松材线虫入侵对马尾松林群落物种多样性的影响

Impact of Invasion of Bursaphelenchus xylophilus on Species Diversity of Pinus massoniana Forests

松材线虫Bursaphelenchus xylophilus入侵会对马尾松Pinus massoniana林的生物多样性和生态系统功能产生很大的影响。以染病(感染松材线虫病)4年马尾松林(4Y)和染病8年马尾松林(8Y)为研究对象,并与未染病马尾松林(UN)和常绿阔叶林(EV)作比较,对松材线虫入侵马尾松林后引起的群落结构变化和演替特征进行研究。结果发现:在染病8年马尾松林中阔叶树种的比率仅次于常绿阔叶林;4种群落的径级分布均以小径级为主,其中阔叶树种在DBH(胸径)≥1 cm木本植物中的占比从小到大依次为UN(64.99%)、4Y(66.61%)、8Y(90.64)、EV(98.83%);4种群落的物种丰富度、Shannon-Wiener指数和Simpson指数均表现为EV>8Y>UN>4Y,乔木物种多样性的变化趋势与DBH≥1 cm木本植物一致,灌木物种多样性在染病后一直保持较低的水平;4Y-UN、8Y-UN、EV-UN、4Y-EV、8Y-EV的Jaccard相似性系数分别为0.349、0.316、0.258、0.232、0.263。上述结果表明,松材线虫入侵马尾松林后,改变了马尾松林的物种组成,促进群落向地带性植被(常绿阔叶林)演替。

The invasion of the pine wood nematode(Bursaphelenchus xylophlius)has a significant impact on the biodiversity and ecosystem function of Pinus massoniana forests.In this paper,P.massoniana forests infected by pine wood nematode for 4(4Y)and 8 years(8Y)were selected as study subjects,and compared with uninfected P.massoniana forests(UN)and evergreen broad-leaved forests(EV).Three permanent sample plots of 30 m×30 m were set up in four community types in Suichang County,Zhejiang Province in 2020,to study the changes of community structure and succession characteristics caused by the invasion of P.massoniana by B.xylophilus.The results showed that the ratio of 8Y broad-leaved tree species was second only to EV;the diameter distribution of the four communities was dominated by small-diameter classes,and the proportion of broad-leaved trees in woody plants with DBH≥1cm was UN(64.99%),4Y(66.61%),8Y(90.64%)and EV(98.83%),respectively;the species richness,Shannon-Wiener index and Simpson index of the four communities were ordered by EV>8Y>UN>4Y,and the variation trend of tree species diversity was consistent with that of woody plants with DBH≥1cm,while the diversity index of shrub species remained low after infection.The Jaccard similarity coefficients of different communities were 0.349 for 4Y-UN,0.316 for 8Y-UN,0.258 for EV-UN,0.232 for 4Y-EV,0.263 for 8Y-EV.The results showed that the species composition of P.massoniana forest changed significantly after the invasion of pine wood nematode,and the invasion of pine wood nematode accelerated the succession of zonal vegetation(evergreen broad-leaved forests).