Soil Nematode Community Response To Vegetation Restoration In Shimenshan In Dalian

The soil sample of different vegetation restoration practices were surveyed from September in 2007 to August in 2008 in Shimenshan in Dalian. The nematodes were collected from the soil using elutriate-sieving-shallow pan method. The species richness, abundance, diversity index and ecological index were analyzed under different vegetation, seasonal and vertical distribution.A total of 8577 soil nematodes were collected, belonging to 2 classes, 7 orders, 26 families and 43 genera. The nemotade of plant parasites were 6 genera, the nemotade of bacterivores were 20 genera, the nemotade of fungivores were 5 genera and the nemotade of omnivores-predators were 12 genera. The nemotade of bacterivores was the dominant taxa in this area, followed by the nemotade of omnivores-predators, it showed the bacterial was higher taxa in soil ecosystem in this area, it was decomposed by bacteria mainly, and the ecosystem was stable.There were 2970 soil nematodes in mixed forest, 865 in broad-leaved forest and 2742 in coniferous forest. The dominant genera were Plectus, Filenchus, Eudorylaimus and Helicotylenchus, the Plectus was the same dominant genus in three kinds of vegetation. The individual density was 4.77 inds. per gram dry soil, which was 6.60 inds. per gram dry soil in 0-10cm layers while 4.08 inds. per gram dry soil in 10-20cm layers, the number of nemotade in 0-10cm layers was 1.62 times that in 10-20cm layers. The soil nematode fluctuated significantly with season, the soil nematode in autumn is significantly more than that in summer and in spring.The results indicated that Shannon-Wiener index, Pielou index, Margalef index and Trophic diversity index were used in analyzing the diversity of nematode community, ranking Cc>Pm>Clc, while Simpson index ranking Pm>Clc>Cc. The value of f/b, MI index, PPI index, MMI index, MI2-5 index, SI index and EI index were used in analyzing the characteristics of the functional structure of the nematode communities, ranking Cc>Pm>Clc, while PPI/MI value ranking Clc>Pm>Cc. It showed that the Clc was disturbed significantly, while WI index, BI index and NCR index ranking Pm>Cc>Clc, it showed that the fungi channel was main in different restoration stages of vegetation, while the coniferous forest is obvious. Moreover, EI index, SI index were less than 50 in different restoration stages of vegetation, it showed that the soil condition was poor and the degree of disturbed was high, which has stressed on the environment, the food webs was degenerating.Soil physical and chemical characters were correlated significantly with the number of nematodes, the number of genera, trophic groups and ecological indices. Thus, we conclude that the dynamics of nematodes are an important biological indicator for vegetation restoration.