Dynamic Analysis of Supply and Demand Coupling of Ecosystem Services in Loess Hilly Region: A Case Study of Lanzhou, China.

The relationship between the supply and demand for ecosystem services (ESs) is a key issue for the rational allocation of natural resources and optimisation of sustainable development capacity. This paper investigateed the dynamic evolution features of supply and demand of four ESs in Lanzhou of China, namely, water supply, food supply, carbon fixation and soil retention services. The cross-sectional data of 2005 and 2017 were used for calculating ESs value and its supply and demand through ArcGIS software, InVEST model, elastic coefficient model and coupling coordination model. Results showed that: 1) from 2005 to 2017, the supply of water supply services increased, the demand of soil retention services decreased, and the supply and demand of food supply and carbon fixation services increased. The high-value areas of service supply were mainly distributed in the rocky mountain areas in the southeast and northwest with high vegetation coverage, while the high-value areas of demand were mainly distributed in the urban areas and surrounding areas with high population density. 2) There were five different types of coupling relations. Water supply service was dominated by a negative coupling type D, which means that the decrease in demand for ESs has had a positive response on the supply of ESs. Negative coupling type C was the main type of food supply and carbon fixation services, which means that the increase in demand for ESs has had a negative response on the supply of ESs. All three services were supplemented by a positive coupling type A, which means that the increase in demand for ESs has had a positive response on the supply of ESs. Soil retention service generally exhibits a positive coupling type B, which means that the decrease in demand for ESs has had a negative response on the supply of ESs. 3) Over the past 12 yr, the coordination degree of supply and demand of water supply, food supply and soil retention services decreased, and the coordination degree of carbon fixation service increased. Various types of ES had a low degree of coupling and coordination, showing different characteristics of temporal and spatial evolution. The areas with imbalanced ESs supply and demand were mainly distributed in urban areas dominated by construction land. The research results are valuable to the optimisation of urban and rural ecological environments and the sustainable development of territory space under the framework of ecological civilisation, including similar ecologically vulnerable areas in other developing countries. [ABSTRACT FROM AUTHOR]