The extent to which nematode communities are affected by soil factors-a pot experiment

AbstractFour similar, agricultural soils with distinct nematode communities were used to determine the extent to which soil and inoculum factors affected nematode community structure. The soils all had a sandy loam texture from the same geographical area and had been in pasture or arable rotation for the last 10 years. Treatments were established in pots containing a middle layer of frozen defaunated soil, sandwiched between an inoculum that was either fresh soil from the same site ('self') or a mixture of soils to give a more diverse inoculum ('mixed'). Principal component analysis indicated that a single soil type given different inocula developed different community structures (i.e., the community under 'self' differed from that under 'mixed') suggesting an inoculum effect. It was also true that different soil types under a single inoculum soil also developed different community structures (i.e., community under 'mixed' differed with soil type), suggesting a soil effect. It is likely that the nematode community structure is influenced by a combination of antecedent land use, soil factors, species introductions and inter-species competition, which should be considered in any interpretation of nematode communities as a biotic indicator.

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Soil factors determined nematode community composition in a two year pot experiment

Nematology ◽

10.1163/156854103773040808 ◽

2003 ◽

Vol 5 (6) ◽

pp. 889-897 ◽

Cited By ~ 21

Author(s):

Bryan Griffiths ◽

Roy Neilson ◽

A. Glyn Bengough

Keyword(s):

Sandy Loam ◽

Soil Layer ◽

Principal Component ◽

Middle Layer ◽

Biological Properties ◽

Nematode Community ◽

Soil Factors ◽

Soil Layers ◽

Initial Inoculum ◽

Variable Water

Abstract Two similar, sandy loam soils from the same geographical region but with distinct nematode communities were used to determine the extent to which water, soil and inoculum factors affected nematode community structure. Treatments were established in pots containing a middle layer of frozen defaunated soil, sandwiched between an inoculum that was either fresh soil from the same site ('self') or a mixture of soils to give a more diverse inoculum ('mixed'). During year 2, half the pots were watered at regular intervals while the other half received only rainfall. For individual nematode taxa, soil layer and watering regime were the main factors discriminating between treatments, while initial inoculum had a larger influence than soil type. Acrobeloides was most affected by the watering regime, being more abundant under variable water conditions, whereas Hoplolaimidae, Longidorus and Pratylenchus were more abundant in deeper soil layers in contrast to other taxa. For the community as a whole, when analysed by principal component analysis, soil factors clearly influenced composition and also indicated that the biological properties of the soils were important.

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Distribution of nematodes in wetland soils with difference distance from the Bohai sea 359–366

Plant Soil and Environment ◽

10.17221/417-pse ◽

2008 ◽

Vol 54 (No. 8) ◽

pp. 359-366 ◽

Cited By ~ 6

Author(s):

H.Y. Wu ◽

X.X. Li ◽

L.B. Shi ◽

Z.H. Wang ◽

F.Y. Ma

Keyword(s):

Community Structure ◽

Bohai Sea ◽

Coastal Wetland ◽

Yellow River ◽

Nematode Community ◽

Soil Nematode ◽

Soil Nematodes ◽

Nematode Communities ◽

Plant Parasitism ◽

Soil Nematode Communities

In order to elucidate the distribution of soil nematodes in coastal wetlands and the effect of different distance from the sea line on soil nematode communities, we investigated the community structure of soil nematodes in one wetland perpendicularly oriented from Bohai sea coastline. In June 2006, soil samples were collected from the Yellow River Delta wetlands, in Dongying city of Shandong Province, China. Soil nematode communities were analyzed at the depths of 0–10 and 10–20 cm. The results showed that plant parasite nematodes were the most abundant trophic groups in both depths and at four sites. The average relative abundance was 91.33% of the nematode community. Several ecological indices which reflected soil nematode community structure, diversity, maturity and plant parasitism were compared in these four sites. The results indicated that the maturity index (MI) and plant parasitism index (PPI) were more sensitive than the other indices for assessing the response of soil nematode communities to soil of coastal wetland.

