Restored wetlands as urban heat mitigators: A UAS-based assessment of land use, land cover, and surface temperature in Bothell, Washington

Urban land use alters surface energy balance and drives localized warming, yet the fine-scale thermal effects of restored ecosystems remain insufficiently quantified. This study applies high-resolution unoccupied aircraft system (UAS) remote sensing to characterize seasonal land surface temperature (LST) variation and energy absorption across restored wetlands, built environments, and forested land covers. Multispectral, RGB, and thermal infrared imagery were collected during summer and winter seasons over a historically degraded wetland in Bothell, Washington, that has undergone more than 20 years of ecological restoration within a rapidly urbanizing suburban landscape. UAS-derived land cover classifications were integrated with LST estimates and analyzed using spatial autoregressive models to account for spatial dependence and landscape heterogeneity. Results reveal consistent and statistically significant thermal differentiation among land cover types. Built surfaces, including artificial turf, paved areas, and buildings, functioned as thermal hotspots across both seasons, while water bodies, wetland vegetation, and forested areas provided the greatest summer cooling through evapotranspiration, shading, and hydrological buffering. Wetlands outperformed forested areas by approximately 1 °C across seasons, reflecting the additional cooling contribution of saturated soils and standing water. Spatial modeling further revealed that thermal benefits extend beyond ecosystem boundaries through landscape-scale spillover effects. These findings position wetland restoration and urban reforestation as functional thermal infrastructure capable of delivering measurable, spatially extensive cooling benefits. Integrating restoration-based strategies into climate adaptation frameworks offers a scalable, multi-benefit pathway for reducing thermal risk while supporting biodiversity, stormwater management, and carbon sequestration.