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Qin, et al.

suggested the risk of localized degradation. Differences values. Areas with persistently low FVC or data gaps
in land use types reflected the combined drive of may further reduce the mean coefficient, contributing to
artificial intervention and natural conditions, with bare the overall anti-persistent trend at the local scale.
land and grassland showing significant growth, and In contrast, the Hurst coefficient of 0.81 (>0.5)
farmland requiring optimized management. for the annual mean FVC indicated strong positive
persistence, with FVC changes tending to maintain
3.3. Sustainability analysis of FVC existing trends (e.g., continuous increase). By spatially
The Hurst index was employed to analyze the long-term averaging FVC across the study area, the differences
memory and persistence of the FVC time series, with among oases, deserts, and mountains were smoothed
results shown in Figure 5. At the regional scale, the out, highlighting the overall regional trend. In recent
annual mean FVC exhibited strong positive persistence, years, the Yarkand River Basin has benefited from the
with a Hurst coefficient of 0.81. To validate this finding, expansion of oasis agriculture, afforestation policies,
the climacogram method was additionally applied, and ecological restoration measures (e.g., windbreak
yielding a similar value of 0.896. The close agreement and sand-fixation forest construction), leading to a likely
between the R/S and climacogram methods confirmed sustained increase in regional mean FVC, particularly
the robustness of the persistence detected at the regional in oasis areas supported by irrigation, which enhances
level. In contrast, the mean Hurst coefficient across the FVC stability. The influence of deserts and mountains
entire raster grid was 0.44, indicating anti-persistence at was diminished after spatial averaging, resulting in a
the local scale, where FVC changes were more likely to smoother time series for the annual mean FVC, reflecting
reverse existing trends. This spatial divergence reflects long-term ecological stability at the regional scale.
the region’s complex heterogeneity: oases, supported From a spatial distribution perspective, the FVC in
by irrigated agriculture, typically show higher FVC the plain areas of the Yarkand River Basin generally
and local persistence (H > 0.5); deserts, constrained exhibited positive and strong positive persistence. In
by scarce precipitation and significant interannual contrast, in mountainous regions, it predominantly
variability, exhibit very low FVC and anti-persistence showed anti-persistence and strong anti-persistence.
(H < 0.5); and mountainous areas, shaped by complex This is primarily because plain areas, as key regions
topography and limited water availability, display for irrigated agriculture, benefit from effective water
unstable FVC dynamics with generally lower Hurst resource management and optimized irrigation

A B

C

Figure 5. Annual fractional vegetation cover change trends in the Yarkand River Basin from 2000 to 2023.
(A) Distribution. (B) Characteristics of sustainability. (C) Climacogram.

Volume 22 Issue 6 (2025) 230 doi: 10.36922/AJWEP025350269