Aridification weakens ecosystem services by reducing complexity and stability of socio-ecological networks

The intensification of aridity threatens ecosystem services (ES) that support fundamental needs for human well-being; understanding how ES responds to aridity-induced changes in the interactions between socio-ecological components is critical for the development of effective coping strategies. There remain, however, challenges in systematically characterizing intricate socio-ecological relationships, and these difficulties hinder our un-derstanding. To address this issue, this study constructed a correlation network among ES, vegetation, climatic, landscape, geomorphological and socioeconomic factors under different aridity gradients on the Loess Plateau. By analyzing the relationship between network structure properties and ES, we highlighted how aridity gradients alter the impact of socio-ecological systems on ES: as aridity increases, the connections between socio-ecological components lessen, and the transitivity and density of the socio-ecological network decrease, which means the complexity and stability of the network decrease. Aridification enhances the pivotal status of vegetation factors in the network, while weakening the relative roles of other components. Furthermore, the transitivity and density of the network have significant positive effects on ES. Importantly, the network structure properties explain 66% of the observed variation in ES under different aridity gradients. We conclude, therefore, that aridification re-duces ES by weakening the links between socio-ecological components. This study has important instructive implications for mitigating the threat of aridity to human well-being.