PARENT SESSION
Oral Session #16: Disturbance in diverse systems: Flooding and other. Presiding: T. Stohlgren.
Monday, August 6, 2001. 1:00 PM to 5:00 PM. Hall of Ideas G.

The effects of Hurricane Floyd on benthic community structure in piedmont North Carolina streams.

REICE, SETH¹, ¹

ABSTRACT- We fortuitously sampled the macrobenthos and water chemistry of 3 NC streams in the weeks prior to Hurricane Floyd (September 16, 1999). The initial sampling was part of our project studying the effectiveness of different sediment and erosion control ordinances by examining changes in benthic community structure. We returned and resampled the same sites in January and February 2000, to see if we could detect the impact of the massive floods caused by the hurricane. I will present data on total benthic abundance, total species richness and Shannon diversity for 1) all taxa, 2) EPT taxa (Ephemeroptera, Plecoptera and Tricoptera) and 3) Chironomidae. We found that species richness and abundance for all taxa was significantly reduced following Hurricane Floyd, even beyond the previously measured impact of the sedimentation from construction. We found that EPT abundance was reduced by two thirds, and chironomid abundance by >50%. EPT and chironomid richness were both cut in half after the hurricane. This shows that the magnitude of the disturbance was sufficiently great to significantly depress species richness. Even after 5-6 months there was no sign of recovery of the stream communities from the devastation wreaked by Hurricane Floyd.

KEY WORDS: Community structure, Biodiversity, Streams, Hurricane Floyd