Undergraduate Honors Thesis Projects

Date of Award

Spring 4-8-2020

Document Type

Honors Paper

Degree Name

Zoo and Conservation Science-BS


Biology & Earth Science


Michael Hoggarth, Ph.D.

First Committee Member

Kevin Svitana, Ph.D.

Second Committee Member

Michele Acker, Ph.D.


Freshwater Mussels, Bridges, Community Structure, Density, Mussel Survey, Ohio

Subject Categories

Environmental Indicators and Impact Assessment | Environmental Monitoring | Fresh Water Studies | Natural Resources and Conservation


Freshwater Mussels (family Unionidae) are one of the most imperiled group of species found in the United States. Construction activities, such as bridges, can affect sedimentation rates and local deposition, as well as the hydrologic flow of the stream. Since mussels are protected in Ohio, surveys must be done prior to bridge construction to determine the impact of the project on mussel resources. Our study used data from survey reports conducted in Ohio from 2013-2019 at bridge sites. We organized the data to determine mussel community structure and density directly underneath bridges compared to away from bridges. We found the average live mussel density underneath a bridge was 0.42 mussels/meter2 while away from bridges was 0.19 mussels/meter2 (T=1.99, P=.05). We calculated the species richness underneath bridges compared to the outside and found no significant difference (T=1.98, P=.08). We discovered that 78% of the mussel species in these reports preferred to live underneath bridges. Bridge preference was also supported when we compared mussel density at the species level directly underneath the bridge and in the Area of Direct Impact zone outside of the bridge. We discovered that all mussel species, except Pluroblema sintoxia (round pigtoe) preferred to be underneath a bridge (T=1.99, P=.01). Our findings support the conclusion that bridges create a suitable environment for freshwater mussel species. Bridges may also create a preferred environment for their host fish species as well, but further research on fish distribution and stream composition would be necessary to support this conclusion.