中文摘要：

为了解青藏高原东缘亚高山/高山森林土壤线虫多样性,于2015年7月以该地区岷江冷杉原始林、混交林和次生林为研究对象,采用淘洗-过筛-蔗糖离心的方法分离土壤线虫,研究了3个海拔森林土壤线虫群落的组成与结构特征.结果表明：共捕获线虫37950条,隶属于20科27属,平均为4217条·100 g^-1干土,原始林以丝尾垫刃属为优势属,混交林和次生林以丝尾垫刃属和拟盘旋属为优势属,且优势属个体数量受林型的影响显著.原始林和次生林的优势营养类群为食真菌线虫,混交林则为食细菌线虫.土壤线虫c-p（colonizer-persister）类群c-p 1、c-p 2、c-p 3和c-p 4数量分别占总数的6.1%、51.1%、30.0%和12.7%.3个海拔森林土壤线虫的自由生活线虫成熟度指数（MI）、总成熟度指数（∑MI）和植物寄生线虫成熟度指数（PPI）随海拔增加而逐渐降低.土壤线虫通路指数（NCR）在混交林高于0.5,在原始林和次生林低于0.5.林型显著影响了土壤线虫成熟度和NCR指数,但林型、土层及二者的交互作用对多样性指数影响不显著.川西亚高山/高山不同森林土壤线虫的组成、营养结构和能流通道存在明显差异,为深入理解土壤线虫在该区森林土壤生态过程中的作用提供了参考.

英文摘要：

In order to understand the diversity of soil nematodes in the subalpine/alpine forests of the eastern Qinghai-Tibet Plateau,soil nematodes in the primary forest,mixed forest and secondary forest of Abies faxoniana were extracted by elutriation and sugar-centrifugation method in July 2015,and the composition and structure characteristics of soil nematode communities were studied in the three forests at different altitudes. A total of 37950 soil nematodes were collected,which belonged to20 families and 27 genera,and the mean density was 4217 ind·100 g^-1 dry soil. Filenchus was the dominant genus in the primary forest,and Filenchus and Pararotylenchus in the mixed forest and secondary forest,respectively. The individual number of each dominant genus was significantly affected by forest type. All nematode individuals were classified into the four trophic groups of bacterivores,fungivores,plant-parasites and omnivore-predators. The fungivores were dominant in the primary and secondary forest and the bacterivores in the mixed forest. The number of soil nematode c-p（ colonizer-persister） groups of c-p 1,c-p 2,c-p 3 and c-p 4 accounted for 6.1%,51.1%,30.0%and 12.7% of the total nematode abundance,respectively. The maturity index（ MI）,the total maturity index（ ∑MI） and the plant parasitic index（ PPI） of soil nematodes decreased gradually with the increase of altitude. The nematode channel ratio in the mixed forest was higher than 0. 5,but that in the primary forest and secondary forest was below 0.5. The forest type significantly affected the soil nematode maturity index and channel ratio,but the forest type,soil layer and their interaction had no significant effect on the diversity index. There were obvious diffe-rences in the composition,nutrient structure and energy flow channel of soil nematodes in the subalpine/alpine forests of western Sichuan,providing an important reference for understanding the function of soil nematodes in soil processes of this region.