山西省沿黄地区生态综合指数评价及时空变化

Evaluation and spatial-temporal variations of ecological comprehensive index along the Yellow River of Shanxi Province, China

生态综合指数可以定量化、可视化地分析一个地区生态环境质量的时空变化特征。本研究以山西省沿黄地区为研究区域,基于2001、2005、2010、2015和2020年5期MODIS卫星数据获取的植被覆盖度、叶面积指数、总初级生产力、陆地表面温度和湿度5项指标,耦合构建生态综合指数(K),并引入主成分分析与空间自相关方法分析2001—2020年山西省沿黄地区生态质量时空变化特征。结果表明:2001—2020年,研究区K均值由0.3354增长至0.4389,沿黄地区生态质量整体提高,但生态质量呈现明显的时空变化特征。在大尺度上呈现“南优北差”的格局,小尺度上丘陵与山地也存在差异;时间上呈现不断向好的趋势但变化速率不同,南部向好趋势强于北部地区。2001—2020年间,K值的全局Moran I值均大于0.93,表明山西省沿黄地区生态质量具有较强的空间相关性。空间集聚类型主要表现为高-高和低-低集聚,高-高集聚区域主要呈块状分布在南部,而低-低集聚区域主要集中连片分布在北部。研究期间,山西省沿黄地区的生态质量得到极大提高,但仍有明显的空间异质性,需要继续加强生态保护。

Ecological comprehensive index can quantitatively and visually analyze the temporal and spatial variations of ecological environment quality in a region. Based on the five indices of fractional vegetation coverage, leaf area index, total primary productivity, land surface temperature and wetness obtained by MODIS satellite data in 2001, 2005, 2010, 2015 and 2020, and coupled the comprehensive quality of the eco-environment(K), we analyzed the temporal and spatial variations of ecological quality along the Yellow River of Shanxi Province from 2001 to 2020 by using the principal component analysis and spatial autocorrelation method. The results showed that the mean value of K in the study area increased from 0.3354 to 0.4389 during 2001-2020. The ecological quality along the Yellow River of Shanxi Province improved overall, but with obvious temporal and spatial variations. On the large scale, it presented a pattern of “better in the south and worse in the north”. There was difference between hills and mountains on the small scale. It showed a trend of continuous improvement in time, but the rate of change was different. The trend of improvement in the south was stronger than that in the north. From 2001 to 2020, the global Moran I values of K were all greater than 0.93, indicating that the ecological quality along the Yellow River of Shanxi Province had a strong spatial correlation. The types of spatial agglomeration were mainly high-high and low-low. The high-high agglomeration areas were mainly distributed in blocks in the south, while the low-low agglomeration areas were mainly concentrated in the north. The ecological quality of areas alone the Yellow River of Shanxi Province had been greatly improved during the research period, but there was still obvious spatial heterogeneity, which need to strengthen ecological protection.