Optimization of Urban Ecological Network Based on MSPA-MCR Model: A Case Study of Jingzhou City

As a key carrier supporting urban ecological health and living environment quality,urban ecological network is a key focus of current urban green space research.Jingzhou City of Hubei Province is taken as the research object.Relying on GIS technology platform,MSPA method is used to analyze the landscape pattern of Jingzhou City.On this basis,the landscape connectivity evaluation method is used to accurately identify and extract the source areas with important ecological value in Jingzhou City.Then,the normalization method and weighting method are combined to create a resistance factor evaluation system to construct the resistance surface.Based on the MCR model,the ecological network of Jingzhou City is successfully constructed,and targeted spatial optimization strategies and development suggestions are proposed.

Construction of Ecological Network for Urban Green Space System from the Perspective of Landscape Ecology:A Case Study of Wanzhou District, Chongqing Municipality

Green spaces in Wanzhou District, Chongqing Municipality were not closely linked and failed to form an integrated ecological network, this paper analyzed and assessed current situation of green spaces in the local area from the perspective of landscape ecology, and then established the landscape ecology-oriented ecological network construction, restructured green paces in Wanzhou District using the landscape composition of "patch–corridor–matrix", and connected the scattered green patches using green corridors, so as to form a reasonable ecological network of green spaces.

Network Approaches to Substance Use and HIV/Hepatitis C Risk among Homeless Youth and Adult Women in the United States: A Review

During the United States economic recession of 2008-2011, the number of homeless and unstably housed people in the United States increased considerably. Homeless adult women and unaccompanied homeless youth make up the most marginal segments of this population. Because homeless individuals are a hard to reach population, research into these marginal groups has traditionally been a challenge for researchers interested in substance abuse and mental health. Network analysis techniques and research strategies offer means for dealing with traditional challenges such as missing sampling frames, variation in definitions of homelessness and study inclusion criteria, and enumeration/population estimation procedures. This review focuses on the need for, and recent steps toward, solutions to these problems that involve network science strategies for data collection and analysis. Research from a range of fields is reviewed and organized according to a new stress process framework aimed at understanding how homeless status interacts with issues related to substance abuse and mental health. Three types of network innovation are discussed: network scale-up methods, a network ecology approach to social resources, and the integration of network variables into the proposed stress process model of homeless substance abuse and mental health. By employing network methods and integrating these methods into existing models, research on homeless and unstably housed women and unaccompanied young people can address existing research challenges and promote more effective intervention and care programs.

Ecological networks and greenways in Europe: reasoning and concepts

The paper gives an overview of approaches towards ecological networks throughout Europe. It does not intend to present a complete picture, but to highlight common developments within countries and regions and show common principles and differences between countries and regions that have to be taken into account when developing a joint European initiative. Countries or regions that have not been included can be active in the same way, but information was not accessible to the authors for different reasons. This overview shows the comparable trends in decline of landscapes and the diversity in approaches to biodiversity conservation and nature conservation planning. Understanding the differences and common issues are of utmost importance to generalise common principles and to understand the way neighbours and other European partners approach problems.

Strategic Ecological Network Competition in Emerging Markets:Theory and Case Analysis of A GPS Vehicle Navigation Firm

Using the case study methodology, firm＇s competition behavior in strategic network and strategic ecosystems are analyzed. With the ecology view, there is consistency between strategic network and strategic ecosystem. Enterprise should pursue for suitable ecological niche to hold a strategic competitive power.

The Synergism between Methanogens and Methanotrophs and the Nature of their Contributions to the Seasonal Variation of Methane Fluxes in a Wetland:The Case of Dajiuhu Subalpine Peatland

Wetland ecosystems are the most important natural methane(CH_(4))sources,whose fluxes periodically fluctuate.Methanogens(methane producers)and methanotrophs(methane consumers)are considered key factors affecting CH_(4)fluxes in wetlands.However,the symbiotic relationship between methanogens and methanotrophs remains unclear.To help close this research gap,we collected and analyzed samples from four soil depths in the Dajiuhu subalpine peatland in January,April,July,and October 2019 and acquired seasonal methane flux data from an eddy covariance(EC)system,and investigated relationships.A phylogenetic molecular ecological networks(pMENs)analysis was used to identify keystone species and the seasonal variations of the co-occurrence patterns of methanogenic and methanotrophic communities.The results indicate that the seasonal variations of the interactions between methanogenic and methanotrophic communities contributed to CH_(4)emissions in wetlands.The keystone species discerned by the network analysis also showed their importance in mediating CH_(4)fluxes.Methane(CH_(4))emissions in wetlands were lowest in spring;during this period,the most complex interactions between microbes were observed,with intense competition among methanogens while methanotrophs demonstrated better cooperation.Reverse patterns manifested themselves in summer when the highest CH_(4)flux was observed.Methanoregula formicica was negatively correlated with CH_(4)fluxes and occupied the largest ecological niches in the spring network.In contrast,both Methanocella arvoryzae and Methylocystaceae demonstrated positive correlations with CH_(4)fluxes and were better adapted to the microbial community in the summer.In addition,soil temperature and nitrogen were regarded as significant environmental factors to CH_(4)fluxes.This study was successful in explaining the seasonal patterns and microbial driving mechanisms of CH_(4)emissions in wetlands.

快速城市化地区森林生态网络识别与评价

以武汉市为例,利用情景分析法,结合基于最小加权费用路径模型的Ecological Network模型识别生态网络,并利用网络连接度指数和斑块关联度指数对整体网络结构和生态源地斑块关联度进行了定量分析与评价。研究发现,武汉市森林生态网络空间分布不均,城市交通网络对生态网络的整体结构影响较大,网络结构、数量与生态源地斑块关联度指数均呈由城市中心向城市远郊区逐渐复杂与增加的趋势。在此基础上,提出了网络保护策略,为武汉市森林生态系统保护与城市空间发展提供了科学依据与参考。

Eukaryotic microbial distribution pattern and its potential effects on fisheries in the fish reserves of Qiantang River in breeding season

To examine the eukaryotic biodiversity of aquatic ecosystems in the Qiantang River,China,eukaryotic microbes in the river were investigated using 18S rRNA gene sequencing during the breeding season(July to August 2018).Four distinct distribution patterns(1.Jiande;2.Tonglu and Fuyang;3.Jiubao;4.Yanguan)of the microbial community and their potential effects on fishery activities were observed.Results show lower abundances of Dinophyta and Fungi and higher abundances of Cryptophyta and Chlorophyta in Tonglu and Fuyang than those in the other three sections.In addition,the reserves(Tonglu and Fuyang)destabilized the original eukaryotic microbial co-occurrence network.Among all the environmental factors measured,nitrogen(nitrite,nitrate,ammonium),water temperature and total chlorophyll a acted as major driving factors that controlled the eukaryotic microbial distribution.Furthermore,the existence of some algae(e.g.,Chrysophyceae,Cryptophytes,and Chlorophyceae)and fungi(e.g.,Rhizophydium)in Tonglu and Fuyang was beneficial to juvenile fish growth and water quality,although some detrimental species(e.g.,Aphanomyces)needed attention.This study provides further insights into the sustainable protection and utilization of rivers.

Using miniaturized GPS archival tags to assess home range features of a small plunge-diving bird:the European Kingfisher(Alcedo atthis)

Background:The European Kingfisher(Alcedo atthis)is a small plunge-diving bird,today considered a species of conservation concern in Europe given its rapid population decline observed across the continent.We implemented a pilot study aimed at providing first data allowing to:(1)assess home range features of the European Kingfisher for populations with unevenly distributed feeding habitats;(2)define conservation implications for habitats exploited by such populations;and(3)evaluate possibilities for developing GPS tracking schemes dedicated to home range stud-ies for this species that could be possibly applied to other small plunge-diving birds.Methods:In 2018 and 2019,we equipped 16 breeding European Kingfishers sampled within the marshes of the Gironde Estuary(France),with miniaturized and waterproof GPS archival tags deployed with leg-loop harnesses(total equipment mass=1.4 g;average bird mass=40.18±1.12 g).Results:On average,we collected 35.31±6.66 locations usable for analyses,without a significant effect on bird body condition(n=13 tags retrieved).Data analyses highlighted rather limited home ranges exploited by birds(aver-age=2.50±0.55 ha),composed on average by 2.78±0.40 location nuclei.Our results also underscore:(1)a rather important home range fragmentation index(0.36±0.08);and(2)the use by birds of different types of small wetlands(wet ditches,small ponds or small waterholes),often exploited in addition to habitats encompassing nest locations.Conclusions:Our study reveals interesting GPS tracking possibilities for small plunge-diving birds such as the European Kingfisher.For this species,today classified as vulnerable in Europe,our results underline the importance of developing conservation and ecological restoration policies for wetland networks that would integrate small wet-lands particularly sensitive to global change.

Ecological Resilience Restoration in the Watershed of the Hancang River

Hancang River is a river on the eastern border of Jinan City. In recent years, with the development of cities, river flow has dropped sharply, river water has been polluted, and the ecological environment of the basin has declined. Improving the water ecological environment and enhancing the resilience of the water ecology of the river basin were set as the research goals, especially coupling of hydrological and ecological processes and the recycling of sewage resources. The “patch-corridor-matrix” theory of landscape ecology, the Least-cost distance model and the Arc Hydro Tools module of the ArcGIS platform were used to describe the river system and basin boundaries, optimize the current water network and the path network of the ecosystem. A novel ecological network and water network were proposed to form the final aquatic ecosystem, which combines the hydrological process with the ecosystem, and three decentralized wastewater treatment systems were designed to reduce the wastewater directly flowing into the river. The ecosystem resilience of the basin will be enhanced.

Molecular ecological networks reveal the spatial-temporal variation of microbial communities in drinking water distribution systems

Microbial activity and regrowth in drinking water distribution systems is a major concern for water service companies.However,previous studies have focused on the microbial composition and diversity of the drinkingwater distribution systems(DWDSs),with little discussion on microbial molecular ecological networks(MENs)in different water supply networks.MEN analysis explores the potentialmicrobial interaction and the impact of environmental stress,to explain the characteristics of microbial community structures.In this study,the random matrix theory-based network analysis was employed to investigate the impact of seasonal variation including water source switching on the networks of three DWDSs that used different disinfection methods.The results showed that microbial interaction varied slightly with the seasons but was significantly influenced by different DWDSs.Proteobacteria,identified as key species,play an important role in the network.Combined UV-chlorine disinfection can effectively reduce the size and complexity of the network compared to chlorine disinfection alone,ignoring seasonal variations,which may affect microbial activity or control microbial regrowth in DWDSs.This study provides new insights for analyzing the dynamics of microbial interactions in DWDSs.

Identifying priority areas for conservation in the lower Yellow River basin from an ecological network perspective

Taking the lower Yellow River basin as the study area,this study aims to construct ecological networks to mitigate the negative impacts of rapid urbanization on the ecosystem.Ecological sources were identified based on morphological spatial pattern analysis(MSPA),habitat quality and landscape connectivity.The ecological resistance surface was constructed and corrected by integrating natural and anthropogenic factors.The spatial range of ecological corridors and some of their key nodes were identified based on circuit theory.The ecological network(EN)was finally optimized using a similarity search and cost connectivity modules.The results show that the optimized ecological network structure is more stable than before.The EN includes 23 ecological sources with a total area of 5464.8 km^(2)and 30 ecological corridor clusters with a total area of 2205.92 km^(2).Through the internal landscape heterogeneity of the corridor,28 ecological node areas and 75 barrier areas were identified as key protection and restoration areas,with a total area of 78.44 km^(2)and 372.79 km^(2),respectively.Through the construction and optimization of EN,this study identifies key areas for promoting ecological sustainability and provides a useful framework for coordinating regional ecological conservation and economic development.

Insights from metagenomic,metatranscriptomic,and molecular ecological network analyses into the effects of chromium nanoparticles on activated sludge system

The objectives of this study were to investigate the influence of chromium nanoparticles(Cr NPs)on the nitrogen and phosphorus removal performance and the bacterial structures of an activated sludge(AS)system.Also,we through molecular ecological networks(MENs)discussed the bacterial interactions.At last we researched the change of the functional genes and their expression patterns related to nitrogen and phosphorus removaT in an AS system.The results showed that long-term exposure to 1 mg/L Cr NPs significantly promoted the denitrifying process and phosphorus removal in the AS system.The relative abundance of denitrifying and phosphorus removal microorganisms,such as Denitratisoma,Thauera,Dechloromonas,and Defluviicoccus,increased significantly.Candidatus Accumulibacter,well-known as polyphosphate-accumulating organisms(PAOs),increased significantly;the relative abundance of Candidatus Competibacter,known as glycogen-accumulating organisms(GAOs),decreased significantly.Furthermore,metagenomic and metatranscriptomic analysis revealed that most of the genera related to denitrifying and phosphorus removal had greatly increased,according to the quantities of denitrifying and phosphorus genes,and the corresponding transcription likewise greatly increased.Lastly,MENs analysis showed that although the overall network became smaller and looser in the presence of Cr NPs,the microbial connections among members related to nitrogen and phosphorus removal were enhanced.The abundance increases of denitrifiers and PAOs,and their increased transcription of functional genes,together with the enhanced interactions may be associated with the promotion of the denitrifying process and phosphorus removal.

