Yes, We Should ‘Give a Dam’ About Beavers

Alaska’s peatlands are critical ecosystems that store large amounts of carbon, but they’re facing growing threats from a warming and drying climate. That combined with isostatic rebound—the process by which land slowly rises after glaciers recedes—is lowering groundwater levels, further compromising peatlands’ ability to function as carbon sinks. 

On Alaska’s lower Kenai Peninsula near the Kachemak Bay Reserve, where peatlands occupy around 26% of the area, a project is underway to explore whether beavers—once prolific in the region—could be key to restoring these vital wetlands.

“Beavers dams used to play a significant role in maintaining natural water flows and creating conditions that support healthy peatlands on the Kenai Peninsula,” says Lindsey Flagstad, Vegetation & Wetland Ecologist at the Alaska Center for Conservation Science (ACCS). “Now, due to extensive trapping, they’ve largely disappeared from the area.”

The Reserve, ACCS, Alaska Wildlife Alliance, and the University of South Florida have partnered to study whether beaver dams—or dams inspired by beavers—can help rewet the landscape. By doing this, they hope to restore the delicate balance of this ecosystem and its associated benefits.

This project brings together a diverse group of collaborators. Community involvement has been a key component, with volunteers participating in dam building and helping set up monitoring equipment.

The research team is investigating how beaver dams influence the area’s hydrology, how water retention affects carbon storage and greenhouse gas emissions, and whether beaver dam-like structures can serve as a long-term restoration solution, as well as how effective they are when compared to actual beaver dams.

Their work is focused on three sites: a newly constructed beaver dam analogue, a historically active beaver dam which was abandoned in 2017, and a control site where no damming has occurred. 

The recently abandoned dam was restored to its former function and an adjacent tributary was selected as a location for an ‘analogue’ structure, which mimics a natural beaver dam. Groundwater monitoring wells installed at all three study sites are tracking how water levels are changing in response to the analogue and repaired dam.

“We think that the analogue dam will allow the water to stay longer in the area, allowing it to interact more with the surrounding soil, dissolve more nutrients, and moderate temperatures; these conditions that support a healthy wetland ecosystem,” says Flagstad.

She and her colleagues also expect an initial spike in methane emissions as the landscape becomes fully inundated by water, replacing air and causing soil organisms to produce methane instead of carbon dioxide. This is why, she notes, long-term monitoring is so important, as the shift to a net carbon sink could take years. 

The implications of this project are far-reaching for Alaska’s Kenai Peninsula. Groundwater availability is a growing concern in the region, as many communities rely on it for commercial and drinking water, and this project could inform water management practices within the region.

The research is also expected to provide valuable insights into the relationship between wetland restoration and carbon management, contributing to broader efforts to mitigate climate change. There are plans to engage stakeholders—including the Alaska Department of Fish and Game, Homer Soil and Water Conservation District, Kenai Peninsula Borough, Kenai Watershed Forum, Kachemak Heritage Land Trust, Center for Alaskan Coastal Studies, and U.S. Fish and Wildlife Service—to demonstrate the benefits of the restoration efforts. The project has also become a valuable educational resource, with many graduate and undergraduate students basing their research on the project.

The support for the beaver research project comes from the Wildlife Conservation Society’s Climate Adaptation Fund, which was established by a grant from the Doris Duke Charitable Foundation.

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