Abstract: Wildland urban interfaces are expanding throughout the world with implications for both cities and their adjacent wildlands. Importantly, WUI regions may be hotspots of extensive hazards, produce necessary ecosystem services, and key habitat for conservation. The trajectories of these areas and there impacts are not well characterized and likely vary among continents and biomes. To address this uncertainty we conducted a global assessment of wildland urban interfaces, their trajectories. We also evaluate the contribution of wildland urban interface areas to fire distributions (hazard), water availability (an ecosystem service), and threatened habitats (conservation). Our analysis identified rapidly increasing area of WUIs, especially in tropical biomes and continents of Africa and South America. WUIs were also associated with a large proportion of fires globally, extensive water resources, and large land areas of high conservation value. WUI impacts to hazards, services, and conservation were high in both Africa and Asia. These analyses suggest rapidly growing urban areas are leading to large sustainability challenges associated with potential hazards, ecosystem services, and threatening endangered species occurring within the WUI.
