南方不同林龄杉木人工林林下物种多样性比较

在湖南株洲市攸县地区,选择4个不同年龄阶段的杉木人工林,采用空间代替时间的方法,研究林下植物组成及多样性变化。结果表明:不同年龄阶段的杉木人工林林下植被的物种丰富度差异不大,在2 700m2样地内有植物22～33种,但其优势物种的生物生态学特性差异较大,各年龄阶段的杉木人工林林下优势物种分别为,葛藤(Pueraria thunbergiana)和铁芒萁(Dicranopteris dichotoma);断肠草(Gelsemium elegans)和蕨(Pteridium aquilinum);圆锥山蚂蝗(Desmodium elegans)和蕨;六月雪(Serissa serissoides)和蕨。不同林龄林下植被的生物多样性差异不大,以广黄分场杉木人工林林下物种多样性指数最高,其灌、草层物种种数均值分别为18.3和11.3,物种多样性指数H均值分别为2.136 3和1.961 0。可见,人工林林分郁闭度和冠层结构左右着林下植物的组成及分布。

Comparison of Undergrowth Plant Diversity in Different Aged Cunninghamia lanceolata Plantations in South China

Cunninghamia lanceolata plantations of 4 different age classes were compared and analyzed.These plantations lie in Youxian County of Zhuzhou city,Hunan province.In this research,space is studied as the object instead of time.The result shows that compared with different stand age gradations,the diversity of under-storey species richness is not so obvious.There are about 22～33 plant species per 2700 m2 in plot.However,the bio-ecological characteristic differences among dominant species are evident.The dominant under-storey species at different age levels of Cunninghamia lanceolata plantations were respectively Pueraria thunbergiana and Dicranopteris dichotoma,Gelsemium elegans and Pteridium aquilinum,Desmodium elegans and Pteridium aquilinum,Serissa serissoides and Pteridium aquilinum.Under-storey species diversity index of different stand ages is almost the same.The species diversity index in Cunninghamia lanceolata plantations of Guanghuang is best,with the average species being 18.3,11.3 and Shannon-wiener index(H) 2.136 3,1.961 0 of shrub layer and herb layer under Cunninghamia lanceolata plantation.So,both canopy density and crown structure of plantation dominate under-storey species composition and distribution.