1. Introduction

As a complex and dynamic process, urbanization is evolving over multiple spatial-temporal scales (Grimm, 2008), and could be characterized as four aspects: economic growth, population migration, social transformation, and urban space expansion (Gu, 2019). How to comprehensively assess the urbanization level is a key issue to maintain the stable growth of urbanization in recent decades. Furthermore, the key scientific gap in urbanization assessment is gradually changing from single scale to multi-scale, and the comprehensive assessment framework involving population, economy, space and society has been distinguished widely (Wang, 2019; Feng, 2021). Meanwhile, there are significant offsets in the urbanization level among countries due to global integration, especially in developing countries. Urbanization rate at the global scale is predicted to rise to 68% by 2050 (United Nations, 2018). The intensive human activities accompanying urbanization have affected the natural environments, causing ruinous ecosystem degradation (Yi, 2018; Zhao, 2022). Therefore, quantitative estimating urbanization is important for ensuring the human-land harmony relationship and achieving regional sustainable development.
Ecosystem health is judged as a key indicator for weighing ecosystem quality (Li, 2021). Compared to other indicators (e.g., biological integrity, ecological footprint and ecological carrying capacity), ecosystem health considers not only critical consequences of human activity, but also, responses of an ecosystem to environmental changes, which becomes an ideal endpoint for ecosystem management (Costanza, 1999; Rapport, 2000). Building healthy ecosystems that sustainably provide a mixed bag of valuable ecosystem services is the crucial design goal of our ongoing ecological engineering (Costanza, 2012). Ecosystem health was first used to assess and identify land health (Leopold, 1941), then Rapport (1989) expanded its connotation by analogy with human health. Costanza (1992) marked ecosystem health by a comprehensive measuring of system resilience, organization and vigor. Since human activities are primarily related to the land resources, the health of terrestrial ecosystems affects important ecological functions and the provision of a range of valuable ecosystem services.
A healthy terrestrial ecosystem should restrain or rapidly recover from some unexpected disturbances issuing from natural or human activities and shows diversity, complexity and robustness (Ma, 2016). Research on terrestrial ecosystem health should consider both health state identification and driving mechanisms analysis (He, 2019). Many studies have estimated ecosystem health for wetlands (Sun, 2016), forests (Meng, 2019) and urbans (Su, 2009). Biological indicator and index system method are the current measures for terrestrial ecosystem health measurement. The former is satisfactory with single ecosystem and requires many measured species data, while the latter is not bound by the number, type and data of ecosystems and is widely used for terrestrial ecosystem health estimation (Liu, 2015). Compared with other methods (e.g., Press–State–Response (PSR), the Ecological Modeling Method (EMM), Driving-Pressure-State-Impact-Response (DPSIR), etc.), the vigor-organization-resilience (VOR) method can better denominate some environmental changes, ecosystem service state, and spatial effects from a microscopic perspective (Xie, 2022), which was adopted in our study.
As a natural-society-economic coupling system, terrestrial ecosystem health status will be affected by multiple natural and human factors (Xu, 2022; Li, 2023), such as land use intensity and social-economic activities (Cheng, 2018; Yang and song, 2020). Furthermore, the interaction among natural (e.g., climate and topography) and anthropogenic factors would enhance the uncertainty of terrestrial ecosystem health (Shen, 2020; Xu, 2022). Likewise, the city is an open human-land coupling social system, and the urbanization process is driven by many aspects. Among them, social and economic factors such as marketization, industrialization, trade, education, democracy, and transportation have become favorable factors to promote urbanization (Zhang and Du, 2022). However, the influence of geographical factors is rarely included, which should be considered when conducting urban dynamics analysis (Christensen, 2016). In addition, the negative impact of urbanization on terrestrial ecosystem health has been explored (Peng, 2015; Zeng, 2023). With the joint efforts of the government, society and individuals to protect and restore ecological environment, this situation has changed. However, its driving mechanism remains unclear.
China’s tremendous economic transformation in the past 20 years has driven the rapid urbanization. Similar to most countries in the world, the urban spatial pattern develops from individual cities to urban agglomerations and metropolitan areas. However, inter-region and inner-region differences in economic growth rates have resulted in uneven and insufficient development. Meanwhile, the irrational land expansion driven by resources has led to serious environmental pollution and landscape fragmentation, seriously threatening the regional terrestrial ecosystem health. In addition, the driving mechanisms of urbanization and terrestrial ecosystem health vary remarkably among regions due to the differences in economic foundation, development patterns, natural resources and social cultures (He, 2019; Cai, 2021). Therefore, it is necessary to explore the tie between terrestrial ecosystem health change and urbanization for simultaneously enhancing economic development and environment conservation in future.
In this paper, we first constructed a comprehensive index determined from the entropy method to assess urbanization, and used the VOR method to quantify and estimate the terrestrial ecosystem health. Then, the bivariate spatial autocorrelation analysis was adopted to describe their spatial dependence. Finally, the driver pathways at the national scale and the regional scale were analyzed based on the partial least squares structural equation model to reveal their driving mechanisms. Our objectives are: (1) Evaluating the spatial and temporal evolutions of urbanization and terrestrial ecosystem health in China from 2000 to 2020; (2) Demonstrating the spatial dependence of terrestrial ecosystem health and urbanization; (3) Revealing the magnitudes and directions of drivers for urbanization and terrestrial ecosystem health changes. Our study could confer a theoretical basis for the harmonized development of high-quality urbanization and terrestrial ecosystem health.