PS 3-39
Vertical movement of the endangered James Spinymussel (Pleurobema collina) in response to floods at different temperatures and substrates
The James Spinymussel (Pleurobema collina) is a species of top priority for conservation in Virginia, but is difficult to study due to its small population sizes, limited species information, and their cryptic appearance and behavior. In particular, previous research on how mussels respond to disturbances is lacking. The goal of this project is to determine how mussels change their vertical position (present on the streambed or burrowed) in response to floods, and how this varies with different substrates and temperatures. This is achieved with linked laboratory and field experiments. Mussels experienced a flood under sandy or rocky conditions at 10 and 20 ℃ in artificial stream channels, and were observed three times a day to record surface expression and burial depth. A long-term field study in the Rivanna River basin, VA involved marking approximately 20 James Spinymussels and 60 Notched Rainbow mussels (Villosa constricta) with Passive Integrated Transponder (PIT) tags in the summer of 2014. Recapture histories from the past year have informed hypotheses that are tested in the laboratory and in the field.
Results/Conclusions
Results from a pilot study conducted with Asian clams (Corbicula fluminea) in the artificial stream channels showed that significantly more clams buried themselves in the sandy habitat (P=0.04), and that on average they were buried deeper (p=0.009). Field data has shown that individual mussels show varying levels of baseline streambed surface expression, and that an increased amount of mussels are visible on the surface of the streambed up to two days after a flooding event and during warmer conditions. The pilot experiments allowed for significant improvement in experimental design, and data collected to date is promising for continued experiments with mussels. This data will be used as a case example for how to quantify responses to disturbance in rare, cryptic organisms.