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A recent ¶¶ÒõÂÃÐÐÉä Boulder Today news articleÌýhighlighted new research led by Peyton Thomas, a new Assistant Professor at the Institute of Arctic and Alpine Research (INSTAAR) and ENVS. Peyton was formally a postdoctoral researcher co-advised by Geography Assistant Professor Keith Musselman. The study, published in Scientific Reports, examines how rapid climate warming in Alaska is altering river conditions and threatening Chinook salmon populations that Indigenous communities have depended on for millennia.

For many Alaska Native and First Nations communities along the Yukon River, steep declines in Chinook salmon since the early 2000s have already caused major disruptions to food security, cultural practices, and travel across frozen rivers. The research team collaborated closely with tribal partners to understand ongoing changes and support community-led adaptation efforts.

Using a combination of climate simulations, hydrologic modeling, and fish growth models, the team assessed how future warming may affect two key subsistence species: Chinook salmon and Dolly Varden (a trout species). Their results suggest that by mid-century, summer river temperatures in parts of the region may regularly exceed the thermal tolerance of juvenile Chinook, further constraining populations. In contrast, Dolly Varden may benefit from slightly warmer water, offering a potential—though culturally complex—alternative for some communities.

Importantly, the team identified several river systems that are likely to remain suitable for Chinook habitat, highlighting priority areas for conservation and restoration.

This work reflects an ongoing collaborative effort between ¶¶ÒõÂÃÐÐÉä researchers and Indigenous communities across Alaska. Over the past two summers, Thomas, Musselman, and colleagues have visited numerous tribal communities to document environmental change, integrate local knowledge with modeling tools, and help identify strategies for navigating an uncertain future. The project also aligns with broader efforts to clarify how climate-driven shifts in hydrology are shaping ecosystems and livelihoods in Arctic and subarctic environments.

For those interested, the full University news feature provides deeper context on the study and its implications for future river management, salmon conservation, and community resilience.

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