On the Possible Use of Indicator Variograms for Building Ecological Indicators

First results of a geostatistical analysis of the maximum annual NDVI (MANDVI) measured by SPOT/VEGETATION over Kenya between 1999 and 2007 are presented here. The purpose of this work is to investigate the use of the spatial correlation of land cover classes using indicator variograms to characterize and summarize spatio-temporal changes in the land cover on an annual basis. More precisely, we used the slopes of the log-log plots of the variograms to characterize spatio-temporal changes in MANDVI. The value of the slope is also known to correspond to the fractal dimension of the spatial correlation of the analysed variable and, since it provides us with a single value rather than with a complex plot, this fractal dimension could be used as environmental indicator to summarize complex changes in the patterns of MANDVI. The use and limitations of this approach are discussed.
JRC.H.3-Global environement monitoring