Measurement and coupling analysis of land carrying capacity of coastal areas in the Yangtze River Delta
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Abstract
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) Amongthe 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 incoordinated coupling period. The land support-pressure coordination degree had four types: moderately imbalanced, basically coordinated, moderately coordinatedand 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.
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