Effects of nighttime warming and changing precipitation on soil microclimate in three temperate steppes along a precipitation gradient

Abstract Background Soil microclimate plays critical roles in influencing terrestrial ecosystem functioning. However, how the impacts of climatic change on microclimate vary with vegetation types remains elusive. Methods Using a 9-year (2014–2022) dataset from a field manipulative experiment conducted on the Mongolian Plateau, this study examined the effects of nighttime warming and changing precipitation on soil microclimate of three temperate steppes (i.e., desert, typical, and meadow steppes) along a precipitation gradient. Results Over the 9 years, nighttime warming increased soil temperature by 0.88, 0.78, and 0.65 °C, decreased precipitation elevated it by 0.63, 0.34, and 0.24 °C, but increased precipitation lowered it by 0.46, 0.84, and 0.90 °C in the desert, typical, and meadow steppes, respectively. Nighttime warming suppressed soil moisture by 0.64% (v/v) in the meadow steppe only. Decreased precipitation reduced soil moisture by 0.84, 0.88, and 1.30%, whereas increased precipitation enhanced it by 0.92, 1.23, and 1.24% in the desert, typical, and meadow steppes, respectively. The response of soil microclimate to the simulated climate change was primarily driven by evaporation, transpiration, and plant cover in the desert and typical steppes, whereas transpiration and plant cover explained those changes in the meadow steppe. Conclusions These findings of the variations of underlying mechanisms of soil microclimate response to climate change with water conditions can improve predictions of ecosystem carbon cycling across diverse grassland ecosystems.