人工马褂木林下草本植物物种多样性与林分郁闭度的关系

Diversity of Understory Herbaceous Species and Canopy Density of Liriodendron chinense Stand

通过对崇明岛5年生人工马褂木林下草本植物分布及生长状况的调查,研究了不同郁闭度下草本植物物种多样性与林分郁闭度的关系。结果表明:在马褂木幼龄林中,随着林分郁闭度的增大,林下草本植物种数呈先增加后减少的趋势,郁闭度为0、(0,0.2]、(0.2,0.4]、(0.4,0.6]、(0.6,0.8]、(0.8,1.0]下的草本植物种数分别为16、16、19、15、9和7种;林下草本植物的平均盖度、平均密度与林分郁闭度在α=0.01水平上呈显著负相关(r盖度-郁闭度=-0.9643,r密度-郁闭度=-0.9815);林分郁闭度为(0.2,0.4]林下草本植物多样性指数最高,其中辛普森指数为0.7548,香农-威纳指数为1.3273,均匀度指数为0.8806。

Species, mean coverage, mean density and α-diversity index of the understory herbaceous plants were investigated in five-year-old Liriodendron chinense forest stands different in canopy density in Chongming Island of Shanghai. Resuits show that with canopy density increasing from 0, （0,0. 2], （0. 2,0. 4], （0. 4,0. 6], （0. 6,0. 8] and （0. 8,1.0], the number of understory herbaceous plant species displayed a rising-and-then-falling trend, like 16, 16, 19, 15, 9 and 7. Significant negative correlations were observed between the canopy density and the mean coverage of herbaceous plants （ r= -0. 964 3 ,P〈0. 01 ） and the mean density of herbaceous plants （ r= -0. 981 5 ,P〈0. 01 ） as well. The Simpson index, Shannon-Weiner index, and Pielou index peaked when the canopy density was （0. 2,0. 4] , being 0. 754 8, 1. 327 3, and 0. 880 6, respectively.