小兴安岭阔叶红松林地表甲虫Beta多样性

Beta多样性用来衡量集群内物种组成的变异性,可以被分解为空间物种转换和物种集群镶嵌两个组分,是揭示群落构建机制的重要基础。目前开展了较多的地上生态系统beta多样性研究,然而地下生态系统beta多样性进展缓慢。以小兴安岭凉水和丰林自然保护区为研究地区,于2015年8、10月采用陷阱法对阔叶红松林进行调查,揭示地表甲虫(步甲科、隐翅虫科、葬甲科)的beta多样性。结果表明:(1)凉水共发现39种、856只地表甲虫,丰林共发现43种、1182只地表甲虫。8月凉水明显具有较高的全部甲虫(三个科的总和)物种多样性和丰富度,10月正好相反。(2)凉水和丰林之间地表甲虫beta多样性的差异仅发现于8月的步甲科和葬甲科之间。(3)凉水和丰林地表甲虫的beta多样性主要由空间物种转换组成,物种集群镶嵌对beta多样性的贡献很小,说明地表甲虫物种组成变异主要由本地物种之间较高的转换引起。研究表明小兴安岭阔叶红松林地表甲虫的beta多样性主要由空间物种转换组成,在揭示群落构建机制过程中,其内部物种交换和环境调控不容忽视。

Beta diversities of ground-beetle assemblages in two broad-leaved Korean pine (Pinus koraiensis) mixed forests in Xiaoxing'an Mountains

The term beta diversity was first introduced by Whittaker in 1960. It is described as variation of the species composition of assemblages. Beta diversity can be partitioned into two antithetic components, that is spatial species turnover and nestedness of species assemblages. Identifying those two components of beta diversity is an important task for revealing the mechanisms of community assembly. Some studies have been performed to disentangle the spatial species turnower and nestedness for communities in aboveground ecosystems, however, beta diversity of assemblages in belowground ecosystems is still unclear. The objective of this study is revealing the beta diversity of ground beetle assemblages and then partitioning the beta diversity into spatial species trunover and nestedness of species assemblages. Field experiments were carried out using pitfall traps in two broad-leaved Korean pine (Pinus koraiensis) mixed forests in Liangshui and Fenglin nature reserves, respectively, Xiaoxing''an Mountains, Northeast China. We collected ground beetles in a 9 hm² plots (300 m×300 m) by regular sampling method in August, October in Liangshui plot. We captured ground beetles in a 9 hm² plot (300 m×300 m) with the same method in August, October in Fenglin plot. There were 450 traps in Liangshui and Fenlin plots in total, respectively. We identified beetles into species level. We analyzed Carabidae, Staphylinidae and Silphidae beetles because their dominance in richness and abundance in each plot. We evaluated beta diversity based on PERMDISP2 method. We partitioned total beta diversity into spatial species turnover and nestedness of species assemblages. In total, 39 species and 856 individuals were captured in Liangshui plot. Forty-three species and 1182 individuals were collected in Fenglin plot. Results of diversity analysis showed that (1) Significantly higher species richness and abundance of entire beetle assemblages (total beetles of those three families) were detected in August in Liangshui plot. While significantly higher species richness and abundance of entire beetle assemblages were detected in October in Fenglin plot. The distribution of species richness and abundance for each Carabidae, Staphylinidae, Silphidae assemblages in Liangshui and Fenglin plots were family dependent. (2) There were no significant differences of beta diversities in ground beetle assemblages between Liangshui and Fenglin plots, except for Carabidae and Silphidae assemblages in August. (3) Beta diversity patterns for entire ground beetle assemblage and each family beetle assemblage were almost completely caused by spatial species turnover in Liangshui and Fenglin plots, while the contributions of nestedness of species assemblage were small. It suggested that beta diversities of ground beetle assemblages were mainly structured by spatial species replacement but not by species loss, suggesting a high proportion of endemics present in the two mixed forests. In this study, we suggested that spatial species turnover is the most important component for beta diversity in broad-leaved Korean pine mixed forest, therefore a more important role of spatial species turnover should be considered for understanding the mechanisms driving ground beetle assemblages in broad-leaved Korean pine mixed forest. This study provides scientific foundation for revealing the mechanisms of community assembly in soil animal community.