黄土高原生态系统服务权衡与协同时空变化及影响因素——以延安市为例

明确黄土高原生态系统服务权衡与协同的时空变化特征及影响因素,深刻理解能源开发和经济发展背景下黄土高原多种生态系统服务之间的相关关系,为实现经济与生态保护的协调发展提供理论依据。以黄土高原典型区延安市为例,探讨1993—2013年间生态服务价值(植被净初级生产力、土壤保持、水源涵养和食物供给)之间权衡与协同关系的时空变化特征,以及退耕还林政策和地形坡度对生态系统服务权衡与协同关系动态变化的影响。结果表明:①各类生态系统服务之间呈现不同的相关关系,食物供给与土壤保持、水源涵养以及NPP之间均为权衡关系,NPP与土壤保持、水源涵养之间为协同关系,土壤保持与水源涵养呈现协同关系;②20年来延安市生态系统服务整体表现为权衡加强协同减弱的趋势;③对比退耕还林区与非退耕还林区权衡与协同的动态变化,发现退耕还林区各类生态服务多呈协同关系且不断加强,而在非退耕还林区多表现为权衡关系;④坡度为15°—25°地区生态服务冲突最为显著,大于25°地区生态服务协同作用显著;⑤NPP与水源涵养的协同关系呈现北部高南部低的分布规律,NPP与食物供给权衡程度在延安市北部较强而东部较弱,水源涵养与食物供给的权衡关系在延安市西南部更为突出而北部最弱。

Spatial and temporal changes in the synergy and trade-off between ecosystem services, and its influencing factors in Yanan, Loess Plateau

Clarifying the temporal and spatial changes in the trade-off and synergy between ecosystem services and its influencing factors in the Loess Plateau (LP) provides the basis for a better understanding of the interaction of ecosystem services in the background of energy and economic development. It also provides a theoretical basis for the coordinated development of economy and ecological protection. Using the partial correlation spatial statistical analysis, we investigated the spatio-temporal variation in the trade-off and synergy between ecosystem services (net primary productivity (NPP), soil conservation, water conservation, and food supply) and analyzed its influencing factors through the study of Grain-for-Green Program (GFGP) and non-Grain-for-Green Program (non-GFGP). We also assessed the effect of terrain slope on the dynamic changes in the trade-off and synergy during 1993-2013. The results obtained were as follows. (1) Various kinds of ecosystem services in Yanan have different correlations. We found that food supply and soil conservation, food supply and water conservation, and food supply and NPP have a trade-off relationship. There was a synergistic relationship between NPP and soil conservation, NPP and water conservation, and soil conservation and water conservation. (2) In addition, between 1993 and 2013, this synergistic relationship showed a downward trend, whereas, the trade-off relationship demonstrated an upward trend. (3) Furthermore, a comparison of the dynamic changes in the trade-off and synergy between GFGP and non-GFGP showed that various ecosystem services in GFGP have a synergistic relationship, and it continued to increase, but it showed a conflicting relationship in non-GFGP. (4) The conflict between ecosystem services in the area of 15°-25° was obvious, but in the area of > 25°, the synergistic relationship was evident. (5) In terms of the synergistic relationship between NPP and water conservation, the strongest evidence was found in the north of Yanan and the lowest was observed in the south. Moreover, the strongest trade-off relationship between NPP and food supply was in the north, whereas, the weakest was in the east. While exploring the trade-off between water conservation and food supply, we found that it is the strongest in the southest of Yanan and the lowest in the north.