The use of primary producers for assessing and monitoring aquatic habitat quality in Great Lakes coastal wetlands

The overall objective of the research presented in this thesis was to provide a scientific basis for the use of primary producers, algae (benthic and planktonic) and vascular aquatic plants (macrophytes) in the evaluation of Great Lakes coastal wetlands. Primary producers in these ecosystems have not been well studied, and there is a lack of knowledge about benthic algae and submergent macrophytes in particular. To achieve this objective, experimental and observational field studies of primary producers were conducted in coastal wetlands throughout the Great Lakes basin, to test predictions regarding the interactions of primary producers with other biota (fish) and abiotic factors along a gradient of human-induced environmental degradation.; I developed, tested and implemented a protocol for assessing benthic algal biomass in twenty-four Great Lakes coastal wetlands and demonstrated how this can be used as an indicator of environmental degradation. I also found that the diversity and abundance of submergent plants declined as benthic algal biomass increased. Regional and basin-wide patterns in the distributions of submergent plants were determined by multivariate analyses of survey data from eighty-one coastal wetlands, and these patterns were found to be indicative of both natural variation and anthropogenic disturbance of the environment. I found that the occurrences of fish and submergent plant taxa in sixty coastal wetlands were highly correlated, and that submergent plants can be used as a tool for assessment of fish habitat in these ecosystems.; In general, this research has demonstrated that primary producers, algal and macrophytic, are good indicators of environmental conditions in Great Lakes coastal wetlands with respect to anthropogenic degradation and fish habitat. It has also shown that there are strong connections among different trophic levels that are affected by human-induced environmental degradation.