Soil microbial responses to passive restoration strategies in drylands: a temporal comparison of soil biodiversity and ecosystem function

Arid and semi-arid (from hereafter dryland) ecosystems cover 70% of Australia, with climate change set to increase this area through desertification. Increased temperatures and reduced water availability are compounded through agricultural overgrazing. This degradation and habitat loss has led to biodiversity loss which disrupts the biogeochemical cycles that maintain these environments, creating a negative feedback loop, and making restoration efforts largely unsuccessful. With soil microbes being important drivers in dryland systems, understanding how different stressors impact the soil biome is needed to improve conservation and restoration efforts and promote resilience and resistance to climate change. Particularly lacking is understanding of these interactions over time.

Fowlers Gap Research Station is the only research station in the arid zone of Australia and was a working sheep station until 2019. Due to agricultural overgrazing the site is largely degraded however exclusion zones have been set up on the property ranging in time from 3 years to 40 years. These exclusion zones provide a powerful comparison for the impact of soil degradation on drylands. To investigate the impact of overgrazing on the soil biodiversity and ecosystem functions, we selected three of the exclusion zones paired with three degraded sites directly outside of the exclusion zone to assess their microbial composition and functional diversity, along with soil physicochemical properties. We aim to build 16S rRNA gene libraries and co-relate them with the soil chemical variables, to assess the impact of overgrazing on these microbial communities and the ecosystem functions they provide. This knowledge can be used to improve monitoring of conservation and restoration initiatives by providing environmental indicators for soil health over time.