PARENT SESSION
Contributed Oral Session 1: Landscape History
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 513 A, Level 5, Palais des congrès de Montréal

Geoecology of abandoned agricultural fields in Southern Indiana.

Davis, Adam^*,1, ¹ Department of Geological Sciences, Bloomington, IN, USA

ABSTRACT- Many factors, both biological and environmental (abiotic), combine to influence the composition and diversity of plant communities that grow in ecosystems. Environmental factors such as light availability, slope, and soil characteristics can influence the variability in plant biodiversity and species distributions within and between ecosystems. As part of an inter-disciplinary project, the soil moisture, soil acidity, slope angle and aspect, available light, and soil nutrient content values were determined for soils of abandoned agricultural fields (abandoned in mid-1970s) in two different geologic settings (one, soil over sandstone; two, soil over limestone) in Southern Indiana. Herbaceous and woody species abundances were also determined in these old fields and relationships between the plant communities and environmental factors investigated. In addition, investigations of clay mineralogy, soil thickness, and bedrock characteristics provided insight into the geological processes behind the environmental factor - plant community relationships. In these old fields, soil properties correlate with type and biodiversity of herbaceous and woody plants. Plant biodiversity of herbaceous plants and woody plants both correlate with soil acidity, and do so in both geologic settings even though soils above sandstones can be as much as 1 pH unit lower than soils above limestones. Soil moisture - plant relationships are less clear, but in one field, topographically low regions with moist soils and areas with sub-meter hydrologic variability have greater biodiversity than hydrologically homogenous upland areas. The properties of soils developed in different geologic settings influence environmental factors which, in turn, influence the plant community composition and biodiversity in old fields of Southern Indiana.

Key words: geoecology, soils, geomorphology, biodiversity