[Effects of Urban Sprawl Dynamics on Ecosystem Health in the Central Yunnan Urban Agglomeration]

The large-scale expansion of urban land in the context of rapid urbanization has led to significant changes in surface structures， which is a major cause of the degradation of global ecosystem structure and functions. Understanding the comprehensive impacts of urban expansion driven by human activities on ecosystems is crucial for maintaining regional ecosystem health and achieving sustainable development. This study focuses on the central Yunnan urban agglomeration， utilizing land use data from 1990， 2000， 2010， and 2020 to measure the scale， intensity， type， and landscape pattern of urban land expansion. The dynamic evolution of urban expansion over the past 30 years is examined， and an evaluation framework of "vitality-organizational strength-resilience" is developed to assess ecosystem health. Additionally， geographic detector techniques are employed to reveal the impacts of urban expansion on ecosystem health. The results showed that： ① The urban expansion of the central Yunnan urban agglomeration exhibited distinct phases， with multiple expansion types coexisting. The landscape pattern changes across different cities were varied， and the degree of expansion clustering was increasing. The core city， Kunming， primarily experienced infill expansion， while other major cities showed characteristics of edge and enclave expansion. ② The overall health of the urban agglomeration's ecosystem improved， with the highest change in ecosystem health observed in Honghe Prefecture （12.55%）， followed by Chuxiong Prefecture （12.42%）， with the lowest in Kunming （7.11%）. ③ The patch shape index of urban land was the most significant driver of changes in ecosystem health in the Central Yunnan Urban Agglomeration. The combined effect of expansion intensity and patch shape index resulted in the most substantial disturbances to ecosystem health.