科研之友
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摘要
Restinga da Marambaia is an emerged sandbar located between Sepetiba Bay and the South Atlantic Ocean in the state of Rio de Janeiro on the southeastern coast of Brazil. This sandbar is occupied by a set of physiognomically distinct plant communities under marine and fluviomarine influences. The objective of this study was to investigate the nematode community structure of Restinga da Marambaia and to characterize the relationships between nematodes and soil properties in different vegetation community types. Composite samples, of 20 soil core at depths of 0-10 and 10-20 cm, were collected in three areas (250 m(2)) in each of the three plant physiognomy types: a closed herbaceous floodplain community (C), a shrub dune thicket community (D) and ridge forest community (F). Total and relative abundance were calculated, and the nematode trophic groups were described. A total of 44 nematode taxa were identified. The total average density of nematodes (ind./100 ml(-1) soil) in F was greater than in C, which was greater than in D (p < 0.05), and was highest in samples obtained from the shallower depth. Phytophagous nematodes made up the main trophic component of the soil nematode community in Restinga da Marambaia, accounting for 42.8%, bacteriophagous nematodes were the second most abundant trophic component at 31.4%, and mycophagous nematodes accounted for 9.8% of the total. Phytophagous nematodes were positively correlated with organic matter and Mg (p < 0.05), whereas predators and omnivores were associated with Mg, K, organic carbon and P (p < 0.05). There were positive correlations between omnivorous and phytophagous nematodes, between predators and omnivores and between bacteriophagous and mycophagous nematodes (p < 0.05). Principal component analysis based on the nematodes genera and trophic groups and chemical characteristics of the soil explained 78.5% and 57.8% of the total variability respectively. Hemicycliophora was the indicator genus for the stabilized sand dune system at the Restinga da Marambaia. These results make it possible to distinguish the different plant communities based on the genus and feeding habits of the soil nematode community. Each plant succession stage has its own nematode community that reflects both its biotic characteristics (plant coverage and soil microbial community) and its abiotic characteristics (the physical-chemical properties of the soil).
- 出版日期2011-12
