[Responses of aboveground and belowground net primary productivity of ephemeral plants to extreme drought and extreme precipitation].

To examine the effects of extreme drought event and extreme precipitation event on productivity of ephemeral plant, we experimentally reduced and increased growing season precipitation amounts by 65% across four slope positions and aspects along sand dunes in the southern edge of the Gurbantünggüt Desert. The results showed that extreme drought significantly reduced aboveground net primary productivity (ANPP) and belowground net primary productivity (BNPP) by 48.8% and 13.7%, respectively, and that extreme precipitation significantly increased ANPP and BNPP by 37.9% and 23.2%, respectively. The sensitivity of ANPP (0.26 and 0.21 g·m·mm) to extreme drought and extreme precipitation was significantly higher than that of BNPP (0.02 and 0.03 g·m·mm). In addition, ANPP (24.22 g·m) and BNPP (5.77 g·m) on the east side of sand dune were significantly increased by 29.7% and 71.7% compared with those on the west side. There was no significant difference in the sensitivity of ANPP and BNPP to precipitation change among different slope positions and aspects.