四川三州植被覆盖度变化及其对生态治理和灾害防治的响应

Vegetation coverage change and response to ecological management and disaster prevention in three prefectures of Sichuan province

[目的]四川三州(凉山彝族自治州、甘孜藏族自治州和阿坝藏族羌族自治州)生态环境脆弱,地质灾害频繁发生,而坡表植被具有蓄水固基的作用。研究该区植被覆盖度动态变化及关键驱动因素有助于预测生态结构的稳健性及防治地质灾害。[方法]选取2002—2022年MODIS遥感数据,基于转移矩阵、趋势分析法分析植被盖度的发展趋势及转移情况,通过相关分析及地理探测模型,研究各驱动因素对植被盖度的影响。[结果]研究区内不同植被覆盖度均有向更高盖度演变的趋势,但整体上随时间递增而趋于稳定,并且气象因素中气温对植被盖度的影响略大于降雨的作用,均为促进作用;自然因素及人为因素共同作用是四川三州植被盖度空间分布差异的主要原因,高程及土地利用为植被覆盖的两类控制性因素,自然因素对研究区植被情况影响更显著,且不同驱动因素叠加对植被盖度解释力度强于单一因素作用。[结论]建议高海拔地区植被盖度恢复应重点考虑植被的耐温特性及严格控制人类对自然空间的过度开发利用,并且应多维度对植被盖度影响因素进行改善。

[Objective]The three prefectures of Sichuan(Liangshan Yi Autonomous Prefecture,Ganzi Tibetan Autonomous Prefecture and Aba Tibetan and Qiang Autonomous Prefecture)have fragile ecological environments and frequent geohazards,whereas slope-surface vegeta-tion has the role of water storage and foundation consolidation,The study of the dynamic change of vegetation cover and key drivers in this re-gion can help predict the robustness of ecological structure and prevent geohazards.[Method]MODIS remote sensing data from 2002 to 2022 were selected to analyze the development trend and transfer of vegetation cover based on transfer matrix and trend analysis method,and the influ-ence of each driving factor on vegetation cover was studied through correlation analysis and geodetection model.[Result]The different vegetation cover in the study area had a tendency to evolve to higher cover,but the overall tendency was stabilized with the increase of time,and the influ-ence of meteorological factors,such as air temperature,was slightly larger than that of rainfall,and both factors had a facilitating effect on the vegetation cover;The combined effect of natural and human factors was the main reason for the differences in the spatial distribution of vegeta-tion cover in the three states of Sichuan,and elevation and land use were the two controlling factors of vegetation cover.Elevation and land use were the two controlling factors of vegetation cover,and natural factors had a more significant impact on vegetation cover in the study area,and the superposition of different drivers explained vegetation cover more strongly than the role of a single factor.[Conclusion]The study suggest that the recovery of vegetation cover at high altitude should focus on the temperature tolerance of vegetation and strictly control the over-exploitation and utilization of natural space by human beings,and that the factors affecting vegetation cover should be improved in a multi-dimensional way.