Community carbon and water exchange responses to warming and precipitation enhancement in sandy grassland along a restoration gradient

Temperature increasing and precipitation alteration are predicted to occur in arid and semi-arid lands, however, the response mechanism of carbon and water exchange at community level is still unclear in semi-arid sandy land. We investigated the responses of carbon and water exchanges to warming and precipitation enhancement along a sand-dune restoration gradient: mobile sand dunes (MD), semi-fixed sand dunes (SFD) and fixed sand dunes (FD). The average net ecosystem productivity (NEP) and evapotranspiration (ET) between May and August increased by 98% and 59%, respectively, from MD to SFD. While they had no significant differences between FD and the other two habitats. Warming inhibited ecosystem NEP, ET and water use efficiency (WUE) by 69%), 49% P<0.001 and 80%, respectively in SFD, while it nearly had no significant effects in MD and FD. However, precipitation addition by 30% nearly had no significant effects on community NEP, ET and WUE, except for warming treatment in FD. In g...