2005−2020年山西省水源涵养功能时空格局及其演变驱动力分析

Temporal and Spatial Dynamics of Water Conservation in Shanxi Province(2005-2020):Patterns and Influence Analysis

水源涵养功能与植被恢复、水土保持及水资源保护等密切相关.山西省地处干旱、半干旱的生态脆弱区,良好的水源涵养功能是其生态安全的重要基础,然而近15年来该省水源涵养功能时空格局及其演变驱动力尚不清楚.鉴于此,该研究采用InVEST(integrated valuation of ecosystem services and trade-offs,生态系统服务和权衡的综合评估模型)软件中Annual Water Yield模型以及ArcGIS软件,研究了2005年、2010年、2015年、2020年4个时期山西省水源涵养时空格局,并综合地理探测器和主成分分析两种方法解析了驱动水源涵养空间分异的主要因素.结果表明:①2005―2020年,山西省单位面积水源涵养量整体呈现先增后减的变化趋势,2020年水源涵养总量相比2005年增加了1.53×108 m 3,增长率为7.3%.②年降水量和土地利用类型是影响水源涵养变化的主要驱动因素.年降水量对水源涵养量变化的效应(q值为0.372~0.477)在不同年份中均超过0.3,是决定水源涵养空间分异特征的主导因素.从土地利用类型来看,水源涵养功能顺序表现为林地>草地>耕地>建筑用地>未利用地>水域,土地利用类型面积的变化对水源涵养量有重要影响.③水源涵养变化更受限于不同因素间的交互作用,在不同年份中,对山西省水源涵养量空间分异解释力最大的驱动因子交互组合为年降水量与年潜在蒸散发量协同(q值为0.486~0.596),以及年降水量与土地利用类型协同(q值为0.468~0.582).山西省以山地丘陵为主的复杂地貌增强了人类活动下生态系统的脆弱性和可变性,要特别关注年降水量与土地利用类型的协同作用,通过调整优化土地利用类型,强化前述两因素的交互作用,以期增强水源涵养功能.

Water conservation function is closely related to vegetation restoration,soil and water conservation and water resources protection.Shanxi Province is located in an arid and semi-arid ecologically fragile area,where the effective water conservation function plays a crucial role in maintaining ecological security.However,the spatial and temporal patterns of water conservation functions in the past 15 years and its driving forces still need to clarified.This study used the integrated valuation of ecosystem services and trade-offs(InVEST)software and ArcGIS software to analyze the spatiotemporal pattern of water conservation in Shanxi Province in four periods:2005,2010,2015 and 2020.The study employed geographical detectors and principal component analysis methods to analyze the primary factors influencing the spatial differentiation of water conservation.The research results showed that from 2005 to 2020,the water conservation per unit area in Shanxi Province exhibited a pattern of initial increase followed by a subsequent decrease.Compared with 2005,the total water conservation in 2020 increased by 1.53×108 m 3,corresponding to a growth rate of 7.3%.Annual precipitation and land use types were the primary driving factors affecting changes in water conservation.The effect of annual precipitation on changes in water source conservation(with a q value ranging from 0.372 to 0.477)had exceeded 0.3 in various years,becoming the primary determinant of the spatial differentiation of water conservation characteristics.From the perspective of land use types,the order of water conservation functions was as follows:forest land>grassland>cultivated land>construction land>unused land>water areas.Changes in the area of land use types had a significant impact on water conservation.The changes of water conservation are constrained by the interaction of multiple factors.The combination of driving factors with the most significant ability to explain the spatial variation of water conservation in Shanxi Province over the years was the synergy between annual precipitation and annual potential evapotranspiration(q value of 0.486-0.596)and the synergy between annual precipitation and land type(q value of 0.468-0.582).The complex landscape of Shanxi Province,characterized by its prevalence of mountains and hills,exacerbates the vulnerability and variability of the ecosystems due to human activities.Therefore,it is crucial to focus on the synergistic effect of annual precipitation and land type,and enhance the interaction between the two by adjusting and optimizing land-use types to improve the water conservation function.