不同演替阶段热带森林地表凋落物和土壤节肢动物群落特征

Characteristics of litter and soil arthropod communities at different successional stages of tropical forests

为了解不同演替阶段热带森林土壤节肢动物群落结构特征及其与地表凋落物的关系,2001年9月采用样线调查法对西双版纳23年次生林、35年次生林、季节雨林地表凋落物及其中的土壤节肢动物进行了调查。所获数据表明,地表凋落物数量(现存量干重)和质量(N和C/N)总体上表现为35年次生林最好,23年次生林次之;蜱螨目和弹尾目为3林地地表凋落物土壤节肢动物群落优势类群,膜翅目蚂蚁、马陆目、鞘翅目、双翅目和半翅目为常见类群。土壤节肢动物个体密度和个体相对密度均表现为35年次生林>季节雨林>23年次生林。群落的丰富度指数以季节雨林最高,多样性和均匀度指数显示为23年次生林最高,35年次生林的优势度指数最高,3林地土壤节肢动物群落类群组成相似性达到较好水平。相关分析表明,3种不同演替阶段热带森林土壤节肢动物个体密度与林地地表凋落物现存量呈正相关,而现存凋落物N元素储量与土壤节肢动物的相关性仅表现在23年次生林和季节雨林。研究认为,热带森林土壤节肢动物群落的发展与森林植被演替密切相关,其群落个体数量和多样性受森林地表凋落物数量、质量的调控,但其他环境因素如捕食效应、人为干扰等影响亦不可忽视。

In order to understand the relationship between soil arthropod community structure and floor litter at different successional stages of tropical forests, we surveyed the floor litter and the soil arthropods in a 23-year secondary forest, a 35-year secondary forest and a primary seasonal rainforest of Xishuangbanna, SW China in September 2001. Soil arthropods were extracted from the litter by Tullgren flannel method. The results showed that both the quantity and quality （N and C/N） of litter in the 35-year secondary forest were higher than those of the 23-year secondary forest and the seasonal rainforest. Acari and Collembola were dominant groups （〉 80%）, while ants, Coleoptera, Diptera, and Archaeognatha were common groups in the three forests. A higher individual density and relative individual density of soil arthropods were found in the 35-year secondary forest （10,067 ind./m^2 and 22.72 ind./g dry litter） compared to the seasonal rainforest （5,654 ind./m^2 and 18.44 ind./g dry litter） and 23-year secondary forest （2,881 ind./m^2 and 5,818 ind./g dry litter）. Pielou and Shannon-Wiener index of soil arthropod community were significantly higher in the 23-year secondary forest, while the richness （Margalef index） peaked in seasonal rainforest, and the dominance index （Simpson index） in 35-year secondary forest was the highest. The soil arthropod community composition was similar among the three forests. The individual density （ind./m^2） of soil arthropods were positively correlated with floor litter mass in three forests, and they were correlated with the standing stock of N of the floor litter in 23-year secondary forest, and the standing stock of N of the floor woody detritus in seasonal rainforest. We conclude that the development of soil arthropod community in tropical forests is closely related to vegetation succession, and the soil arthropod community structure can be regulated through plant litter during the forest succession process, but other environmental effects including predator effect and human disturbance should not be ignored.