Abstract:

Based on Landsat 5/8 remote sensing data， this paper systematically analyzed the spatiotemporal variation characteristics of fractional vegetation cover （FVC） in the Heihe River Basin using pixel binary model， univariate linear regression model， landscape pattern index and center of gravity migration model. The results showed that： （1） The FVC in the Heihe River Basin showed an overall trend of first increase and then decrease， with significant improvement from 1999 to 2019 （the growth rate of extremely high coverage was 612.2 km²·a^-1）， but it degraded after 2019 （the growth rate of extremely low coverage reached 1 172.3 km²·a^-1）. （2） Landscape pattern analysis showed that the degree of fragmentation of high and medium coverage increased （LSI>100， AI<60）， while the aggregation of extremely high and extremely low coverage was high （AI>80）， reflecting the strong interference of human activities on the transition zone. （3） The center of gravity migration showed that ecological degradation in the northeast coexisted with ecological recovery in the northwest， and the landscape heterogeneity of the oasis area in the middle reaches was enhanced. This study developed a multi-scale landscape pattern analysis method， which can provide a scientific basis for ecological management and sustainable development of inland river basins in arid areas.

Key words: fraction vegetation coverage, landscape pattern analysis, center of gravity migration model