Warming experiment design
Our study was conducted within an experimental warming × precipitation infrastructure within an area of 50 m × 110 m that was established in July 2011. The design of the experiment was detailed in Liu et al. (2018). In brief, the experiment manipulated the temperature (+2 °C, control) and precipitation (+50%, control, -50%) with a completely randomized design. Each treatment had six replications with a plot area of 2.2 m × 1.8 m (Liu et al. 2018). The warming treatment was applied by two infrared heaters (220 V, 1200 W, 1.0 m long, and 0.22 m wide) (Ma et al. 2017). In the current study, we only compared ambient and warming conditions.