Abstract
Analysis of Land-Cover Change in the Lake Tahoe Basin, 1940 to 2002 Track: Remote Sensing Imagery Author(s): Christian Raumann Since the onset of urbanization, significant human-induced land-use/land-cover changes in the Lake Tahoe basin have resulted in well-documented ecologic consequences. In spite of past and ongoing efforts to understand how humans have affected the landscape, data and analysis regarding historical land-cover change have been previously lacking. We derived high-resolution land-use/cover, impervious-surface, and transportation data for 1940, 1969, 1987, and 2002 through visual interpretation of historical DOQs and IKONOS imagery. In addition, we derived a separate impervious-surface layer from IKONOS imagery using image processing and GIS data integration to model and refine the multi-date impervious-surface estimates. Using post-classification comparison and GIS analysis, we found the most significant changes during the 62-year study period to be an increase in urban land area and a corresponding decrease in natural-cover class area; varying increase and decrease in the density of forest stands; conversion of shrublands, grasslands, and wetlands to conifer forest; and tree mortality. Christian Raumann U.S. Geological Survey Western Geographic Science Center 345 Middlefield Road, MS-531 Menlo Park , CA 94025 US Phone: 650-329-5648 Fax: 650-329-4429 E-mail: craumann@usgs.gov |
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