深圳市马占相思过熟林群落组成及物种多样性分析

Community composition and species diversity study of Acacia mangium overmature forests in Shenzhen city

中国华南地区受台风影响最为频繁。对常年遭受台风侵袭的两种马占相思过熟林(受台风影响较小且现有密度为种植密度70%±5%的马占相思林Ⅰ,受台风影响较大且现有密度为种植密度50%±5%的马占相思林Ⅱ)开展群落调查,调查共记录了维管植物21科,30个属,35种,马占相思林Ⅰ群落物种总数仅为马占相思林Ⅱ的41.38%。马占相思林Ⅰ中马占相思重要值为77.8,其次是下木层的乡土树种银柴,其重要值随着样地内马占相思的增加而减少。马占相思林Ⅱ中,马占相思重要值排第1,仅为44.46,下木层乡土树种豺皮樟和银柴的重要值合计约为20,成为马占相思最主要的伴生乔木。马占相思林Ⅰ乔木层、灌木层、草本层的Pielou均匀度指数均与马占相思林Ⅱ没有显著差异。马占相思林Ⅰ乔木层的Simpson指数、Shannon-Wiener指数、物种数量、Margale丰富度指数均小于马占相思林Ⅱ,但两者的灌木层、草本层的Simpson指数、Shannon-Wiener指数、物种数量、Margale丰富度指数均没有显著差异。

South China was most frequently affected by typhoon. Community surveys in two types of Acacia mangium over-mature forests(Acacia mangium Ⅰ disturbed lightly by typhoon with 70%±5% of the planting density, Acacia mangium Ⅱ disturbed heavily by typhoon with 50%±5% of the planting density) were carried out. Thirty five species of vascular plants belonging to twenty one families and thirty genera were found totally in the two types of Acacia mangium over-mature forests, and the total number of species in the Acacia mangium Ⅰ community was only 41.38% of Acacia mangium Ⅱ. The importance value of Acacia mangium in Acacia mangium Ⅰ was the largest, 77.8, followed by the native tree species of Aporosadioica in the undergrowth layer whose importance value decreased with the increase of Acacia mangium. In Acacia mangium II, the importance value of Acacia mangium was also the first, only 44.46, and the importance value of the native wood species of Litsea retundifolia and Aporosadioica in the undergrowth layer was about 20 totally, which were the main associated trees of Acacia mangium. The Pielou evenness index of the tree layer, shrub layer or herb layer in Acacia mangium Ⅰ was not significantly different from that of Acacia mangium Ⅱ. The Simpson index, Shannon-Wiener index, species number, Margale richness index of the tree layer of Acacia mangium Ⅰ were all lower than those of Acacia mangium Ⅱ, but there were no significant differences on Simpson index, Shannon-Wiener index, species number, Margale richness index of the shrub and herb layers.