基于土壤线虫群落分析的油页岩废渣地不同植被类型恢复过程中的土壤食物网能流状况

土壤健康与生态系统功能是当前生态学研究的重要课题。土壤线虫是评价生态系统健康状况的指示生物,特别是用于评价土壤污染和恢复的过程。对广东茂名油页岩废渣场人工实施不同生态恢复改造状况下的土壤线虫属的重要值及土壤线虫反映的土壤食物网能量通道进行了分析,以通过污染地土壤食物网内的能量流动状况反映种植不同植物物种相同时间后的土壤养分与健康状况。结果表明在废渣场种植不同植物物种约8年后,乌墨林和大叶相思林下土壤线虫类群数(属)分别为54和45,重要值最高的是食细菌的棱咽属(Prismatolaimus)和拟丽突属(Acrobeloides);而红荷林和荒草地的线虫类群数分别为41和38,重要值最高的是杂食性的真矛线属(Eudorylaimus);废渣地线虫属的数量最少,仅为34个,重要值最高的是食真菌的丝尾垫刃属(Filenchus)和滑刃属(Aphelenchoides)。食物网能流分析表明:细菌能流通道比重最高的是大叶相思林和乌墨林,而真菌能流通道比重最高的是废渣地,红荷林和荒草地居中,各样地植物能流通道比重都比较小,仅为2%—10%之间。总体来讲,在有植被覆盖的生态系统,养分周转更快,特别是乌墨和大叶相思林,而无植被的废渣地,土壤养分周转速率倾向于更慢的真菌能流通道,这表明在养分条件比较差的情况下,真菌通道的食物网可能会起更大的作用。研究还说明了在油页岩废弃地恢复过程中,植物资源的输入不仅仅刺激植物能流通道,同时也会刺激细菌和真菌能流通道,植被是土壤线虫群落发展的主要驱动力。

Energy flow analysis of soil food webs based on soil nematode communities:a case study from an oil shale mined land afforested with different pioneer tree species

Soil health and ecosystem functioning are important topics in current ecological research. Soil nematodes are effective bio-indicators of ecosystem health, especially when evaluating soil pollution and restoration progress. In this study, soil nematode assemblages were measured at three 8-year-old plantations:Syzygium cumini, Acacia auriculiformis, Schima wallichii; a natural restored grassland, an oil shale waste (as the non-vegetated control) at an oil shale mined land in Maoming of Guangdong, China. Importance values of soil nematodes and energy flow analysis based on nematode assemblages were used to evaluate the status of soil health and nutrient cycling during the recovery process. The results showed that there were 54 and 45 genera of nematodes in the S. cumini plantation and in the A. auriculiformis plantations, respectively, in which the bacterivorous nematodes of Prismatolaimus and Acrobeloides had the highest importance value. There were 41 and 38 genera of nematodes in the S. wallichii plantation and in the grassland, respectively, in which the omnivorous nematodes of Eudorylaimus had the highest importance value. There were only 34 genera of nematodes in the "oil shale waste" site, in which the fungivorous nematodes of Filenchus and Aphelenchoides had the highest importance value. Energy flow analysis indicated a greater proportion of bacterial energy flow in S. cumini and A. Auriculiformis plantations, and the highest proportion of fungal energy flow in the oil shale waste site. Compared with the bacterial and fungal energy flow channels, the proportion of plant energy flow channel (i.e. energy flow from roots to herbivorious nematodes, then to higher trophic levels) was as low as 2%-10% across all the studied sites. Overall, the bacterial energy flow was more dominant in vegetated ecosystems, especially in the S. cumini plantation and in the A. auriculiformis plantations, implying faster nutrient turnover rates; whereas the fungal energy flow was more dominant in the non-vegetated ecosystems, implying slower nutrient turnover rates. This study also indicated that vegetation is the primary driver of the development of soil nematode communities.