Tessier 9726555 A substantial amount of current ecological work focuses on the interfaces between population, community and ecosystem ecology. One focus within this area consider how food-web structure interacts with abiotic features of the environment. This proposal would explore these features by considering community structure characteristics systematically along a gradient of lake forms that exhibit substantial differences in their basin features with consequent differences in physico-chemical features and the occurrence of fishes, a major player in lake food webs. In temperate zone lakes with warm-water fisheries, lake size and depth strongly regulate the types of fishes that are present within a basin. Environmental stress is more common in smaller water bodies to the extent that fishes are excluded from shallow or small basins. Fishes have been shown to have controlling influences over lake food webs and shifts in suspension-feeding zooplankton and their food sources can be expected with changes in fishes. This work would involve a systematic comparison of how food-web structure and trophic coupling change along a gradient of lake size and depth. Investigation will combine comparative data and experiments along the lake gradient to evaluate interactions between habitat and food-web characteristics. It would specifically examine the nature of heterogeneity within the suspensio-feding zooplankton and their resource assemblages. The ultimate goal of this project is to integrate considerations of life-history strategies into food-web, and ultimately ecosystem-process evaluations.