乌兰布和沙漠典型灌木群落结构及数量特征

灌木群落是乌兰布和沙漠生态系统中最重要的组成部分,根据野外样地的调查资料,从各群落物种组成、生活型谱、盖度特征、物种多样性、群落相似性等方面对乌兰布和沙漠中典型灌木群落结构和数量特征进行分析,为该区生物多样性保护与植物资源持续利用提供理论依据。结果表明:(1)梭梭、白刺、沙冬青、沙蒿、油蒿、盐爪爪是乌兰布和沙漠中主要灌木群落类型;各典型灌木植被群落中仅出现12科47属共计58种植物,各群落间物种组成差异较大,但均以藜科、菊科、禾本科、蒺藜科、豆科等干旱荒漠区的表征科数量居多;(2)沙漠中分布范围最广的梭梭群落、白刺群落、沙冬青群落和油蒿群落其生活型谱均以一年生植物所占比例最大,与研究区干旱的气候特征相吻合;(3)各群落中灌木层植物所占群落盖度的比重均超过了50%,其贡献率大于草本植物;(4)分布于生境条件较好的群落类型其物种多样性相对较高,从整体看各典型灌木群落的H′多样性指数的变化范围在0.98～3.42之间,而D多样性指数的变化范围在0.415 5～0.879 5之间,其物种多样性指数较低,物种组成比较简单;(5)各典型植物群落的相似性系数在0.068 2～0.604 7之间,均未达到极相似水平,其中白刺群落、梭梭群落以及沙冬青群落之间呈轻度相似水平,而其他各群落之间相似性系数均低于0.25,表明各群落间生境差异较大。

Analysis on Typical Shrub Plant Community Characteristics and Quantitative Characteristics in Ulanbuh Desert

The shrub community is the most important ecosystem components in Ulanbuh desert.The community structure and quantitative characteristics of shrub community was researched,which can provide the theory basis and the practice foundation for protecting biodiversity and sustainable utilization of plant resources in the area.According to the quadrat investigation material,the community structure and quantitative characteristics of typical shrub community was analyzed by the species composition,life form spectrum,coverage characteristics,species diversity and similarity of community.The results showed that:(1)The main community type was the community of Haloxylon ammodendron,Nitraria tangutorum,Ammopiptanthus mongolicus,Artemisia desertorum,Artemisia ordosica and Kalidium foliatum.The plants belong to 58 species,47 genera,and 12 families.Most of plants belong to chenopodiaceae,asteraceae,gramineae and leguminosae,which were the characteristic families in arid desert region.(2)The annual plant made the biggest percentage in the community of H.ammodendron,N.tangutorum,A.mongolicus and A.ordosica,which were widely distributed in Ulanbuh desert,so it showed the arid climate in study area.(3)The proportion of shrub plant coverage were more than 50%,so the contribution rate of shrub plant for community coverage was greater than herbs.(4)The communities which were distributed in the better habitat conditions had high biodiversity.The H′ diversity index varied between 0.98~3.42.The D diversity index varied between 0.415 5~0.879 5,the species composition of each shrub community was relatively simple.(5)The similitude coefficient of each community varied between 0.068 2~0.604 7,so each community’s similarity did not reached the level of very similar.There was mild similar among the three community,which were N.tangutorum,H.ammodendron and A.mongolicus,but the similitude coefficient between the other communities were less than 0.25.It showed there were great difference between community habitats.