摘要
分析了不同放牧强度下青藏高原高寒杂草类草甸植物群落种类组成与结构、物种多样性、生物量的变化状况.结果表明:重牧(HG)条件下草层垂直分化不明显,仅1层结构,而轻牧(LG)和中牧(MG)与对照(CK)条件下禾草和矮嵩草能得到较好的生长,草场垂直结构分异为2层;不同放牧强度下莎草科、禾本科和杂类草的重要值变化趋势不尽相同,HG会导致种类组成的下降,CK和适度放牧下种类组成仍保持较高的水平;尽管短期过度放牧抑制了优良牧草的生长和发育,种类组成降低,但因放牧时间短,组成群落的主要优势种具有较强的耐牧性以及植物生态-生物学特性和遗传性,其群落结构是稳定的;植物地上生物量表现出MG>LG>CK>HG,即适度放牧可提高地上生物量;地下生物量在CK条件下最高,其次为MG、HG和LG,CK、MG与LG、HG有显著性差异.植物根冠比从大到小依次为HG、CK、MG、LG,HG的根冠比显著大于LG.
Changes of community structure,aboveground biomass,species diversity and the relationship between biomass and species diversity in an alpine-cold forb meadowunder different grazing intensities in the northeast Tibetan Plateau,China,were studied. Results showthat： 1） The vertical structure differentiation was not obvious in heavy grazing（ HG） with only 1 layer structure,while,in light grazing（ LG）,moderate grazing（ MG）and non-grazing（ CK）,the vertical structure changed to two layers because of the better growth of grasses and Kobresia humilis; 2） the important value（ IV） of Sedge,Gramineae and Forbs varied differently under different grazing intensities; The community compositions maintained at a high level in CK and MG,while it decreased in HG; 3） despite that short-term overgrazing might inhibit the growth of desirable forage and decrease the communities composition,the communities composition remained stable,because the constructive and dominant species had strong adaptability owing to their grazing resistance,eco-biological and hereditary characteristics; 4） the order of aboveground biomass was Sedge Gramineae Forbs in CK,LG and HG,while the order was Gramineae Sedge Forbs in MG,and the order of total biomass was MG LG CK HG; the order of rootshoot ratio was HG CK MG LG and the difference between HG and LG was significant.
出处
《冰川冻土》
CSCD
北大核心
2015年第5期1372-1380,共9页
Journal of Glaciology and Geocryology
基金
中国科学院战略性先导科技专项(B类)项目(XDB03030502)
国家自然科学基金项目(31270523
31070437)资助
关键词
高寒杂草类草甸
牧压强度
物种丰富度
地上/地下生物量
alpine-cold forb meadow
grazing intensity
species richness
aboveground and below ground biomass
