淇河流域生态系统服务权衡及空间分异机制的地理探测

Geographical detection of ecosystem services trade-offs and their spatial variation mechanism in Qihe River Basin

复杂的地形地貌使小流域具有生产、水源供给和调节等多种生态系统服务功能和显著的区域差异性,然而对小流域生态系统服务权衡关系及外部驱动机制集成测度一直是地理学、生态学和经济学研究的难题。以太行山南段淇河流域为研究对象,利用气象数据、土地利用/覆被数据、植被NDVI等多源数据,使用CASA模型和InVEST模型分别估算固碳、土壤保持及水源供给服务,运用空间叠置法和相关性分析测度生态系统服务权衡关系,进一步利用地理探测器中因子探测和交互探测分析自然环境和人类活动影响对生态系统服务权衡关系的空间影响。结果表明:①2000—2015年,淇河流域多年平均固碳量为375.55 gC m^(-2) a^(-1),且多年递减速率为18.20 gC m^(-2) a^(-1);多年平均土壤保持量为396.72 t hm^(-2)a^(-1),多年递减速率为1.2 t hm^(-2) a^(-1);多年平均水源供给量为67.26 mm/a,以0.16 mm/a的速率递减。②研究时段内,生态系统服务关系以强权衡和低协同为主导,且存在显著的空间分异特征,低协同分布区域减幅为16.21%,强权衡增幅最多(11.85%),表明流域生态系统服务能力呈升高趋势;生态系统服务两两关系中固碳与水源供给、水源供给与土壤保持表现为权衡关系,固碳与土壤保持呈协同态势。③地理探测器结果表明:固碳与土壤保持方面,植被NDVI(0.306)>气温(0.241)>土地利用程度(0.002);固碳与水源供给方面,植被NDVI因子解释力最强(0.381);水源供给与土壤保持方面,降水、气温和高程因子解释力均高于0.5;交互探测后各影响因子解释能力显著增强。

The complex topography makes the small watershed have many ecosystem services,such as production,water supply and regulation,and significantly regional differences.However,the balance of ecosystem service and the integration measurement of external driving mechanism in the small watershed,which have always been a difficult problem in the research of geography,ecology and economics.This paper takes Qihe River Basin in the south of Taihang Mountain as the research object,using CASA and InVEST models estimate carbon sequestration,soil conservation and water resources supply services respectively,based on the multi-source data such as meteorological data,land use/cover data,Normalized Difference Vegetative Index(NDVI).The spatial overlay analysis method and correlation analysis are used to measure the ecosystem services trade-off relationship,and the spatial impacts of natural environment and human activities on the ecosystem service trade-off relationship are further analyzed by factor detection and interaction detection in the geographical detector.The results indicate that①from 2000 to 2015,the average annual carbon sequestration is 375.55 gC m^(-2) a^(-1),and the annual deceleration rate is 18.20 gC m^(-2) a^(-1) in the Qi River Basin;the annual average soil conservation is 396.72 t hm^(-2) a^(-1),and the annual decline rate is 1.2 t hm^(-2) a^(-1);the average annual water resources supply is 67.26 mm/a with decreasing rate of 0.16 mm/a.②The ecosystem service relationship is dominated by strong balance and low coordination.There are significant spatial differentiation characteristics during the research period,low coordination distribution area reduced 16.21%and strong balance increased 11.85%,indicating the ecosystem service capacity of the river basin is increasing;In the pairwise relationship of ecosystem services,carbon sequestration and water resources supply,water resources supply and soil conservation show a trade-off relationship,while carbon sequestration and soil conservation show a synergistic trend.③Geodetector result show that NDVI(0.306)>temperature(0.241)>land use degree(0.002)in terms of the carbon sequestration and soil conservation;for carbon sequestration and water supply,vegetation NDVI has the strongest explanatory power(0.381);for water resources supply and soil conservation,the explanatory power of precipitation,temperature and elevation factors are higher than 0.5;the explanatory power of each influencing factor is obviously enhanced after interactive detection.