[Changes in Ecosystem Services and Equity Identification in Nanchang Under the Influence of Construction Land...

The expansion of construction land and the changes in ecosystem services and their interactions are a major factors affecting urban development and ecological protection. Using spatial econometric models， this study explores the spatial interaction between the expansion of urban land for construction and ecosystem services and tests the existence of a correlation between the two. In this context， the study identifies and measures the levels of ecological equity and expansion efficiency for each township in the study area. This has significant implication on the comprehensive management and control of urban development and ecological protection in the study area. By quantifying the number and pattern of construction land expansion in Nanchang from 2000 to 2020， this study uses the InVEST model to comprehensively estimate water production， carbon storage， soil conservation， habitat quality， etc.， and ecosystem services. Furthermore， it uses the spatial lag model （SLM） and spatial error model （SEM） to conduct a regression analysis of the mutual relationship between the two. Finally， it uses the fair efficiency index to identify the ecological equity of towns and townships in the study area. The results showed that： ① The expansion of construction land in Nanchang from 2000 to 2020 has gradually shifted to a predominant expansion mode of "fly-in" expansion， while the central urban area has maintained a predominant expansion mode of "filling-in." At the same time， the comprehensive ecosystem services in the entire region showed an upward trend， but the ecosystem services in the central urban area declined significantly. ② There was a clear spatial spillover effect of land use expansion and ecosystem service changes from 2000 to 2020. The change in ecosystem services of one area was not only significantly affected by the local land use expansion but also by the expansion of adjacent areas. The impact of land use expansion on the change of different types of ecosystem services was different， with a more significant impact on water production and habitat quality but a weaker or non-significant impact on carbon storage and soil conservation. The shift in the expansion pattern of cities increased the intensity of the impact of urban expansion on the comprehensive change of ecosystem services. ③ The coordination of ecological equity and expansion efficiency in each township of Nanchang improved significantly from 2000 to 2020. The total difference in ecological equity index has decreased from 0.378 4 to 0.080 5， and significant progress has been made in the development and protection of ecology in each township. The regional ecological equity showed an optimizing trend， but there are still some areas that pay more attention to the efficiency of expansion and ignore the protection of the ecological environment. Therefore， the research results suggest that urban development should adhere to a multi-factor， multi-dimensional comprehensive consideration； reasonably adjust development policies； and strengthen the regulatory efforts on the expansion mode of construction land to avoid the deterioration of the ecological environment caused by blind land expansion.