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Biome-Level Biogeography of Streambed Microbiota

Applied and Environmental Microbiology ◽

10.1128/aem.01809-07 ◽

2008 ◽

Vol 74 (10) ◽

pp. 3014-3021 ◽

Cited By ~ 23

Author(s):

Robert H. Findlay ◽

Christine Yeates ◽

Meredith A. J. Hullar ◽

David A. Stahl ◽

Louis A. Kaplan

Keyword(s):

Community Structure ◽

Microbial Community ◽

Microbial Biomass ◽

Bacterial Community ◽

Microbial Community Structure ◽

Bacterial Community Structure ◽

Phospholipid Fatty Acid ◽

Principal Component ◽

Community Structures ◽

Microbial Community Structures

ABSTRACT A field study was conducted to determine the microbial community structures of streambed sediments across diverse geographic and climatic areas. Sediment samples were collected from three adjacent headwater forest streams within three biomes, eastern deciduous (Pennsylvania), southeastern coniferous (New Jersey), and tropical evergreen (Guanacaste, Costa Rica), to assess whether there is biome control of stream microbial community structure. Bacterial abundance, microbial biomass, and bacterial and microbial community structures were determined using classical, biochemical, and molecular methods. Microbial biomass, determined using phospholipid phosphate, was significantly greater in the southeastern coniferous biome, likely due to the smaller grain size, higher organic content, and lower levels of physical disturbance of these sediments. Microbial community structure was determined using phospholipid fatty acid (PLFA) profiles and bacterial community structure from terminal restriction fragment length polymorphism and edited (microeukaryotic PLFAs removed) PLFA profiles. Principal component analysis (PCA) was used to investigate patterns in total microbial community structure. The first principal component separated streams based on the importance of phototrophic microeukaryotes within the community, while the second separated southeastern coniferous streams from all others based on increased abundance of fungal PLFAs. PCA also indicated that within- and among-stream variations were small for tropical evergreen streams and large for southeastern coniferous streams. A similar analysis of bacterial community structure indicated that streams within biomes had similar community structures, while each biome possessed a unique streambed community, indicating strong within-biome control of stream bacterial community structure.

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Assessment of Cu applications in two contrasting soils—effects on soil microbial activity and the fungal community structure

Ecotoxicology ◽

10.1007/s10646-017-1888-y ◽

2018 ◽

Vol 27 (2) ◽

pp. 217-233 ◽

Cited By ~ 18

Author(s):

Katharina M. Keiblinger ◽

Martin Schneider ◽

Markus Gorfer ◽

Melanie Paumann ◽

Evi Deltedesco ◽

...

Keyword(s):

Community Structure ◽

Microbial Biomass ◽

Fungal Community ◽

Agricultural Soils ◽

Sandy Loam ◽

Oxidative Enzymes ◽

Microbial Biomass C ◽

Soil Microbial ◽

Fungal Community Structure ◽

Fungal Abundance

AbstractCopper (Cu)-based fungicides have been used in viticulture to prevent downy mildew since the end of the 19th century, and are still used today to reduce fungal diseases. Consequently, Cu has built up in many vineyard soils, and it is still unclear how this affects soil functioning. The present study aimed to assess the short and medium-term effects of Cu contamination on the soil fungal community. Two contrasting agricultural soils, an acidic sandy loam and an alkaline silt loam, were used for an eco-toxicological greenhouse pot experiment. The soils were spiked with a Cu-based fungicide in seven concentrations (0–5000 mg Cu kg−1 soil) and alfalfa was grown in the pots for 3 months. Sampling was conducted at the beginning and at the end of the study period to test Cu toxicity effects on total microbial biomass, basal respiration and enzyme activities. Fungal abundance was analysed by ergosterol at both samplings, and for the second sampling, fungal community structure was evaluated via ITS amplicon sequences. Soil microbial biomass C as well as microbial respiration rate decreased with increasing Cu concentrations, with EC50 ranging from 76 to 187 mg EDTA-extractable Cu kg−1 soil. Oxidative enzymes showed a trend of increasing activity at the first sampling, but a decline in peroxidase activity was observed for the second sampling. We found remarkable Cu-induced changes in fungal community abundance (EC50 ranging from 9.2 to 94 mg EDTA-extractable Cu kg−1 soil) and composition, but not in diversity. A large number of diverse fungi were able to thrive under elevated Cu concentrations, though within the order of Hypocreales several species declined. A remarkable Cu-induced change in the community composition was found, which depended on the soil properties and, hence, on Cu availability.

