HR: 1330h
AN: NB33G-09    [Abstracts]
TI: The Effect of Contrasting Drought Disturbance Regimes on Autrophic Communities
AU: * Ledger, M
EM: m.e.ledger@bham.ac.uk
AF: School of Geography, Earth and Environmental Sciences, University of Birmingham Edgbaston, Birmingham, B15 2TT United Kingdom
AU: Milner, A M
EM: a.m.milner@bham.ac.uk
AF: School of Geography, Earth and Environmental Sciences, University of Birmingham Edgbaston, Birmingham, B15 2TT United Kingdom
AU: Milner, A M
EM: a.m.milner@bham.ac.uk
AF: Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775 United States
AB: Experimental channels (4 blocks x 3 channels; 12.5 m long x 0.3 m wide) fed by stream water were used to assess the effects of contrasting dewatering regimes on autrophic communities over a 21 month period from May 2000 to April 2002. Communities in undisturbed control channels were compared with those subject to different episodic dewatering (5-day duration) regimes. Epilithic biofilms in each channel were sampled quantitatively (6 stones, upper surface area x-y cm2) at monthly endpoints, enabling comparison of disturbed communities with contemporaneous controls. Aliquots were drawn from samples to determine biofilm ash-free dry mass, chlorophyll content and auotrophs were identified to species. Frequent droughts were found to decrease the richness and abundance of core autotrophic taxa and promoted a shift in dominance from eukaryotic green algae to cyanobacteria.
DE: 1812 Drought
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly