[Effects of Different Land Use Typess on the Molecular Ecological Network of Soil Bacteria].

The bacterial community composition in four land-use types was determined and the visualized bacterial network was constructed by 16S rDNA Illumina MiSeq high-throughput sequencing technology and a molecular ecological network method. The results show that Proteobacteria, Acidobacteria, Bacteroidetes, Chloroflexi, Actinobacteria, Planctomycetes, Verrucomicrobia, Cyanobacteria, Gemmatimonadetes, Firmicutes, Nitrospirae, and Chlorobi are the main bacteria in this area. The number of nodes of urban green land, paddy field, and dry field bacteria networks is higher, and that of natural forest land is lower. The number of connections and average connectivity of dry fields are the highest; following are those of urban green land and paddy field, and those of natural forest land are the lowest. The four bacterial networks are dominated by positive correlation, and the ratio of competition relationship is TL > LD > HT > ST. The average network path and modularity of the soil bacteria networks of paddy field and dry land are small, while the average connectivity and clustering coefficient are higher. Some flora of Acidobacteria, Firmicutes, and Proteobacteria play an important role in the soil bacterial network in this area. The classification of operational taxonomic units is different among the key nodes of different bacterial molecular ecological networks, and there is almost no overlap. The relative abundance of bacteria of some key nodes in the four bacterial networks is low (<1%), and these are not the main bacteria in this area. The soil microflora in dry land are mainly affected by TP (P<0.05), the soil microflora in paddy field were mainly affected by clay, silt, and water content (P<0.05), and that in natural forest land and urban green land were mainly affected by C/N (P<0.05). The above results show that different land-use patterns lead to changes in soil physical and chemical properties and the interaction between soil bacteria species. The bacterial network of dry land soil is larger and the relationship between species is more complex. The bacteria in different land-use types are mainly cooperative, and the competition is weak. Compared with other land-use types, there is stronger competition between the bacteria in natural forest soil. The soil bacteria in paddy field and dry land are the most sensitive to the external environment, respond more quickly, and the community structure is easier to change. The response of soil bacteria in natural forest land and urban green land is slower, and the disturbance of environmental factors does not affect the whole bacterial ecological network in a short time, and thus the community structure is more stable. Some bacteria have the phenomenon of species role transformation between networks. The abundance and community distribution of microorganisms cannot indicate the strength of their connectivity between network nodes; low-abundance bacteria in soil play an important role in the construction of bacterial networks.

[Dynamic evaluation of ecosystem integrity in Greater Khingan Range area, China.] / å¤§å ´å®‰å²­åœ°åŒºç”Ÿæ€ç³»ç»Ÿå®Œæ•´æ€§åŠ¨æ€è¯„ä»·.

The impacts of global climate change and human disturbance on terrestrial ecosystems has been expanding in intensity and scope. However, there is a lack of evaluation methods for large-scale heterogeneous landscape systems during ecosystem integrity assessment. From the perspective of landscape ecology, this study chose the indicators of landscape structure and landscape stability to comprehensively evaluate regional landscape change characteristics and ecosystem integrity dynamics of Greater Hinggan Mountains area using land use data and NPP data of 2005, 2010 and 2015 with GIS data processing and analysis platform. The results showed that Greater Hinggan Mountains area was dominated by forest land. The dominance degree of forest land was stable at 64.9%, which was much higher than the grassland that with the second dominance. The landscape diversity index was 0.59 in all three periods, accounting for 42.4% of the maximum value of landscape diversity index. Such a result indicated that the landscape resistance was stable in this area. From the view of landscape biomass, farmland and residential land had increased year by year, while forest area had decreased year by year, indicating that the effects of human disturbance on Greater Hinggan Mountains area were increasing.

[Pollution Characteristics and Source Apportionment of Polycyclic Aromatic Hydrocarbons in Soils of Shenyang North New Area].

Topsoil (0-20 cm) samples (n=101) in 5 different land use types in Shenyang North New Area (SNNA), Shenyang, China were collected using the uniform grid layout method to investigate the spatial distribution characteristics, composition spectrum, and source analysis of 16 polycyclic aromatic hydrocarbons (PAHs) listed as priority pollutants by the Environmental Protection Agency of the United States. Results showed that the total concentration of the 16 PAHs (ΣPAHs) in soils of SNNA ranged from 123.7 µg·kg-1 to 932.5 µg·kg-1. The PAH components were mainly dominated by 3-ring and 4-ring PAHs, of which the proportion of 3-ring PAHs was the highest. The spatial distribution of the ΣPAHs concentration was obvious, showing a decreasing tendency from south to north and from east to west. In the five soil types, the average concentrations of the ΣPAHs were relatively higher in the urban green space and the artificial forest, followed by the vegetable land, while the total PAH concentrations in paddy fields and corn fields were relatively lower and had no obvious spatial distribution differences. Source apportionment results studied using characteristic ratio analysis and factor analysis/multivariate linear regression showed that the main sources of PAHs in the topsoil of SNNA were mixed sources. Industrial coal combustion and motor vehicle exhaust were the main PAH contributors, with a combined contribution rate of 79.6%. The oil spill and coke oven contribution rate was about 16.2%, and the biomass fuel combustion was about 4.2%.

[Dynamics of natural capital in Shenyang based on improved three-dimensional ecological footprint]. / 基于改进三维生态足迹的沈阳市自然资本动态.

Natural capital trends of Shenyang from 1995 to 2014 were analyzed using improved three-dimensional ecological footprint model. The results showed that, from 1995 to 2014, the ecological carrying capacity per capita of Shenyang fluctuated within a narrow range generally; the per capital ecological footprint, ecological deficit, footprint size and the footprint depth per capita increased along a wave-like curve. The changing rates of footprint size and depth tended to stabilize gradually. The way of natural capital utilization of cultivated land changed from capital flow in 2004 to capital stock, the capital stock replaced capital flow and became a source to meet the need of na-tural resources in the regional cultivated land, the use ratios of stock-flows increased gradually. The capital flow had been used by woodland and the occupancy rates of capital flows remained unchanged. The capital stock had been used by grassland and water, and the use ratios of stock-flows increased gradually. The development of Shenyang was in an unsustainable state. Coordinating the relationship between natural capital stock consumption and the utilization of stock-flows was one of the key ways to realize the sustainable development of Shenyang. Developing new resource, rationally planning the land and improving land utilization should be to reduce the consumption of natural capi-tal, at the same time, the protection of ecological environment should be to achieve sustainable development.

[Optimization of ecological footprint model based on environmental pollution accounts: a case study in Pearl River Delta urban agglomeration].

To solve the problem of ignoring the calculation of environment pollution in traditional ecological footprint model accounts, this paper put forward an optimized ecological footprint (EF) model, taking the pollution footprint into account. In the meantime, the environmental capacity's calculation was also added into the system of ecological capacity, and further used to do ecological assessment of Pearl River Delta urban agglomeration in 2005. The results showed a perfect inosculation between the ecological footprint and the development characteristics and spatial pattern, and illustrated that the optimized EF model could make a better orientation for the environmental pollution in the system, and also, could roundly explain the environmental effects of human activity. The optimization of ecological footprint model had better integrality and objectivity than traditional models.