摘要:土壤动物群落结构和多样性可能随凋落物分解进程和基质质量的变化不断改变。为了解亚热带森林凋落叶分解过程中土壤节肢动物群落变化特征，以四川盆地亚热带森林麻栎（Quercus acutissima）和柳杉（Cryptomeria fortunei）凋落叶为对象，于2011-2015年采用分解袋法研究了2种凋落叶分解过程中土壤节肢动物组成、结构和多样性动态变化。整个研究期间，柳杉和麻栎凋落叶分解袋中共捕获土壤节肢动物3855只，分属于16目51科，且均以等节跳科和棘跳科为优势类群；麻栎凋落叶中土壤节肢动物的个体密度随分解进程呈现增加趋势，在分解的1079天达最高值后降低，而柳杉凋落叶则在分解的156天急剧增加后快速降低，2种凋落叶中土壤节肢动物类群数量具有相似的动态变化过程；2种凋落叶中土壤节肢动物总体以菌食性数量比例最高，腐食性最低，且随凋落叶分解进程，植食性土壤节肢动物占比明显下降，菌食性则上升；非度量多维尺度（NMDS）分析显示，2种凋落叶中土壤节肢动物群落组成具有显著差异，聚类分析表明，2种凋落叶土壤节肢动物群落结构相似性随分解进程不断降低。亚热带森林凋落叶分解过程中土壤节肢动物群落组成、结构和多样性受凋落叶类型影响。



Abstract:Soil fauna are crucial decomposers in terrestrial ecosystem. The structure and diversity of soil fauna may vary with changes in decompsition stages and litter quality during litter decomposition, but how the compositon and structure of soil arthropod vary during litter decompostion in subtropical forests remain poorly understood. In this study, we conducted a four-year litter decomposition experiment (2011-2015) to explore the compositon, structure and diversity of soil arthropod during litter decomposition. Two dominant tree species with contrasting leaf traits (coniferous vs. broadleaf) were used for field incubation in a subtropical forest of Sichuan Basin, southwestern China. Fresh senesced litter was collected using 1m×1 m litter traps in our study site between September and October 2011. The litter contained a coniferous species (Cryptomeria fortunei) and a broadleaf species (Quercus acutissima). The litter samples were air-dried for 2 weeks at 25℃ and 10±0.05 g was placed in 20 cm×20 cm nylon litterbags. A total of 130 litterbags (11 sampling times×5 plots×2 tree speices+20 spare litterbags) were carefully placed on the forest floor in late November 2011. A total of 11 sampling events were performed during our four-year litter decomposition study. Throughout the four years of decomposition, 3855 individuals and 51 families of soil arthropod were extracted from the litterbags. According to the individual proportion and composition of the taxa, Isotomidae and Onychiuriclae were the two numerically dominant taxa regardless of tree species during the decompositon. The individual density of the soil arthropod in the broadleaf litter showed an increasing trend with the decomposiotn proceeded and reached the maximum level at 1079 days of decomposition, and that in the coniferous litter increased to the maximum level at 156 days of decomposition and then rapidly decreased. The family richness of the soil arthropod in both the broadleaf and coniferous litter had a similar dynamic during litter decompostion. The fungivorous and saprophyte soil arthropod were the highest and least proportion of funcational groups of soil arthropod during the decompostion, respectively. As the decompsition proceeded, the proportion of the phytophaga soil arthropod decreased and that of the fungivorous soil arthropod increased. The NMDS analysis showed that the composition of soil arthropod community had sigificant difference between the broadleaf and coniferous litter. The cluster analysis indicated that the similarityof soil arthropod community structure between the broadleaf and coniferous litter continued decrease during the study. The results suggest that the composition, structure and diversity of soil arthropd are affected by litter type during litter decomposition in subtropical forests.





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