Urbanization and Atmospheric Deposition: Use of Bioindicators in Determining Patterns of Land-Use Change in West Georgia

Changes in land use disrupt ecosystem patterns and processes and serve as precursors to other biotic and abiotic stressors. Forest ecosystems in the urban core typically differ structurally and functionally from those in rural areas. The overall objective of the study was to determine concentrations of selected air-borne contaminants (N, S, and heavy metals) over space and time and relate these to land-use changes. Elemental concentrations in lichens, soils, and tree cores were examined from 36 plots distributed along an urban-to-rural gradient surrounding Columbus, GA, USA. In situ lichen tissue exhibited the most significant differences among land-use types, with Cu, N, Pb, S, and Zn concentrations all significantly greater at urban sites. Lichen transplants revealed differences in concentrations between species, but not between land-use types. No discernable trends were observed regarding concentrations in soil and tree core data. Lichens appear to be a sensitive indicator of land-use change in this particular case study.