乌兰布和沙漠典型灌木群落多样性及其生态位

Species diversity of typical shrubs and niches of dominant shrub species in the Ulanbuh Desert

通过了解乌兰布和沙漠典型灌木群落多样性及主要优势种的生态位特征,对完善和科学保育植物群落的多样性具有重要意义。分析表明:①研究区8个典型灌木群落多样性Shannon-Wiener指数和丰富度Margalef指数依次均为:沙冬青群落>白刺群落>红砂群落>油蒿群落>驼绒藜群落>梭梭群落>盐爪爪群落>霸王群落;均匀度Pielou指数以红砂群落最高,梭梭群落最低;Shannon-Wiener、Margalef和Pielou指数的范围分别为1.050~1.795、0.306~1.197和0.487~0.727,且各群落间存在差异。②白刺的重要值和生态位宽度均最大,说明其适应能力强,分布范围大,作为乌兰布和沙漠植被群落中的广域种具有重要的生态地位和作用。优势物种间的生态位重叠值多数较小,小于0.5的占总种对的85.26%。③乌兰布和沙漠优势物种间总体呈不显著的正关联,大部分灌木群落类型间Jaccard相似性在0.30~0.60,表明该植被群落结构及其物种之间处于稳定共存的状态。

This study focuses on measurement of the species diversity of typical shrub communities and the niches of dominant shrub species in the Ulanbuh Desert,which is important for scientific conservation and management of the diversity of shrub communities.The results showed that the Shannon-Wiener and richness Margalef indices of eight typical shrub communities in the Ulanbuh Desert was greatest in the Ammopiptanthus mongolicus community,followed by the Nitraria tangutorum community,the Reaumuria songarica community,the Artemisia ordosica community,the Ceratoides latens community,the Haloxylon ammodendron community,the Kalidium foliatum community,and finally the Sarcozygium xanthoxylon community.Pielou’s evenness index was highest in the R.songarica community and lowest in the H.ammodendron community.The Shannon-Wiener,Margalef,and Pielou’s indices ranged from 1.050 to 1.795,0.306 to 1.197,and 0.487 to 0.727,respectively.Among the communities,important value and niche breadth were highest in the N.tangutorum community.Thus,this species is a generalist species that plays an important role in desert shrub communities due to its strong ecological adaptability.The niche overlap values of most shrub species were small,at less than 0.5 for 85.26%of the shrub species across the study area.Macro-associations among the 20 dominant species were slightly positive.The Jaccard similarity between most shrub community types ranged from 0.30 to 0.60.This result indicates that the plant communities were relatively stable.