权衡城市扩张、耕地保护与生态效益的京津冀城市群土地利用优化配置情景分析

京津冀城市群作为影响我国经济发展的重要区域,具有多重战略意义。然而,快速的城市扩张在提高社会、经济水平的同时,伴随着资源供求矛盾加深、耕地被侵占、生态退化,以及水、大气环境污染等众多突出问题,如何优化调整城市空间结构与布局,实现社会、经济发展与生态环境保护等多目标的协同优化是京津冀规划管理与决策的关键。从土地覆盖/利用数量和空间布局两个重点方面出发,通过多目标优化模型和CLUE-S模型的构建,提出了多目标权衡下的土地扩张优化情景预案,以期为京津冀城市群扩张布局与土地利用优化配置规划与管理提供科学参考。结果表明:一方面,利用多目标遗传算法(MOGA)可以很好地实现对京津冀土地利用结构优化配置及其与社会、经济及生态效益等多目标的定量化求解,为决策人提供满足不同权衡目标的多种选择,并通过与CLUE-S模型相结合,实现京津冀城市群土地利用格局的空间优化配置情景模拟;另一方面,研究结果表明,综合考虑了社会、经济和生态效益的优化方案中,林地的增加可以相对满足政策要求,增幅较大,耕地较未优化方案减幅放缓,符合耕地保有量的要求,同时,也从空间上减少了对重要生态用地的侵占。本研究的方法与结果可为京津冀城市群土地利用规划与生态安全格局建设提供理论与应用参考。

Scenario simulation balancing multiple objectives for optimal land use allocation of the Beijing-Tianjin-Hebei megaregion

The Beijing-Tianjin-Hebei (BTH) megaregion, a fundamental core economic region of China, is of great strategic significance. However, dramatic landscape urbanization has resulted in a growing threat to the eco-environment, such as an obvious decrease of arable land, water resource shortages, environmental pollution, etc., which has severely restricted future regional socio and economic development. Thus, land allocation optimization across the entire megaregion is an urgent issue challenging regional planners and decision-makers. In this study, we used the BTH megaregion to develop a research framework to integrate a multi-goal optimized and spatial configuration model to simulate an optimized land use allocation scenario by balancing the socio, economic, and ecological goals in 2020. We found that: 1) a multi-objective generic algorithm is suitable for multi-objective land use structure optimization and provides a foundation to predict changes in multi-objective land use structures; 2) by integrating the optimized schemes based on the genetic algorithm and CLUE-S model, an optimized land use allocation scenario could be established; 3) by comparing the similarities and differences between the optimized and non-optimized land allocation scenarios, we found that in the optimized scenario forest land increased more significantly and degradation of cultivated land decreased, which reduced encroachment into important ecological land and met the purpose of optimizing the land use structure. Both the research framework and findings of this study could support the planning and decision-making for the synergetic development of the Beijing-Tianjin-Hebei megaregion.