Brook Trout Population Responses to Climate Variation Across the Southeast

Image of stream in forest

Project Information

Dr. Yoichiro Kanno, Colorado State University

Proposed Project Completion: April 2023

Implements Science Plan Theme: Impacts

Project Cooperators: Yoichiro Kanno (Colorado State University), Nathaniel Hitt (USGS Leetown Science Center), Benjamin Letcher (USGS Leetown Science Center), Jacob Rash (North Carolina Wildlife Resources Commission), Matt Kulp (Great Smoky Mountains National Park), Andrew Dolloff (U.S. Forest Service Southern Research Station)

Overview

The project aims to characterize how climate change impacts on brook trout (Salvelinus fontinalis) populations differ over space in the Southeast USA. Brook trout are the only native salmonid in the region, but their populations have suffered the most precipitous declines within their native range. In the Southeast, brook trout persist in small, isolated headwater streams of the Appalachian Mountains. Given the lack of dispersal, their populations are regulated primarily by local-scale abiotic factors such as stream temperature and flow. However, thermal and flow regimes differ among streams, mediated by landscape features such as elevation, gradient, surficial geology, and groundwater. How climate interacts with specific local conditions to drive brook trout population dynamics remains unexplored at the regional scale, but this knowledge is critical when prioritizing management actions (e.g., translocations, habitat restoration, non-native trout removal) by identifying populations at greater risk and with higher resiliency. The researchers will evaluate the utility of GIS-derived indices of groundwater input (i.e., thermal stability) using stream temperature data at >200 locations, and develop a spatially- explicit Bayesian hierarchical model that accounts for removal sampling data (>300 locations) to synthesize populations responses to climate variation. They hypothesize that site-to-site variation in trout responses to climate can be partly explained by habitat characteristics, and test the relative importance of several habitat characteristics, in particular groundwater influences as a driver to sustain trout populations. Products of this study will be a regional brook trout and habitat data set from multiple sources, statistical models, and trout population vulnerability maps.