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FVC and climate in Yarkand Basin

the methodological concerns, confirming that the County-level heterogeneity further supports these
persistence estimated by the R/S approach is reliable and trends. FVC in Yecheng County was positively
that both methods provide consistent evidence of strong correlated with temperature by approximately 25%,
long-term memory in regional FVC dynamics. Results while in Shache County, it was positively correlated
show that the Hurst coefficient for the annual mean FVC with precipitation by approximately 60%, indicating
is 0.81 (>0.5), indicating strong positive persistence that southern counties and cities benefit from improved
at the regional scale, where FVC changes tend to water and heat conditions. In Zepu County, FVC was
maintain existing trends (e.g., continuous increase). In negatively correlated with temperature by approximately
contrast, the mean Hurst coefficient for the entire raster 40%, possibly due to high temperatures exacerbating
grid is 0.44 (<0.5), suggesting anti-persistence at the drought stress. The differing responses of forested areas
local scale. This discrepancy arises from the spatial (with medium to high coverage of roughly 60% and
heterogeneity among oases, deserts, and mountainous fluctuation of approximately 2%) and bare land validate
areas within the region. Despite the overall positive this mechanism.
persistence trend, local-scale complexities reduce the The results of this study are highly consistent with
mean Hurst coefficient across the entire grid. recent research by Piao et al., which reported that
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The similarity between the Hurst parameters of FVC climate change and human activities drive global
(0.81–0.90) and those reported for climatic processes, vegetation greening. This is consistent with the growth
such as temperature and precipitation (e.g., Dimitriadis trend of FVC in this study, emphasizing the roles
et al., H ≈ 0.83), suggests a potential linkage between of precipitation and oasis management. Wei et al.
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vegetation dynamics and the long-term memory of analyzed the impact of climate fluctuation on vegetation
climate drivers. This resemblance suggests that vegetation growth, consistent with the increase in FVC in farmland.
cover does not evolve in isolation but may exhibit Cao et al. found that drought exacerbates agricultural
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similar persistence properties to climatic variability at stress, aligning with the decline trend in farmland.
the macroscale. Such findings highlight the coupled and Wang et al. used MODIS data to analyze land surface
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enduring interactions between vegetation and climate temperature and vegetation dynamics, supporting the
in arid ecosystems. Future research could therefore high-temperature stress mechanism in Zepu County. Qi
extend Hurst analysis to temperature and precipitation et al. investigated precipitation patterns and vegetation
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processes in the Yarkand River Basin, providing a more recovery, supporting the mechanism of FVC increase
comprehensive understanding of the co-evolution and in grasslands. Urban et al. explored the interactive
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feedback mechanisms between climate and vegetation. effects of climate and land use, supporting the overall
In terms of climate drivers, the temperature increased driving mechanism. Gao et al. emphasize the short-
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from 8.4°C to 9.4°C (an increase of approximately term response of arid zone vegetation to climate
1°C), promoting an increase in farmland FVC from fluctuation, consistent with the local decline observed
0.67 to 0.77 (high coverage of roughly 50%), possibly in 2022–2023.
due to the extended growing season caused by the The findings of this study on FVC dynamics in
temperature increase. The FVC of bare land increased the Yarkand River Basin have been corroborated by
from 0.03 to 0.06, indicating a slight upward trend, related research conducted in other arid and semi-
particularly in Zepu and Bachu counties (low coverage arid regions, thereby reinforcing the robustness and
of approximately 80% and high volatility of about 70%), applicability of our conclusions. For example, in the
possibly due to accelerated soil moisture evaporation Taihangshan–Yanshan region, Yan et al. documented
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caused by rising temperatures. Precipitation increased a gradual upward trend in FVC (0.02/10 years) from
from 35 mm to 49 mm, with a peak of approximately 2000 to 2021, characterized by spatial heterogeneity
80 mm in 2005, significantly driving grassland FVC primarily influenced by evapotranspiration and
from 0.26 to 0.40 (increase of roughly 80%), particularly surface temperature. This aligns with our findings
in Bachu and Tumushuke counties, consistent with of significant positive correlations with precipitation
improved soil moisture due to increased precipitation. (r > 0.6) and negative correlations with temperature
The decrease of approximately 30% in farmland may (r < −0.5) in grasslands and farmlands, underscoring the
be related to salinization caused by over-irrigation, pronounced climatic influence on vegetation dynamics.
contrasting with the increase of approximately 45% in Similarly, Qiao et al. identified a fluctuating upward
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grasslands, reflecting the differing responses of different FVC trend (0.26%/year) from 2000 to 2023 in the
land-use types. Qilian Mountains, exhibiting nonlinear responses to

Volume 22 Issue 6 (2025) 237 doi: 10.36922/AJWEP025350269