雷竹凋落叶不同分解环境中土壤动物群落特征

为研究火烧迹地雷竹(Phyllostachys violascens)凋落叶分解过程中土壤动物群落特征,以毗邻雷竹林为对照,采用凋落物袋法研究雷竹凋落叶分解速率及土壤动物群落结构的变化特征。结果显示,两个样地雷竹凋落叶分解过程总体上可以划分为3个阶段,即分解初期(质量损失率较高)、分解中期(凋落叶的质量损失率较上阶段减缓)、分解后期(质量损失率再次上升)。调查共捕获土壤动物824只,其中火烧迹地375只,对照样地449只,以绥螨科、蚁科、线虫纲和等节(虫兆)科为优势类群,所占百分比为49.27%,火烧迹地土壤动物类群数变化幅度较个体数小。统计分析表明,火烧迹地和对照样地凋落叶分解过程中土壤动物类群数无显著差异(P0.05)。两个样地土壤动物均匀度指数、多样性指数和丰富度指数均呈上升趋势,而优势度指数则逐渐降低,凋落叶分解过程中土壤动物个体数、类群数均与降水量存在显著相关关系(P0.05)。主坐标分析(PCoA)表明,凋落叶分解初期受火烧干扰较大,后期受分解时间累积效应影响较大。试验表明,火烧干扰延缓了雷竹凋落叶的分解速率,但随着时间的延续,火烧迹地雷竹叶分解速率则迅速提升,土壤动物群落也得到恢复。

Soil Fauna Community Dynamics of Phyllostachys violascens Litter in Different Decomposition Environments

Objective] This study was aimed to investigate the relationship among the soil animal, decomposition rate of plant litter and climate factors during litter decomposition of Phyllostachys violascens after fire disturbance. Method] Litter bags set in experimental plots were used to collect litters and soil animals in Puyang town of Dujiangyan. Result] The results showed that 824 soil animal individuals were captured totally, among that, 375 and 449 of that were collected in litter bags in burned plots and control plots respectively. Generally, it tend to decompose fast at first, then get slowly and quickly decay again in the anaphase in all plots but the decomposition rate of litter in burned plots was much higher than that in the control plots. Accounting for 49.27 percent of the total animals collected, Phytoseiidae, Formicidae, Nematodes and Poduridae consisted of the dominant species in general. The analysis of variance showed that there is no significant difference in the group density between the soil fauna in the burned plots and the control plots (P>0.05), but the results of correlation analysis showed that the individual density and group density of soil faunas were significantly correlated with rainfall amount (P<0.05). Conclusion] It was revealed that rainfall is an important environmental factor affecting the litter decomposition rate of P. violascens and the litter decomposition rate showed a positive correlation with the quantity and varieties of the soil animals. The litter of P. violascens after forest fire decomposed faster than that in control areas throughout the whole trial period, indicating that forest fire might have a negative impact on litter decomposition.