Consecutive wildfires affect stream biota in cold- and warmwater dryland river networks

Abstract

AbstractClimate change and fire suppression have altered fire regimes globally, leading to larger, more frequent, and more severe wildfires. Responses of coldwater stream biota to single wildfires are well studied, but measured responses to consecutive wildfires in warmwater systems that often include mixed assemblages of native and nonnative taxa are lacking. We quantified changes in physical habitat, resource availability, and biomass of cold- and warmwater oligochaetes, insects, crayfish, fishes, and tadpoles following consecutive megafires (covering >100 km2) in the upper Gila River, New Mexico, USA. We were particularly interested in comparing responses of native and nonnative fishes that might have evolved under different disturbance regimes. Changes in habitat and resource availability were related to cumulative fire effects, fire size, and postfire precipitation. The 2nd of 2 consecutive wildfires in the basin was larger and, coupled with moderate postfire discharge, resulted in increased siltatio...