coasts, forests, grasslands, shrublands, etc. Despite their large influence on the landscape, there are very few programs that monitor them at the landscape, regional, or continental scale. This is partially due to how much time it takes to find and identify beaver dams in satellite and aerial images. To make it easier for us to find and understand the influence of beavers at larger scales, we built a model that can automatically find beaver dams in satellite and aerial imagery. While our model is trained to find beaver dams, this type of model has promise for finding other landscape features too. The model isn’t perfect, but it is a strong starting point and will continue to improve as more people use it.
Incorporating beaver dams in a physically-based hydrological model
A current challenge in ecohydrology is the incorporation of beaver dams into hydrological models. Select works have attempted to solve this problem using routing approaches, Manning coefficient variations, pond dynamics, or fully-distributed hydraulic models; however, all these approaches assume that all beaver dams are homogeneous structures and react in the same way to rainfall events. Recent findings highlight the importance of including the functional heterogeneity of beaver dams, especially the water path past the dam (dam flow state). To overcome the challenge of accounting for different dam flow states interrupting downstream water transmission in different ways, we developed BEAVERPY, a flow state-based Python package that can be coupled with the platform Cold Regions Hydrological Model (CRHM) to represent both streamflow modulation by ponds and dams, while also simulating infiltration and evapotranspiration. We used the broad-crested weir equation for the overflow dams, the Darcy equation for the seep flow dams, and the v-notch weir equation for the gapflow dams, verifying each case with synthetic experiments. To calibrate and validate the model, we instrumented the ponds and streams in a peatland fen in the Canadian Rocky Mountains in Alberta with level sensors and ‘DamCams’ (trail cameras) to capture flow type. Then, we used LIDAR DEM data and high-resolution imagery to delineate the hydrological response units. Each pond is represented as an HRU, which can interact with soil and routing modules. Finally, we conducted a scenario-testing experiment to understand the sensitivity of different beaver dam flow states for several storms. The results indicate the importance of including flow state dynamics for the beaver dam representations, and highlight the importance of integrating animal-ecological aspects into the streamflow modelling. This research has implications for understanding the use of beaver as a nature-based solution for flood mitigation and river restoration.
Beaver dams overshadow climate extremes in controlling riparian hydrology and water quality
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.
Beaver: The North American freshwater climate action plan
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.
A Review of Two Novel Water-Tight Beaver Dam Analogs (WTBDA) to Restore Eroded Seasonal Creeks in Drain Tile Zones to Permanent Beaver Wetlands
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.
The Impact of Beaver Dams on the Morphology of a River in the Eastern United States with Implications for River Restoration
A case study of the impacts of beaver dams on a low gradient, fine-grained alluvial channel on the Atlantic Coastal Plain, illustrating the role that exists for beavers in stream restoration.
The Utah Beaver Restoration Assessment Tool: A Decision Support and Planning Tool
A decision support and planning tool for beaver management, to analyze all perennial rivers and streams in Utah. This model assess the upper limits of riverscapes to support beaver dam-building activities.
Partnering with Beaver to Restore Wetland
A short presentation from the Society of Wetland Scientists webinar in April 2021, given by Mark Beardsley of Eco Metrics, LLC in Colorado. Beardsley amplifies many voices of the beaver community in a presentation about how a lack of understanding of stream ecosystems has prevented human and beaver from reaching a complete state of collaboration. He describes in detail how active beaver wetlands create ecosystem services more abundant than wetlands without beaver.
Great Expectations: Deconstructing the Process Pathways Underlying Beaver-Related Restoration
Although the beaver-related restoration has broad appeal, especially in water-limited systems, its effectiveness is not yet well documented. This article presents a process-expectation framework that links beaver-related restoration tactics to commonly expected outcomes by identifying the set of process pathways that must occur to achieve those expected outcomes. Due to changes in expectations, a more useful paradigm for evaluating process-based restoration would be to identify relevant processes and to rigorously document how projects do or do not proceed along expected process pathways using both quantitative and qualitative data.
Partnering with Beaver to Restore Wetland
An excerpt from a presentation at the Society of Wetland Scientists webinar, given by Mark Beardsley of EcoMetrics, LLC. Mark covers the history and perception of the beaver, as well as how beaver behavior contributes to wetland restoration.
Idaho Beaver Restoration Assessment Tool Building Realistic Expectations for Partnering with Beaver in Conservation and Restoration
Traditional restoration efforts are barely scratching the surface of what could be restored. Moreover, a disproportionate amount of funds are spent on too few miles of streams and rivers leaving millions of miles of degraded streams neglected. To fill this gap, restoration practitioners are increasingly trying restoration techniques that are more cost?effective, less intensive, and can more practically scale up to the enormous scope of degradation.
Fish-Habitat Relationships and the Effectiveness of Habitat Restoration
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.
Emulating Riverine Landscape Controls of Beaver in Stream Restoration
We have developed and implemented a simple approach that emulates the ecosystem engineering effects of beaver. This approach is less expensive and disruptive than typical large-scale engineering efforts and has the potential to restore both fish habitat and floodplain vegetation more rapidly than simply revegetating and waiting for the riparian zone to mature. (Pg 246 – 255)
Artificial beaver dams are a hot restoration strategy, but the projects aren’t always welcome.
Beaver (Castor Canadensis) of the Salinas River: A Human Dimensions-Inclusive Overview for Assessing Landscape-Scale Beaver-Assisted Restoration Opportunities
Study to gather and produce human dimensions-inclusive, basin-centralized beaver knowledge through an explorative, benefits-maximizing approach to landscape-scale BAR opportunities assessment in the Salinas River.
Beavers as commoners? Invitations to river restoration work in a beavery mode
This paper examines the relationship of ecological restoration to community development. The author presents several opinions on the role of beaver in ecological restoration, the historical relationship of human and beaver, and the beaver’s role within a “multispecies commons”.
Simple hand-built structures can help streams survive wildfires and drought
Low-tech stream restoration gains using beaver dam mimicry gains popularity as an effective fix for ailing waterways in the American West.