摘要
采用野外调查和室内分析相结合的方法,对祁连山退化草地狼毒群落土壤种子库进行研究。结果显示：（1）狼毒群落土壤种子库毒杂草物种的数量和密度占优势;（2）禾草的种子库密度随退化梯度的增加而减少直至消失,多年生杂草存在于各个植被梯度且密度较大;（3）群落物种数量及其密度呈现05cm〉1015cm〉510cm的分布规律,各土层内密度差异明显;（4）不同梯度下种子库（015cm）的Shannon-wiener指数、均匀度指数和丰富度指数波动变化趋势基本一致,而优势度指数与之变化趋势相反,土壤种子库05cm与种子库（015cm）物种多样性的变化具有较大的相似性;（5）随着退化梯度的增加,种子库和植被的相似系数减小,狼毒等毒杂草的大量繁衍显著的改变了草地群落的功能群结构,自然状态下种子库对原生地带性植被建群种更新的贡献率降低,植被恢复问题严峻。
Soil seed bank characteristics of Stellera chamaejasme community in degraded grassland of Qilian Mountains were studied by adopting field investigation and laboratory analysis.It was studied in aspects of species composition,distribution pattern,species diversity and similarity.The results showed that： 1） The densities and quantities of poisonous weeds were predominate in the soil seed bank of Stellera chamaejasme community.2） The seed densities of perennial grasses were reduced,and even disappeared with the increase in different vegetation gradient,while the perennial weeds widely exited in seed bank with greater density.3） There were obvious differences among each soil layer,and the distribution law of the density and quantity of Stellera chamaejasme community showed as follows： upper layer（05cm）〉 lower layers（1015cm）〉 middle layer（510cm）.4） The dominance index of the soil seed bank in upper layer（015cm） had some differences with its change trend,but others indexes variation trends were similar,such as Shannon-Wiener index,evenness index and richness index.In addition,the changes of species diversity in the upper layer（05cm） were highly similar to that of the upper layer（015cm）.While,the instability of vertical direction was the largest in middle layer（510cm）.5） The seed bank had smaller contribution rate to the vegetation regeneration of original prairie grasses under vegetation gradients.And the community structure was significantly changed because of the mass rearing of poisonous weeds such as Stellera chamaejasm.The potential of germination and restoration in original prairie grasses became smaller in natural state.So,vegetation restoration became a serious problem.
出处
《中国草地学报》
CSCD
北大核心
2010年第1期79-85,共7页
Chinese Journal of Grassland
基金
国家自然科学基金项目(40971039)
国家"十一五"科技支撑计划项目(2007BAD46B07)
甘肃省生态经济重点学科和西北师范大学知识与科技创新工程(NWNU-KJCXGC-03-46)资助
关键词
狼毒群落
种子库
空间分布
物种多样性
地上植被
Stellera cja,aekasme community
Seed banks
Spatial pattern
Species diversity
Standing vegetation
