This project is one that I have been working on using treeholes as a model ecosystem, but I am also interested in investigating the same type of question in other ecosystems. I have previously determined that scirtid beetles have positive effects on growth of two dipteran detritivores, the eastern treehole mosquito, Ochlerotatus (=Aedes) triseriatus, and the ceratopogonid midge, Culicoides guttipennis. This effect, however, is observed only at lower resource levels. I have also shown that the beetles have higher survival at low pH than either the mosquito or the midge. Consequently, I am interested in how pH and resources interact with the biotic commensalistic interaction. Again, I am using laboratory microcosms to test the hypothesis that low pH eliminates the commensalism. However, I found that the commensalism is more pronounced under low pH and low resource conditions! Further investigation into the exact mechanism behind this phenomenon is ongoing. I am also planning on determining the interactions in the field, and how varying densities play a role in the commensalism.
2. Effects of Environmental Change on Aquatic Insect Communities
I am interested in cataloguing the biodiversity of macroinvertebrates in various subwatersheds in central NC. My students and I are using standard methods for determining biodiversity of aquatic insects, including rapid biological assessment. Our main objective is to determine the effects of land use change and urban development on communities of insects inhabiting small headwater streams in and around Charlotte suburbs. These small headwater streams are keys to the overall health of the river system, since this is where much of the water downstream is derived from. Healthy riparian vegetation zones surrounding these streams prevent erosion and subsequent sediment deposition into these streams. Along with the sedimentation, organic and inorganic pollution may increase as development proceeds and riparian vegetation is replaced with impervious or disturbed surfaces.
3. Scale effects in micro- and mesocosm experiments
Since I, and so many other ecologists, rely on microcosm studies to such a large degree, I am interested in determining whether there are artifacts of scaling and simplifying ecosystems in artificial habitats. I would like to take two model systems, treeholes and temporary ponds, and test simple biological interactions in the natural habitat and in a variety of scaled down micro- and mesocosms. For treeholes, the microcosms I use are approximately the same size as real treeholes, or are at least in the natural range. However, many ‘cosm experiments testing various factors in temporary ponds simulate the habitats in much smaller containers than the actual size of the ponds. Are some communities more amenable to ‘cosm experiments? Is there any relevance to the real habitats in any micro/meso cosm experiment? I have placed a number of experimental units on trees in our Davidson Ecological Preserve that vary in their depth and width. I am planning on starting a long-term experiment on community assembly in those habitats.
Page last updated by Chris Paradise on 11 May 2000