Landscape Dynamics and Sustainability Assessment of Isolated Island Habitats (Zijin Mountain) on the Loess Plateau from 1975 to 2018

摘要

Based on Landsat Multispectral Scanner (MSS)/Thematic Mapper (TM)/Enhanced Thematic Mapper Plus (ETM+)/Operational Land Imager (OLI) sensors data (1975-2018), MODIS NDVI data (2000-2018), some average annual precipitation and temperature data of surrounding meteorological stations (1980-2015) and ASTER GDEM digital elevation model data, we carried on the fragmentation degree, spatial-temporal differentiation and correlation analyses on the climate change factors (average annual precipitation and temperature), human activity factors (urban and rural residential land, regional lighting index, land use change) and remote sensing index (normalized differential vegetation index, NDVI) in Zijin Mountain region. The results show that some ecological, cultural and geographical indicators have changed in the Zijin Mountain region for the past 44 years. The study area of urban and rural construction land has increased by 4.29 times. Over the 32 years, the average vegetation index of the whole basin has increased by 35.12%, the area of shrubs has increased to 52.60% of the basin's available area, and the area of forest has increased by about 1.3%. The average annual precipitation change rate of 36a (1980~2015) was +18.7 mm/10a, and the annual average temperature change rate was +0.42 °C/10a. Above all, the study area has had a warm-humid tendency to develop. In the past 44 years, the habitat fragmentation index of the ecological environment has increased by 6.04 times. The Zijin Mountain region has been transformed from an original mountain grassland ecosystem to a mountainous dry-farming agricultural ecosystem. Human activities have changed the original ecological structure, accelerated the habitat fragmentation, and become the leading factor in the degradation of ecological structure.