降水变化和氮素添加对青藏高原高寒草原群落结构和物种多样性的影响

发布时间：2018-09-08 19:31

【摘要】：全球变化对草地物种组成和物种多样性有显著影响,而高寒草原研究较少。以青藏高原紫花针茅高寒草原为对象,通过三年的野外小区完全随机试验,模拟分析了降水变化和氮素添加对物种群落结构和物种多样性的影响,降雨水平设置减少50%降雨、对照和增加50%降雨3个水分处理,氮添加设置对照和加氮2个水平。结果显示:(1)氮添加后随降雨梯度递增分别导致物种数由24,25,21减少到21,21,20。(2)年际变化、水分和氮素处理对群落盖度影响显著,年际变化和水分处理交互效应显著。群落盖度2015年2014年2013年;随着降雨梯度递增,群落盖度呈增加趋势;添加氮素处理的群落盖度显著高于对照。(3)种丰富度、Simpson指数、Shannon-Wiener指数、Pielou指数在年际间有显著差异,另外,氮素处理显著影响丰富度指数,Pielou指数在不同降水处理间差异显著。氮素添加显著影响青藏高原高寒草原物种组成、群落盖度以及丰富度指数,而降水作用只影响群落盖度;降水变化除了对Pielou指数有影响外,降水变化和氮素添加均不影响多样性指数。
[Abstract]:Global change has a significant impact on species composition and species diversity of grassland, but less research on alpine steppe. The effects of precipitation changes and nitrogen supplementation on species community structure and species diversity were simulated and analyzed by three years of complete random experiments in field plots of Stipa arundinacea alpine steppe in the Qinghai-Tibet Plateau. Rainfall level was reduced by 50%. Control and 50% rainfall increased 3 water treatments, nitrogen addition set up two levels of control and nitrogen addition. The results showed that: (1) with the increase of rainfall gradient, the number of species decreased from 24 ~ 25 ~ (21) to 21 ~ 21 ~ 20 ~ (20). (2) interannual changes were observed. The effects of water and nitrogen treatments on community coverage were significant, and the interannual variation and the interaction of water treatment and water treatment were significant. The community coverage increased with the increase of rainfall gradient in 2015 and 2013. The community coverage of nitrogen added treatment was significantly higher than that of the control. (3) the Shannon-Wiener index Shannon-Wiener index and Pielou index of species richness were significantly different among different years. Nitrogen treatment significantly affected the richness index and Pielou index, which were significantly different among different precipitation treatments. Nitrogen addition significantly affected species composition, community coverage and richness index of alpine steppe in the Qinghai-Xizang Plateau, while precipitation only affected community coverage. The variation of precipitation and nitrogen addition did not affect the diversity index.
【作者单位】：中国科学院西北高原生物研究所;中国科学院大学;中国科学院植物研究所;青海省三角城种羊场;中国科学院藏药研究重点实验室;
【基金】：国家重点基础研究发展计划项目(2012CB026105) 国家科技支撑计划项目(2014BAC05B01) 国家自然科学基金(40801076)
【分类号】：S812

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