Using High-Resolution Models to Predict the Effects of Climate Change on Aquatic Ecosystems in the Crown of the Continent

Climate trends and projections have prompted interest in assessing the thermal sensitivity of aquatic species. How species will adapt and respond to these changes is uncertain, however, climatic and hydrologic changes may shift species habitat distributions and physiological functions both spatially and temporally. This is particularly true for salmonids (e.g., trout, char, and salmon), which are cold-water species strongly influenced by changes in temperature, flow, and physical habitat conditions. Therefore, understanding how habitats are likely to change and how species may respond to changes in climatic conditions is critical for developing conservation and management strategies. The purpose of this study is to develop a high-resolution stream temperature model for the Crown of the Continent Ecosystem (CCE) to simulate potential climate change impacts on thermal regimes throughout the riverscape. A spatially explicit statistical regression model is coupled with high-resolution climate data such as air temperature, precipitation, solar radiation, baseflow and surface runoff. This empirically based model is used to predict daily stream temperatures under historic, current and forecasted climate conditions. The model is parameterized with empirical stream temperature data, which has been gathered from agencies across the region. The current database of empirical stream temperature data consists of over 800 sites throughout the CCE, which provide time series data to the model application. The biological integration and application of this model is on bull trout (Salvelinus confluentus) populations within the CCE. The model will be used to assess species vulnerabilities caused by spatial and temporal changes in stream temperature and hydrology. By evaluating the magnitude, timing and duration of climatic changes on the riverscape, we can more accurately assess potential vulnerabilities of critical life history traits, such as growth potential, spawning migrations and reproductive capacity. The CCE is a transboundary study area, spanning the US and Canada. All data products and research efforts developed under this project will be made available to managers and conservation planners in the CCE through a web-based tool and data portal, which will be applicable to any aquatic species of interest.