Sensitivity of Landsat 7 & 8-derived vegetation indices on semi-arid rangelands of southwestern Uzbekistan
Аннотация
Consistent use of vegetation indices (VIs) for monitoring rangeland ecosystems in Middle Asia, and particularly Uzbekistan has been limited. In the face of intense rangeland degradation in Uzbekistan, understanding the applicability of VIs is an immediate priority for the assessment of the current state of these rangelands. This article focuses on comparing and evaluating the potential of five intensively used VIs (NDVI, SAVI, EVI, PVI and TSAVI) to detect changes in condition and productivity of Artemisia spp. rangelands across different seasons and years. The results indicate a high degree of similarity in the response of the tested VIs when multi-season and multi-year vegetation data were combined. However, there was significant variability when vegetation data were parsed into seasons and/or variable precipitation years. We recommend that a remote sensing assessment of rangelands in various stages of invasion by native non-palatable plants should rely on a multi-season analysis of NDVI or SAVI.