Responses of plant productivity and carbon fluxes to short-term experimental manipulations of climate change and species loss in a Mongolian grassland

We examined the responses of primary productivity and carbon fluxes (net ecosystem productivity, gross primary productivity, and ecosystem respiration) to climate (using open top chambers and electric heating) and species richness manipulations (by non-random species removal) in Mongolian grasslands. We observed a decreasing tendency in plant productivity and carbon flux due to warming, which would be mitigated by watering. This suggests that decrease in soil moisture due to concomitantly increasing evaporation and rain interception by open top chambers rather than increasing temperature might explain the decreasing tendency of productivity and carbon fluxes due to climate manipulations. Plant productivity was reduced only in the plots with the lowest species richness, and carbon fluxes did not change according to non-random species richness manipulations, suggesting that productivity and carbon fluxes are relatively robust to species loss. Our results would be associated with the compensation of the loss of perennial grasses and sedges by annual forbs. Such a compensatory mechanism might have caused negligible interaction effects of climate and species richness manipulations on productivity and carbon fluxes. Because our result was limited by a short experimental duration, in future studies, the long-term functional consequences of climate warming and species loss should be fully examined. •Productivity and carbon fluxes decreased due to warming.•Productivity and carbon fluxes were relatively robust to non-random species loss.•Compensatory mechanisms can mediate warming and species loss interaction effects.