Ecological responses of Stipa steppe in Inner Mongolia to experimentally increased temperature and precipitation 1: Background and experimental design

Both temperature and precipitation are predicted to increase in the region of the Stipa steppe of Inner Mongolia. We conducted an experiment to simulate both the individual and combined effects of warming and increased precipitation on community structure (biomass and diversity) and ecological processes (soil respiration and ecosystem carbon exchange). Open-topped chambers were used to simulate climatic warming, and irrigation was applied to simulate a 20% increase in precipitation. Open-topped chambers were effective in producing significant increases in mean air temperature in each year of the experiment (2011–2015), with the average increase ranging from 2.5°C to 3°C in the final 3 years of the study. Mean soil temperature was significantly increased in 2 of the 5 years of observation. Irrigation significantly increased soil moisture. The experimental treatments thus produced environmental changes consistent with those expected in the region by mid-century and provide a basis for examining the likely effects of climate change on the grassland ecosystem as reported in companion papers.