河北省植被覆盖变化及对生态建设工程的响应

在分析河北省2000—2015年植被覆盖变化特征的基础上, 结合地形、气候和社会经济数据, 通过构建空间计量模型识别研究区植被变化的影响因素, 进而利用人工神经网络量化生态建设工程对植被变化的影响程度。结果表明, 河北省南部及东北部的植被指数比西北部高, 研究时段内大部分地区植被得到改善, NDVI基本上不变、增加和降低区域的比例分别为15.14%, 61.75%和23.11%。2000年植被NDVI分布的影响因素主要有海拔高度、人均GDP和人口密度, 起消极作用; 2015年影响因素增加降水量和生态建设工程造林量, 起积极作用。生态建设工程对植被NDVI的影响绝大部分为正值, 且多为轻度改善, 显著改善地区分布在承德市和张家口市, 这些地区也是NDVI变化值和生态建设工程造林量(EPA)变化值的热点区域。生态建设工程对NDVI的影响为负值的情况主要出现在张家口市的西北部地区、秦皇岛和唐山市的东部地区以及南部的城市建成区。研究结果可为科学评价河北省生态建设工程绩效提供依据, 为区域生态环境保护和植被恢复提供支持。

Change of Vegetation and Contribution of Ecological Construction Projects in Hebei Province

This study analyzed the characteristics of vegetation change, and built spatial econometric models to identify the affecting factors of vegetation change in Hebei Province with topographic, meteorological, and socio-economic data. On this basis, the hotspot analysis and artificial neural network were used to further quantify the specific impact extent of the ecological projects on vegetation change. The results showed that vegetation index in the southern and northeastern regions of Hebei Province was higher than that in the northwestern areas. Vegetation improved in most areas during the study period and the area proportion of NDVI sustained regions, increased regions and decreased regions is 15.14%, 61.75% and 23.11%, respectively. The main influencing factors of NDVI were elevation, per capita GDP and population density in 2000, which had a negative effect on vegetation in Hebei Province, while NDVI in 2015 was also affected by the additional factors, precipitation and ecological construction program, which had a positive effect. The impacts of ecological construction projects on NDVI were positive in most areas, and most of them were slightly improved. The areas with significant improvement were distributed in Chengde City and Zhangjiakou City, which were also hot spots of NDVI change and EPA (Ecological Project Area) change. The negative impact of ecological construction project on NDVI mainly occurred in the northwest of Zhangjiakou City, the east of Qinhuangdao and Tangshan, and the urban built-up area in the south of Hebei Province. The research results provide a basis for the scientific evaluation of the performance of national ecological construction projects and support for ecological protection and vegetation restoration of Hebei Province.