基于生态系统服务视角的“土地分离与共享框架”解析

“土地分离和共享框架”是协调物质生产和生态保护、促进土地可持续利用的重要理论。本文梳理了“土地分离与共享框架”和生态系统服务间关联,剖析生态系统服务应用于该框架的理论基础,结合美国典型土地共享案例,分析了土地利用策略选择对粮食生产、生物多样性、直接和间接生态系统服务的影响,并探讨了该框架对中国生态系统工程的启示。结果表明：随着人类对土地功能认知的不断深入,“土地分离与共享框架”的拓展表现为从单一的粮食供给服务需求演进到粮食供给服务和其他生态系统服务的综合需求。当粮食供给服务与其他服务处于权衡状态时,在生态脆弱、恢复力差的地区,不同生态系统服务间多处于凸权衡关系,一般适宜采用分离策略;在生态系统稳定、恢复力强的地区,不同生态系统服务多处于凹权衡关系,一般适宜采用共享策略。结合美国典型土地共享案例发现,其土地利用实践中选择土地功能共享策略是比较适宜的;生态系统服务作为政策评估工具,可在策略选择和评估实施效果中发挥一定作用。研究结果可为可持续土地利用提供理论与方法支撑,并为中国制定土地利用策略提供参考。

Land sparing versus sharing framework from ecosystem service perspective

Land sparing versus sharing framework is an important theory for balancing food production and biodiversity conservation for sustainable land use. In this article, the relationship between the "land sparing versus sharing framework" and ecosystem services was summarized by revealing the theoretical basis of the combination of ecosystem services and land sparing versus sharing framework. The impacts of land-use decisions such as the USDA Conservation Reserve Program on food production, biodiversity, and other direct and indirect ecosystem services were analyzed. The application of this framework in Chinese environmental conservation projects was discussed, aiming at providing a reference for the coupling of land-use optimization and ecosystem services provision. The results show that: (1) The framework of "land sparing versus sharing" was based on multiple demands of ecosystem services from cultivated land. From an ecosystem service perspective, expansion of the framework can be seen as demand change from food production alone to multiple demands containing food production and other ecosystem services. (2) When food production service and other services are in a state of trade-off, in ecologically fragile and low resilience areas, where the relationship between ecosystem services shows a "convex tradeoff," land sparing strategy is often appropriate; whereas land sharing strategy is appropriate in ecologically stable and high resilience areas where the relationship between ecosystem services shows a "concave tradeoff." (3) Land sharing optimizes the demand of ecosystem services, according to the study of the land-use practices in the United States. Assessment of ecosystem services can be used as a tool to measure the effect of land-use policies and strategies.