Objective Since the first successful practice in London in the 1930s, greenbelt has become an important land control and land use planning idea. Greenbelts help solve problems related to urban sprawl and provide multiple ecological, social and economic functions that have profound impact on the sustainable development of regions. In the past hundred years, the construction of greenbelts have been on the rise in the world, but some greenbelts have also encountered a lot of resistance and destruction in the implementation process, and the gap between planning and implementation is large. On the surface, the obstruction of greenbelt construction is the contradiction between green space protection and development and construction, between ecological land and construction land. In essence, it is a long-term game and coordination of land, capital and other resources for multiple stakeholders such as local governments, citizens, economic organizations and social groups. At present, there are few researches on the greenbelts from the perspective of "agent-agent" and "agent-environment" interaction and adaptation mechanism between multi-stakeholder and greenbelt system. This study takes Beijing’s greenbelt (the first greenbelt and the second greenbelt) as an example, according to the "bottom-up" research paradigm of complex adaptive system theory (CAS), depicts the adaptation process of multi-agent to promote the evolution of the greenbelt system, and explores the mechanism of the evolution of the greenbelt, to seek targeted solutions to optimize the greenbelt planning and promote the implementation of greenbelt policies.
Methods Based on the theory of complex adaptive system, the system characteristics of the greenbelt are analyzed from the perspectives of basic characteristics, structural composition and adaptive mechanism. Taking Beijing’s greenbelt as an example, the evolution process of greenbelt is divided into different stages according to the degree of agent emergence, structure complexity and system maturity. At the same time, based on the four characteristics of complex adaptive systems (aggregation, non-linearity, flow, diversity) and three mechanisms (tagging, inter model, and blocks), the interaction between multiple agents and the environment is explored.
Results The research results show that the construction of the greenbelt system is participated by the multi-agent system. In the process of the evolution of Beijing’s greenbelt, multiple agents such as municipal and district government, village collectives, private enterprises, township governments and citizen have emerged and interacted with each other more frequently, which also reflects the strong adaptive and self-organizing ability of greenbelt system. In the embryonic stage, the main agent of greenbelt construction is single, and rapid urbanization in the macro external environment becomes the biggest hindrance of greenbelt in the embryonic stage. In the experiment breakthrough stage, in 1993, Beijing Municipal Government proposed to introduce market mechanism in greenbelt construction. This macro-level external force and rapid urbanization jointly promoted the process of self-organization. Private enterprises spontaneously joined the greenbelt construction and interacted with the government and village collective entities to promote the system evolution. In the orderly implementation stage, both external environmental forces and self-organizing forces play a strong role in the evolution of greenbelt. Major social and cultural events, "urban and rural integration", "reducing quantity and improving quality and green" policies, and diversified citizen participation have all promoted the improvement of self-organizing ability. Top-down macro planning, policy and bottom-up micro agent interaction and self-organization jointly promote the evolution of greenbelt system.
Conclusion The construction of greenbelt can not only rely on the "top-down" greenbelt policy to promote, but also need to rely on the self-organization law, through the external environment to "guide" individuals to change their own behavior rules, and "bottom-up" to achieve the goal of greenbelt construction. In order to regulate the evolution of greenbelt, we must fully consider the complex relationship between agents, the behaviors of agents and the environment, the adaptive ability of different agents and the external influence of social environment. In order to realize the sustainable development of greenbelt, it is necessary to enhance the initiative and creativity of government, attach importance to the collaborative governance of multiple agents and enhance the adaptability of multiple stakeholders. This conclusion is consistent with the conclusions found in previous studies: different political and economic systems, development stages, social and cultural characteristics, planning methods and management methods will affect the implementation effect of greenbelt planning; The implementation of greenbelt needs to coordinate the interests of multiple parties and build a "community of interests". Although the implications of the sustainable development of the greenbelt proposed in this paper are relevant to Beijing’s greenbelt, the basic conceptual framework of CAS can also be used as the thinking framework of other greenbelt governance. At present, the research of greenbelt system based on CAS theory is still in the exploratory stage, and there are many shortcomings. On the one hand, the evolution process of the greenbelt system is only discussed qualitatively, and it has not been discussed quantitatively. On the other hand, it mainly discusses the interaction between the agents of the multi-agent system, and the other three subsystems are less discussed. Future studies need to continue to explore the above limitations in order to more comprehensively understand the complexity of the greenbelt system.
DownLoad: