Modeling FISH Species Response to Changes in Water Availability and Climate in the North Carolina Piedmont, USA

Streamflows are essential for maintaining healthy aquatic ecosystems and for supporting human water supply needs. Changes in climate, land and water use practices are altering the availability of water throughout the Southeast US. Understanding the potential impact of these changes on aquatic ecosystems is critical for long-term water management. Boosted regression trees and WaSSI, a rainfall-runoff model, were used to predict the relation between streamflow and fish species richness under plausible scenarios of projected future water withdrawal, climate change, and increases in impervious surfaces. Streamflow variability, monthly discharge, the fraction of flow originating on impervious surfaces, and river basin accounted for 44% of the variability in the training data. On average, fish species richness was predicted to decline significantly with increased withdrawals and impervious surfaces, but little change was seen under future climate scenarios. Sensitivity and resiliency maps were developed to identify potential watersheds of concern. Such findings may help resource agencies and stakeholders develop management strategies that prioritize watersheds vulnerable to altered streamflow and better support the protection and long-term conservation of species of special concern.