The microbial aerial thread: co-restoring source and sink across dryland-urban gradients

Dryland ecosystems serve as major sources of atmospheric bioaerosols through aeolian transport of dust-associated microorganisms. These microbial communities are dispersed across vast distances, connecting dryland soils and vegetation to distant recipient ecosystems, particularly urban areas. This review synthesizes current understanding of microbial ecology in arid soils, microbial dispersal through dust, and interactions with urban ecosystems. We propose that restoration efforts should move beyond isolated, site-level interventions toward integrated strategies that account for the atmospheric connectivity between dryland source areas and urban sink environments. Practical restoration approaches, including dryland soil stabilization to reduce harmful dust emissions, microbial inoculant development, and urban green infrastructure designed to function as dispersal corridors, can generate cross-boundary synergies that enhance ecological resilience across the dryland-urban gradient. By reconceptualizing cities as nodes within broader ecological networks linked by microbial dispersal, and by leveraging insights from dryland ecology to guide urban restoration under resource-limited conditions, this framework offers a pathway for co-restoring connected landscapes in an era of accelerating urbanization and desertification.