Research Of Soil Fauna Community In Different Urban Forests In Shanghai

Soil fauna is an important composition of urban forest ecosystem and can play an active and effective role in promoting for the circulation of materials, energy flow, information transfer of the whole ecosystem. All the time urban greening construction pay attention to the effect of plant on the ground. The soil environment would not be defended and governed until soil suffered obvious pollution and damage. In fact using the ecological functions of soil ecosystem in a rational way could quickly improve the functionality and stability of the whole urban ecosystem. So there is important practical significance for exploring the ecological relationship between aboveground and underground by researching the soil fauna community characteristics in different urban forests.Four kinds of urban forests (Cinnamomum camphora forest, Platanus forest, Metasequoia glyptostroboides forest, near-nature forest) were chosen as the study plots and soil fauna was sampled and investigated and environment factors were measured in April 2014, July 2014, October 2014 and January 2015 (respectively representing spring, summer, autumn, winter). The soil fauna included soil fauna in litter, macro-soil fauna in soil, meso-and micro-soil fauna in soil which included dry type meso-and micro-soil fauna and wet type meso-and micro-soil fauna. The environment factors included boimass, organic carbon, total nitrogen, total phosphorus of litter and temperature, water content, bulk density, pH, organic matter, total nitrogen, total phosphorus of soil. Then the soil fauna community characteristics of urban forest and the relationship between soil and environment were analysed. The main conclusions are as follows:1. A total of 9754 soil fauna individuals which belong to 5 phyla,14 classes and 29 groups were collected. The dominant groups were Nematoda and Arcarina, and the common groups were Collembola, Enchytraeidae, Hymenoptera, Opisthopora, Rotatoria. In litter soil fauna community, the dominant groups were Acarina and Collembola and the common groups were Diptera larvae, Opisthopora, Enchytraeidae, Isopoda. In macro-soil fauna community, the dominant groups were Opisthopora and Diplopoda and the common groups were Hymenoptera, Araneae, Scolopendromorpha, Chilopoda, Coleoptera, Coleoptera larvae and Hemiptera. In meso-and micro-soil fauna community, the dominant groups were Nematoda and Arcarina and the common groups were Collembola, Enchytraeidae, Hymenoptera, Rotatoria, Opisthopora. The number of dominant and commom groups in macro-soil fauna community was bigest. As the ratio of dominant in litter and meso-and micro-soil fauna community was very high, the number of dominant and commom groups was small.2. As soil was deepened, the density and group number of dry type soil fauna reduced. But the group number was epual between 10-15cm layer and 15-20cm layer. The group number of litter soil fauna was highest and the density was less than 0-5cm layer. Special species appeared in both litter and soil layer. As soil was deepened, the density and group number of wet type soil fauna also reduced and the distribution in every layers was relatively homogeneous. In litter soil fauna community, the density of spring was highest and the autumn was lowest; the group number of spring and summer were highest and the winter was lowest; diversity level of summer was highest and winter was lowest. In macro-soil fauna community, the density of summer was highest and the winter was lowest; the group number of summer was highest and the spring and winter were lowest; diversity level of summer was highest and winter was lowest. In meso-and micro-soil fauna community, the density of autumn was highest and the summer was lowest; the group number of autumn was highest and the spring was lowest; diversity level of summer was highest and summer was lowest.3. In litter soil fauna communities of different urban forests, the dominant group of Cinnamomum camphora forest and near-nature forest was Acarina and the dominant group of Platanus forest and Metasequoia glyptostroboides forest were Acarina and Collembola. The density of Platanus forest was highest and the Metasequoia glyptostroboides forest was lowest. In macro-soil fauna communities of different urban forests, the dominant groups of Cinnamomum camphora forest and Platanus forest were Opisthopora and Diplopoda, the dominant groups of Metasequoia glyptostroboides forest were Opisthopora, Diplopoda and Scolopendromorpha; the dominant groups of near-nature forest were Opisthopora, Diplopoda and Hymenoptera. The density of Cinnamomum camphora forest was highest and the Metasequoia glyptostroboides forest was lowest. In meso-and micro-soil fauna communities of different urban forests, the dominant groups of Platanus forest, Metasequoia glyptostroboides forest, near-nature forest were Nematoda and Arcarina, the dominant groups of Cinnamomum camphora forest were