My current research is being conducted on the Verdigris, Caney, and Neosho rivers in the Tallgrass Prairie ecoregion of Oklahoma . These three rivers once harbored a broad diversity of native Unionid communities, (Isley 1924), that are now listed as threatened or endangered. However, more recent surveys by Vaughn (1998), indicate significant declines in Unionid diversity and abundance in these areas. To address this issue, we are taking an ecosystem approach to assess the macroinvertebrate, mussel, and fish communities in these rivers. We hope to gather baseline data on macroinvertebrate and fish assemblage within each river as well as characterize diversity and abundance of the remaining Unionid communities. We hope these data will provide an insight to the relative aquatic health of these rivers. In addition, the Verdigris and possibly Neosho rivers harbor expanding populations of the invasive zebra mussel, Dreissena polymorpha. The detrimental effects of this invasive species on native mussels and ecosystems in general, have not been well characterized in more southern latitudes. Therefore, we will be using stable isotope techniques to assess the degree of trophic connectivity within the three rivers and determine the functional position of this invasive in these systems.

I am also continuing to gather data on several lakes in Oklahoma that have recent introductions of zebra mussels. On a weekly basis, we measure veliger densities and settling, standard water chemistry, and adult densities. Additional monitoring has included growth rates and length distributions at various depths and under different seasonal temperatures.