Effects of experimental warming and increased precipitation on soil respiration in an alpine meadow in the Northern Tibetan Plateau

Uncertainty on the response of soil respiration (R-s) to warming and increased precipitation on the Tibetan Plateau can limit our ability to predict how alpine ecosystems will respond to future climate change. Based on a warming (control, low-and high-level) and increased precipitation (control, low-and high-level) experiment, the response of R-s to experimental warming and increased precipitation was examined in an alpine meadow in the Northern Tibetan Plateau from 2014 to 2017. The low-level warming increased soil temperature (T-s) by 1.19 degrees C and decreased soil moisture (SM) by 0.02 m(3) m(-3), whereas the high-level warming increased T-s by 2.88 degrees C and decreased SM by 0.04 m(3) m(-3) over the four growing seasons in 2014-2017. The low-and high-level increased precipitation did not affect T-s, but increased SM by 0.02 m(3) m(-3) and 0.04 m(3) m(-3), respectively, over the four growing seasons in 2014-2017. No significant main and interactive effects of experimental warming and increased precipitation on R-s were observed over the four growing seasons in 2014-2017. In contrast, there was a significant inter-annual variation of R-s in 2014-2017. There was a marginally significant quadratic relationship between the effect of experimental warming on R-s and warming magnitude. There was a negligible difference of R-s between the low-and high-level increased precipitation over the four growing seasons in 2014-2017 and R-s also showed a quadratic relationship with precipitation. Therefore, experimental warming and increased precipitation did not change R-s and R-s responded nonlinearly to experimental warming and increased precipitation in the alpine meadow in the Northern Tibetan Plateau. Growing season precipitation may play a more important role than experimental warming and increased precipitation in affecting R-s in the alpine meadow in the Northern Tibetan Plateau. (C) 2018 Elsevier B.V. All rights reserved.