内蒙古荒漠-草原过渡带灌木群落特征

Characteristics of shrub communities in the desert-steppe ecotone of Inner Mongolia,China

荒漠-草原过渡带是草原逐渐被荒漠取代的区域。沿阿拉善左旗-乌拉特后旗调查灌木群落,分析植物群落的结构和物种多样性,以期为生物多样性保育提供理论依据。结果表明:该荒漠-草原过渡带有62种植物,隶属于18科、47属,禾本科、藜科、豆科和菊科的植物较多。植物主要由灌木和多年生草本构成,以旱生植物为主,主要包括红砂(Reaumuria soongarica)群落、霸王(Sarcozygium xanthoxylon)群落、沙冬青(Ammopiptanthus mongolicus)群落、白刺(Nitraria tangutorum)群落和旱蒿(Artemisia xerophytica)等群落。草原化荒漠植物群落的建群种重要值和生物量较高;荒漠草原植物群落的盖度和密度较高;草原化荒漠沙冬青群落和红砂群落的多样性和草本层多样性较高,红砂群落灌木层多样性较高;荒漠草原的霸王群落多样性最高,红砂群落草本层多样性最高。不同群落间相似性较低。建议重点保护具有建群和“沃岛效应”的灌木群落,同时重视多年生草本植物对维持荒漠-草原过渡带植物多样性的作用。

The desert-steppe ecotone is a transition area in which steppe is gradually replaced by desert.In this study,vegetation was investigated along desert-steppe ecotone from Alxa Left Banner to Urad Back Banner.Plant community structure and species diversity were analyzed to give theoretical support to biodiversity conservation.The results of the survey showed that there were 62 plant species,belonging to 18 families and 47 genera in desert-steppe ecotone of Inner Mongolia.There were more species in Poaceae,Chenopodiaceae,Fabaceae and Asteraceae.Plant species were mainly composed of shrub and perennial herb,and mainly consisted of xerophyte.The main communities included Reaumuria soongarica community,Zygophyllum xanthoxylon community,Ammopiptanthus mongolicus community,Nitraria tangutorum community and Artemisia xerophytica community etc.The importance value of constructive species and biomass were higher in steppe desert plant community.The coverage and density were higher in desert steppe plant community.The diversity and herb layer diversity of A.mongolicus community and R.soongarica community were higher in steppe desert.Shrub layer diversity of R.soongarica community was higher in steppe desert.The diversity of S.xanthoxylon community was highest in desert steppe.Herb layer diversity in R.soongarica community was highest in desert steppe.The similarity was low between different communities.It is suggested that shrub communities with constructive and"fertile island"effect should be protected primarily,while perennial herb should be considered in maintaining plant diversity of desert-steppe ecotone.