The highlights from Year 3 (2021-22) to Year 5 (2023-24) are listed below.
Year 5 Highlights (2023-24)
Beavers may provide some natural mitigation of the effects of climate change on the Columbia Wetlands by increasing wetland resilience and complexity, and specifically by increasing open water area. Most of the research undertaken on beavers has not been in a floodplain system the size of the Columbia Wetlands, where the river is large and undammed and the floodplain is up to 2 km across. Beavers in the Columbia Wetlands are not damming the Columbia River itself, they are damming small side channels and wetlands within the floodplain, and the impacts of this type of dam-building activity are very different from the impacts of dam-building activity in incised streams or even in river floodplains of around 500 m in width. Crucially, while in an incised stream system water flow is unidirectional, only flowing over the beaver dams one way, in a floodplain system the water flows over beaver dams in both directions. In the spring, as the flood pulse rises, water flows over the beaver dams from the Columbia River into the wetlands; once the flood pulse has receded, the water flows out of the wetlands (either over, through, or under the dams, if they are present) into the Columbia River. Thus, the influences of beaver dams on the morphology, hydrology, and vegetative characteristics of these wetlands are likely profound, and as yet not well understood.
The western upland bench of the Columbia Valley provides a suitable landscape for many small wetland features where minimal investigative work has been completed. The Freshwater Atlas of BC, an open-source database that maps provincial freshwater attributes, identifies 349 lake and 479 wetland polygons on the bench between Canal Flats and Spillimacheen. In 2023, we visited 371 of the 828 (45%) mapped polygons either via drone or in person to generate a summary of wetland status and identify potential restoration sites. Our project goal is to restore 5 – 10 hectares of wetlands on the upland bench of the Columbia Valley using Beaver Dam Analogues – in 2023, we identified 22 potential sites that are suitable for restoration with this method. We focused on collecting detailed information for permit applications and effectiveness monitoring at nine of these sites, which would allow us to flood 13 ha within the FWA mapped boundaries. These measurements include stream flow and water quality, the size of the remnant beaver dam gap needing repair, estimated flood area, bathymetry, vegetation community mapping, vegetation plots, and orthomosaic drone imagery. In early 2024, we submitted permit applications for two of these sites.
This report focuses on the use of environmental DNA (eDNA) metabarcoding to investigate climate change vulnerability of wetlands and restoration effectiveness. The eDNA method allows estimation of species richness from collected benthic samples without the need for traditional microscopic taxonomic identification. We are using eDNA metabarcoding method to quantify the genetic composition and the biodiversity of vulnerable wetlands and assess the effects of restoration activities in the context of an adaptive-management framework. eDNA monitoring includes analysis of samples for macroinvertebrates, fish, and diatom genomic sequences to evaluate use of these taxa as a component of wetland effectiveness monitoring. In addition, to the genomics work we are monitoring other key ecosystem attributes including hydrology, SARA-listed species, migratory birds and vegetation and mapping.
Year 4 Highlights (2022-23)
This short video documents efforts made by the Columbia Wetlands Stewardship Partners (CWSP) to conserve high-value cottonwood stands and wildlife trees in the Columbia Wetlands. Cottonwoods provide habitat for large raptors, great blue herons, woodpeckers, as well as important forage and building materials for beavers. These important wildlife trees are limited and valuable in the Columbia Wetlands.
The cottonwood conservation project promotes retention of mature wildlife trees in the Columbia Wetland by protecting trees from beaver herbivory. Wetland mapping and surveys in Year 1 identified critical stands of cottonwoods within the project areas.
Building on the work completed in Year 3, the work in Year 4 was aimed at targeting high value cottonwood trees. Mature cottonwoods that had existing nest structures were prioritized, as well as stands with multiple mature trees and younger recruitment trees. Almost all of these stands were near significant evidence of beaver activity.
Year 3 Highlights (2021-22)
As part of the 4-year study into the Columbia Wetlands, we are conducting research into the impacts of beaver dams on individual wetlands within the Columbia Wetlands complex. As this is a 2-year project, in this report we present preliminary results and describe the completed and ongoing work. 38 study wetlands are being studied for this research, covering 2395.61 ha or approximately 9% of the total area of the Columbia Wetlands.
The purpose of the cottonwood/beaver project is to assess the status of important cottonwood stands and install wire protectors if they are required to protect critical stands from beaver harvesting. If feasible, start to assess the regeneration of cottonwood on the levees. This subproject used the wetland mapping from Yr1 to identify the stands of cottonwoods, used a survey of important wildlife cottonwood trees to identify critical trees and small stands, and then after seeking permission of selected landowners, installed wire around selected cottonwood trees. In total 45 large trees, often near active beaver colonies were protected. The project brought in a Youth Climate Corp to assist with the installation of the wire.
