平江红椿林群落植物多样性

红椿(Toona ciliata Roem.)是国家二级保护濒危种。采用相邻格子法和中点四分法,研究平江县芦头国有林场红椿林的物种组成、群落外貌、群落垂直结构和群落各层多样性特点。结果表明:在1 200m2的样地里共有维管植物81种,隶属于53科70属,群落的科属组成不够集中;群落内区系地理成分复杂,具有明显垂直结构分层,各层有明显优势种;乔木层的Simpson指数最大,为0.217,灌木与草本层Simpson指数分别为0.033和0.039,随着海拔梯度的增加,建群树种红椿也明显增多,多样性指数Shannon-wiener指数也有所增加,而Pielou指数和Simpson指数变化很小。生活型谱矮高位芽植物在群落植物中占的比重最大为33.33%,其次是小高位芽植物。由频度级分析得出,群落仍处于发展的不稳定时期,频度级为C物种数将不断增多,从而达到稳定阶段。由于红椿林生长的地理环境不利于种子的萌发和幼苗的成长,且生长对光照有强烈的依赖性,林下更新困难,已成为红椿林濒危的主要原因,应加强对红椿生境的恢复和重建技术研究,以利其种群的扩大。

Plant Diversity of Toona ciliata Community in Pingj iang County

Toona ciliata is the Grade-Two endangered species of China.Contiguous grid method and the midpoint of quartering,species composition,community appearance,vertical structure of community & characteristics of diversi-ty of each layer of the community of T.ciliata forest were studied.Result shows that in 1 200 m2 of vascular plots where a total of 81 species,70 genera belonging to 53 families,communities composed of families and genera is not e-nough focus;geographic component of flora of community is complex,with significant vertical hierarchical structure, there are obvious dominant species in the layers;Simpson index of the tree layer is the largest ,being 0.217;Simpson index of shrub and herb layer is 0.033 &0.039 respectively.T.ciliata increase significantly with the increase of al-titude gradient;diversity index (Shannon-wiener index)has also been increase,while Pielou index & Simpson index changed little.Specific gravity of life-form spectrum (short phanerophyte )in plant of communities accounted for the largest share of 33.33%,followed by small phanerophytes.By the frequency of the level analysis concluded that the community is still in an unstable period of development,the frequency of the number of species in the order of C will continue to increase,so as to achieve stable stage.Since the geographical environment of growth for T.ciliata forest is not conducive to seed germination and seedling growth;the growth have strong dependence to light ;regen-eration is difficult,which has become the main reason for the endangered forest of T.ciliate;habitats rehabilitation and reconstruction of technical for T.ciliate should be strengthened in order to facilitate the expansion of its popula-tion.