Australian drylands as a case-study of the impacts of climate, groundcover, and vertebrate activity on soil biodiversity

Drylands cover approximately 30% of the Earth’s surface, forming the largest terrestrial biome, yet they are among the most threatened ecosystems globally. These systems are strongly constrained by water availability and characterised by high climatic variability, making them particularly vulnerable to climate change. Dryland functioning is fundamentally driven by soil microbial communities, which regulate key biogeochemical processes including nutrient cycling, soil stability, and water retention. Australian drylands provide a globally important case study, covering approximately 70% of the continent and experiencing extreme climatic variability. In the absence of recent volcanic activity, ecosystem functioning in these landscapes is heavily dependent on biological inputs, with soil microbial communities playing a central role in maintaining soil fertility. Strong coevolutionary relationships between dryland plants, soil microbes, and animals further structure these systems, with nutrient inputs from animal excrement and soil disturbance by digging fauna enhancing microbial activity and resource redistribution. This tight coupling between above- and belowground biodiversity makes Australian drylands uniquely valuable for examining how changes in soil microbial communities influence ecosystem resilience and for evaluating trophic rewilding as a restoration tool under a changing climate.