CS39B Zooplankton - Community Dynamics
Date: Wednesday, June 12, 2002
Time: 11:45:00 AM
Location: Sidney
 
BinksJA, University of Toronto, Mississauga, Canada, jbinks@utm.utoronto.ca
Arnott, S, E, Laurentian University , Sudbury, Canada, sarnott@nickel.laurentian.ca
Sprules, W, G, University of Toronto, Mississauga, Canada, gsprules@cyclops.erin.utoronto.ca
 
THE INFLUENCE OF BIOTIC AND ABIOTIC FACTORS ON ZOOPLANKTON COMMUNITY RECOVERY FROM ACIDFICATION
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Freshwater systems in Sudbury, Canada provide a unique opportunity to examine factors that shape community structure once a past stressor is removed. Lakes are improving chemically, but biological recovery is slow. For biotic recovery to occur, species must first arrive to the recovering lake and then must survive and reproduce. Survival and reproduction may be influenced by biotic interactions with established species and abiotic conditions. We conducted mesocosm experiments in a 2x2 factorial design to determine the influence of pH (5.5 and 6.5) and the local community (with and without Swan Lake zooplankton) on colonizing species. Bosmina, Daphnia and Sida had higher abundances in the augmented pH treatment (6.5) but were not influenced by local community interactions. Recovery of these species is probably limited by the chemical recovery of the lake. Cyclopoids appear to be influenced by a combination of pH and local community structure at pH 5.5. However, community interactions at pH 6.5 do not influence their abundance. These results suggest that although chemical recovery has started to occur in many lakes, further recovery is necessary for biotic recovery to progress.