A Framework of Ecological Classification That Demonstrates the Hydrological and Thermal Variance of Current Fish Fluvial Habitats Across the Conterminous United States

Without an understanding of flow and temperature preferences of fish, evaluating the impact of climate change on fish and their habitats would be difficult. This study aims to examine the hydrological and thermal preference of fish and to look for specific climate drivers of those hydrological and thermal characteristics. With knowledge of both, we performed ecological classifications of fluvial fish habitats for nine aggregated ecoregions of the conterminous United States. We matched flow and temperature gages with sampled fish sites and inspected fish occurrences to determine their preference of habitat characteristics. A sequence of screening processes was performed to filter a subset of metrics and corresponding fish groups that could portray stream habitats within each ecoregion. Through correlation analysis, a set of climate metrics was identified and associated with the selected flow and temperature metrics, and a concise list of climate metrics was obtained through screening and combination. Finally, these climate metrics and the fish groups they support allowed us to perform ecological classifications to portray stream habitats within each ecoregion. Due to the large-scale nature of our ecological classifications, the impact of changes in these habitats resulting from climate change will be informative to support management and decision-making efforts across ecoregions.