Oral Presentation Society for Freshwater Science 2026 Annual Meeting

Severe storm response in Central Appalachian streams: focusing on benthic macroinvertebrate community dynamics (135869)

Quinn Weigel 1 , Kelley Sinning 1 , Amaryllis Adey 1 , Caleigh Meehan 2 , Megan Underwood 1 , Lisa M Tabor 1 , Teresa Brown 3 , Stephen Schoenholtz 4 , Erin R Hotchkiss 2 , Daniel McLaughlin 4 , Carl Zipper 4 , Sally Entrekin 1
  1. Virginia Tech Aquatic Entomology Lab, Blacksburg, United States
  2. Department of Biology, Freshwater Ecology & Biogeochemistry Lab, Blacksburg, VA, USA
  3. Department of Natural Sciences , University of Virginia’s College at Wise, Wise, VA, USA
  4. Virginia Tech Water Resources Research Center, Blacksburg, VA, USA

Though headwater ecosystems in central Appalachia are distinct for their high biodiversity, including aquatic insects, intense seasonal weather patterns including sustained storm systems could pose a threat. Tropical hurricanes, flooding, and icemelts have caused an increasing appearance in freshwater stream integrity declines, coinciding with greater ecological damage. Macroinvertebrate communities act as complex bioassessment indicators for these systems, and factors such as richness, biomass, and taxa dominance can indicate quality of taxa refugia. After preliminary analysis of Hurricane Helene confirmed immediate declines in richness and abundance, our hypothesis that amplified storm events reduce an ecosystem's macroinvertebrate community resilience can be further applied to another storm event, and expanded to include how intensity of stream flow surges correlate with specific assemblage abnormalities. Predictions include increased dominance of sediment and salinity tolerant taxa, community disruption in later months post impact, and significant biomass differences among salinity classes. Hurricane Helene of September 2024 and a historic freeze in mid February 2025 each caused multiple days of streamflow output beyond the 90th percentile of normalcy, with both events distinct in their increased precipitation. Hydrological and macroinvertebrate data from nine Virginian and West Virginian headwater streams included in or adjacent to the affected storm event regions were collected from September 2023 to August 2025, with macroinvertebrates identified to the highest taxonomic resolution possible (e.g., genus). Study streams were located in multiple watersheds across a salinity gradient where specific conductivity ranged from 19–1,185 μS·cm⁻¹, with intersecting effects of salinity and high flow events to be evaluated. A full year of pre-hurricane collection data acted as a comparative baseline for measuring the two storm events’ disturbance, wherein significant decreases in overall taxa richness due to the hurricane were found. Data will highlight both fluctuation in community biomass and dominance of subjects such as Leuctra stoneflies. Through this combined monitoring, population dynamics can be understood with higher fidelity, especially when considering other similar disturbance events that interact with salinity. Creating a profile of ecosystem behavior after significant disturbances could help assist in forming recovery expectations and disturbance predictability in a world with consistently record breaking storm events.