Investigating spatiotemporal dynamics of grassland changes by using multi-temporal Landsat images: A case study in central Xilingol, China, 1985 – 2010

A case study is conducted in the central Xilingol Rangeland of China to map temporal trajectories and spatial patterns of the grassland changes by using time-series Landsat images. 9 available scenes of Landsat images without cloud cover from 1985 to 2010 are selected for the experiment. First, the object-oriented image classification using different object features is conducted on the time series Landsat images. Then a hierarchy of layers in different years for change detection is deployed to evaluate the qualitative and quantitative characteristics of land cover changes. The trajectory matrices of grassland changes are also generated. Following the factor analysis is conducted on the trajectory results. The experimental results show that the grassland during the periods, 1989–1991, and 2000–2004, is improved. The changes are closely related to the interactions of human activities and climate factors (precipitation change in particular). However, in general, Xilingol grassland is degraded from 1985 to 2010. More effort should be taken to protect the Xilingol Rangeland.