大兴安岭针阔混交林土壤动物群落多样性时空分异与形成机制

Greater Hinggan Mountains, which located at southern edge of Eurasia permafrost zone, is the only cold temperate regions of China, and is also is global climate change sensitive zone. By the impact of high intensity development and natural disaster interference, the nature forest area of Greater Hinggan Mountains region began to shrink, and result in the loss of soil biodiversity and the ecological functions decline. While studies on distribution pattern of soil animal communities have been paid few attentions, we do not know the impact of high intensity development and natural disaster interference on soil animal community diversity. In this project, based on our preliminary work, we study the spatial-temporal distribution pattern of soil fauna community diversity and community structure by investigating the relationship between the disturbance and soil fauna community of conifer-broadleaved Forest, which was a transition type formed by the deforestation, fire disturbance in southeastern of Greater Hinggan Mountains region. The objectives of this project are to (1) to analyze the impact of environment factors on soil fauna community diversity, (2) to study the spatial-temporal differentiation of above-below ground soil fauna community diversity, and mechanism of formation of soil fauna community diversity..Our hypothesis is that the soil animal community assembly is dissimilarity between above ground and below ground, former is mainly related to the available resources, the latter mainly soil properties change caused by disturbance. To address the hypothesis, we investigate above-below ground soil animal community and soil properties at study area. We will use these data to analyze spatial heterogeneity of above-below ground soil animals commuinty diversity, the food resource and food webs, the form traits of dominant groups, and phylogenetic structure, using geostatistics, ecological morphology, molecular biology, community ecology theory and methods, to unravel the regulation function of biological interactions, environmental filtering and diffusion limitations on soil fauna community diversity formed. The study will help to understand the key process of above ground and below ground soil animal community diversity formation, and also benefit to underground community diversity of soil animals formed for further study of soil animal diversity in boreal forest restoration and reconstruction to provide a scientific basis.

大兴安岭是我国全球气候变化敏感地带，其原生兴安落叶松林因干扰退化对地下生物多样性产生的影响已成为当前重要的生态学问题之一。项目以大兴安岭东南部受采伐、火灾干扰后形成的过渡植被类型—针阔混交林为研究对象，在前期工作基础上，进一步研究土壤动物多样性时空变化格局与形成机制。综合应用地统计学、生态形态学、群落生态学、分子生物学等交叉学科理论与方法，从生物多样性、形态特征、谱系结构角度出发，分析不同空间与时间尺度下地上与地下土壤动物群落多样性变化规律，探讨生态位过程与中性过程对土壤动物多样性形成的影响机制，阐明土壤动物群落多样性对生物间相互作用、环境过滤和扩散限制及食物网结构变化的响应，揭示不同干扰方式与不同干扰强度引起的森林环境变化条件下，土壤动物优势类群多样性对时空变化的适应性与群落稳定性的自我维持，为进一步研究大兴安岭森林土壤动物群落演变规律及其在寒温带针叶林恢复重建中的关键作用提供科学依据。

大兴安岭是我国全球气候变化敏感地带，其原生兴安落叶松林因干扰退化对地下生物多样性产生的影响已成为当前重要的生态学问题之一。项目以大兴安岭东南部受采伐、火灾干扰后形成的过渡植被类型—针阔混交林为研究对象，研究土壤动物群落结构与多样性时空格局与形成机制。研究共采集1 122 342 头土壤动物，其中土壤线虫14 3948条，隶属2纲8目37科65属；已鉴定地表土壤动物978 376头，隶属2门7纲21目107科173属。与天然次生混交林相比，地表动物类群基本呈减少的趋势，Shannon- Wiener指数（H′）与Pielou均匀性指数（Js）相对增大；部分常见类群生态位宽度与部分类群之间生态位重叠指数变化幅度较大，但普通生态位重叠指数偏低。地表土壤动物群落变化主要受时间与胁迫方式以及土壤主要理化性质的影响。土壤线虫在采伐、火烧干扰胁迫下，与天然次生林地表土壤动物群落组成共有种变化较大，具有较高的异质性。土壤食物网分解过程多以细菌主，植物寄生线虫成熟度指数（PPI）呈现增加趋势。土壤线虫食物网处于结构化的状态。地表土壤动物具有高度的空间异质性，空间分布呈自相关性，其变异函数理论模型通过指数模型、球状、高斯模型以及直线模型拟合。土壤动物群落构建主要受扩散限制与生物间相互作用的影响，其中重度火烧干扰下，弹尾虫、蜱螨类群落构建是物种间的相互作用的影响，而大型土壤动物则主要受扩散作用的影响；土壤线虫群落具竞争性的群落结构，但其群落构建的影响因素进一步确认。土壤动物遗传多样性变化与干扰类型、干扰时段相关，地表温度对其影响最大，其次是土壤有机质，pH影响最小。以上结果表明，采伐与火烧干扰明显改变了土壤动物群落组成与多样性，且通过影响地上与土壤生态过程影响土壤动物群落多样性时空分布格局以及土壤动物群落构建的过程，其影响具有长期性。该发现对于进一步研究多尺度过程与干扰对寒温带针叶林地表土壤动物的生态学过程影响以及土壤动物对生态学功能恢复提供依据。