长白山北坡土壤线虫的群落结构特征

对长白山北坡不同海拔（7262200m）的阔叶红松林、红松云冷杉混交林、暗针叶林、岳桦林和高山苔原中土壤线虫进行了研究。在2001、2002年春天，分别在样地的枯枝落叶层、不同深度的表层土（0-5、5-10、10．20cm）掘取土壤样品进行分析。土壤线虫群落中共有27个科，60个属，其中Plectus和Tylenchus两属为优势属，优势属线虫主要分布在枯枝落叶层中。土壤线虫数量与土壤含水量显著相关（r=0．357；p〈0.01）。在不同深度和植被群落中丰富度最大的是食细菌类群线虫。土壤线虫总数和营养类群在不同土壤深度中差异显著（p〈0.05）；食真菌类群／食细菌类群（F／B）和食真菌类群数量与食细菌类群数量之和与植食类群数量之比（WI）在不同深度也存在明显差异（P〈0．05）。总之，土壤水分是影响土壤线虫密度和营养组成的最主要因素之一，海拔梯度并未显著影响土壤线虫的生态指标，如营养多样性和Shannon指数。

Soil nematode community structure on the northern slope of Changbai Mountain,Northeast China

Soil nematode communities were investigated in the Changbai Mountain in Broad-leaved Korean Pine forest, Korean Pine and spruce-fix mixed forest, Dark Coniferous forest, Erman’s birch forest and Alpine tundra along different altitude gradients from 762 m to 2 200 m a.s.l. Soil animal samples were collected from the litter layer and the soil depth of 0–5 cm, 5–10 cm and 10–20 cm at each site in the spring of 2001 and 2002. In total 27 nematode families and 60 genera were observed. The dominant genera were Plectus Bastian and Tylenchus Bastian and most of them live in litter layer. The total number of soil nematode was significantly correlated with soil moisture (r=0.357; p<0.01). Nematodes were classified in bacterivores, fungivores, plant parasites, omnivores-predators, and omnivores according to known feeding habitats or stoma and esophageal morphology. Species richness of fungivorous nematode was higher than others in different vegetation communities and soil depths. The total number of soil nematode and trophic groups varied significantly (p<0.05) in response to different soil depths. The fungivore/bacterivore ratio (F/B) and the ratio of (fungivores + bacterivores)/plant-parasites (WI) also changed significantly (p<0.05) in different soil depths. In conclusion, soil moisture is proved to be one of the most important variables affecting nematode density and trophic composition, and the altitude gradient does not significantly affect the ecological indices of soil nematode such as trophic diversity (TD) and the Shannon index (H′).