景观连通性视角下植被恢复地区生态系统服务的因果关系OACHSSCD

Large-scale vegetation restoration has profoundly altered regional landscape structure and function,while its impacts on the causal relationships among ecosystem services remain unclear.Most studies have primarily focused on trade-offs and synergies among ecosystem services and their external driving factors.However,the causal relationships and their changes driven by the nonlinear interactions among ecosystem services have not been revealed effectively.Taking Yan'an City as a case study area and focusing on the changes in regional landscape connectivity before and after vegetation restoration,this research comprehensively utilized the Morphological Spatial Pattern Analysis(MSPA),quantitative ecosystem service models,and the Geographic Convergent Cross Mapping(GCCM)methods to analyze the temporal dynamics of causal relationships among the four key ecosystem services,including carbon sequestration,soil retention,water yield,and baseflow regulation.The results showed that:(1)With the advancement of vegetation restoration,the core area of landscape connectivity zones in Yan'an City increased from 29.29%in 1990 to 39.33%in 2020.This expansion primarily occurred in northern counties(Wuqi,Ansai,Zichang,and Yanchang),while southern counties such as Fuxian and Huangling showed a general enhancement in landscape connectivity levels.(2)The causal relationships of the four services within connectivity core areas showed significant differences before and after vegetation restoration.From 1990 to 2000,the connectivity core areas exhibited a bidirectional causal relationship between carbon sequestration and water yield,dominated by the effect of carbon on water yield,with a maximum ρ value of 0.38**.In contrast,causal relationships among other services were absent or not significant.(3)During the period from 2010 to 2020,the causal relationships changed notably.The"carbon-water"services shifted from bidirectional to unidirectional causality,with water yield exerting a strong causal influence on carbon sequestration,peaking at a ρ value of 0.76** by 2020.Additionally,carbon sequestration exhibited a unidirectional causal influence on baseflow regulation,with a maximum ρ value of 0.19** by 2020.These changes in causal patterns indicated that after vegetation restoration,the improvements in landscape connectivity have strengthened the coupling between carbon and water services.Future management should prioritize the gradual expansion of the core connectivity zones in northern counties and the enlargement of the medium and high level of core areas in the central counties.These areas should be integrated with natural vegetation in the southern counties to form a stable north-south connected ecological network of Yan'an City,thereby enhancing the overall regional ecological stability and the sustainable ecosystem service provisions.