Soil nutrient stability outperforms microbial abundance stability as an early-warning indicator in a Tibetan alpine...

Climate warming often exhibits seasonal asymmetry, yet its effects on the stability of soil-microbial coupled systems remain poorly understood. Traditional assessments relying on total microbial abundance may mask early stress signals due to functional redundancy within microbial communities. Here, we conducted a seasonally asymmetric warming experiment in a Tibetan alpine meadow to compare the temporal stability of soil nutrients (carbon, nitrogen, and phosphorus) with that of total bacterial and fungal abundance. We found that soil nutrient stability responded earlier and more sensitively to warming than total microbial abundance stability. The apparent stability of total microbial abundance concealed internal community reorganization driven by shifts in soil nutrient conditions. Furthermore, bacterial stability was primarily regulated by dominant taxa, whereas fungal stability depended on species asynchrony. Our findings suggest that soil nutrient stability acts as a robust and sensitive early-warning indicator for ecosystem disturbance under climate change. We recommend integrating soil element stability into long-term monitoring programs to enhance early detection of climate impacts in vulnerable alpine ecosystems.