Alaska’s coastal temperate rainforest is expected to see an increase of 1.7-3.7 °C in air temperature in the next 80 years. This will have diverse effects on rivers throughout the region by altering tree lines, shifting the percent of moisture that falls as rain and snow and altering river water temperature all of which will change the habitats within these rivers and streams. Dr. Hood and his student Michael Windfree are working to quantify these effects to better understand the current relationship between landscape patterns and instream water temperature. With a better understanding of how land cover influences stream temperature future models will better be able to predict how changes to temperature and land cover may impact pacific salmon populations.
The coastal temperate mean annual air temperatures expected to increase by 1.7-3.7°C by the end of the century. This projected temperature increase will have a variety of effects on landcover and hydrology in the CTR including shifts in: tree line, annual precipitation, and the rain/snow fraction of precipitation. Ultimately these climate-driven changes have the potential to alter the physical characteristics of aquatic habitats in coastal streams within the region. Of particular interest are potential changes to thermal regimes in the region’s ~4000 anadromous streams, which support culturally and economically important Pacific salmon runs. The purpose of this proposal is to quantify landscape controls on stream temperature in anadromous streams throughout southeast Alaska. This will not only increase our understanding of the variability in thermal regimes among streams across the region, but also provide a framework for linking future climate scenarios of air temperature and precipitation to thermal regimes of streams, and allow us to better identify how linked changes in landcover and temperature may impact Pacific salmon habitat. The proposed project has four primary objectives: 1) Establish a network of approximately 50 new stream temperature monitoring sites in anadromous streams across Southeast Alaska, 2) Develop models identifying relationships between stream temperature and landscape characteristics within the study watersheds, 3) Use downscaled climate models to project future changes to stream temperature at a watershed scale, and 4) Evaluate potential impacts of changing stream temperature on Pacific salmon habitat. This project represents the first comprehensive effort to assess stream temperature regimes across southeast Alaska. The study will include watersheds within all five of the biogeoclimatic provinces that comprise southeast Alaska. The expected benefits from the project include: 1) Developing an understanding of how watershed thermal regimes vary spatially across the landscape of southeast Alaska, 2) Identifying those watersheds that are most sensitive to climate-driven changes in their thermal regimes, 3) Developing a framework for projecting future changes in stream temperatures (including those streams that may exceed the optimal thermal rage for salmon), and 4) Providing a foundation for an ongoing stream temperature monitoring network within the region. Funding is requested to support a UAF Water and Environmental Research Center (WERC) masters’ student (Michael Winfree), who will be primarily responsible for field and analytical aspects of the project. Requested funds will support a graduate research assistantship for Winfree and also provide nominal support for materials and travel related to the rainforest (CTR) of southeast Alaska is being strongly affected by climate change, with project. Winfree’s graduate committee includes WERC faculty Eran Hood, Sveta Stuefer, and Chris Arp and he will be mentored by Hood and Sanjay Pyare (University of Alaska Southeast) while working in southeast Alaska.