关键词: 土壤线虫, 急尖长苞冷杉, 生物多样性, 群落结构, 西藏

Abstract:

In order to understand nematode community characteristics and diversity in the soil ecology system in clear cutting slash of fir forests in sub-alpine zone in southeast Tibet, we investigated the nematode community structures in 0-30 cm soil layers and analyze the community composition and characteristics by collecting data of nematode density, genus number, diversity and nutrition index. A total of 14 496 nematodes were isolated using the Shallow dish method and they belonged to 2 classes, 6 families, 65 genera. The average density was 989 nematodes·(100 g)^-1 dry soil; and approximate 48.6% of the nematodes distributed in top soil (0-5 cm), obviously gathering in the top soil. The dominant genera were Boleodorus and Helicotylenchus. Herbivorous ones were the major nutritional communities. Bacterivorous types were a major part of non-herbivorous nematodes. Soil organic matters were mainly decomposed by bacteria. Statistics analysis showed that the nematode diversity and evenness in winter were higher than that in spring, but there was no significant seasonal variation in SR index. In different soil layers, H', SR values decreased with the depth; and J', λ values increased with the depth. There were obvious differences in the 4 indexes between 0-5 cm and 25-30 cm soil layers (P<0.05). It is concluded that characteristics of soil nematode community is a potential indicator for the forest ecosystem succession process and the interference degree in clear cutting slash of fir forests in southeast Tibet.

Key words: soil nematode, Abies georgei var .smithii, biological diversity, community structure, Tibet