2000年来吕梁连片贫困区植被净初级生产力时空变化特征

多年来吕梁连片贫困区实施的生态恢复措施对其生态环境产生了较大影响,为掌握该区域在生态恢复措施实施(2000年)以来植被净初级生产力的变化状况,利用2000—2018年时序的遥感数据和基于光能利用率的CASA模型对其进行了模拟,并分析了导致其变化的主要控制因素,结果显示:(1)2000年以来吕梁连片贫困区NPP整体上升,其中93.46%的区域NPP呈增长状态,6.54%的区域呈减少状态,2010—2015年区域NPP出现下降。(2)受人类活动影响,过去18年来区域土地利用类型变化较为显著,耕地面积缩减,草地面积基本保持稳定,林地与城镇面积增加且城镇面积扩张迅速,不同土地利用下的NPP特征差异显著,耕地NPP年均值增长最为迅速,为5.9 gC m^-2 a^-1,林地最为平稳,为1.32 gC m^-2 a^-1。(3)研究区降水量波动对区域NPP的变化影响显著,未来气候变化中降水量的变化可能对区域NPP产生直接影响。研究结果将为区域生态恢复、精准扶贫及黄河中游地区的经济发展提供重要的理论支撑。

Spatio-temporal variation characteristics of net primary productivity in Lvliang contiguous poverty areas since 2000

Over the years, the ecological restoration measures implemented in Lvliang contiguous poverty area have had a great impact on its ecological environment. In order to grasp the change of net primary productivity of vegetation in this area since the implementation of ecological restoration measures (2000), this study used the remote sensing data of 2000-2018 and the CASA model based on the utilization rate of light energy to simulate it, and analyzed the main control factors leading to its change. The results showed that:(1) net primary productivity (NPP) in Lvliang contiguous poverty area increased as a whole since 2000, of which 93.46% of the regional NPP increased, 6.54% of the regional NPP decreased, and the regional NPP decreased from 2010 to 2015. (2) Affected by human activities, in the past 18 years, the regional land use type changed significantly, the cultivated land area decreased, the grassland area remained basically stable, the woodland and urban area increased, and the urban area expanded rapidly. The NPP characteristics under different land use types were significantly different. The annually average NPP of the cultivated land increased most rapidly, which was 5.9 gC m^-2 a^-1, and the forest land was the most stable, which was 1.32 gC m^-2 a^-1. (3) The fluctuation of precipitation in the study area had a significant impact on the change of regional NPP. The change of precipitation in the future climate change may have direct impact on regional NPP. The results will provide importantly theoretical support for regional ecological restoration, targeted poverty alleviation and economic development in the middle reaches of the Yellow River.