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滇中地区土壤侵蚀时空变化及多尺度驱动因子

Spatiotemporal variation of soil erosion and multi-scale driving factors in central Yunnan region

  • 摘要:
    目的 滇中地区作为长江上游的关键生态屏障区,土壤侵蚀问题突出。探究该地区多时空演变规律及多尺度的驱动因子,对后续指导区域土壤侵蚀治理和生态恢复可持续发展具有重要意义。
    方法 基于RUSLE模型和GIS/RS技术,定量反演滇中地区1990—2022年土壤侵蚀时空动态,并运用地理探测器从区域整体与子流域2个尺度系统解析自然−人为因子对土壤侵蚀的驱动因子。
    结果 1)滇中地区土壤侵蚀以微度和轻度为主,空间上呈现“东北−河谷强侵蚀,西北弱侵蚀”的分布格局,时间上呈“总量收缩−极端增强”变化趋势。2)全区尺度上,植被覆盖度( \overlineq = 0.290)与土地利用类型( \overlineq = 0.156)解释力最高,且植被覆盖度与坡度构成主导驱动组合( \overlineq = 0.557);在子流域尺度,植被覆盖度和坡度( \overlineq = 0.603)、土地利用类型( \overlineq = 0.517)交互驱动显著升高,人为活动的影响随尺度减小而增强。高风险区主要分布于海拔10002000 m、坡度 > 35°、中等风化地层、植被覆盖度为10%~30%的草地区域。
    结论 研究成果揭示滇中地区土壤侵蚀的尺度依赖性与驱动因子异质性,可为差异化、精准化的水土保持措施提供科学依据。

     

    Abstract:
    Objective As a critical ecological barrier in the upper reaches of the Yangtze River, the central Yunnan region faces prominent soil erosion issues. Investigating the multi-spatiotemporal evolution patterns and multi-scale driving factors in this region is of great significance for guiding subsequent soil erosion control and sustainable ecological restoration.
    Methods Based on the RUSLE model and GIS/RS technology, this study quantitatively inverted the spatiotemporal dynamics of soil erosion in central Yunnan region from 1990 to 2022. The geodetector method was employed to systematically analyze the driving factors of natural and anthropogenic effects on soil erosion at two scales: the regional scale and the sub-basin scale.
    Results 1) Soil erosion in central Yunnan region was dominated by slight and light levels. Spatially, it showed a distribution pattern of ''strong erosion in the northeast and river valleys, and weak erosion in the northwest.'' Temporally, it exhibited a trend of ''overall contraction with intensified extreme erosion.'' 2) At the regional scale, fractional vegetation cover ( \overlineq = 0.290) and land use type ( \overlineq = 0.156) had the highest explanatory power, and fractional vegetation cover combined with slope constituted the dominant driving combination ( \overlineq = 0.557). At the sub-basin scale, the interaction effects of fractional vegetation cover and slope ( \overlineq = 0.603) and land use type ( \overlineq = 0.517) increased significantly, and the impact of human activities strengthened as the scale decreased. High-risk areas were mainly distributed in grassland regions with elevations of 1 000–2 000 m, slopes >  35°, moderately weathered strata, and fractional vegetation cover of 10%–30%.
    Conclusions The findings reveal the scale dependency and heterogeneity of driving factors of soil erosion in central Yunnan region, which can provide a scientific basis for differentiated and precise soil and water conservation measures.

     

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