Effect of spatial proximity to watering points on soil condition in conservation and pastoral locations in Australian rangelands

Rangelands are increasingly prioritised for private conservation due to their abundance of threatened species, large landholdings, and low per-unit land value. Conservation management has been reported to have wide-ranging social and environmental benefits; however, belowground differences associated with contrasting management histories remain poorly understood. Here, we compared soil physicochemical properties and microbial communities between neighbouring conservation and pastoral locations in the arid rangelands of southern Australia. The conservation property had undergone 14 years of management change, including livestock removal and water-point decommissioning. We sampled along 200 m transects extending from decommissioned watering points at the conservation location and active watering points at the pastoral location. Soil physicochemical differences were generally strongest near watering points. Soil organic carbon (SOC) and total nitrogen (TN) were lower at the conservation location at 0 m, likely reflecting localised nutrient enrichment associated with livestock activity around the active pastoral watering points. Bacterial (16S rRNA) alpha diversity was higher at the conservation location at 0 m, while fungal (ITS) alpha richness did not differ between locations. Soil microbial community composition showed more consistent differences between locations: bacterial communities differed at the 0, 25 and 50 m sampling distances, while fungal communities differed at 0, 25, 50 and 100 m. Overall, differences in soil condition between locations were generally stronger near watering points and became less apparent with distance. Microbial community composition showed particularly clear responses to location and distance, highlighting its potential as a complementary indicator for assessing soil condition in Australian rangelands. Together, these patterns identify watering points as important locations for assessing soil condition and support further evaluation of microbial community composition as a complementary indicator for monitoring Australian arid rangelands.