DISSERTATION RESEARCH: The Effects of Habitat Structure on Ecological Communities and Processes at the Aboveground-Belowground Interface

Urban development creates new habitats for soil- and ground-dwelling organisms, which may move in from surrounding 'natural' habitats. Our research focuses on measuring biodiversity and ecosystem processes in four habitats commonly found in urban environments: lawns, unmowed fields, and shredded-bark and gravel mulches. The hypothesis of this study is that different habitats support different biological communities, which in turn affect nutrient cycling, plant health, and pollution potential. In 2003, the investigators of this project established replicated plots of the four habitats from which to sample insects, spiders, collembolans and other arthropods. They found that the abundances of these arthropods differ among the habitats. For example, spiders were more numerous in bark mulch habitat while some collembolans were more abundant in unmowed habitat. Arthropod sampling will continue in 2004-2005. In addition, the investigators will measure earthworm populations in each habitat and compare carbon and several forms of soil nitrogen to quantify differences in nutrient cycling. Decomposition, or the breakdown of carbon in decaying organic matter, will be studied by measuring the decrease in weight of leaves in litterbags through time. Studying the amounts and forms of carbon and nitrogen in soil, water and the atmosphere are important because these elements play roles in global climate change and water pollution. In addition, studying the effects of urban habitats on organisms like arthropods is important for conserving biodiversity in urban landscapes. Our research will provide information that may contribute to the conservation of beneficial organisms (such as spiders) through habitat management, and to the maintenance of proper levels of carbon and nitrogen in soil to help keep lawn and garden plants healthy.