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    2000—2020年昆仑山植被覆盖度时空变化驱动力分析及生态评价

    Driving force analysis and ecological assessment of spatiotemporal changes in vegetation cover in the Kunlun Mountains from 2000 to 2020

    • 摘要:
      研究目的 植被覆盖度是反映生态环境稳定性的重要指标,昆仑山地区生态脆弱,植被覆盖度变化的驱动因素研究较少。文章旨在分析昆仑山地区植被覆盖度时空变化及驱动因素和区域生态评价。
      研究方法 本文基于归一化植被指数(Normalized Difference Vegetation Index, NDVI),探究了2000—2020年昆仑山植被覆盖度的时空变化规律。使用地理探测器(GeoDetector, GD)和随机森林 (Random Forest, RF)模型,识别了昆仑山地区NDVI变化的主导因子,使用RF和长短期记忆网络(Long Short−Term Memory Network, LSTM)开展了多因子NDVI的回归拟合。使用遥感生态指数(Remote Sensing Ecological Index, RSEI)评估了昆仑山环境质量变化状况。
      研究结果 2000—2020年昆仑山地区NDVI在时间上呈波动增加趋势,空间上呈“西高东低、北高南低”的分布格局。RF重要性最高的因子为高程(DEM)、降水(Pre)、到城镇距离(Town)和国内生产总值(Gross Domestic Product, GDP),GD解释力最高的因子为蒸散发(ET)、DEM、GDP和温度(Temp)。RF比LSTM更适用于昆仑山地区NDVI的回归拟合。RSEI数值上升的区域面积为80.52%,但整体波动较大,波动较大区域面积为78.86%。
      结论 DEM、GDP、Pre和ET是影响该区域植被覆盖度的主要因素,区域生态环境质量有明显改善,生态保护措施成效显著。保护昆仑山生态脆弱区的生态稳定对区域生态政策的实施具有重要意义。

       

      Abstract:
      This paper is the result of ecological geological survey engineering.
      Objective Vegetation cover is a critical indicator of ecosystem stability. Researches about the factors influencing vegetation cover changes in the ecologically sensitive Kunlun Mountains region are limited. This study aims to analyze the spatiotemporal variations of vegetation cover and their driving factors in the Kunlun Mountains and to perform a regional ecological assessment.
      Methods The Normalized Difference Vegetation Index (NDVI) was used to examine the spatiotemporal patterns of vegetation cover from 2000 to 2020, and the Geodetector (GD) and Random Forest (RF) models were applied to identify the primary drivers of NDVI changes. Meanwhile, RF and Long Short−Term Memory Network (LSTM) models were used for predict the NDVI variations, and the Remote Sensing Ecological Index (RSEI) was used to evaluate environmental quality.
      Results NDVI showed a generally temporal increasing−decreasing−increasing trend, characterized by a spatial distribution that higher values in the west and north and lower values in the east and south. The RF model identified the digital elevation model (DEM), precipitation (Pre), distance to towns (Town), and gross domestic product (GDP) as the most influential factors, whereas the GD model showed evapotranspiration (ET), DEM, GDP, and temperature (Temp) had the greatest explanatory power. The RF model was more effective for NDVI regression analysis than the LSTM model in the study area. The RSEI value showed an increase in 80.52% of the area, but the overall variation was considerable, with 78.86% of the area showing significant variation.
      Conclusions DEM, GDP, Pre, and ET are the primary factors affecting vegetation cover in the region and the significant improvement in the regional ecosystem over the past two decades. It also reveals a significant enhancement in regional ecological quality, indicating that ecological conservation measures have been effective.

       

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