桉树造林再造林群落植物多样性的变化

摘要

以广西钦州市桉树造林(第1代)和再造林(第2代)群落为研究对象,以当地15～20a马尾松群落作对照,于2006-2009年开展林下植物多样性研究.结果表明:经9 a的恢复后,按树林群落木本、藤本和草本植物的物种数分别为50、17～19种和26～28种,马尾松林群落的木本、藤本和草本植物的物种数依次为34～48、13～24种和16种;两类群落的木本、藤本数与总物种数的差异不显著(P＞0.05),但草本植物数与总物种数的差异显著(P＜0.05),表明桉树造林后能显著增加草本植物的物种丰富度.桉树再造林的木本植物种类数为39种,比第1代的降低了22.2%,差异显著(P＜0.05);其草本植物种类数为16种,与第1代(14～16种)的接近.桉树造林再造林对木本植物的Shannon-Wiener指数(H')、Simpson指数(D)和均匀度指数(Js.w)的影响不显著(P＞0.05),而对草本植物的H'、D和Js.w的影响显著(P＜0.05).桉树造林和再造林过程中采取的采伐、炼山、整地、施肥和铲草抚育等措施是导致群落植物多样性及其功能群变化的主要原因.%A survey was conducted to study the plant species diversity of eucalyptus communities after afforestation ( generation 1 ) and reforestation (generation 2) in Qinzhou City of Guangxi Province during 2006-2009 using 15-20-year-old Pinus massoniana communities as the control group. Results showed that, after nine years of recovery, the species numbers of woody plants, liana and herbaceous plants in the eucalyptus communities were 50, 17-19 and 26-28 respectively, and 34-48,13-24 and 16 in the P. massoniana communities. There were no significant differences in species number between the woody plant, liana and the total plant species in both forest types(p＞0.05), but a significant difference was observed between the herbaceous plant and the total plant species(p＜0.05). It is clear that eucalyptus afforestation can increase the species richness of herbaceous plants. The woody plants in the eucalyptus communities after reforestation ( generation 2)were 39 species with a decrease by 22.2 percent over the generation 1 (p＜0.05), and the herbaceous plants were 16 species with the same number as the generation 1. Shannon-Wiener index, Simpson index and Pielou index of the woody plants showed no significant difference between both types of the communities(p＞0.05), but those of the herbaceous species had significant differences(p＜0.05). It is revealed that plant species diversity and functional groups in eucalyptus communities after afforestation and re forestation are significantly influenced by clear-cutting, weed burning, site preparation and fertilization.