Divergent responses of grassland productivity and plant diversity to intra-annual precipitation variability across climate regions: A global synthesis

Global warming intensifies the hydrological cycle and may result in changes in the frequency and intensity of precipitation events. Although the effects of changes in precipitation amount and inter-annual precipitation variability on terrestrial plant productivity and carbon sequestration have been well studied, how intra-annual precipitation variability affects terrestrial ecosystem function remains unclear. Here, we synthesized field manipulative experiments from 71 publications to quantify the effects of intra-annual precipitation variability increases (IPVI) on community biomass and plant diversity in grasslands worldwide.  At the global scale, we found that IPVI generally increased grassland community aboveground biomass (AGB) by 6%, and decreased grass biomass and soil ammonium nitrogen by 12% and 31%, respectively. IPVI stimulated AGB, belowground biomass, and plant species richness in arid regions, but not changed them in humid regions. Changes in AGB under IPVI were related to ..., ,