9521184 Duffy One of most pervasive and irreversible effects of environmental change wrought by human activity is the reduction in species diversity on local and global scales. The consequences of declining for ecosystem function remain largely unquantified and unpredictable. The loss of species in low diversity but high recruitment environments, like estuaries, may severely alter production levels and trophic transfers. This research will involve a series of mesocosm experiments to test the effects of invertebrate grazer species on: 1) the structure of eelgrass communities, particularly the algal epiphytes, 2) functional processes within the eelgrass ecosystem, especially primary and secondary production, vascular detritus processing, and organic matter export to underlying sediment, and 3) the responses of the plants to nutrient enrichment. The results of this work are likely to provide the first experimental evidence about the roles of mesograzers in shallow water vegetation communities, including their individual and collective effects on community structure and function. ***
