Interactive effects of grazing and global change factors on soil and ecosystem respiration in grassland ecosystems: a global synthesis

1.As the key carbon (C) fluxes between biosphere and atmosphere, soil respiration (Rs) and ecosystem respiration (Re) play vital roles in regulating global C balance and climate-biosphere feedback in the Earth system. Despite the fact that numerous manipulative studies and a few meta-analyses have been conducted to examine the responses of Rs and its components [i.e., autotrophic (Ra) and heterotrophic respiration (Rh)] as well as Re to grazing (G) or global change factors, the interactive effects between grazing and global change factors remain poorly understood. 2.Here we performed a comprehensive meta-analysis of manipulative experiments with both grazing and global change factors to quantify their individual and interactive effects on Rs and its components as well as Re. 3.Our results showed that grazing and drought significantly decreased Rs by 12.35% and 20.95%, respectively, whereas warming (W), nitrogen addition (N) and increased precipitation (P) stimulated it by 2.12%, 5.49%...