Impacts of human disturbances on the supply and demand of ecosystem services in the middle reaches of Yangtze River urban agglomeration across multiple scales.

Understanding the impacts of human activities on the supply and demand of ecosystem services can lay a solid foundation for reducing environmental damage in ecologically valuable areas and is thus of great significance for regional sustainable development. We focused on the middle reaches of Yangtze River urban agglomeration and evaluated six key human pressure indicators: population density, gross domestic product (GDP), land use type, traffic network, energy consumption, and building height. Using multi-source data, including land use, meteorology, and socioeconomic information, and applying various ecological models such as InVEST, we quantified and spatially characterized the supply and demand of four ecosystem services: carbon storage, water yield, soil conservation, and grain production. We used structural equation model to analyze the relationship between human distur-bance and the supply and demand of different ecosystem services, aiming to explore the impacts of different human disturbances on the supply and demand of ecosystem services across various spatial scales. The results showed that the spatial distribution characteristics of different human disturbances varied significantly. Population density, GDP, and transportation network exhibited high levels of disturbance in densely populated areas, while land use, energy consumption, and building height had greater impacts in the core cities of the urban agglomeration. Ecosystem services in urban areas were at a state of undersupply, whereas non-urban areas experienced oversupply, with this imbalance being intensified with increasing spatial scales. The magnitudes of the impacts of human disturbances on ecosystem service supply and demand also varied across scales. At the grid scale, local land use and vegetation cover were the primary and direct drivers, while at the county and larger scales, socioeconomic factors, regional policies, and climate change exerted a combined influence. Population density, economic development, and land use were the main factors affecting the supply-demand relationship of ecosystem services. The feedback mechanisms and cumulative effects of multiple human disturbances directly exacerbated ecosystem service degradation. These findings would provide scientific guidance for policy formulation aimed at balancing ecological protection with human activities.