He Chunyang, Tian Jie, Gao Bin, Zhao Yuanyuan
Center for Human-Environment System Sustainability (CHESS), State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, 100875, People's Republic of China,
Environ Monit Assess. 2015 Jan;187(1):4199. doi: 10.1007/s10661-014-4199-2. Epub 2014 Dec 16.
Quantitatively distinguishing grassland degradation due to climatic variations from that due to human activities is of great significance to effectively governing degraded grassland and realizing sustainable utilization. The objective of this study was to differentiate these two types of drivers in the Liao River Basin during 1999-2009 using the residual trend (RESTREND) method and to evaluate the applicability of the method in semiarid and semihumid regions. The relationship between the normalized difference vegetation index (NDVI) and each climatic factor was first determined. Then, the primary driver of grassland degradation was identified by calculating the change trend of the normalized residuals between the observed and the predicted NDVI assuming that climate change was the only driver. We found that the RESTREND method can be used to quantitatively and effectively differentiate climate and human drivers of grassland degradation. We also found that the grassland degradation in the Liao River Basin was driven by both natural processes and human activities. The driving factors of grassland degradation varied greatly across the study area, which included regions having different precipitation and altitude. The degradation in the Horqin Sandy Land, with lower altitude, was driven mainly by human activities, whereas that in the Kungl Prairie, with higher altitude and lower precipitation, was caused primarily by climate change. Therefore, the drivers of degradation and local conditions should be considered in an appropriate strategy for grassland management to promote the sustainability of grasslands in the Liao River Basin.
定量区分气候变化导致的草地退化和人类活动导致的草地退化，对于有效治理退化草地和实现可持续利用具有重要意义。本研究的目的是利用残差趋势（RESTREND）方法区分1999 - 2009年辽河盆地这两种驱动因素，并评估该方法在半干旱和半湿润地区的适用性。首先确定归一化植被指数（NDVI）与各气候因子之间的关系。然后，假设气候变化是唯一驱动因素，通过计算观测到的和预测的NDVI之间归一化残差的变化趋势，确定草地退化的主要驱动因素。我们发现RESTREND方法可用于定量有效地区分草地退化的气候和人类驱动因素。我们还发现辽河盆地的草地退化是由自然过程和人类活动共同驱动的。草地退化的驱动因素在整个研究区域差异很大，该区域包括具有不同降水量和海拔高度的地区。海拔较低的科尔沁沙地的退化主要由人类活动驱动，而海拔较高、降水量较低的浑善达克沙地的退化主要由气候变化导致。因此，在制定草地管理的适当策略时，应考虑退化驱动因素和当地条件，以促进辽河盆地草地的可持续性。
