Sharing wetlands
Beavers are increasingly recognized – even celebrated – for their contributions to wetland and watershed health. “Beaver habitat just provides incredible benefits to the ecosystem,” says Winkler’s boss, Kristin Marshall, habitat restoration and floodplain resilience program director for SCD.
Beavers benefit hydrology, biodiversity, climate change resilience, and salmon recovery in western Washington’s watersheds. Their dams help slow the flow of water through stream systems, diminishing flooding during the wet months of winter and spring and increasing streamflow during the region’s increasingly warm and dry summers. Water backed up behind a beaver dam seeps into the soil and replenishes groundwater stores, reducing water temperature downstream. And by creating complex wetlands and adding woody debris to streams, they provide crucial rearing habitat for salmon, especially coho.
But beavers can also play havoc with human endeavors. They sometimes build dams across culverts – they favor narrow points of streams for their construction work – causing roads to flood. Other dams flood yards, driveways, or agricultural fields. The standing water in a new beaver pond may kill trees and other plants. Or the animals choose vegetation that people really want to preserve – fruit trees, or native plants installed as streamside buffers in salmon restoration projects – for their building materials.
“They want to be in the same places that we want to be, really,” says Jennifer Vanderhoof, a wildlife biologist with King County and president of Beavers Northwest, a nonprofit that provides beaver management services in western Washington and SCD’s collaborator on the Living with Beavers program. “And after us humans, they’re the species that can affect their landscape the most.” It can be tough sharing the landscape with another ecosystem engineer – a sentiment that might ring true to beavers, too.
Prior to European settlement, many of the riversheds that drain into Puget Sound would have had thousands of beaver-created wetlands and the beavers to go with them. But widespread trapping nearly extirpated the animals from the area that is now Washington State by the mid-1800s. So when the settlers later built roads and towns and laid out the boundaries of farm fields, they did so in an artificially beaver-less landscape.
But in the last 20 years, what Vanderhoof calls the beaver trifecta — a near-cessation of trapping due to both a state ban on body-gripping traps, a broader collapse in the price of beaver pelts, and the Endangered Species Act listings of multiple Puget Sound populations of salmon that triggered stream restoration efforts — has enabled beaver populations to bounce back in many areas.
Meanwhile, expanding development has brought more people living in closer proximity to beaver habitat, as well as an expansion of pavement that sends more stormwater runoff through local streams. Sometimes, beavers get blamed for flooding related to urban development, or dams that previously didn’t interfere with human infrastructure begin to do so with more runoff entering the system, Winkler says.
The small beaver dam on the Hulbert Creek tributary is a perfect illustration of these forces. It sits in a larger landscape of newly laid asphalt and half-finished traffic circles and is surrounded by an amalgam of native and invasive vegetation that reflects the area’s position at the fringes of urban growth: salmonberry and Himalayan blackberry, salal and creeping buttercup. The homeowner’s association reached out to SCD last year because of flooding on the greenbelt’s walking trails.
“This historically hasn’t been flooded,” says Sara Rocero, poking at the muddy path with the toe of her sport sandal. Rocero, a habitat restoration project manager with SCD who has joined Winkler for today’s site visit, lives nearby and enjoys walking on the greenbelt paths herself; she says beavers have been in the area since at least 2015. Today, the ground sucks at our shoes as we walk, despite the dry, sunny weather. “Beavers but also an increase in development creating more impervious surface directs more water into this area,” she says.
Funding the work
The grant that gave the Living with Beavers program its start is one of roughly 90 distributed by a cross-agency group called the Habitat Strategic Initiative Lead (HSIL), a collaboration between the Washington Department of Fish and Wildlife and the Washington Department of Natural Resources. The group's purpose is to distribute grant funds provided by the federal Environmental Protection Agency, including funds for estuary and floodplain restoration in Puget Sound. HSIL grants emphasize Integrated Floodplain Management (IFM), an approach to managing floodplains that is cooperative and inclusive. The idea is to find projects that can benefit fish, farms, and flood control all at the same time, rather than pitting different stakeholders against each other as has often happened in the past.
The Living with Beavers program is not formally considered IFM, but it illustrates an important aspect of the approach, which is bringing together groups who may normally have contentious or even antagonistic relationships – in this case, property owners and beavers. The conservation district functions as the beavers’ proxy; the beavers themselves communicate mostly through their works.