Gradient characteristics of China's land use patterns and identification of the east-west natural-socio-economic transitional zone for national spatial planning

Countries and regions with vast territory tend to have economic gradients and uneven land use pattern. Ecological sensitive zones, transitional zones and state poverty counties have been found near the Hu Huanyong Line (Hu Line) of China in previous studies. However, there is little knowledge about the identification of a comprehensive transitional zone that considers natural and socio-economic elements from national scale. Based on exploring gradient characteristics of land use patterns and the driving factors behind them, we propose a quantitative identification framework of natural-socio-economic transitional zone via multi-source data and methods of gradient analysis and change-point analysis. Taking China as an example, this study showed evidence of the discontinuity in each factor between the east and the west, and identified an east-west natural-socio-economic transitional zone (EWNSETZ) along the Hu Line. The EWNSETZ, determined by combining the integrated abrupt change zone of natural and socio-economic factors with the farming-pastoral ecotone (FPE), accounted for about 1/5 of China’s total land area and had more balanced distribution of land use types but more fragile environment and inferior combination of resources. Measures such as completing ecological compensation mechanism, developing tourism and green industries, increasing the supply of water resources and speeding up the construction of infrastructure and facilities can be used to promote the ecological-economic coordinated development of the EWNSETZ and eventually to drive the development of the western region. In particular, comprehensively consider the natural geographical conditions, key ecological function areas distribution and ecosystem services supply and demand of the EWNSETZ, the strategic orientation in its different parts should be focusing on different key points.