Graduate Program

Biological Sciences

Degree Name

Master of Science (MS)

Semester of Degree Completion

2005

Thesis Director

Robert Fischer

Thesis Committee Member

Charles Pederson

Thesis Committee Member

Thomas Nelson

Abstract

Much of the Midwest, as well as Illinois' landscape, has largely been transformed from its original habitat of prairie, savanna, wetlands, and forest into corn and soybean fields and urban areas. As a result, less than 1% of the original habitat in Illinois remains intact today. These modifications can lead to habitat fragmentation and affect riparian zone vegetation, which is an important link between the land-water interface and influences processes such as organic matter inputs and water temperature regimes. As a result of fragmentation, riparian zone loss has occurred and catchment vegetation associated with streams can vary from agricultural fields, to forest patches, to residential areas. Thus, the objectives of this study were to: 1. determine whether habitat quality has an affect on abiotic stream variables, 2. establish if a relationship exists between habitat quality and heterotrophic density and metabolism, and 3. ascertain which abiotic stream variables can be used to predict heterotrophic density and metabolism. Through the use of The Stream Habitat Assessment Procedure we found that although varying habitat quality exists within the Embarras River watershed; no such effects can be seen in the water quality data. A multiple regression model reveals that there are several SHAP metrics (substrate stability, instream cover and deposition) important in predicting the oxygen consumption of benthic heterotrophic microbes only, while no useable models exist for predicting bacterial/fungal densities. Further analysis revealed a list of variables that are useful in predicting the density and metabolism of heterotrophic microbes, but were different for each class of microbes (benthic/suspended and fungal/bacterial), indicating that no one set of water quality variables can be used to predict the activity or metabolisms of heterotrophic microbes as a unit.

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