Meadow transformations alter above- and below-ground ecological networks and ecosystem multifunctionality

Human-mediated environmental change transforms ecosystems worldwide. Understanding the detailed impact of these unprecedented changes on biodiversity and ecosystem functioning, however, is challenging. Meadow ecosystems on the Tibetan Plateau transform as a result of climate change and anthropogenic disturbances. Evaluating the consequences of these meadow transformations on above- and below-ground community structure, ecological network and ecosystem functioning is critical for predicting the impact on biodiversity and developing mitigation strategies.Here, we used a natural experiment across replicated sites to assess the responses of ecological networks of soil microbial communities and plant-pollinator communities to meadow transformations and investigate the impacts of these changes on ecosystem multifunctionality.As a result of swampy meadow desiccation, species richness and ecological network complexity at multiple trophic levels increased, pollination networks became more robust while soil microbial networks became more vulnerable to species loss. Pollination function appeared to benefit from increased diversity in resources and the formation of dry soil, but important below-ground functions decreased. When alpine meadows degraded further because of extensive grazing pressure, above-ground diversity and network complexity tended to decline. Soil microbial richness and composition remained unchanged but associations among soil microbes homogenized, and ecosystem productivity and pollination function decreased.Our study provides empirical evidence that human-mediated meadow transformations influence above- and below-ground ecological networks and ecosystem functioning simultaneously. The findings highlight that ecosystem transformations can have contrasting effects on above- and below-ground diversity and ecological networks, as well as ecosystem functions. Such contrasting responses call for targeted and nuanced management strategies to conserve biodiversity and ecosystem functioning in the Tibetan Plateau.