Nematoda, Arcarina and Collembola. The density of Metasequoia glyptostroboides forest was highest and Cinnamomum camphora forest was lowest. Besides, the common groups of different types of soil fauna in different urban forest were different.4. In the aspect of soil fauna vertical distribution in different urban forest, the density of dry soil fauna which were in soil reduced as the soil depth increased, but the groups of each forest had different degree of reverse vertical distribution. The dengsities of soil fauna in litter of most forests awere less than the 0-5cm layer. Only the density of soil fauna in litter in Cinnamomum camphora forest was larger than 0-5cm layer which was relative to the abundant litter. The density of wet soil fauna reduced as the soil depth increased as a whole, but reverse vertical distribution appeared in Platanus forest and near-nature forest. The groups of wet soil fauna were less and reduced as the soil depth increased as a whole, but reverse vertical distribution appeared in Platanus forest and near-nature forest. In litter soil fauna community, the highest densities of Cinnamomum camphora forest and Platanus forest appeared in spring and lowest in winter. The highest densities of Metasequoia glyptostroboides forest appeared in summer and lowest in spring. In macro-soil fauna community, the highest densities of Cinnamomum camphora forest and Metasequoia glyptostroboides forest appeared in summer and lowest in winter. The highest densities of Platanus forest and near-nature forest appeared in summer and lowest in spring. The higher groups of each forest appeared in summer and autumn. In meso-and micro-soil fauna community, The higher densities of Cinnamomum camphora forest, Metasequoia glyptostroboides forest and near-nature forest appeared in autumn and winter and lower in spring and summer. Besides the highest groups appeared in autumn. The highest dengsity of Platanus forest appeared in spring and lowest in summer.5. The density-group index of litter soil fauna in Platanus forest was much higer than other forest plots which showed high diversity level. The density-group index of near-nature forest was lowest and the diversity level was worse. The Jaccard similarity coefficients between near-nature forest and other forest were all lower which showed big difference. The density-group indice of macro-soil fauna in Cinnamomum camphora forest and Platanus forest were higher, but other indice were lower. The density-group indice of near-nature forest was close to above two forests and other indice showed high diversity level. So the diversity level of macro-soil fauna in near-nature forest was highest and Metasequoia glyptostroboides forest was lowest. The density-group index and Margalef abundance index of meso-and micro-soil fauna in near-nature forest were highest and showed highest diversity level. The lowest diversity level appeared in Metasequoia glyptostroboides forest.6. Through analysing many environment factors in different urban forests, the difference of litter quality among forests was small, but the soil quality was bigger. The soil of Metasequoia glyptostroboides forest was loose and had more nutrient. The soil quality of near-nature forest was worst and Cinnamomum camphora forest and Platanus forest were in the middle of the above two forests. It could be inferred through redundancy analysis(RDA) that temperature, water content and other outside factors are the main environmental factors which influenced litter soil fauna community structure in urbon forest. The result showed that the positive corrections occurred between the individual number of Enchytraeidae and soil organic matter and water content, that the positive corrections occurred between the individual number of Collembola, Isopoda Thysanoptera, Hemiptera and temperature, that the positive corrections occurred between the individual number of Lepidoptera larvae, Diplopoda and litter biomass and pH. Besides soil bulk density, water content, organic matter, total nitrogen, total phosphorus are the main environmental factors which influenced soil meso-and micro-fauna community structure in urbon forest.The result showed that the positive corrections occurred between the individual number of Rotatoria, Diptera larvae and water content, that the positive corrections occurred between the individual number of Acarina, Enchytraeidae and soil organic matter and total nitrogen, that the positive corrections occurred between the individual number of Isopoda, Collembola, Hymenoptera and pH, that the positive corrections occurred between the individual number of Thysanoptera, Psocoptera and temperature, that the negative corrections occurred between the individual number of most groups and soil bulk density. As a whole, the plant aboveground and soil quality underground could greatly influence soil fauna. In future, the construction of urban forest should consider as much factors as possible to improve the whole ecological benefits.