城市食物系统演化的人地耦合启示及驱动力——以北京食物系统为例

为探明“城市化如何驱动食物系统变化”以及“食物系统变化蕴含何种人地耦合关系”的问题,本文以北京食物系统为例,研究了该食物系统自1978年以来的演变过程,揭示食物系统演变蕴含的人地耦合关系;并建立食物系统变化指标体系和城市化驱动力指标体系,运用驱动力评价、格兰杰因果关系检验、回归分析与网络分析相结合的方法研究北京食物系统演变的驱动力及作用机制。结果发现：近40多年来北京食物系统总体经历了本地农业生产不断弱化、食物消费需求持续增长、食物流通里程不断增加的演变过程。这种变化从地理学视角来看本质上是城市食物消费蕴含的人地耦合关系从邻近扩展到更远距离的过程——即食物系统近远程耦合的演化过程。在驱动该过程的影响因素中,居民收入增长是主要的初始驱动力,要素非农化是主要中间环节,人口集聚则具有最广泛的影响,最终导致外埠供应比例不断上升,食物里程持续增长。研究表明：蕴含在食物系统中的人地关系不只局限于特定的地点、特定的区域,而是以“流空间”与地点空间相互连接、相互渗透的形式呈现出来。因此,需要采取一种整合“流空间”与地点空间的理论视角及研究方法来认知此类开放系统中的人地耦合关系。

Human-land coupling enlightenment and driving forces of urban food system evolution: A case study of Beijing food system

In order to explore "how urbanization drives the change of food system" and "what human-land coupling relationship is implied by the change of food system", this paper took the food system of Beijing as an example to study the evolution process of the food system since 1978, and revealed the human-land coupling relationship implied by the change of food system. In addition, the index systems of food system change and urbanization driving force were established, and the driving force evaluation, Granger causality test, regression analysis and network analysis were combined to study the driving force and action mechanism of food system evolution in Beijing. The results show that the food system in Beijing has experienced a process of weakening local agricultural production, increasing food consumption demand, and increasing food circulation mileage in the past 40 years. From a geographical perspective, this change is essentially a process in which the human-land coupling relationship contained in urban food consumption expands from proximity to a greater distance -- that is, the evolution process of local and tele-coupling of food system. Among the influencing factors driving this process, income growth is the main initial driving force, non-agriculturalization of elements is the main intermediate link, and population agglomeration has the most extensive impact, which is ultimately led to the increasing proportion of external supply and the continuous increase of food miles. The research shows that the human-land relationship contained in food system is not limited to a specific place or region, but in the form of "flow space" and place space interconnected and permeated. Therefore, it is necessary to adopt a theoretical perspective and research method integrating "flow space" and place space to recognize the human-land coupling relationship in such open systems.