Exacerbated grassland degradation and desertification in Central Asia during 2000-2014

Grassland degradation and desertification is a complex process, including both state conversion (e.g., grasslands to deserts) and gradual within-state change (e.g., greenness dynamics). Existing studies hardly separated the two components and analyzed it as a whole based on time series vegetation index data, which however cannot provide a clear and comprehensive picture for grassland degradation and desertification. Here we proposed an integrated assessment strategy, by considering both state conversion and within-state change of grasslands, to investigate grassland degradation and desertification process in Central Asia. First, annual maps of grasslands and sparsely vegetated land were generated to track the state conversions between them. The results showed increasing grasslands were converted to sparsely vegetated lands from 2000 to 2014, with desertification region concentrating in the latitude range of 43-48°N. A frequency analysis of grassland versus sparsely vegetated land classi...