PARENT SESSION
Contributed Oral Session 73: Aquatic Ecology: Management of Streams and Lakes
Wednesday, August 10, 8:00 AM - 11:30 AM, Meeting Room 513 A, Level 5, Palais des congrès de Montréal
Lake level effects on aquatic communities and water quality in Ontario, Canada.
White, Michael*,1, Hogsden, Kristy1, Xenopoulos, Marguerite*,1, Metcalfe, Robert2, Dillon, Peter1, 1 Trent University, Peterborough, Ontario, Canada2 Ontario Ministry of Natural Rresources, Peterborough, Ontario
ABSTRACT- Natural fluctuations in lake water levels can have many implications for aquatic biota, either directly via changes in habitat size or physical properties, or indirectly via changes in water quality. Using archived data from long-term monitoring sites in Ontario (e.g., HYDAT, ELA, Dorset, Turkey lakes) and other published research, we compiled long term changes in lake levels across Ontario and investigated how they relate to biological and physical parameters in these lakes. Lake levels did not fluctuate more than 1 m annually in any of the natural lakes. In contrast, regulated lake levels can fluctuate up to 10 m in very short periods (daily). Using multivariate statistics, we found that lake level changes were primarily correlated with alkalinity (r = -0.94), dissolved inorganic carbon (r = -0.93), dissolved organic carbon (DOC; r = -0.96) and sulfate concentration (r = -0.68). Lake-level reductions of DOC concentration resulted in increased water transparency but did not significantly affect algal biomass (measured as chlorophyll a). Preliminary results suggest that fish richness declines with reduced lake levels. Additional research is needed to better understand the role of natural lake level fluctuations on biodiversity and water quality to facilitate better management plans for waterpower reservoirs and increase our understanding of climate change.
Key words: lake level, biodiversity, fish, water quality