Human Disturbance and Vegetation Recovery in Urban Green Spaces: A Quasi-Experimental Study on a University Campus

Understanding the impact of human disturbance on urban vegetation is a key issue in urban sustainability, particularly in complex urban ecosystems. Using the COVID-19 lockdown as a quasi-natural experiment, this study examined vegetation responses to varying disturbance intensities across a university campus, comparing a low-disturbance phase (April 2022) with short-term recovery (July 2022, when human activity resumed) and long-term recovery (April 2024). Human disturbance was quantified based on activity restriction, duration, and population density, while vegetation responses were assessed using the Normalized Difference Vegetation Index (NDVI) and Fractional Vegetation Cover (FVC) across woodlands, lawns, and greenways. Results revealed significant spatial and temporal variability: High-intensity zones showed rapid but short-lived recovery, driven by seasonal phenology and the structural filling of exposed surfaces, but failed to sustain these gains over the long term. In contrast, moderate- and low-intensity areas exhibited more stable, long-term recovery, consistent with the Intermediate Disturbance Hypothesis. Woodlands demonstrated strong ecological stability, lawns maintained consistent recovery under regular management, and greenways showed greater resilience in enclosed segments. These findings indicate that regulated human activity can coexist with ecological resilience, providing evidence-based insights for differentiated management of urban green spaces and sustainable recovery strategies.