Identification and optimal regulation of the production-living-ecological space based on quantitative land use functions

Abstract: Territorial spaces are generally multifunctional, including production, living and ecological functions. Delimiting scientifically Production-Living-Ecological space (PLE) has become essential to identify and estimate the functions of land use, particularly for the planning and administration system in the sustainable development strategy of modern agriculture. In this study, taking the city of Zhangjiakou as a research object, an evaluation system was established for the value of land use functions, with emphasis on an integrated perspective of production suitability, living suitability, and ecological importance. A 1 km×1 km grid cell can be used to integrate the multi-source data from the land use, remote sensing, soil, hydrology, and socio-economic statistics. The evaluation methods were mostly associated with the environmental and ecological economics. Three classifications were divided according to the value of production, living and ecological function. 25 types of function composite patterns in the PLE space were achieved, using the natural breakpoint method, the spatial overlay analysis, and the arrayed rule in combinatorics. The results indicated that: 1) The PLE space in Zhangjiakou city covered 9 functional composite patterns, in addition to the uniform space of production-living-ecological, where the proportion of the space dominated by ecological function was the maximum, 42.50%, the space dominated by living function was the second, 5.6%, and the space dominated by production function was the minimum, 2.81%. It indicated that maintaining ecological stability was the main mission of the land use function in the current stage of social and economic development in Zhangjiakou. More than 80% of the space showed all three PLE functions, indicating that there was very significant versatility in this case. 2) There was obvious spatial consistency between the space dominated by production function and that by living function, while, there was obvious spatial complementarity between the spaces dominated by ecological function. Specifically, the spatial consistency was mainly distributed in the Yanghe river valley basin, Sanggan river basin and Huliu river basin, whereas, the spatial complementarity was mainly distributed in the mountain of Yanshan and Taihang in the east of the study area. The function of composite patterns was found with the prominent diversity in spatial distribution, showing a "local agglomeration, global dispersion" spatial features. In the same function combination, the spatial aggregation was higher, but lower in the different function combination. It infers that there was a relatively strong ability for the integration and complementarity between the same functional combination modes, whereas, there can be fierce conflicts and contradictions in regional land use, particularly on the different functional combination modes. 3) Five types can be divided during the optimization of partition of PLE, including the comprehensive improvement zone, ecological conservation zone, main production-living and ecological improvement zone, main living-production ecological improvement zone, and balanced production and life-ecological improvement zone. The coordinated development of functions in PLE can be realized for the space dominated by production function, and by living function, whereas, the ecological conservation as the primary goal can be served as the main mission in the space dominated by ecological function for the sustainable development strategy.