昆嵛山杉木和火炬松种群的自然更新与群落特征

The Population Regeneration and Community Characteristics of Cunninghamia lanceolata and Pinus taeda in Kunyu Mount

为了解昆嵛山引进物种杉木和火炬松的适应性和定居情况,利用样方法、样线法和统计方法,调查了杉木和火炬松的密度、胸径及其林下植物的种类组成、数量等,结合群落中土壤种子库特征,从种群和群落结构组成层次上分析了引进的这两种乔木对昆嵛山生态环境的适应性.结果表明:(1)杉木种群能正常生长并生产种子和幼苗,具有自然更新能力,按照胸径分级各个径级植株都有一定的数量;火炬松植株能够正常生长,但是种群由Ⅳ级以上大树组成,未发现幼苗存在.(2)杉木林土壤种子库平均种子储量398.5粒/m2,其中杉木种子储量为3.35粒/m2;火炬松林土壤种子库平均种子储量为10.4粒/m2,但无火炬松种子存在.(3)杉木群落的物种丰富度指数和多样性指数表现出乔木层>草本层>灌木层的格局,而火炬松群落则呈现草本层>灌木层>乔木层的趋势.因为火炬松种群在昆嵛山不能自然更新,衰落是不可避免的,而且群落结构中的乔木物种多样性少,稳定性差,建议在火炬松群落处引入本地的常绿针叶树种黑松和赤松,以便在火炬松退出时不影响稳定的群落结构,有利于山地的水土保持.

To understand the adaptation of Cunninghamia habitat, the density and DBH of the two species population lanceolata and Pinus taeda introduced in the new , the flora, the number of the community and the soil seed bank were studied and analyzed with methods of quadrats,line transects and statistics. The results showed that： （1） Cunninghamia lanceolata grew well and produced seeds and seedlings, and there were certain amount of plants with different DBH ,which indicated C. lanceolata had natural regeneration ability. Pinus taeda grew well, but less or no seeds and seedling were found. （2） The capacity of soil seed bank in C. lanceolata community is 398.5 seeds/m^2 ,including 3.35 seeds/m^2 of C. lanceolata seeds,while that of P. taeda community is 10.4 seeds/m^2 and without any P. taeda seeds. （3） The species richness and species diversity index indicated ： tree layer herbage layer 〉 shrub layer in C. lanceolata community, while the P. taeda community displayed differently in the following orders ： herbage layer, shrub layer, tree layer from high to low. It is inevitable that P. taeda population should decline because it can not naturally regenerate in Kunyu Mountain. In addi- tion, there was a lower tree diversity and stability in P. taeda community. We suggested that local evergreen conifer trees such as P. thunbergii and P. densiflora can be introduced into P. taeda community in order to stabilize community structure in favor of water-soil conservation in mountain area.