CS39A Zooplankton - Feeding, Reproduction, Growth and Molecular Diversity
Date: Tuesday, June 11, 2002
Time: 9:30:00 AM
Location: View Royal
 
PatersonMJ, Freshwater Institute, Winnipeg, Canada, patersonm@dfo-mpo.gc.ca
 
BIODIVERSITY AND THE TEMPORAL VARIABILITY OF ZOOPLANKTON COMMUNITIES AT THE EXPERIMENTAL LAKES AREA, NORTHWESTERN ONTARIO
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It has been suggested that decreases in biodiversity should result in increased temporal variability and lower stability of affected communities. I tested this hypothesis by examining correlations between within-season temporal variance and species richness using more than 250 lake-years of zooplankton data collected at the Experimental Lakes Area, Ontario. The effect on temporal variability of other factors including water chemistry, lake morphometry, hydrology, climate, and food web structure was also examined. Data were collected at regular intervals during the ice-free season and temporal variation was estimated using the coefficient of variation (CV). The data set included both unimpacted lakes and lakes subjected to a variety of manipulations that have strongly affected biodiversity including eutrophication, acidification, biomanipulation, and flooding. Temporal variability was negatively correlated with average daily species richness and was the strongest predictor of temporal variation for both individual zooplankton populations and total zooplankton biomass. Other important predictors of temporal variability included hydrologic residence time and trophic status. Correlation patterns were similar for both unimpacted and manipulated lakes. Zooplankton communities in manipulated lakes were more variable because of reductions in diversity.