Temperature Sensitivity of Soil Organic Carbon Decomposition During Alpine Mine Slopes Restoration

Abstract

Temperature sensitivity (Q 10 ) of soil organic carbon (SOC) decomposition is a key metric for assessing land‐climate carbon (C) feedbacks. However, knowledge of Q 10 during slope ecological restoration remains limited, particularly in alpine mine areas that are highly sensitive to climate change, constraining accurate predictions of slope C‐climate feedbacks. Here, we investigated Q 10 variation and its drivers across five representative mine slopes on the Qinghai‐Tibet Plateau through laboratory incubation experiments. We found that Q 10 values were slightly higher than those reported for other ecosystems on the Tibetan Plateau, with the highest altitude sites exhibiting the greatest temperature sensitivity. Metagenomic analyses showed that microbial functional profiles shifted from greater lignin‐oxidation potential at low altitudes to higher abundances of hydrolytic genes at high altitudes. In addition, the abundance of genes involved in the degradation of starch, hemicellulose, cellulose, and chitin increased with altitude and exhibited the strongest positive correlations with DOC (dissolved organic carbon). Microbial biomass carbon (MBC) was identified as the strongest predictor of Q 10 variation in alpine mine slopes. Overall, our results suggest that altitude‐related variation in Q 10 was associated with DOC and MBC. Collectively, these findings underscore the importance of substrate availability and microbial biomass in shaping soil C‐climate feedback strength in alpine slope ecosystems and provide a scientific foundation for improving soil C stability and management in alpine mine slope restoration.