Experimental warming triggers divergent ecosystem multifunctionality responses across Tibetan montane grasslands

Aim Anthropogenic climate warming is profoundly altering the structure, functioning, and multifunctionality of high-elevation grassland ecosystems, especially across the diverse montane grassland communities on the Tibetan Plateau. However, the influences of warming-induced changes on multiple ecological functions of these mountainous grassland ecosystems remain unclear. Methods Here, we conducted a manipulative field experiment across a natural elevational gradient (4500–5300 m) to evaluate warming impacts on aboveground (AEMF), belowground (BEMF), and whole-ecosystem multifunctionality (EMF) across three typical mountain grasslands (steppe, meadow, and screes). Results This study demonstrated that warming had inconsistent impacts on multiple ecosystem functions across mountainous grasslands, with the EMF, AEMF, and BEMF indexes generally decreasing in water-limited steppe, increasing in temperature-limited screes, and remained unchanging in meadow. The divergence responses of ecosystem multifunctionality indexes to warming across mountain grasslands were highly driven by biodiversity, productivity, and soil carbon. The findings further suggested that warming could have a stronger impact on productivity and carbon sequestration than on biodiversity in Tibetan mountainous grasslands. Conclusions Given that these changes can have broad implications for multiple ecosystem functions, future efforts to predict ecosystem responses to climate change should place comparable emphasis on productivity and carbon dynamics as on biodiversity.