Effects of experimental warming on soil respiration and its components in an alpine meadow in the permafrost region of the Qinghai‐Tibet Plateau

Summary The response of soil respiration ( R s ) and its components (autotrophic [ R a ] and heterotrophic respiration [ R h ]) to climate warming is one of the uncertainties in ecosystem carbon (C) models. Here we conducted a warming experiment in an alpine meadow dominated by Koresbia in the permafrost region of the Qinghai‐Tibet Plateau ( QTP ) to examine effects of warming on R s and its components. Infrared heaters were used to simulate a 2°C warming of the surface soil temperature. Deep collars (50 cm to exclude root growth) were inserted into soil to measure R h : R a , which was calculated by subtracting R h from R s . Average R s and its components ( R a and R h ) were significantly stimulated by 21.5, 27 and 15.6%, respectively, in warmed plots from January 2011 to October 2013. The contribution of R h to R s decreased in the warmed plots because of the smaller relative increase in R h than in R a . Annual soil C release increased by 263 and 247 g C m −2 in 2011 and 2012, respectively. Stimulation in R a and R h was related to the significant increase in root biomass (0–50 cm) and in labile soil C in the deeper layer (40–50 cm). The temperature sensitivities ( Q 10 ) of R s and its components all increased with larger values in R a , followed by R s and R h . Our results suggest a positive feedback between soil C release and climatic warming in the permafrost region of the QTP .