Microbial mechanisms of mesofauna pattern changes affecting soil greenhouse gas emissions and ecosystem multifunctionality.

In mountainous regions, global warming has changed the biological diversity and community structure of both aboveground and belowground organisms, and it may cause biota to move from lower altitudes to higher altitudes. However, our understanding of such migrations of soil mesofauna caused by global warming on soil processes and functions remains limited. We carried out a 79-day experiment comprising treatments without mesofauna (WM), native mesofauna (NM), migratory mesofauna (MM), and both native and migratory mesofauna together (TM) to reveal the effects of soil mesofauna migration on greenhouse gas emissions, ecosystem multifunctionality, and the underlying mechanisms. We found that soil mesofauna enhanced CO2 emissions (46.59% for NM, 75.72% for MM, and 107.21% for TM) and N2O emissions (82.57% for NM, 121.47% for MM, and 204.69% for TM) when compared to WM. Soil multifunctionality was reduced by 207.64% under TM compared to NM. Partial least squares path modeling indicated that soil properties and microbial diversity have positive effects on soil multifunctionality. The diversity of soil mesofauna had a positive direct effect on soil CO2 and N2O emissions. Random forest analysis showed that mite Shannon diversity, springtail Shannon diversity, and springtail beta diversity emerged as the most critical biotic factors for predicting soil CO2 emissions, soil N2O emissions, and multifunctionality. These findings provide deeper insights into the responses of soil processes and functions to soil mesofauna migrations, as well as the management of mountain ecosystems.