【摘要】 区域碳循环是全球变化研究中的核心内容,大兴安岭森林生态系统是对全球温度变化最敏感的植被类型之一,其植被多样性对土壤有机碳密度和碳循环具有重要影响,深入理解该区土壤有机碳密度分布特征对于未来区域生态环境的可持续发展具有重要的科学意义。采用野外调查和室内测试分析相结合的手段,研究了大兴安岭4种主要森林类型(针叶混交林、针阔混交林、阔叶混交林、落叶林)的植被多样性和土壤有机碳密度分布特征,并采用多因素方差分析确定植被类型和土层深度对土壤有机碳密度的交叉影响。结果表明,大兴安岭4种林型Margalef丰富度指数、Shannon-Wiener多样性指数和Mclntosh均匀度指数表现为落叶林>针阔混交林>阔叶混交林>针叶混交林;Simpson优势度指数则表现为针叶混交林>阔叶混交林>针阔混交林>落叶林;Cody指数表现为落叶林>针阔混交林>针阔混交林>针叶混交林;Sorenson指数表现为针叶混交林>阔叶混交林>针阔混交林>落叶林。土壤有机碳含量和有机碳密度均呈一致的变化规律,其中以表层土壤最高,随土壤深度的增加逐渐降低;随剖面深度的增加,土壤有机碳密度逐渐降低,以表层土壤(0~20 cm)有机碳密度最高,针叶混交林、针阔混交林、阔叶混交林、落叶林土壤有机碳密度分别占土壤剖面总有机碳密度的35.24%、31.61%、31.70%、32.39%。相关性分析表明,4种林型Margalef丰富度指数、Shannon-Wiener多样性指数、Cody指数和Sorenson指数与有机碳含量和有机碳密度呈显著或极显著的正相关;从相关系数绝对值来看,多样性指数与有机碳含量的相关系数高于有机碳密度的相关系数。双因素分析表明,林型对有机碳含量和有机碳密度具有显著的影响(P<0.05),林型×深度的交互作用对有机碳含量具有显著的影响(P<0.05);林型和林型×深度的交互作用对Margalef丰富度指数和Shannon-Wiener多样性指数具有显著的影响(P<0.05);林型对Cody指数和Sorenson指数具有显著的影响(P<0.05)。综合分析表明,大兴安岭林型和土壤深度对土壤有机碳密度的影响存在一定的交互作用。更多还原

【Abstract】 Regional carbon cycle is the core content in global change research. Forest ecosystem in Da Xing’an mountain is sensitive to global climate change, thus, it is necessary to deeply understand the distribution of soil organic carbon density in this region. Here, four dominant forest types, i. e. larch forest, coniferous mixed forest, broadleaved mixed forest, and coniferous and broadleaved mixed fores were selected to investigate the variation of soil organic carbon density and plant community diversity in Da Xing’an Mountains of Northeast China by multi-factor analysis of variance. Results showed that Margalef, Shannon-Wiener, Mclntosh and Sorenson index showed larch forest>coniferous mixed forest>broadleaved mixed forest>coniferous and broadleaved mixed forest, while Cody index showed that coniferous and broadleaved mixed forest>broadleaved mixed forest> coniferous mixed forest>mixed forest. Soil organic carbon content and density showed the same change trend with the highest in the surface soil layer, and gradually decreased with the increasing of soil depth. Soil carbon density of coniferous and broadleaved mixed forest, broadleaved mixed forest, coniferous mixed forest, mixed forest was concentrated in the top 20 cm of soil which accounted for 35.24%, 31.61%, 31.70%, 32.39%, respectively. Correlation analysis showed that there was a significantly difference between Margalef, Shannon-Wiener, Mclntosh, Sorenson index and soil organic carbon content and density, while the correlation coefficient of soil organic carbon content was higher than soil organic carbon density. Double factor analysis showed that forest type had a large effect on soil organic carbon density(P<0.05), and forest type×soil depth had a large effect on soil organic carbon content(P<0.05). Forest type, forest type×soil depth had a large effect on Margalef and Shannon-Wiener index(P<0.05). In total, forest type and soil depth has the interaction effect on the soil organic carbon density.更多还原