Undergraduate Honors Thesis Projects

Date of Award

2015

Document Type

Honors Paper

Degree Name

Biology-BS

Department

Biology & Earth Science

Advisor

Michael Hoggarth, Ph.D.

First Committee Member

Kevin Svitana, Ph.D.

Second Committee Member

Jonathan DeCoster, Ph.D.

Keywords

Big Walnut Creek, Mussels, Mussel Recovery, Water Quality, Land Use, Bioassessment

Subject Categories

Environmental Monitoring | Other Ecology and Evolutionary Biology | Terrestrial and Aquatic Ecology

Abstract

Since the enactment of the 1977 Clean Water Act, biologists have created numerous multimetric assessment tools to evaluate the biological integrity of water resources, using biological criteria. The integrity of Big Walnut Creek, Ohio, has been in flux since the 1955 construction of Hoover Dam, and while current water quality is high, mussel communities in the creek have yet to recover to historical levels. This study sought to determine the cause of the decline in the mussels in the lower section of the creek below the dam. Historical creek data, including a fish-based index of biotic integrity (f-IBI), invertebrate community index (ICI), qualitative habitat evaluation index (QHEI) and modified index of well-being (MIWB), were compared to a recent mussel-IBI for the creek. These data were compared to urbanization data (i.e. percent plant cover) describing land use in 1 km2 sample regions around each biometric data collection site. Data were analyzed using linear region and student t-tests to understand any correlative relationships with the status of mussel communities. Mussel-IBI data were compared to percent land developed (r2=0.225, p>0.01), percent plant cover (r2=0.1 p>0.01), road density (r2=0.007, p>0.01), census tract data as a measure of population density (r2=0.003, p>0.01), riparian zone width (r2=0.107, p>0.01) and creek width (r2=0.001, p>0.01). Ohio EPA biometric data were compared to percent plant cover data: f-IBI (r2=0.185, p>0.01), MIWB (r2=0.004, p>0.01), ICI (r2=0.028, p>0.01) and QHEI (r2=0.265, p>0.01). No significant correlations were found between urbanization and integrity, suggesting that land use does not directly affect the lower section of Big Walnut Creek. Therefore, it is possible (pending future research) that the mussel communities could recover in time, similar to the fish and invertebrate communities in the creek.

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