Shaping the science on beaver expansion

Beavers may be new to the Arctic, but they’re already leaving their mark. 

The industrious rodents are expanding their range as a result of environmental change, pushing their way north into permafrost and tundra landscapes. Their arrival carries many consequences for subsistence users. Creeks that once supported reliable fishing are now beaver-dammed. Fish and wildlife migration pathways appear altered or blocked. Cross-country routes used by people for fishing and travel are now submerged in beaver-engineered wetlands. 

“People would point to a spot and say, ‘When I was a kid, we used to fish here, and now there’s a beaver dam,’” said University of Alaska Fairbanks researcher Will Samuel. “Or, ‘This creek used to have a lot of fish and now it doesn’t.’ Those observations come directly from people who know these systems best.”

Supported by an Alaska Sea Grant Community Partnership Development Grant, Samuel and fellow UAF scientist Ken Tape engaged in a project to identify actionable research into beaver expansion in the Arctic. The work was part of the Arctic Beaver Observation Network (A-BON), an international group of scientists, Indigenous leaders, and land and wildlife managers working to better understand and respond to the issue. Rather than beginning with predefined research questions, Samuel and Tape’s effort centered on listening, relationship-building and co-developing priorities based on local observations. 

“Our main goal was to develop partnerships,” Samuel said. “We wanted to understand what questions were already being asked on the ground, and then think about how science could help answer those questions in a useful way.”

Samuel noted that relationships between beavers and fish are nuanced and can vary widely across regions, habitats and species, underscoring the importance of place-based research. He said that carefully documenting where, when and how beaver activity affects fish is critical for understanding which impacts are harmful, which may be neutral or beneficial, and how those outcomes differ across the Arctic. 

With that in mind, the research team visited the community of Noatak in summer 2024 and Noatak, Selawik and Kotzebue in 2025, meeting with tribal councils, the Native Village of Kotzebue, and staff from the Alaska Department of Fish and Game, National Park Service and U.S. Fish and Wildlife Service. Community members shared observations, identified areas of concern and guided researchers to specific sites where beaver dams overlap with important fish habitat.

Local concerns were strikingly consistent across the communities, Samuel said. Residents expressed worry about beaver dams fragmenting habitat or preventing fish from reaching spawning grounds. They also raised questions about sedimentation of spawning areas, changes in water temperature or quality and potential impacts on fish health.

These questions are especially complex in Arctic systems, Samuel noted. Whereas beaver dams in more southern regions are often beneficial to fish and wildlife, the Arctic’s permafrost, ice dynamics, extreme seasonality and low-gradient rivers mean that beaver impacts here may differ from those documented elsewhere. “Most of what we know about beavers and fish comes from places that just aren’t comparable to the Arctic,” Samuel said. “Once you factor in permafrost and ice, the system behaves very differently.”

A central goal of the pilot-scale project was to determine what research is most needed and how future studies can produce actionable science for residents. Although the arrival of beavers in the Arctic is controversial for some local communities, Samuel and Tape hope to pursue multiple follow-on studies to document their effects on fish and other components of Arctic ecosystems.