Abstract：
Understanding the vegetation dynamics and their drivers in Nepal has significant scientific reference value for implementing sustainable ecological policies. This study provides a comprehensive analysis of the spatio-temporal variations in vegetation cover in Nepal from 2003 to 2022 using MODIS NDVI data and explores the effects of climatic factors and anthropogenic activities on vegetation. Mann-Kendall test was used to assess the significant trend in NDVI and was integrated with the Hurst exponent to predict future trends. The driving factors of NDVI dynamics were analyzed using Pearson\'s correlation, partial derivative, and residual analysis methods. The results indicate that over the last 20 years, Nepal has experienced an increasing trend in NDVI at 0.0013 year-1, with 80% of the surface area (vegetation cover) showing an increasing vegetation trend (~ 28% with a significant increase in vegetation). Temperature influenced vegetation dynamics in the higher elevation areas, while precipitation and human interventions influenced the lower elevation areas. The Hurst exponent analysis predicts an improvement in the vegetation cover (greening) for a larger area compared to vegetation degradation (browning). A significantly increased area of NDVI residuals indicates a positive anthropogenic influence on vegetation cover. Anthropogenic activities have a higher relative contribution to NDVI variation followed by temperature and then precipitation. The results of residual trend and Hurst analysis in different regions of Nepal help identify degraded areas, both in the present and future. This information can assist relevant authorities in implementing appropriate policies for a sustainable ecological environment.
摘要：
了解尼泊尔植被动态及其驱动因素对实施可持续生态政策具有重要的科学参考价值。本研究使用MODISNDVI数据对2003年至2022年尼泊尔植被覆盖的时空变化进行了全面分析，并探讨了气候因素和人为活动对植被的影响。使用Mann-Kendall检验来评估NDVI的显着趋势，并与Hurst指数整合以预测未来趋势。利用皮尔逊相关性分析了NDVI动力学的驱动因素，偏导数，和残差分析方法。结果表明，在过去的20年里，尼泊尔在0.0013year-1经历了NDVI的增加趋势，其中80％的表面积（植被覆盖率）显示出增加的植被趋势（〜28％，植被显着增加）。温度影响高海拔地区的植被动态，而降水和人为干预影响了低海拔地区。Hurst指数分析预测，与植被退化（褐变）相比，更大区域的植被覆盖率（绿化）有所改善。NDVI残差面积的显着增加表明人为对植被覆盖的积极影响。人为活动对NDVI变化的相对贡献较高，其次是温度，然后是降水。尼泊尔不同地区的残差趋势和Hurst分析结果有助于确定退化地区，无论是现在还是将来。这些信息可以帮助有关当局实施适当的政策，以实现可持续的生态环境。
