Contrasting responses of α- and β-multifunctionality to aboveground plant community in the Qinghai-Tibet Plateau

The aboveground plant communities are crucial in driving ecosystem functioning, particularly being the primary producers in terrestrial ecosystems. Numerous studies have investigated the impacts of aboveground plant communities on multiple ecosystem functions at α-scale. However, such critical effects have been unexplored at β-scale and the comparative assessment of the effects and underlying mechanisms of aboveground plant communities on α- and β-multifunctionality has been lacking. In this study, we examined the effects of aboveground plant communities on soil multifunctionality both at α- and β-scale in the alpine meadow of the Tibetan Plateau. Additionally, we quantified the direct effects of aboveground plant communities, as well as the indirect effects mediated by changes in biotic and abiotic factors, on soil multifunctionality at both scales. Our findings revealed that: 1) Aboveground plant communities had significantly positive effects on α-multifunctionality whereas, β-multifunctionality was not affected significantly. 2) Aboveground plant communities directly influence α- and β-multifunctionality in contrasting ways, with positive and negative effects, respectively. Apart from the direct effects of plant community, we found that soil water content and bacterial β-diversity serving as the primary predictors for the responses of α- and β-multifunctionality to the presence of aboveground plant communities, respectively. And β-soil biodiversity appeared to be a stronger predictor of multifunctionality relative to α-soil biodiversity. Our findings provide novel insights into the drivers of ecosystem multifunctionality at different scales, highlight the importance of maintaining biodiversity at multiple scales and offer valuable knowledge for the maintenance of ecosystem functioning and the restoration of alpine meadow ecosystems.