Changes of microbiome in response to sugars in a wilt pathogen-infested soil

Sugars are frequently and abundantly found in root exudates,but influence of specific sugars on the fate of soil-borne pathogens,microbiome structure,and particularly microbial interactions are not well understood.A 42-day of microcosm incubation was conducted with two soils:a natural watermelon Fusarium wilt pathogen(i.e.,Fusarium oxysporum f.sp.niveum(FON))-infested soil(Low-FON soil)and the soil further receiving the wilt pathogen inocula(High-FON soil).Both soils were supplemented with four simple sugars before incubation.The results show that,in both soils,FON was enriched by all sugars although co-living with tremendously diverse microbes;and bacterial richness,evenness,and diversity were decreased and bacterial community structure was changed by all sugars.Bacterial richness and evenness were negatively correlated with FON quantity in both Low-FON and High-FON soils,indicating that FON may tend to live in soil with low alpha-diversity.In both Low-FON and High-FON soils,the sugar-spiked networks had more links,higher density,larger modules,and shorter harmonic geodesic distance,suggesting greater potentials for microbial interaction and niche-sharing.The positive links between some of the keystone taxa and FON indicates that these keystone taxa may have promoted FON.This may be one of reasons why FON could proliferate vigorously after sugar supplementation.

Biogeographic distribution patterns of algal community in different urban lakes in China: Insights into the dynamics and co-existence

Urban lake ecosystems are significant for social development,but currently we know little about the geographical distribution of algal community in urban lakes at a large-scale.In this study,we investigated the algal community structure in different areas of urban lakes in China and evaluated the influence of water quality parameters and geographical location on the algal community.The results showed that obvious differences in water quality and algal communities were observed among urban lakes in different geographical areas.Chlorophyta was the dominant phylum,followed by cyanobacteria in all areas.The network analysis indicated that algal community composition in urban lakes of the western and southern area showed more variations than the eastern and northern areas,respectively.Redundancy analysis and structural equation model revealed that nutrients and p H were dominant environmental factors that affected the algal community,and they showed higher influence than that of iron,manganese and COD Mn concentration.Importantly,algal community and density exhibited longitude and latitude relationship.In general,these results provided an ecological insight into large-scale geographical distributions of algal community in urban lakes,thereby having potential applications for management of the lakes.

资源型城市生态空间结构演变特征研究--以徐州市为例

The territorial and spatial planning is an essential tool for ecological civilization construction in spatial development and urban governance.Since ecological space has been an important part of the territorial and spatial planning,this study established a spatial structural pattern of"ecological source-ecological corridor-ecological node"along with methods including landscape connectivity analysis and ecological resistance surface analysis.Taking the ecological space of Xuzhou City,a typical resource-based city,as a case study,this research analyzed the ecological spatial network structure and evaluated the evolution characteristics before judging the breadth threshold value of the ecological corridor and providing planning control strategy.The study found that since the urbanization of Xuzhou City resumed its growth,the quantity of ecological sources,corridors,and nodes have grown along.The resistance of the ecological corridor increases year by year,with the proper breadth threshold value around 100–200 m.The development of an ecological network structure shows a single-polarization evolution characteristic that is high quality and high resistance.

Soil microbiome mediated nutrients decline during forest degradation process

Degradation succession in forests is an important and serious land use/cover change problem in ecology,and during these processes soil microbial communities mediate the recycling of most important nutrients.To reveal the effect of degradation succession processes on soil microbial community diversity,structure,and species interrelationships,we collected abundant samples(21 per vegetation type)in broad-leaved forest,coniferous forest,and meadow to observe the microbial community dynamics.The results showed that diversity and structure of soil prokaryotic and fungal communities responded differently to different forest degradation processes,diversity of soil microbial communities increased during degradation processes.Soil microbial communities abundance changes may indicate that prokaryotic communities showed a living strategies change as an ecological adaption to harsh conditions during forest degradation process.While for fungal communities,their abundance changes may indicate that environmental selection pressure and plant selectivity during forest degradation process.Changes in soil prokaryotic communities and fungal communities were both correlated with soil carbon and nitrogen loss.The soil microbial interaction network analysis indicated more complex species interrelationships formed due to the loss of soil nutrients during degradation succession processes,suggesting soil microbial communities might form more complex and stable networks to resist the external disturbance of soil nutrient loss.All results suggested soil microorganisms,including bacteria,archaea and fungi,all involved in the soil nutrient decline during the forest degradation process.