新疆北部荒漠一年生短命植物层片对氮素添加的响应

Response of the Ephemeral Annuals Layer to Nitrogen Addition in Desert of Northern Xinjiang

一年生短命植物层片是新疆北部荒漠早春季节植物群落的重要组成部分,为了解其对不断激增的氮沉降的响应,设置0 g/m^(2)(CK)、3 g/m^(2)(N1)、6 g/m^(2)(N2)、12 g/m^(2)(N3)4个氮素添加梯度,研究氮素添加对植物物种多样性和生物量的影响。结果表明:(1)新疆北部荒漠一年生短命植物层片的物种丰富度和多样性对短期氮素添加的响应不显著,但物种多度随着氮素添加水平的不断增加呈下降趋势;(2)氮素添加没有显著改变一年生短命植物层片群落生物量,但不同常见植物生物量对氮素添加表现出不同的响应模式;(3)氮素添加下物种丰富度与群落生物量之间呈显著负相关关系。这表明一年生短命植物个体生长对氮素添加的响应是敏感的且这些响应具有物种差异性,这些差异导致氮素添加的促进和抑制作用可能相互抵消,使得荒漠植物群落一年生短命植物层片对短期氮素添加具有一定的缓冲能力,生产力相对稳定,多样性不会发生明显变化。

The annual ephemeral layer is an important component of plant community in early spring of desert in northern Xinjiang,China.Understanding the response of Ephemeral annuals layer to nitrogen addition is critical for desert areas.Our objective here is to analyze the response of the community species diversity and biomass of annual ephemeral layer to nitrogen additionin typical desert of northern Xinjiang,China.Field experiments were established in 2018 in the desert of northern Xinjiang.Four treatments of N addition(CK,0 g/m^(2);N1,3 g/m^(2);N2,6 g/m^(2);N3,12 g/m^(2))were used.Vegetation investigation was conducted every two weeks from April 1 to May 31 and plant biomass were measured.Although the response of species richness and diversity of annual ephemeral layer to nitrogen addition was not significant,the species abundance tended to decrease with the increase of nitrogen addition.Nitrogen addition did not significantly change the community biomass of annual ephemeral layer,but the biomass of different common plant showed different response patterns to nitrogen addition.There was a significant negative correlation between species richness and community biomass under nitrogen addition.It is suggested that the individual growth of annual ephemerals are sensitive to nitrogen addition and these response differences are species-dependent;the annual ephemeral layer of desert plant communities is relatively stable under short-term nitrogen addition.