大中型土壤动物对内陆盐沼沿退化序列环境的指示研究

Response of soil large-and mesofauna to edaphic characterization along vegetation second succession sequence of inland saline marsh

通过野外定位观测和室内分析,分析了扎龙盐沼湿地土壤大中型土壤动物分布格局及其对湿地退化的响应。结果表明,大中型土壤动物对研究区典型湿地退化序列的土壤环境表现出明显的响应。沼泽表层具有最高的个体密度(达728只/m2),羊草草原表层的类群数最高(具有10个科的土壤动物),也具有最高的Shannon-Wiener指数。裸地无论是土壤动物的个体密度还是种群密度都显著低于其他生境中的土壤动物。裸地的优势类群为鞘翅目、双翅目以及弹尾目。羊草草原的大中型土壤动物以膜翅目、等翅目和双翅目幼虫为优势种群。拂子茅苔草区优势种群为膜翅目和双翅目幼虫。芦苇沼泽以环口螺科和双翅目幼虫为优势种群。典范对应分析表明,影响土壤动物的环境因子可以分为两大类:以湿度和有机质为代表的指标,可以反映湿地湿润和丰富腐殖质的特征;以碱化度为代表的另一类指标,可以反映该区域土壤盐渍化程度。保护湿地植被对于维护湿地土壤动物的多样性特征具有十分重要的意义。

The spatial distrubution patterns of soil large- and mesofauna along typical vegation second succession sequences of inland marsh were examined in a field experiment. Within the study plots, at 1500 m distance there was an obvious response to the soil sequence by the soil fauna. In reed marsh the highest individual density was 728 individuals/m2 whereas it was a mere 8 individuals/mz in bareland. Nevertheless, the largest species density value and Shannon--Wiener index were in the surface horizon of chinese grassland, with 10 species/m2 and 1.75 respectively, versus 4 speeies/m2 and 0.91 in bareland. Dominant species in bareland and grassland were Coleoptera, Diptera and Collembola, but were Hymenoptera and Diptera larvae in grassland, and mead- ow, but Cyclphoridae and Diptera larvae in reed marsh. A canonical correspondence analysis was applied to examine the response of soil fauna to soil properties of typical vegetation second succession sequences. Two types of environmental factors affecting soil fauna species living patterns were found, high moisture and humus content resulted in a richness of individual density and diversity of soil microfauna. The other factor is salinity, and exchangeable sodium percentage in particular, which restrain the activity of soil microfauna. Protection and restoration vegetation in inland saline marsh regions would help wetland conservation and soil fauna biodiversity.