ABSTRACT 97-06880 Moran RUI: The relative strength of top-down and bottom-up forces in old-field arthropod communities. Top-down regulation of a food chain refers to how predators control the populations of other species, while bottom-up regulation refers to how resources such as minerals and water affect the organisms and their interactions. This study will be conducted on the arthropods (insects, spiders, and others) that inhabit fields. Arthropods are often the dominant species in fields and therefore are important in understanding how natural communities are controlled. Top-down and bottom-up processes are present in all communties, but the importance of each is not well-understood for places with high numbers of species. This study will begin to address this question by manipulating resources and the level of predation simultaneously to determine the predominant force in an arthropod community.
