2000—2020年白尼罗河上游地区植被动态及其驱动因子

Vegetation Dynamics and Driving Factors in Upper White Nile River Region During 2000—2020

[目的]明确21世纪白尼罗河上游的植被动态及变化的驱动因子,为该区域生产活动、环境政策的制定与调整提供科学指导。[方法]以白尼罗河上游地区为研究区,基于降水、温度和人口数据,利用趋势分析、偏相关分析及残差趋势法确定了该地区2000—2020年植被(NDVI)变化特征及其主导因子的空间差异。[结果]白尼罗河上游地区NDVI平均以0.105/10 a的速率上升,且温度变化对于NDVI的影响强于降雨;人类活动总体对植被造成负面影响,但是这一负面影响的趋势正在逐渐减弱;在5种土地类型中,灌木地的植被为气候变化及人类活动变化背景下最为脆弱的(所受正面影响小,负面影响大);流域内15.01%陆地范围植被变化主要受人类活动主导,另外84.99%受气候变化主导。[结论]虽然流域内整体植被呈现增长趋势,但是个别地区植被发生了严重退化,尤其是城镇的扩张以及农田开垦的扰动对植被造成了破坏,当地在寻求增加粮食产量及旅游业收入的前提下应当做好植被的监测与管理工作。

[Objective]The vegetation dynamics and driving factors of change in the Upper White Nile River region in the 21st century were determied in order to provide scientific guidance for the formulation and adjustment of production activities and environmental policies in the region.[Methods]The study was conducted in the Upper White Nile River region.Precipitation,temperature,and population data were analyzed by trend analysis,partial correlation analysis,and the residual trend method to determine the spatial differences in vegetation(NDVI)changes and their dominant factors in the region from 2000 to 2020.[Results]The average NDVI in the Upper White Nile River region increased at a rate of 0.105/10 a.Temperature change had a stronger impact on NDVI than precipitation.Overall,human activities had a negative impact on vegetation,but this negative impact gradually weakened over time.Shrubland was the most vulnerable of the five land cover types under the background of climate change and human activity changes(with small positive impacts and large negative impacts).Human activities mainly dominated vegetation changes in 15.01%of the land area within the watershed,while climate change dominated 84.99%of the land area.[Conclusion]Although vegetation in the basin showed an overall increasing trend,vegetation degradation had occurred in some areas,especially due to urban expansion and disturbance of farmland cultivation that have caused damage to vegetation.Local vegetation monitoring and management should be done effectively,so as to increase food production and tourism income.