9318130 Bell In models developed for marine vegetated habitats which emphasize ecosystem function, macrophytic vegetation is not generally considered to have major direct links to higher trophic levels. Instead, plants are veiwed as important important trophic contributors to the detrital pool. In the study proposed here we expand the veiw of the role of plants and consider how habitat structure provided by macrophytes, either as physical or predator refuge, or as a site of resource accumulation, might be important to ecosystem function. %%% This study is proposed to 1) explore the relationship of fauna known to be trophically-linked (i.e. small resident fish and epiphytal amphipods) to plant cover, height, and arrangement of plants across spatial scales and 2) develop a model depicting sedimentation processes that influence seagrass patch development and maintenance. Twenty four seagrass beds of varying size and shape will be sampled during the Spring and Fall of 1994 and 1995 in Tampa Bay, Florida. Seagrass patches will be characterized for physical attributes on a landscape level (from aerial photographs), and on a sub-landscape level (i.e. within a landscape, patch level). Regression analyses techniques will be used to investigate relationships between the physical attributes of the seagrass beds at both landscape and sub-landscape scales. The relationship of faunal components and bed physical attributes will also be examined using regression analysis techniques. In the same 24 seagrass beds, sedimentation rates will be measured at each of the four compass headings and expansion/contraction of bed margin recorded monthly. These combined data should allow us to determine if sedimentation plays a major role in defining seagrass patch characteristics, whether patch characteristics have important influence on fauna, and hence, ecosystem function. %%% Our techniques and results should be of general interest to ecosystem research programs where macrophytes are the dominant vegetat ion, including freshwater and salt marshes. Given that macrophyte-dominated areas are often those reported to provide critical habitat for higher trophic levels as feeding/refuge/nesting sites, the role habitat structure plays in these ecosystems may be similar to that in seagrass beds. It is anticipated that results from our study can be used to build a predictive basis for determining the ecosystem level implications of habitat degradation.
