关中—天水经济区生态系统服务的权衡关系

Trade-offs between ecosystem services in Guanzhong-Tianshui Economic Region

关中—天水经济区是西部大开发规划中提出的需要重点发展的第三个经济区,经济迅速发展的同时带给生态环境巨大压力,因此研究关中—天水经济区的生态系统服务变化以及生态系统服务之间的关系,对经济区的可持续发展具有重要意义。本文测算了2000年至2010年关中—天水经济区的净初级生产力(NPP)、保水量以及土壤侵蚀量——反映狭义上的保土服务功能(减少土壤侵蚀),引入玫瑰图以及生产可能性边界方法研究这三种生态系统服务之间的权衡和协同关系,并对2030年关中—天水经济区的土地利用类型进行情景模拟,在不同情景下研究净初级生产力(NPP)保水以及土壤侵蚀三者的空间分布和相互之间权衡和协同关系。结果表明:NPP与保水之间存在协同关系,NPP的增加会促进保水量的提高,反过来,保水量的增加有利于NPP的积累;NPP与土壤侵蚀以及保水与土壤侵蚀之间为权衡关系,NPP、保水的增长有利于减少土壤侵蚀,增加土壤保持量;保护情景下获得的NPP与保水量最多,土壤侵蚀量最少,是最优的土地利用类型方案,最有利于生态环境;不同情景下NPP与土壤侵蚀以及保水与土壤侵蚀之间也存在权衡关系。

Natural ecosystems offer society important goods and services. With the rapid population growth and ongoing natural resource use, humans have enhanced the production of some services at the expense of others. This paper examines changes in ecosystem services, and the relationship between ecosystem services, in Guanzhong-Tianshui Economic Region. These ecosystem changes are of great significance to the sustainable development of this economic region. The methods of ＂rose map＂ and ＂production possibilities frontiers （PPFs）＂ are applied to evaluate the trade-offs and co-benefits between NPP, water conservation, and soil erosion. Furthermore, the CASA （Carnegie-Ames-Stanford Approach） model, ULSE （Universal Soil Loss Equation） model, and the water storage capacity method are used to estimate net primary productivity （NPP）, water conservation, and soil erosion. The study takes soil retention （the reduction of soil erosion） as a model ecosystem service, using 2000-2010 data from the study area. Three land use strategy scenarios- planning, exploitation and protection- are applied to evaluate potential changes in ecosystem services and trade-offs between NPP, water conservation, and soil erosion. The study reveals noticeable trade-offs between NPP, water conservation, and soil erosion, with co-benefits from NPP and water conservation. There are also trade-offs between NPP, water conservation, and soil erosion under the three scenarios. The ＂protection＂ scenario is the most favorable land use strategy for regulating ecosystem service capacity; that scenario results in the highest NPP, water conservation, and soil retention. The results could impact natural capital and ecosystem services planning, management, and land use decision-making.