A comparison of soil nematode community structure and environmental factors along fen-bush-forest succession in a peatland, northeastern China

Soil nematodes are one of the key components of the soil organism community and one of the major players in soil functions. The lack of knowledge in the structure and function of the soil nematode community in peatland succession needs to be given more attention. The soil nematode community structure including abundance, richness, diversity, and many ecological indices as well as soil factors were measured and compared in three different habitats along a natural fen-bush-forest successional sere in a peatland, northeastern China. A total of 36 soil nematode genera were identified, and multivariate analysis separated the three habitat samples from each other. The abundance, richness, and diversity increased from fen to forest. The dominant trophic group changed from bacterivores in the fen and bush to bacterivores and plant parasites in the forest. According to the RDA analysis with soil properties, it was found that the community structure of soil nematodes in the fen was more affected by the soil nitrogen content, by soil C/N ratio in the bush, and by soil phosphorus content and soil pH in the forest, respectively. Though the nematode channel ratio in three habitats indicated that the energy flow in the soil micro-food web was all dominated by bacterial channels, the trophic group with the highest metabolic footprints was bacterivores in the bush but omnivore-predators (Op) in fen and forest. This study demonstrated that the community composition and trophic structure of soil nematodes as well as the predominant environmental factors significantly changed along fen-bush-forest successional sere. The genera Udonchus and Eudorylaimus may have the potentials to be indicators of vegetation succession and soil microbe food web in fens.