三江平原湿地岛状林土壤动物群落结构特征及影响因素

Characteristics and influencing factors of soil fauna community structure in an island forest in wetland,Sanjiang Plain

土壤动物是陆地生态系统结构的重要组成部分,对营养物质循环具有重要的作用。湿地土壤动物群落结构及影响因素研究,可为揭示湿地生物多样性及其功能提供基础资料。2005年生长季对三江平原湿地岛状林土壤动物进行了野外调查和室内分离、鉴定。结果表明,岛状林土壤动物隶属4门9纲24目,优势类群为线虫和膜翅目2类,常见类群7类,稀有类群15类;优势类群和常见类群都具有明显的季节动态变化。多样性分析表明,土壤动物的个体总数、类群数和丰富度指数最大值都出现在7月份,多样性指数和均匀度指数5月份最小,10月份最大,而优势度指数5月份最大,10月份最小。土壤动物垂直分布格局,除5月份外,其他各月都表现出明显的表聚性;5月份的逆向分布格局是由土壤动物的栖息特征和表层土壤温度特征共同决定的。土壤动物分布影响因素分析认为,在局域尺度内,土壤营养物质含量、容重和湿度是主要的影响因子。土壤动物功能类群可划分为腐食性、捕食性和植食性土壤动物,其数量比例关系整体上表现为腐食性土壤动物>捕食性土壤动物>植食性土壤动物。

Soil fauna is a main component of the terrestrial ecosystem and plays an important role in ecosystem material cycling. Investigation of soil fauna may provide foundamental data for studying biodiversity and functions in the wetland. By the field investigation and experimental measurement, the characteristics of soil fauna community structure in the island forest of wetland, Sanjiang Plain, northeastern China were studied during the growing seasons in 2005. Soil fauna extracted from the island forest could be sorted into four phyla, nine classes and 24 orders, including two dominant groups, seven common groups and 15 rare groups. The significant seasonal changes of the component and number of dominant groups and common groups can be found. The maximum values of the individual number, the group number and the rich index of soil fauna all appeared in July. The maximum and the minimum values of the diversity index and the evenness index appeared in October and May respectively, while those of the dominant index appeared in May and October. The vertical distribution of soil fauna indicated that the individuals and groups of soil fauna were mainly distributed in the surface of the soil, except in May. The reversed distribution structure in May was determined by the living characteristics of the soil fauna and the soil temperature structures. The analysis of the influencing factors showed that the content of nutrient material, soil bulk density and soil humidity determined the diversity and distribution pattern of soil fauna. The soil fauna functional groups can be divided into the saprophagous, carnivorous and phytophagous, showing the order of saprophagous 〉 carnivorous 〉 phytophagous according to the numbers of individuals.