The application of a remotely-sensed diversity index to monitor degradation patterns in a semi-arid, heterogeneous, South African landscape

We present a remotely-sensed degradation assessment technique based on the measurement of landscape heterogeneity (a key determinant of degradation st atus). The moving standard deviation index (MSDI) is derived by passing a m oving standard deviation filter across the Landsat TM band 3 (red band). De graded/unstable landscapes exhibit higher MSDI values than their undisturbe d/stable counterparts. Significant differences in MSDI were detected (p < 0 .001) across four fence-lines which separated rangeland of contrasting cond ition. The relationship of the index to normalized difference vegetation in dex (NDVI) was tested in five different ecosystems and significant correlat ions were obtained in all cases (p < 0.001). We propose the MSDI as a power ful adjunct to vegetation indices. (C) 1999 Academic Press.