桂西北香合欢群落物种多样性及种间生态位特征

Species Diversity and Interspecific Niche Characteristics of Albizia odoratissima Community in Northwest Guangxi

为了解香合欢(Albizia odoratissima)群落植物物种多样性和生态位特征,以广西壮族自治区国有雅长林场香合欢群落为研究对象,计算物种重要值、Shannon-Weiner指数、Simpson多样性指数、Margalef丰富度指数和Pielou均匀度指数,采用Levins、Hurlbert和Pianka方法分析物种生态位宽度和种间生态位重叠特征。结果表明,乔木层、灌木层和草本层的优势物种分别是香合欢、黄檀(Dalbergia hupeana)和荩草(Arthraxon hispidus),其重要值分别为0.29、0.13和0.61;乔木层、灌木层和草本层物种Shannon-Weiner指数分别为2.13、2.71和0.92,Simpson多样性指数分别为0.81、0.91和0.35,Margalef丰富度指数分别为4.61、4.16和3.20,Pielou均匀度指数分别为0.65、0.85和0.29。乔木层生态位较宽的植物,主要有灰毛浆果楝(Cipadessa cinerascens)、香合欢和粗糠柴(Mallotus philippensis),灌木层有香合欢,草本层有荩草。乔木层、灌木层和草本层种间生态位重叠较多,竞争比较激烈。其中,乔木层生态位重叠共55对,占比70.51%;灌木层共98对,占比81.67%;草本层共41对,占比91.11%。香合欢群落结构简单,物种数量少,多样性较低,优势种相对明显,种间资源竞争较激烈,生态稳定性较脆弱;香合欢、粗糠柴和灰毛浆果楝具有较宽的生态位和较强的生境适应能力,适合作为南方地区乡土树种推广和利用。

In order to understand plant species diversity and niche characteristics of Albizia odoratissima community,taking A.odoratissima community in Guangxi state-owned Yachang forest farm as research object,importance value,Shannon-Weiner index,Simpson index,Margalef index and Pielou evenness index were calculated,and interspecific niche overlap characteristics were analyzed by Levins,Hurlbert and Pianka methods.Results showed that dominant species in tree layer,shrub layer and herb layer were A.odoratissima,Dalbergia hupeana and Arthraxon hispidus,with important values of 0.29,0.13 and 0.61 respectively.Shannon-Weiner indexes of tree layer,shrub layer and herb layer were 2.13,2.71 and 0.92 respectively,Simpson indexes were0.81,0.91 and 0.35 respectively,Margalef richness indexes were 4.61,4.16 and 3.20 respectively,and Pielou evenness indexes were 0.65,0.85 and 0.29 respectively.Plants with wide niche breadth in tree layer mainly included Cipadessa cinerascens,A.odoratissima and Mallotus philippensis,in shrub layer included A.odoratissima,and in herb layer included Arthraxon hispidus.There were many niche overlaps and fierce competition among species in tree layer,shrub layer and herb layer.Among them,there were 55 pairs of niche overlaps in tree layer,accounting for 70.5%,98 pairs in shrub layer,accounting for 81.5%,and 41 pairs in herb layer,accounting for 91.1%.Community had few species,low diversity,relatively obvious dominant species,fierce resource competition and fragile ecological stability.A.odoratissima,M.philippensis and C.cinerascens had wide niches and strong habitat adaptability,so these were suitable to be popularized and utilized as native tree species in southern China.