广西桉树林取代马尾松林对植物多样性的影响

对广西钦州市马尾松林和巨尾桉人工林的植物多样性开展研究，旨在阐明桉树林取代马尾松林对植物多样性和植物功能群的影响，促进对桉树人工林的科学认知。研究表明，采伐马尾松林种植桉树后10年，在1 800 m2样地内，桉树林的物种数为95～98种（木本植物50种，藤本17～19种，草本24～28种），而马尾松林为63～88种（木本植物32～48种，藤本13～24种，草本16种），两类林分的木本、藤本和总物种数差异不显著（P为0.237～0.937），而草本植物差异显著（P=0.038），表明桉树林取代马尾松林将显著增加草本植物的物种丰富度。桉树林取代马尾松林对铁芒萁有显著的负效应，重要值减少50%（P=0.077），而对五节芒（P=0.057）和东方乌毛蕨（P=0.079）有显著的正效应，重要值提高0.85～3.76倍。桉树林和马尾松林木本植物的Shannon Wiener指数(H′)、Simpson指数(D)和均匀度指数(Jsw)差异不显著（P为0.299～0.957），而草本植物的H′、D和Jsw差异极显著（P≤0.002）。桉树林取代马尾松林对群落的物种多样性和功能群具有显著的影响，然而，桉树人工林建立过程中采取的采伐、炼山、整地、施肥等措施是导致群落物种多样性和功能群变化的主要原因。 

Effects of eucalypt plantation replacing Masson pine forest on plant species diversity in Guangxi.southern China

By studying plant species diversity of euealypt (Eucalyptus grandis x E. Urophylla) plantation and Pinus massoniana forest in Qinzhou City of Guangxi, southern China, the objective of this research was to examine and illustrate the effects of eucalypt plantations replacing P. Massoniana forest on plant species diversity and functional types and promote understanding on eucalypt plantations. Ten years after eucalypt plantations were established, 95-98 species (50 woody, 17-19 liana, 24-28 herbaceous) presented in the eucalypt plantations, compared with 63-88 species (32-48 woody, 13-24 liana, 16 herbaceous) in the P. Massoniana forest, in the 1 800 m~2 sample plots. Woody, liana and total plant species in both forest types had no significant difference (P ranged from 0.237-0.937), but herbaceous species had a significant difference (P=0.038). It is clear that eucalypt plantation replacing P. Massoniana forest would increase opportunities for colonization of herbaceous species relative to P. Massoniana forest. Eucalypt plantations replaced P. Massoniana forest had a significant negative effect on Dicranopteris linearis with decreased by 50 % of important value. In contrast, both Miscanthus floridulus and Blechnum orientale showed a significant positive effects (P ranged from 0.057-0.079) with increased by 0.83-3.76 times of important value. Shannon-Wiener's index, Simpson's index and Pielou's index of the woody plant species between both types of forests had no significant difference (P ranged from 0.299-0.957), but those of the herbaceous species had strongly significant differences (P≤0.002). The results of the present study, revealed that plant species diversity and functional types in eucalypt plantations were significantly influenced by clear-cut, clear-burned, prepared site and fertilized measures of forest management.