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Partitioning of heterogeneity in an object-oriented riparian boundary classification system for a South African savanna.
Saah, David*,1, Benning, Tracy1, 1 University of California, Berkeley, Berkeley, CA
ABSTRACT- Riparian boundaries have structural characteristics that are distinguishable from upland vegetation. These riparian elements within a savanna matrix located in Kruger National Park, South Africa are the result of several agents of spatial heterogeneity including fire, flood events and geomorphic gradients. We developed a riparian classification system for this study region by integrating information on fire frequency, flood plain hydrology and terrain unit data with ecologically relevant indices derived from a multispectral tassel cap analysis of Landsat ETM data. Results from this work indicate that riparian boundaries account for 8% of the total classified area and were found to be primarily located within the 500 year floodplain as well as in areas with low fire frequency. The tassel cap greenness and wetness indices were found on average to be 19% and 24% greater in riparian boundaries compared to upland vegetation types respectively. Distinct structural differences along lateral gradients were also found on main stem rivers. Main stem riparian boundaries were an average of 500 meters wider on basalt geology compared to those found on granite substrate. In addition, basalt vegetation tended to be sparser with an average canopy cover of 13% while the typical canopy cover from the granites averaged 20%. An initial accuracy assessment of this classification was conducted using a confusion matrix. Results from this assessment indicate an overall accuracy of 93%.
Key words: Spatial Heterogeneity, Object oriented Classification, Riparian Boundaries, Tassel Cap Analysis