贵州省特有植物百里杜鹃野生种群及所在群落特征

Characteristics of wild populations and their communities of endemic plant Rhododendron bailiense in Guizhou Province

对贵州省盘州市保基乡雨那洼村(PZ)和大方县普底乡永兴村(DF)的百里杜鹃(Rhododendron bailiense Y.P.Ma,C.Q.Zhang and D.F.Chamb.)野生种群及所在群落进行实地调查;在此基础上,对种群的径级结构和动态指数以及群落的物种组成、生活型、不同层次各种类重要值和物种多样性进行比较和分析。结果表明:这2个百里杜鹃种群的径级结构均呈正态分布,且Ⅱ级(2.5 cm<DBH≤5.0 cm)株数明显高于其他径级;PZ种群的大径级〔Ⅲ级(5.0 cm<DBH≤15.0 cm)和Ⅳ级(DBH>15.0 cm)〕株数多于DF种群,而小径级〔Ⅰ级(DBH≤2.5cm)和Ⅱ级〕株数却少于DF种群。PZ和DF整个种群的动态指数分别为28.40%和34.56%,考虑外部干扰时整个种群的动态指数分别为7.10%和2.88%,Ⅰ级动态指数分别为-90.00%和-42.11%,抗干扰敏感指数分别为25.00%和8.30%。2个种群所在群落的维管植物总计37科56属66种,但共有种仅5种;2个群落均以高位芽植物为主,地上芽植物次之。2个群落中,百里杜鹃重要值在灌木层种类中最大,且在乔木层种类中排第2位。2个群落各层次的物种多样性指数均较小,且灌木层的Patrick指数、Berger-Parker指数、Simpson指数和Shannon-Wiener指数均最大。综上所述,供试的2个百里杜鹃种群均属于增长型种群,但种群内缺少幼苗,种群稳定性差;百里杜鹃为供试群落的优势种,但群落的物种丰富度、稳定性和均匀性均较低。建议根据每个群落的实际情况加大对百里杜鹃野生种群及所在群落的保护力度。

Field survey was conducted for the wild populations and their communities of Rhododendron bailiense Y.P.Ma,C.Q.Zhang and D.F.Chamb.in Yunawa Village of Baoji Township in Panzhou City(PZ)and Yongxing Village of Pudi Township in Dafang County(DF)of Guizhou Province;on the basis,diameter structure and dynamic index of populations as well as species composition,life form,important value of each species and species diversity at different layers of communities were compared and analyzed.The results show that diameter structures of the two populations of R.bailiense both show a normal distribution,and individual number of classⅡ(2.5 cm<DBH≤5.0 cm)is evidently higher than that of other diameter classes;individual number of large diameter class〔classⅢ(5.0 cm<DBH≤15.0 cm)and classⅣ(DBH>15.0 cm)〕of PZ population is more than that of DF population,while that of small diameter class〔classⅠ(DBH≤2.5 cm)and classⅡ〕is less than that of DF population.Dynamic indexes of whole population of PZ and DF are 28.40%and 34.56%,respectively,when considering external interference,those are 7.10%and 2.88%,respectively,dynamic indexes of classⅠare-90.00%and-42.11%,respectively,and anti-interference sensitivity indexes are 25.00%and 8.30%,respectively.There are 66 species of vascular plants in 56 genera of 37 families in communities of the two populations,but there are only five common species;phaenerophytes are dominant plants and chamaephytes follow in the two communities.In the two communities,important value of R.bailiense is the largest among species in shrub layer and is the second among species in tree layer.Species diversity indexes of each layer of the two communities are relatively small,and Patrick index,Berger-Parker index,Simpson index,and Shannon-Wiener index of shrub layer are the largest.In general,the two test populations of R.bailiense belong to growing population,but there is a lack of seedlings in the populations,and the population stability is poor;R.bailiense is dominant species in the test communities,but species richness,stability,and evenness of the communities are relatively low.It is suggested to strengthen the conservation of R.bailiense wild populations and their communities according to the actual situation of each community.