Drivers and Uncertainties of Forecasted Range Shifts for Warm-Water Fishes Under Coupled Climate and Land Use Change

We sought to quantify the effects of coupled climate and land use change on 14 warm-water fish species distributions, identify drivers of change, and evaluate uncertainty of projections. For each species, current range projections were compared to scenario-based projections and aggregated into consensus projections. Multiple regression and model selection techniques were used to assess model likelihood in explaining change in probability of occurrence. The Extrapolation Detection Tool was used to evaluate transferability of models to scenario-based climates. Changes in total probability of occurrence ranged from 60% increase for plains minnow and 60% decrease for bigeye shiner. Inclusion of climate-driven land use generally led to range increases in comparison to climate-only projections, including a 27% increase in smallmouth bass distribution. Climate and land use drivers of range shift varied by species. Novel climate encompassed an increasing portion of the study area with increasing greenhouse gas emissions and time. Although generally hypothesized to expand, our results highlighted that warm-water fish species exhibit a range of responses from expansion to near-extirpation.  These results provide the first estimation of coupled climate and land use change on freshwater fishes and stress the importance of accounting for climate-induced land use change in species distribution modeling.