Climate Vulnerability of Aquatic Species to Changing Stream Temperatures and Wildfire Across the Yukon and Kuskokwim River Basins, Alaska

Alaska is an ecologically, commercially, and recreationally diverse state, providing value to people and terrestrial and aquatic species alike. Presently, Alaska is experiencing climatic change faster than any other area of the United States, but across the state, comprehensive environmental monitoring is logistically difficult and expensive. For instance, only about 1% of U.S Geological Survey (USGS) stream gages are in Alaska, and only about 50% of those gages measure water temperature, an important climate change indicator.



In this study, predictive models are being used to map stream temperatures under current and future climate scenarios across the Yukon and Kuskokwim River basins (YKRB) at the stream reach (~ 1 km) scale. These models are derived from satellite remotely-sensed land surface temperatures coupled with regional Weather Research and Forecasting (WRF) and Alaskan Frame‐based Ecosystem Code Extended (ALFRESCO) model projections. This project draws upon and leverages two current projects focused on understanding 1) boreal aquatic ecosystem vulnerability to wildland fire and climate change and, 2) freshwater habitat potential for Chinook salmon in the YKRB. Predictions will be applied across digital river networks developed for the YKRB as part of the two current projects.



Researchers are also exploring a machine learning approach to improve predictions and provide a comparison among spatial and temporal scales and with a previous linear modeling approach. The overarching goal is to develop products (e.g., GIS layers, cloud-processed results viewer) of aquatic habitat vulnerability for important commercial, sport, and subsistence fish species, like Chinook salmon, in the YKRB. Tools are being developed that can be used to apply a similar approach in other areas of Alaska outside the YKRB.



Salmon in Alaska will be directly impacted by changing stream temperatures and available habitat for spawning and rearing. Managers and researchers can use the deliverables from this work to identify areas in the YKRB to focus future resources and effort for conservation and management of aquatic habitats and species across temporal and spatial scales.