车八岭山地常绿阔叶林冰灾后土壤节肢动物群落的多样性

2008年初车八岭山地常绿阔叶林受到中国南方80年一遇的冰灾的重创。为了揭示灾后林冠开度的梯度对土壤节肢动物多样性与分布的影响, 在受冰灾影响的车八岭山地常绿阔叶林设置2 ha固定样地, 按照冠层受损程度选取17个20 m×20 m的样方, 用半球面影像技术获取林冠开度, 并分凋落物层、0–10 cm和10–20 cm的矿质土层采集凋落物及土壤样品, 分析土壤节肢动物多样性。利用双向聚类分析(two-way cluster analysis)对凋落物层的土壤节肢动物和样地进行聚类, 以典范对应分析(canonical correspondence analysis)研究冠层开度、土壤有机质、电导率以及自然含水量与0–10 cm表土层土壤节肢动物的关系。结果表明土壤节肢动物的多度、丰富度和多样性随土壤层的加深而下降, 具有明显的表聚性; 林冠开度与凋落物层的土壤节肢动物类群数量呈负相关; 甲螨亚目、中气门亚目和前气门亚目动物对光照的适应范围广; 膜翅目、鞘翅目幼虫、综合纲和伪蝎目动物具有明显的避光性; 土壤节肢动物类群的分布与林冠开度、土壤自然含水量、电导率和有机质关系密切。因此可以推论, 冰灾对车八岭山地常绿阔叶林冠层的破坏及土壤因子的变化会进一步影响土壤节肢动物群落的组成和分布。本项研究还表明, 土壤节肢动物群落能有效地表征它们所栖息的生态系统的特点, 可用于监测冰灾后森林恢复和演替动态。而双向聚类分析和典范对应分析对于揭示土壤节肢动物的空间异质性及其与环境因子的相互关系具有理想的效果。

Soil arthropod diversity following an ice storm in a montane evergreen broadleaved forest in Chebaling National Nature Reserve, China

In 2008, an ice storm caused extensive damage to the montane evergreen broadleaved forest in Chebaling National Nature Reserve, Guangdong Province, China. To assess the response of soil arthropod diversity and distribution to a gradient of canopy openness following the ice storm, 17 plots, each 400 m~2, were selected within a 2-ha permanent plot. Canopy openness was estimated with hemispherical photography in each plot. We sampled the litter layer and two soil layers (0-10 cm and 10-20 cm) to measure arthropod diversity and soil properties. We used two-way cluster analysis to group sites based on arthropod abundance in the litter layer. We also utilized canonical correspondence analysis to reveal relationships between soil arthropods in the 0-10 cm layer and four environmental variables, i.e., canopy openness (CO), soil organic matter (SOM), electric conductivity (EC), and natural moisture content (NMC). Results showed that abundance, richness and diversity of arthropod communities decreased with depth. A negative association was found between canopy openness and the number of arthropod groups in the litter layer; some arthropod taxa, such as the Oribatida, Prostigmata and Mesostigmata, were found in a wide range of light conditions, whereas the Hymenoptera, Symphyla, Pseudoscorpiones and Lepidoptera larvae may be photophobic. The distribution of arthropods in the 0-10 cm soil layer was closely related to CO, SOM, EC, and NMC on the first and second canonical axes. Hence, a series of changes in canopy structure and soil factors following the ice storm appeared to have affected the composition and distribution of soil arthropod communities. Findings from the present study also indicated that arthropod communities could serve as indicators to characterize the ecosystems they inhabit, thus being particularly suitable for monitoring forest regeneration and successional dynamics following ice storms.