HR: 0800h
AN: B31B-0327    [Abstracts]
TI: Environmental Effects on Plant Communities of Abandoned Agricultural Fields in Southern Indiana.
AU: * Davis, A M
EM: adavis@vinu.edu
AF: Department of Earth Science and Agriculture, Vincennes University McCormick Science Center, Vincennes, IN 47591, United States
AB: Plant community characteristics are influenced by different environmental factors depending on geologic setting, climate, species composition, successional stage, land use, and geographic and temporal scales. Plant communities that have colonized abandoned agricultural fields (old fields) in Southern Indiana vary in composition, structure, and diversity. They vary on a regional scale manifesting as differences between old fields. They vary at local scales manifesting as differences within old fields. In a study of 6 old fields in Southern Indiana, certain environmental variables were found to correlate more strongly with plant community characteristics in some fields than they did in others. Water table depth was a larger component in multiple regression models for fields that exhibited a greater range of water table depths. An old field with a perched spring water table contained facultative wetland species while others did not. Soil acidity correlated more strongly with biodiversity in 1 of the fields than it did in the others. Acid tolerant species were present in this field and not in the others. Multiple regression models were constructed using environmental variables (nutrient levels, base cation concentrations, water table depth, soil moisture, photosynthetically available radiation, soil acidity, slope, aspect and thickness of organic rich soil horizons) as the independent variables and plant community characteristics as dependent variables. The multiple regression models with species distributions as the dependent variables, described a greater percentage (70 per cent in some cases) of the variance than models with biodiversity and plant density dependent variables, which described between 10 and 40 per cent of the variance. These differences were also observed in strengths of correlations in simple linear regression analysis. Soil , hydrologic, slope, and light characteristics can account for some of the variety observed in successional plant communities. The important influences on plant communities differ based on geographic scale and geologic setting.
DE: 0410 Biodiversity
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0476 Plant ecology (1851)
DE: 0486 Soils/pedology (1865)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting