I am interested in the ecological services freshwater mussel communities provide to stream ecosystems. Overall, we know that freshwater mussels are important benthic/pelagic energy couplers filtering out particles from the water column and depositing organic matter and nutrients to the surrounding sediment.   In turn, these nutrient and organic subsidies  facilitate local macroinvertebrates and algae. I am interested in how species composition of the community influences the magnitude of services performed by the mussel bed. 

Mussels are thermo-conformers  passively adjusting their body temperature according to  environmental temperatures. Stream temperature constrains reproductive timing, metabolism and resource acquisition   potentially influencing the rate and magnitude of ecological services performed mussel communities. I am interested in determining how physiological set-points (high-temperature, low-temperature, optimal temperatures)  influence resource capture and assimilation (physiological condition) and ecological services performed different species of freshwater mussels. Given the high biological diversity of mussels in a given bed, could different mussel species be particularly important under different thermal regimes?

I am interested in determining which factors promote the vast diversity and abundance of freshwater mussels. There is a clear link between fish diversity and mussel richness given that mussels rely on host fish to complete their life cycle. However, in addition to known factors such as habitat and fish community structure, I am interested in how both temperature and productivity gradients constrain or promote mussel richness and abundance.

Ecological significance of freshwater mussel communities.

Factors influencing richness and abundance of freshwater mussels.

Physiological ecology of freshwater mussels.

I am using re-circulating stream mesocosms in a thermally-controlled room to manipulate mussel species composition (dominance).  Using laboratory derived physiological null models, I am predicting the condition and performance of mussels at the individual and community level strictly associated to temperature. Deviations from these models will lend insight into species interactions (competition/facilitation) occurring within communities. This information will help us scale up our findings to predict interactions and ecological services provided by real mussel beds.

Use of physiological null models to predict species interactions.

Proposed water sales and impoundment management threaten the natural flow regime of several rivers in southeastern Oklahoma. Shifts in flow regime coupled with warmer than average summers have resulted in drought conditions.  Long reaches of dry riverbed expose mussels to lethal temperatures and isolate pools  resulting in poor connectivity limited dispersal potential.  I am studying the consequences of mussel mortality on nutrient flux and water quality. I have developed a quantitative model predicting the conditions for which mussels become thermally stressed.

Influence of water management practices on freshwater mussel communities.

Kiamichi River at medium flood stage.

(flows get considerably larger!)

Kiamichi River at reduced flow

(This site is known to dry up entirely!)

Environmental room housing re-circulating mesocosms

Various mussels interacting in a stream mesocosm.

Heather and Wavey “sampling” for mussels. Note the two different techniques!

Mussel communities display a checkerboard distribution in dominance

Environmental chamber

Setting up a mussel enclosure experiment

Recirculating stream mesocosm