9310890 Grace The ability to predict changes over time and in response to altered environmental conditions has become a priority in ecology. By strengthening the link between basic and applied research, ecologists can use information to predict future impacts of habitat alterations on biodiversity and community structure. The research in this Dissertation Improvement grant has two main objectives: (1) to elucidate causal processes in coastal marsh communities, and (2) test a structural equation model that will predict several attributes of community structure from biotic and abiotic variables. The research involves experimental manipulations of salinity, water level, soil fertility, and herbivory in a Louisiana coastal marsh system. Examining the responses of communities to experimental alterations over three growing seasons will provide evidence of the effects of different variables on community structure and provide estimates on potential rates of change in these systems. %%% In order to protect marshes from erosion and damage due to salt water intrusion and sea level rise, resource managers must first know how these variables affect marsh communities. The development and testing of a model to predict marsh community structure will not only help preserve these threatened systems, but will move the field of ecology closer to being a more predictive science. ***
