PARENT SESSION
Contributed Oral Session 147: Aquatic Communities, Disturbance, and Dispersal
Friday, August 12, 8:00 AM - 11:30 AM, Meeting Room 511a, Level 5, Palais des congrès de Montréal
The scaling of environmental variability in the littoral areas of a lake.
Cyr, Hélène*,1, Walker, Steve1, 1 Department of Zoology, Toronto, Ontario, Canada
ABSTRACT- Recent theoretical models show that the scaling of environmental variability affects the dynamics and persistence of populations. These models explore the effect of different noise colors, without much evidence as to the actual scaling of environmental variability in nature. Here we compare the scaling of temperature variability in different parts of the littoral zone of a large lake basin (22 km2). Water temperature affects all aspects of the lives of aquatic organisms (e.g., energy use, growth, reproduction), and in littoral areas it is also an indicator of physical disturbance from internal waves, and possibly of nutrient pulses from resuspended sediments. We measured water temperature every 16 minutes from May to August 2000 along six depth transects (1.5 to 9.5 m) in the South Arm of Lake Opeongo, ON. We used wavelet analysis to compare the scaling of temperature variability. Downwind sites were warmer than upwind sites in the Spring, and this difference persisted in the deeper portion of the littoral zone throughout the summer. Water temperature varied as red to brown noise in different portions of the littoral zone. Shallow sites differed in long-term temperature variability (14 days), but had similar short-term (hourly) variability. Deeper sites in the upwind portion of the littoral zone had higher long-term (14 days) variability and lower short-term (hourly) variability than downwind sites. This spatial heterogeneity suggest that littoral habitats are a good system to test the effect of scaling of environmental variability on the dynamics and composition in natural communities.
Key words: environmental variability, wavelet analysis, littoral zone, lake