[Landscape Pattern and Dynamic Change of Fractional Vegetation Cover in a Typical County in an Arid Region].

Abstract

The dynamic change in fractional vegetation cover （FVC） in arid areas is an important basis for the development and evolution of desertification as well as critical component land desertification control. Using Hebukeser （also known as Hefeng）, a typical arid zone county, as the study area, we analyzed the changes in the ecological landscape pattern of vegetation with different coverages； investigated the dynamic changes of landscapes with different FVC from the perspectives of change frequency statistics, geocoding method, and migration of the center； and elaborated on the dynamic shift of various types of landscapes and the rule of migration of the center. The finding showed that： Over the course of the 20-year period, the county's average FVC increased from 18.00%-20.39%. Notable differences were observed in the county's spatial distribution, with low FVC predominating and very high and high FVC primarily distributed in the northern and central villages. The area with four changes in vegetation cover accounted for 71.98% of the total area, primarily representing the distribution area of the very high FVC, and the area with no change accounted for just 0.08%. The proportion of stable and fluctuating area was the same, 39.60% and 42.54%, respectively； the conversion between different types of FVC was frequent, with "very low → low," "low → very low," and "low → medium" conversion types. The center of medium, high, and very high FVC was distributed in the north, indicating that the vegetation in the north was growing well and that ecological projects like restoring pasture to grassland had yielded excellent results. The distribution of landscape patches with very low and low FVC was more compact and stable, while the diversity of the overall landscape pattern remained stable and unchanged, with the Evenness Index increasing from 0.17-0.19. The degree of fragmentation between various types of FVC was low, and the distribution was more centralized. During the past 20 years, the FVC in Hefeng had fluctuated upward with large amplitude. The desert area in the county's south was the highest priority for future vegetation protection as well as desertification prevention and control. Future vegetation protection and desertification control efforts should prioritize the southern desert area.