Rusak, J. A. York University, jrusak@yorku.ca
McQueen, D. M. York University,
Somers, K. M. Dorset Environmental Science Centre,
Yan, N. D. Dorset Environmental Science Centre,
Ramcharan, C. W. Louisiana State University,

 
CHANGES IN THE PELAGIC ZOOPLANKTON COMMUNITY FOLLOWING WHOLE-LAKE MANIPULATIONS AND THE BIGGER PICTURE FROM REFERENCE LAKES
 
We compared changes in the temporal structure and variability of the zooplankton community in two manipulated north-temperate lakes with reference communities in 7 nearby unmanipulated lakes. We manipulated Ranger and Mouse lakes by moving the large and smallmouth bass from the former into the latter, originally piscivore-free, lake. Variability in the mean annual biomass of the entire community, small and large cladocerans, and the calanoid and cyclopoid copepods was contrasted among reference and manipulated lakes using Levene's test. Contrary to predictions, variability generally did not differ between experimental and reference communities. Changes in community structure were investigated by estimating synchrony among all lakes as well as in subsets that displayed common temporal patterns. Temporal coherence was low when all lakes were included, but increased rapidly as atypical patterns were removed. In subsets that included both the experimental and as many as five reference lakes, a substantial portion of the variation in patterns of mean annual biomass could be accounted for by factors common to all lakes. These two results indicate the importance of reference communities when deciphering treatment effects and that, even with large manipulations, a substantial portion of the interannual variability can still be extrinsic in nature.
 
Day: Wednesday, Feb. 3
Time: 04:45 - 05:00pm
Location: Hilton of Santa Fe
 
Code: CS66WE0445H