海南蚂蟥岭流域土壤动物生态地理类群的调查,共获得土壤动物样本2036只,隶属3门7纲18个类目,说明蚂蟥岭流域土壤动物生态地理类群并不丰富。比较流域内5种不同土地利用方式中的土壤动物生态地理类群时发现:桉树人工林地对应尚未开发的原生灌木丛地,其土壤动物生态地理类群的Jaccard相似性系数仅为0.375;土壤动物类群与个体数量分别减少了53.33%与62.74%;土壤动物群落复杂性指数(C_j)下降了1.056;土壤动物群落密度-类群指数(DG)降低了4.620。研究结果还进一步表明:桉树人工林土壤动物多样性的减少,损伤了土壤生态系统中土壤动物分解者的生态功能,造成了桉树人工林种植地枯枝落叶滞留、物质循环功能受阻、肥力下降,流域内土壤生态系统日趋恶化。

Mahuangling watershed is located in Danzhou city in northwest Hainan province, China, facing to the Beibu Bay of the South China Sea, with a total area of about 52.7 km². In the 1990s incorrect forestation of eucalyptus resulted in large area of soil erosion of bare land, higher vulnerability of ecosystem and degradation of soil environment and decrease in biodiversity and other ecological problems in the watershed area. To reconstruct the ecosystem in this area, we carried out surveys on ecological geographical groups of soil fauna from December, 2005 to December, 2007. The results of our research can provide a scientific basis for the government to carry out ecosystem reconstruction as well as ecological and economic sustainable development in Mahuangling watershed. By comparison of eco-geographical groups of soil animals in eucalyptus plantations with those of other soil animals under different land use patterns, we deeply discussed the significance of soil animal diversity, focusing on the role of eco-geographical groups of soil animals in balancing of soil ecosystem. In our research, a total of 2036 samples of soil fauna under 3 Phylums, 7 classes, 18 groups were tested, of which Acarina and Collembola were the dominant groups, while Hymenoptera and Homoptera were common groups, and the remaining 14 groups were the rare ones. The result indicates that soil animal groups in Mahuangling watershed were not rich in type and quantity, and the ecosystem there was fragile. Compared to the corresponding virgin bush land, the Jaccard coefficient of eco-geographical groups of soil animal in the watershed was only 0.375; group number and population of soil animal decreased by 53.33% and 62.74% respectively; community complexity index (Cj) decreased by 1.056; soil fauna density-group index (DG) declined by 4.620. Further study showed that: 1) Eco-geographical groups of soil animal changed significantly in eucalyptus artificial woodland there with the large amount of biodiversity loss in the soil fauna. 2) The loss of soil animal diversity in eucalyptus plantations had done serious harm to the ecological function of the soil fauna in soil ecosystems in the area, making the forest litters hold up, material circulation system disrupted, nutrition substances not added, fertility declined, and the soil ecosystem continually deteriorated.