1990—2022年黄河流域植被时空变化特征及未来趋势预测

Characteristics of spatio⁃temporal changes and future trends forecast of vegetation cover in the Yellow River Basin from 1990 to 2022

黄河流域生态环境脆弱,是我国水土流失最严重的地区,植被对该地区生态恢复和保护发挥重要作用。而以往研究对影响植被变化各驱动因素之间的协同效应及植被未来趋势预测的研究有限。利用像元二分模型反演了1990—2022年的植被覆盖度(Fractional Vegetation Coverage;FVC),结合趋势分析、重心迁移、转移矩阵和地理探测器等方法,分析了植被覆盖度时空变化特征及驱动因素对植被影响的空间异质性;并利用未来土地利用模拟(FLUS)模型预测了植被未来变化趋势。结果表明:(1)30年来流域植被覆盖度呈上升趋势,空间上表现为东南高西北低的分布特征;植被改善的面积占流域总面积的47.17%,流域中部地区植被恢复趋势明显。(2)流域植被变化受降水、植被类型、土壤类型以及土地利用类型的影响较大;同时研究揭示了影响FVC变化的驱动因子最适宜的范围和类型。(3)2040年黄河流域植被覆盖度呈上升趋势,中部地区植被恢复趋势明显,青海省部分地区植被有退化趋势。该研究结果为黄河流域生态保护和恢复提供科学依据。

The Yellow River Basin has a fragile ecological environment and is the most serious area of soil erosion in China.The vegetation plays an important role in the ecological restoration and protection of the region.Previous studies have been limited in examining the synergies between the drivers affecting vegetation change and the prediction of future trends.In this study,we used the dimidiate pixel model to invert the vegetation cover(FVC)from 1990 to 2022.Combining the methods of trend analysis,center of gravity migration,transfer matrix,and geodetector to analyze the spatial and temporal change characteristics of vegetation cover and the spatial heterogeneity of the influence of drivers on vegetation cover.The Future Land Use Simulation(FLUS)model was also used to predict future trends in vegetation.The results showed that:(1)the vegetation cover showed an upward trend over the past 30 years.The spatial distribution was characterized by high in the southeast and low in the northwest.The area with improved vegetation accounted for 47.17%of the total area of the watershed,and the trend of vegetation restoration in the central part of the watershed was obvious.(2)Vegetation change in the watershed was strongly influenced by precipitation,vegetation type,soil type,and land use type.Meanwhile,we revealed the most suitable range and type of driving factors affecting FVC changes.(3)The vegetation cover of the Yellow River Basin in 2040 will show an upward trend.The trend of vegetation is obvious recovery in the central area,and the vegetation has a trend of degradation in some areas of Qinghai Province.The results of the study provide a scientific basis for the ecological protection and restoration of the Yellow River Basin.