长江中游城市群生态足迹指标与社会经济发展的适配性

生态足迹是量化区域自然资本利用可持续性的关键指标。本文运用三维生态足迹模型评估长江中游城市群2000—2015年的可持续发展情况，结合非均衡指数和环境库兹涅兹曲线分析生态足迹指标与社会经济发展的适配性。研究表明：①长江中游城市群人均生态承载力下降而人均三维生态足迹不断增大（增幅6.81%），区域生态赤字较为严重；其中，长株潭城市群和环鄱阳湖城市群人均三维生态足迹的变化拐点分别出现在2007年和2009年；区域草地与耕地的资本存量消耗量（足迹深度）不断提升，而林地和水域的资本流量（足迹广度）更新速度能够满足资源消费需求；总体来看，长江中游城市群资本存量损耗严重（但优于成渝和长三角城市群），环鄱阳湖城市群自然资本可持续利用空间优于武汉城市圈和长株潭城市群。②足迹广度与足迹深度存在地域互补性，即资源富饶的地区一般有较大的足迹广度和较低的足迹深度。聚类分析结果表明：荆门、咸宁、襄阳等地区足迹广度大而足迹深度小，其自然资本利用格局较优；而武汉、鄂州、黄冈等地区而足迹广度小足迹深度大，其生态可持续性差。③长江中游城市群人均三维生态足迹与水资源、人口的匹配度较差，与GDP匹配度较高；此外，研究发现当城市群城镇化率达到某一阈值时，其与人均三维生态足迹和足迹深度关系可能发生转变：武汉城市圈、长株潭城市群和环鄱阳湖城市群的人均三维生态足迹与城镇化率间均呈现倒“U”型特征；除环鄱阳湖城市群（城镇化率上升，足迹深度增加）外，武汉城市圈与长株潭城市群足迹深度与城镇化率符合环境库兹涅兹曲线的特点。研究结果能够为实现城市群自然资本可持续利用及绿色发展提供理论支持。

Coordination between ecological footprint index and socioeconomic development of the urban agglomeration in the middle reaches of the Yangtze River Basin

Ecological footprint is a key index to quantify the sustainability of regional natural capital utilization. Based on a three-dimensional ecological footprint (EF_3D) model, this study evaluated the sustainable development of the urban agglomeration in the middle reaches of the Yangtze River Basin (UAMRYR), and introduced the disequilibrium index and environmental Kuznets curve to analyze the coordination between the ecological footprint index and socioeconomic development. The results show that: (1) Per capita biological capacity of the UAMRYR was decreasing while its per capita EF_3D presented an increasing trend with an average annual growth rate of 6.81%, which led to serious ecological deficit. The inflection points of per capita EF_3D of the Changsha-Zhuzhou-Xiangtan City Group (CZTCG) and Poyang Lake City Group (PYLCG) appeared in 2007 and 2009, respectively. The capital stock of regional grassland and cultivated land showed an increasing trend, while the capital flow of forestland and water areas could meet the demand of resource consumption. A serious loss of capital stock can be found in the UAMRYR, but the situation was better than that of the Chengdu-Chongqing and Yangtze River Delta City Groups. The sustainable utilization space of natural capitals in the PYLCG was better than that in the Wuhan urban agglomeration (WUG) and CZTCG. (2) There was a regional complementarity between footprint size (EF_size) and footprint depth (EF_depth), and areas with rich resources generally had lower EF_size and larger EF_depth. Cluster analysis showed that Jingmen, Xianning, and Xiangyang had a better pattern of natural capital utilization owing to their large EF_size and small EF_depth, while Wuhan, Ezhou, and Huanggang had a poor ecological sustainability owing to their small EF_size and large EF_depth. (3) The matching degrees of EF_3D with water resources and population were poor. In comparison, a high matching degree was observed between EF_3D and GDP. When the urbanization rate of the urban agglomeration reached a certain threshold, its relationship with per capita EF_3D and EF_depth may change. The correlation between per capita EF_3D and urbanization rate of the WUG, CZTCG, and PYLCG showed an inverted U shape. In addition, EF_depth of the PYLCG increased with the increase of urbanization rate, and the correlation between EF_depth and urbanization rate of the WUG and CZTCG accorded with the Kuznets curve. Findings can provide theoretical support for the sustainable use of natural capital and green development in the UAMRYR.