Dryland soil ecosystems cover >40%of the world’s surface and are responsible for supporting of the 40% global population agriculturally. On a national scale they cover the majority of the Australian landmass and include major agricultural regions central to our food security and economy. Dryland soil ecosystems are uniquely vulnerable to climate change and are predicted to increase in scale and aridity with severe implications for their ecosystem services and support of human populations. This talk will describe the results of a global survey of dryland soil gradients which demonstrated a reduction in both bacterial and fungal diversity as a function of increasing aridity which was driven largely by a decoupling of nutrient regimes and decrease in soil carbon availability. Despite this some taxonomic groups, such as Chloroflexi, showed non-linear responses and increased in intra-phylum diversity with aridity. Studies conducted across Australia using “rain-out” shelters to investigate drought and ambient conditions across aridity gradients nationally showed a strong biogeographic signal to dryland soil community composition and shifts in key bacterial and fungal taxa such as Actinobacteria, Alpha-proteobacteria, Planctomycetes and Ascomycota. Network interactions between stress-tolerant taxa increased as drought progressed temporally. Combined, these results highlight the profound impact on drought of the microbial denizens of our soils that underpin soil function and both national and global food security.