雅鲁藏布江中游地区土壤淡色丝孢菌群落多样性及物种生态位研究

Diversity and eco-niche of soil moniliaceous hyphomycetes in the middle reaches of Yarlung Zangbo River,Tibet of China

从雅鲁藏布江中游地区采集土壤样品35份,主要涵盖农田、城市花园、高山草甸、湿地和防护林带五种生态类型,从中分离获得土壤淡色丝孢菌12属。利用种群优势度、Shannon-Wiener多样性指数、均匀度、生态位宽度、群落相似性等指标对该地区不同生境的土壤淡色丝孢菌物种(属级)的生态多样性及物种生态位进行了分析。结果表明,土壤淡色丝孢菌的数量和类群分布在该地区不同生态类型土壤中差异明显。农田生境中土壤淡色丝孢菌物种多样性指数最高,均匀度较高;防护林带生境中土壤淡色丝孢菌物种多样性指数最低,均匀度也最低。对不同生态类型土壤中淡色丝孢菌的相似性分析发现,农田和防护林带生境的相似性系数最大,说明这两种生境具有较多的共同物种;湿地和城市花园生境的相似性系数最小。物种生态位结果分析表明,在上述五种生境中,拟青霉属Paecilomyces、刺座霉属Volutella、曲霉属Aspergillus和青霉属Penicillium具有较宽的生态位宽度,属于广适性物种;而白僵菌属Beauveria和绿僵菌属Metarhizium生态位很窄,只存在于某个生境中,属于狭适性物种。

Twelve genera of soil moniliaceous hyphomycetes were isolated from thirty-five samples which were collected from five ecosystem-types of the middle reaches of Yarlung Zangbo River of Tibet.The population dominance index,Shannon-Wiener index,evenness,niche breadth and community similarity were used to analyze the diversity and eco-niche of soil moniliaceous hyphomycetes in five ecosystem-types.The results showed that the amount and species（at generic level） distribution of soil moniliaceous hyphomycetes had an obvious variability in different ecosystem-types.The diversity index of soil moniliaceous hyphomycetes of farmland was the highest and the evenness was also higher while the diversity index of shelter-belt was the lowest and the evenness was the lowest too.The analysis of the fungal community similarity between different ecosystem-types showed that farmland soil and shelter-belt soil had the highest similarity,indicating that the soil moniliaceous hyphomycetes in this two ecosystem-types had more common species.The similarity coefficient of the fungi between wetland soil and urban garden soil was the lowest.The results of niche breadth analysis indicated that species of Paecilomyces,Volutella,Aspergillus and Penicillium had wider niche breadth and wider adaptability.While Beauveria and Metarhizium had narrower niche breadth and narrower adaptability.