Global satellite data reveal widening recovery gap between urban and rural vegetation

A global study has revealed a striking divergence in how urban and rural vegetation respond to climate stress. The study was led by Jin Wu from the School of Biological Sciences, Faculty of Science, and professor Yuyu Zhou from the Department of Geography, Faculty of Social Sciences, at The University of Hong Kong (HKU), with Dr. Zhengfei Guo as the first author.

Published in the Proceedings of the National Academy of Sciences under the title "Global divergence in urban-rural vegetation resilience driven by broken ecological trade-offs," the study found that urban vegetation is more resilient than its surrounding rural counterparts, challenging the view that cities are uniformly detrimental to ecosystem stability and highlighting the potential role of sustainably managed urban green spaces under climate change.

Using satellite observations spanning 751 cities across 109 countries from 2001 to 2022, the research team conducted a global multidecadal assessment of vegetation resilience, defined here as the capacity of vegetation to recover following disturbance.

A surprising and widening urban resilience advantage

Across 751 cities worldwide, vegetation in urban cores was more resilient than surrounding rural vegetation in 78% of cities. This advantage was particularly pronounced in hot and arid regions, where vegetation is strongly constrained by water availability.

More importantly, the urban–rural resilience gap has widened over the past two decades. This divergence was driven primarily by declining resilience in rural vegetation, while urban vegetation remained comparatively stable or improved slightly over time. Among the factors examined, a management-associated water-subsidy proxy showed the strongest statistical association with the urban resilience advantage, followed by canopy structure. These relationships are consistent with the possibility that urban management can help buffer vegetation against increasing climate stress, although the study does not establish irrigation itself as a direct causal mechanism.

The findings also reveal a deeper shift in how ecological stability can be maintained in cities. In 32% of cities, urban vegetation showed a "dual advantage": It experienced smaller greenness losses during disturbances and recovered faster afterward than surrounding rural vegetation.

This pattern is consistent with a management-mediated relaxation of the usual resistance–resilience trade-off. Together, the results suggest that, when supported by sustainable and equitable management, urban green spaces may serve as managed refugia for vegetation resilience under climate change.

Wu said, "Vegetation remaining within cities can show unexpectedly strong recovery capacity under environmental stress. Its resilience advantage is closely associated with management-related factors, particularly water subsidy and canopy structure, highlighting the potential of well-designed and sustainably managed urban green infrastructure."

Guo, the study's first author, said, "The urban resilience advantage was strongest in hot and arid regions, where vegetation is especially vulnerable to water stress. In nearly one-third of cities, urban vegetation also suffered less damage while recovering faster, suggesting that human management may reshape the balance between resistance and recovery."

Zhou added, "Urban green space can serve as a resilient ecological buffer against climate change. With deliberate, sustainable and equitable management, urban green infrastructure could provide important support for future urban planning and climate adaptation."

For Hong Kong, the findings provide practical insights for building more climate-resilient urban green spaces. Integrating sustainable water management, appropriate canopy structure and long-term green-infrastructure planning could help maintain vegetation resilience as the city faces increasing climate stress.