Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Award

Fall 2016

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Department of Biology

Advisor(s)

Christine May

Lihua Chen

Abstract

Freshwater mussels are keystone species in their ecosystems, improving water and substrate quality for other organisms while they are alive, and buffering stream pH and providing shelter with their shells after they die. Approximately 70% of all freshwater mussel species are endangered globally. The James Spinymussel (Pleurobema collina) is a critically endangered species that lives in disparate tributaries of the James River of Virginia. Like other freshwater mussels, they have a cryptic appearance and behavior, making them difficult to find and therefore, to study and conserve. Previous studies indicate a higher percentage of mussels are surfaced during their breeding season, but studying mussels at this time may interrupt their reproduction. The ability to predict how mussels’ surface expression changes in response to other events, ideally ones that can occur several times a year, would aid in conservation.

This study looked at patterns of mussel surfacing in response to flooding disturbances. To research these patterns, a field mark-and-recapture study was coupled with artificial stream channels experiments performed at James Madison University. A 230m long field site has been monitored since the summer of 2014 at Swift Run in Earlysville, VA, and has a population of James Spinymussels as well as a common species, the Notched Rainbow mussel (Villosa constricta). Artificial stream channels were set up with rocky and sandy substrates to mimic conditions at the field site, and V. constricta mussels were used in experiments where they were subjected to a flood at either 15°C or 25°C, to simulate winter and summer temperatures. At the field site, approximately 50% of the mussels detected were surfaced a week after a high flow event in October 2015. Correspondingly, fewer mussels were surfaced during low flows. In artificial stream channel experiments, there were more mussels surfaced at high temperatures and in rocky substrates. There was a significant difference in the number of mussels surfaced in categories of ‘before’, ‘immediately after’, and ‘later after’ a simulated flood in the treatment combinations of 15°C sandy (p

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