Urbanization Pressures on Climate Adaptation Capacity of Forest Habitats

Urbanization extensively shapes the wildland-urban interfaces (WUIs). However, the effects of urbanization on forest habitats in WUIs as thermal refuges for biodiversity remain elusive. Here, we show that urbanization-induced increases in human footprints cause canopy degradation of forest habitats in WUIs, including declines in forest coverage (-12.61% ± 0.05%), leaf area index (-0.45 ± 0.01 m² m^-2), and canopy height (-3.74 ± 0.02 m). Canopy degradation weakens forest-based climate change adaptation, inferred by reduced forest habitat connectivity (-9.45% ± 0.08%) and elevated daily mean surface temperature (0.41°C ± 0.01°C) in WUIs, leading to a rise in frequency (0.22 ± 0.01 days) and intensity (1.05°C ± 0.02°C) of annual mean thermal extremes compared to that in nearby wildlands. A 10.01% ± 0.07% lower mean species richness in WUIs than nearby wildlands demonstrates local biodiversity loss in WUIs driven by intense human footprints, declined habitat connectivity, and increased thermal stress. We highlight the need for urban planning to fully integrate solutions for climate adaptation and biodiversity conservation.