Urbanization is one of the important factors leading to biodiversity loss and habitat fragmentation. As an important component of urban ecosystem, soil fauna community plays a key role in improving soil structure and fertility, and promoting material circulation of urban ecosystem. To investigate the distribution characteristics of medium and small-sized soil fauna community in green space and the mechanisms underlying their responses to environmental change during urbanization, we selected 27 green space plots with a gradient of urban, suburban, and rural areas in Nanchang City as study objects, and measured plant parameters, soil physicochemical properties, and distribution characteristics of soil fauna community in these plots. The results showed that a total of 1755 soil fauna individuals were captured, belonging to 2 phyla, 11 classes, and 16 orders. The dominant groups were Collembola, Parasiformes, and Acariformes, which accounting for 81.9% of total soil fauna community. The density, Shannon diversity index, and Simpson dominance index of soil fauna community were significantly higher in suburban area than those in rural area. In the green space of the urban-rural gradient, there were large structure variations in different trophic levels of medium and small-sized soil fauna community. Herbivores and macro-predators occupied the largest proportion in rural area, and less in other areas. Results of the redundancy analysis showed the crown diameter, forest density, soil total phosphorus contents were the main environmental factors affecting soil fauna community distribution, with interpretation rate of 55.9%, 14.0% and 9.7%, respectively. Results of the non-metric multidimensional scale analysis showed that there were variations in soil fauna community characteristics in green space of the urban-rural gradient, and that the aboveground vegetation was the dominant factor for this change. This study improved our understanding of urban ecosystem biodiversity in Nanchang, and provided basis for maintaining soil biodiversity and urban green space construction.
城市化是导致生物多样性下降及生境破碎的重要因素,土壤动物群落作为城市生态系统的重要组成部分,在改善土壤结构及肥力、促进生态系统物质循环等方面起着关键作用。为探究城市化进程中绿地中小型土壤动物群落分布特征及其对环境因子的响应机制,本研究沿南昌市城区-郊区-乡村梯度27个绿地样方为对象,调查样方内植物信息、土壤理化性质和中小型土壤动物群落分布特征。结果表明: 共捕获土壤动物1755头,隶属于2门11纲16目,其中,优势类群为弹尾纲、寄螨目和真螨目,个体数占比达81.9%;土壤动物密度、Shannon多样性指数和Simpson优势度指数均表现为郊区显著高于乡村。城乡梯度中绿地中小型土壤动物的不同营养级结构差异较大,植食者和大型捕食者在乡村占比最多,而在其他地区占比较小。冗余分析表明,冠幅、林分密度、土壤全磷是影响研究区绿地中小型土壤动物群落分布的主要环境因子,解释率分别为55.9%、14.0%、9.7%。非度量多维尺度分析说明,城乡梯度绿地中小型土壤动物群落特征呈现一定差异,地上植被因子是土壤动物群落特征差异的主导因素。本研究补充了南昌城市生态系统的研究体系,为维持土壤动物多样性和城市绿地建设规划提供决策依据。.
Keywords: community characteristics; environmental factor; soil fauna; urban and rural green space.