长三角沿海地区土地承载力测度与耦合分析

Abstract

客观准确把握长三角沿海地区土地承载力发展状态及其区际演化差异，是开展土地资源优化配置与可持续发展的基础。该研究从支撑方-施压方维度构建了沿海地区土地承载力评价指标体系，借助遥感影像解译数据与社会经济统计数据，运用熵值法、耦合协调分析法及土地承载力指数法，对2000、2010及2018年长三角11个沿海地区的土地承载力时空分异特征及支撑-施压耦合协调关系进行了综合研究，结果表明：1）长三角沿海区域各年份综合施压力均高于支撑力，始终处于超载状态，且支撑力指数与施压力指数分别呈现波动式上升、波动式下降趋势；2）在各时期共计33个沿海地区样本中，有9个区域土地承载力指数大于1，沿海地区盈余状态占比27.3%。其中，上海市和杭州市在各时期的支撑力与施压力水平均未发生变化，其余地区在支撑力与施压力水平上则呈现出等级的持续上升、持续下降或升降交替变化趋势；3）长三角沿海地区耦合度介于0.9～1.0之间的区域占比为97%，其均处于协调耦合期；土地支撑-施压协调度涵盖中度失调型、基本协调型、中度协调型、高度协调型4种类型，其中，江苏省以中度失调型居多，浙江省以基本协调型居多，形成“北低南高”的空间格局，并呈现由南北两侧逐渐向上海市进行高值汇聚的态势；4）长三角沿海区域整体承载力水平始终处于超载但超载程度趋于减弱，且各时期均存在土地超载与盈余并存的区域发展状态；空间上呈现出江苏省“南北超载中部盈余”、上海市“全域盈余”以及浙江省“北部盈余南部超载”的格局特征。

Understanding the difference in land carrying capacity and its evolution incoastal areas in the Yangtze River Delta is important for optimally allocatingits land resources and sustaining its social and economic development. This paper presents an evaluation index system for calculating the land carrying capacity of these areasusing the support- pressure concept. We analyzed the spatiotemporal change in land carrying capacity of 11 coastal areas in the delta in 2000, 2010 and 2018, using a combination of the entropy model, the coupling coordination-degree model and the land capacity carry model. The data used in the models were obtained from remote sensing image interpretation and the national socioeconomic statistics database. The evaluation index system could be used to complement the existing evaluation research results, especially in the context of the development model of the Yangtze River Delta urban agglomeration. It could further improve our understanding of the evolutionary change in land carrying capacity in the coastal areas. Our results indicated that: 1) The coastal areas were overloaded in all three years, with the stress imposed to the lands more than what the lands could support. The supporting force index had been wavily increased while the pressure index had been in decline over the three years. In terms of support evaluation factors, the "construction investment support" was significantly higher than the "land resources basic support" and "policy control support". In terms of evaluation factors for pressure, the mean measurement values were ranked in "land use disturbance pressure" < "coastal disaster damage pressure" <"socioeconomic development pressure". 2) Among the total 33 coastal areas sampled in each of the three years, nineareas had a land carrying capacity index >1, indicating that the surplus status of the coastal areas accounted for 27.3%. The support and pressure levels remained unchanged for Shanghai and Hangzhou, but for other areas they showed continuous rise, decline, or alternate rise and fall. 3) Areas with coupling degree between 0.9 and 1.0 accounted for 97% of the total areas, all in coordinated coupling period. The land support-pressure coordination degree had four types: moderately imbalanced, basically coordinated, moderately coordinated and highly coordinated. Spatially, most coordination types in Jiangsu were moderately imbalanced, and Zhejiang were dominated by basically coordinated with a spatial pattern of "low in north and high in south". The coastal areashad formed a spatial pattern that converged toward Shanghai in all directions. 4) The land carrying capacity of all coastal areas in the Yangtze River Delta was overloaded, but the degree of the overload appeared to have been weakening. The studied areas in each of the three years were in a state with overload and surplus coexisting. The capacity showed a spatial pattern of "overload in south-north and surplus in center" in Jiangsu province, "global surplus" in Shanghai, and "surplus in north and overload in south" in Zhejiang province. The spatial variation of land carrying capacity in the coastal areas in the Yangtze River Delta showed that the capacity in 2000 could be divided into four states: high surplus, low surplus, low overload and high overload, while in 2010 and 2018 there were only three states.