Date of Award

2015

Degree Type

Thesis

Department

Biological, Geological and Environmental Sciences

First Advisor

Krebs, Robert

Subject Headings

Freshwater mussels -- Habitat -- Ecology -- Mahoning River (Ohio and Pa.), Freshwater mussels -- Environmental aspects -- Mahoning River (Ohio and Pa.), Biodiversity -- Mahoning River (Ohio and Pa.), Hydrology -- Ohio, Mahoning River (Ohio and Pa.) -- Environmental aspects, land use, freshwater mussels, community structure, distribution, steam hydrology

Abstract

Freshwater mussel communities have experienced drastic declines in diversity and abundance in many streams throughout North America. Among the reasons for these declines is the human-driven alteration of the landscape, as urban and agricultural use impart many known stressors to aquatic systems. Impairments include increased sedimentation, increased pollutants, increased flood frequency and intensity, and decreased diversity and abundance of many organisms, including fish, macroinvertebrates, and mussels. Attempts to explain the abundance and diversity of mussel communities using small-scale factors such as substrate type and flow velocity provided little to no predictive power. Instead, reach-scale variables, such as stream morphology and riparian vegetation, and catchment-scale variables, such as land use, performed better as predictors of mussel diversity and abundance. In this study, surveys of mussel communities were performed in Eagle Creek in 2013 and throughout the entire upper Mahoning River watershed in 2014. Stream morphology was assessed at the sites surveyed in 2014. No published surveys exist for the mussel community of the upper Mahoning River watershed, which is a headwater system in the upper reaches of the Ohio River watershed. The Eagle Creek watershed had the highest proportion of forested land in the upper Mahoning River watershed and supported the largest and most diverse mussel community, although evidence for recruitment was limited in this stream. Across the region, abundance and species richness were strongly correlated with drainage area. Abundance and species richness decreased with increased shear stress, electrical conductivity, and agricultural and urban land use. Conductivity was also correlated with agricultural land use, and no live mussels were found where conductivity exceeded 0.9mS. Overall, the upper Mahoning River watershed had a low diversity and abundance of freshwater mussels, likely due to the intensive anthropogenic land use. Even where condition

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