模拟降水年际和年内变化对黑沙蒿群落物种多样性和生产力的影响OA北大核心CHSSCDCSTPCD

Under the influence of global climate change,the precipitation pattern in arid and semi-arid desert areas of northwest China has changed significantly,which was manifested by the increase of extreme precipitation and drought events,and the impact on the structure and function of desert plant communities has aroused widespread concern.A typical desert shrub community of Artemisia ordosica in the Maowusu Sandy Land was selected as the study site.Using artificial rain shelters,a factorial fully randomised control experiment was conducted to manipulate both precipitation levels(W-:30％reduction in rainfall,control group W:natural rainfall,W+:30％increase in rainfall)and rainfall intervals(control group T:5-day rainfall interval,T++:15-day rainfall interval).The study aimed to monitor the species composition and productivity of the Artemisia ordosica community under different precipitation treatments.The results of the two-factor completely randomized controlled experiment to monitor the species composition and productivity of Artemisia ordosica community under each precipitation treatment showed that:(1)the prolongation of precipitation intervals significantly increased the importance values of shrubs and weeds,and decreased the importance values of grasses,compared with the control group with a 5-day precipitation interval.(2)An increase of precipitation increased the diversity of the plant community of Artemisia ordosica compared to control natural precipitation.(3)Both increased precipitation or extended precipitation intervals increased aboveground primary productivity of Artemisia ordosica.Longer precipitation intervals increased the water content of the deep soil,which helped Artemisia ordosica to utilize the soil water and thus promoted its productivity accumulation and enhanced its dominance in the community.