亚热带3个地点青钱柳群落特征比较

【目的】以亚热带3个区域青钱柳天然群落为研究对象,通过调查其物种组成、结构特征、种群结构以及更新状况,探究影响青钱柳种群更新的主要原因,为青钱柳野生资源的保护和可持续利用提供科学依据和技术支撑。【方法】采用典型样方调查的方法,对3个青钱柳群落四川沐川(群落M)、广西金钟山(群落J)和湖北鹤峰(群落H)]进行样方调查,分析其物种组成、物种多样性特征和区系特征,并评价群落间的相似性。以径级代替年龄的方式分析种群结构和更新情况。【结果】四川沐川群落(群落M)、广西金钟山群落(群落J)和湖北鹤峰群落(群落H)分别有维管植物32科50属70种、50科79属96种和59科100属126种;3个群落区系特征差异不显著,均以亚热带和温带成分为主;物种多样性和物种丰富度变化趋势较为一致,表现为乔木层>灌木层>草本层。3个群落的物种多样性和丰富度总体表现为群落H>群落J>群落M;群落结构为中等不相似,相似度表现为群落M与群落J的较高,群落M与群落H的次之,群落J与群落H的较小。【结论】整体来看,不同地理分布的青钱柳群落物种组成差异明显,相似性水平低,但其结构特征具有一定的相似性;乔木层树种优势显著,导致林分郁闭,林下光照减少,影响种群更新;灌木层植物种类较多,分布较为均匀;草本层占据较少空间,以蕨类植物为主;青钱柳种群天然更新在径级结构上出现不同程度的残缺现象,导致更新不连续。从天然更新的角度看,适当开辟林窗,有利于促进林下青钱柳幼苗幼树的生长及均匀分布,完成种群更新,使群落向着长久稳定的方向发展。

Comparisons of community characteristics among three natural forests of Cyclocarya paliurus in the subtropical region of China

【Objective】In order to explore the main factors that affect the regeneration of natural Cyclocarya paliurus forests and a provide a scientific strategy and theoretical basis for the protection and sustainable utilization of natural resources,the diversity of plants,species composition and structure of different geographical distributions of C.paliurus communities were investigated.【Method】A typical sample-plot survey method was used to investigate species composition,species diversity characteristics,flora characteristics,and community similarity in different geographically distributed communities of C.paliurus.Their population structure and regeneration status were evaluated using a diameter grade approach,instead of age.【Result】There were 70 species belonging to 50 genera and 32 families in the Muchuan community of Sichuan Province(M community),96 species belonging to 79 genera and 50 families in the Jinzhongshan community of Guangxi Province(J community),and 126 species belonging to 100 genera and 59 families in the Hefeng community of Hubei Province(H community),respectively.However,the floristic characteristics were not significantly different among three communities investigated,all of which showed obvious subtropical and temperate elements.The dynamic trends of species diversity and species richness were similar among the three communities,all of which showed the order of tree indexes was tree layers>shrub layers>herb layers.The species diversity and richness of three communities were generally represented as H community>J community>M community.The structures of communities were moderately dissimilar,where the similarity among three communities was M and J>M and H>J and H.【Conclusion】Overall,the species composition of the communities in different geographical locations was obviously different,and the similarity level was low,but its structural characteristics were similar.The tree layer species were dominant in all communities,which led to stand closure and reduced understory light,and eventually affected the regeneration of C.paliurus populations.There were more plant species in the shrub layers,and their distribution was more uniform,but the herb layers(mainly ferns)took up less space.From the viewpoint of the natural generation,properly opening forest gaps would be helpful to promote the growth and uniform distribution of C.paliurus seedlings in the forest in order to complete the natural regeneration of the population,and develop a stable community.