Habitat benefits associated with beaver dams has led to massive enthusiasm regarding beaver promotion and beaver dam mimicry in California. However, natural and artificial beaver dams do not make sense everywhere. For instance, in built environments beaver can cause flooding of infrastructure, clogging of irrigation diversions and removal of ornamental landscape trees. As such, where on the landscape and to what extent should we promote beaver dam building and beaver dam mimicry?
StoryMap
Project Area & Regions
Project Goals
The main goal of this project was to implement the Beaver Restoration Assessment Tool (BRAT) over 78,835 km of perennial rivers and streams within the Sierra Nevada, Cascades, Coast, and Klamath mountains of California and to help meadow and stream restoration practitioners identify the most appropriate locations for Beaver Dam Analog (BDA) and beaver-assisted restoration projects. This included calibration, validation and refinement of the BRAT models based on feedback for TNC staff and project partners. Further information can be found on the BRAT website in the TNC BRAT folder.
Project Objectives
- Develop and run BRAT on the perennial portion of the 1:24K NHD network (78,835 miles) segmented at 300 m including:
- Existing (based on 2014 LANDFIRE data, the most current data available) beaver dam capacity estimates (dams /km)
- Historic beaver dam capacity estimates (based on LANDFIRE BPS data (dams /km)
- Potential for human beaver conflict (probability)
- Refine conflict model. This resulted in a model that assesses risk and opportunity for using beaver in conservation and restoration.
- Develop and calibrate the Beaver Dam Building Strategy layer.
- Validate the performance of the BRAT capacity model using a web-map based inventory of existing beaver dams and field based data collection of dam locations.
- Write an Interpretive report with management recommendations and implications for BDA and beaver-based restoration in the Sierra Nevada, Cascades, Coast and Klamath Mountains of California.
Existing Capacity Estimates (Truckee Watershed)
Customizations for this project
TNC staff extended the BRAT model to include strategy outputs/maps that were used to identify opportunities for conserving existing beaver populations, areas suitable for promoting the growth of dam building beaver populations, and identifying areas that would require restoration prior to promoting beaver.
TNC staff and project partners also provided detailed review of preliminary BRAT data and we incorporated their suggested changes into the model. This resulted in improvements to the risk, limiting factors, and restoration and conservation outputs.
TNC staff and project partners also provided detailed review of preliminary BRAT data and we incorporated their suggested changes into the model. This resulted in improvements to the risk, limiting factors, and restoration and conservation outputs.
Deliverable data
Deliverable data products include:
- KMZ of each of four primary BRAT outputs (existing capacity, historic capacity, risk, limiting factors, and conservation and restoration opportunities)
- Shapefiles and layer packages of each of four primary outputs (existing capacity, historic capacity, risk, limiting factors, and conservation and restoration opportunities)
- Posting of existing and historic beaver dam capacity output layers to public website
- Full interpretive report with management recommendations
- Priority watershed-wide virtual inventory of existing beaver dams as KMZ
- Atlas of BRAT outputs
