College of the Life and Environmental Science, Minzu University of China, Beijing 100081, China.
School of Urban Planning and Design, Peking University, Shenzhen 518055, China.
Int J Environ Res Public Health. 2019 Jun 14;16(12):2112. doi: 10.3390/ijerph16122112.
The Eastern Sichuan Region (ESR) is one of the key pilot regions for Grain for Green Program (GGP) implementation in the upper reaches of the Yangtze River basin in China. Therefore, monitoring the effect of the GGP on the ecosystem in the ESR is important. In this study, the Mann-Kendall Trend Test Model was used to ascertain the changes in vegetation coverage. The transfer matrix was used to explore the changes in Land Use/Land Cover (LULC). LULC change direction model (LCDM) was used to preliminarily assess the impact of LULC changes on the ecosystem. The Pressure-State-Response model (PSR), reflecting the human pressure and the ecosystem state, was applied to analyze the spatial-temporal characteristics of the ecosystem health index (EHI). The time span of this study was from 1990 to 2015. The results show that the vegetation coverage changed significantly ( < 0.05), and ecosystem function developed towards positive because of the increase in the coverage of forestland and water land and decrease in the coverage of farmland. The spatial distribution of the EHI was influenced by the pattern of land use. The eastern region, associated with a large area of forestland and grassland, has a low population density and a low degree of land use exploitation, resulting in a high EHI value. The situation was completely opposite in the western region. Regarding the temporal scale, in spite of the decreasing pressure indicator, most counties had experienced an increase in the EHI. There was a clear correlation between the increased EHI values and the restored areas at the third stage (2000-2005) ( < 0.05, r = 0.164), but this correlation disappeared at the latter stage (2005-2015) ( > 0.05). The changes showed significant variations in time and area because of differences in the process and the intensity of the implication of the GGP.
川东地区（ESR）是中国长江上游流域退耕还林还草工程（GGP）的重点试点地区之一。因此，监测 GGP 对该地区生态系统的影响非常重要。本研究采用 Mann-Kendall 趋势检验模型来确定植被覆盖度的变化，利用转移矩阵来探讨土地利用/土地覆盖（LULC）的变化，利用土地利用变化方向模型（LCDM）来初步评估 LULC 变化对生态系统的影响，利用反映人类压力和生态系统状态的压力-状态-响应模型（PSR）分析生态系统健康指数（EHI）的时空特征。本研究的时间跨度为 1990 年至 2015 年。结果表明，植被覆盖度发生了显著变化（<0.05），由于林地和水域覆盖度增加以及耕地覆盖度减少，生态系统功能向积极方向发展。EHI 的空间分布受土地利用格局的影响。东部地区森林和草地面积大，人口密度低，土地利用开发程度低，EHI 值较高；而西部地区情况完全相反。从时间尺度上看，尽管压力指标呈下降趋势，但大多数县的 EHI 都有所增加。在第三阶段（2000-2005 年）（<0.05，r=0.164），EHI 值的增加与恢复区明显相关，但在后一阶段（2005-2015 年）（>0.05），这种相关性消失了。由于 GGP 实施过程和强度的差异，变化在时间和区域上表现出显著的差异。
