Abstract: Desert steppe is an ecotone between desert and steppe. Desert steppe is very fragile. Furthermore, it is difficult to restore once destroyed. Desert steppe in Siziwang Banner is one of the most arid types in the temperate steppe of Inner Mongolia. The evolution of landscape pattern in desert steppe is not only related to the diversity of grassland ecosystem, but also has important significance for the restoration of ecological functions of neighboring ecosystems. In this study, we assessed the change of landscape pattern and habitat quality in Siziwang Banner desert steppe based on remote sensing technology, landscape ecology theory, and  InVEST model. We analyzed its responses to climate factors based on the key parameter NPP to enhance our understanding of desert steppe. From 2003 to 2017, the fragmentation degree of ecosystem landscape pattern in Siziwang Banner was increased, the connectivity of dominant patch landscape was further weakened, and the overall habitat quality was decreased by about 2%, showing obvious regional differences. The NPP of Siziwang Banner decreased year by year, with a spatial distribution pattern of decreasing in the north and increasing in the south. NPP in Siziwang Banner grassland was more correlated with cumulative precipitation than with air temperature. There was an obvious legacy effect, with a lag time of 2.96 months.

Key words: desert steppe, landscape pattern, habitat quality, net primary productivity of grassland, legacy effect.