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Faculty Opinions recommendation of Varietal effects of eight paired lines of transgenic Bt maize and near-isogenic non-Bt maize on soil microbial and nematode community structure.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1064831.517764 ◽

2007 ◽

Author(s):

Elizabeth Hood

Keyword(s):

Community Structure ◽

Nematode Community ◽

Bt Maize ◽

Soil Microbial

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Altitudinal gradient affect abundance, diversity and metabolic footprint of soil nematodes in Banihal-Pass of Pir-Panjal mountain range

Scientific Reports ◽

10.1038/s41598-021-95651-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Shahid Afzal ◽

Humira Nesar ◽

Zarrin Imran ◽

Wasim Ahmad

Keyword(s):

Elevation Gradient ◽

Carbon Assimilation ◽

Shannon Index ◽

Nematode Community ◽

Mountain Range ◽

Soil Nematode ◽

Nematode Communities ◽

Nematode Abundance ◽

Belowground Carbon ◽

Abundance And Diversity

AbstractDespite enormous diversity, abundance and their role in ecosystem processes, little is known about how community structures of soil-inhabiting nematodes differ across elevation gradient. For this, soil nematode communities were investigated along an elevation gradient of 1000–2500 masl across a temperate vegetation in Banihal-Pass of Pir-Panjal mountain range. We aimed to determine how the elevation gradient affect the nematode community structure, diversity and contribution to belowground carbon assimilation in the form of metabolic footprint. Our results showed that total nematode abundance and the abundance of different trophic groups (fungivores, herbivores and omnivores) declined with the increase of elevation. Shannon index, generic richness and evenness index indicated that nematode communities were more diverse at lower elevations and declined significantly with increase in elevation. Nematode community showed a pattern of decline in overall metabolic footprint with the increase of elevation. Nematode abundance and diversity proved to be more sensitive to elevation induced changes as more abundant and diverse nematode assemblage are supported at lower elevations. Overall it appears nematode abundance, diversity and contribution to belowground carbon cycling is stronger at lower elevations and gradually keep declining towards higher elevations under temperate vegetation cover in Banihal-pass of Pir-Panjal mountain range.

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Nematode community structure and functional guilds differ in tea fields and tropical forest

Geoderma ◽

10.1016/j.geoderma.2021.115006 ◽

2021 ◽

Vol 392 ◽

pp. 115006

Author(s):

Hannah Karuri

Keyword(s):

Community Structure ◽

Tropical Forest ◽

Nematode Community ◽

Functional Guilds

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Urban community structure detection based on the OD of traffic analysis zones

Modern Physics Letters B ◽

10.1142/s0217984919501641 ◽

2019 ◽

Vol 33 (13) ◽

pp. 1950164

Author(s):

Qing-Feng Dong ◽

Dian-Kun Chen ◽

Ting Wang

Keyword(s):

Community Structure ◽

Quantitative Methods ◽

Urban Community ◽

Spatial Location ◽

Traffic Analysis ◽

Association Mining ◽

Community Structures ◽

City Community ◽

Traffic Characteristics ◽

Structure Detection

At present, the detection of urban community structures is mainly based on existing administrative divisions, and is performed using qualitative methods. The lack of quantitative methods makes it difficult to judge the rationality of urban community divisions. In this study, we used complex network association mining methods to detect a city community structure by using the Origin-Destinations (OD) at traffic analysis zone (TAZ) level, and successively assigned all the TAZs into different communities. Based on the community results, we calculated the community core degree of each TAZ within every community, and then calculated the Traffic Core Degree and Location Core Degree indicators of the community based on OD passenger flow and spatial location relationship between communities. Finally, we analyzed the correlation among three indicators to ensure the rationality of the community structure. We used the city of Zhengzhou in 2016 as an example case study. For Zhengzhou, we detected a total of six communities. We found a relatively low correlation between Traffic Core Degree and Location Core Degree. Within each group, the correlation between community core degree and Traffic Core Degree was higher than that between community core degree and Location Core Degree, indicating that the urban community structure is more reasonably based on traffic characteristics. The development of a quantitative approach for determining reasonable city community structures has important implications for transportation planning and industrial layout.

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Community Detection in Political Discussions on Twitter

Social Science Computer Review ◽

10.1177/0894439315617254 ◽

2016 ◽

Vol 35 (2) ◽

pp. 244-261 ◽

Cited By ~ 10

Author(s):

Frederic Guerrero-Solé

Keyword(s):

Community Structure ◽

Community Detection ◽

Reliable Method ◽

Community Structures ◽

Network Community ◽

High Polarization

In November 9, 2014, the Catalan government called Catalan people to participate in a straw poll about the independence of Catalonia from Spain. This article analyzes the use of Twitter between November 8 and 10, 2014. Drawing on a methodology developed by Guerrero-Solé, Corominas-Murtra, and Lopez-Gonzalez, this work examines the structure of the retweet overlap network (RON), formed by those users whose communities of retweeters have nonzero overlapping, to detect the community structure of the network. The results show a high polarization of the resulting network and prove that the RON is a reliable method to determinate network community structures and users’ political leaning in political discussions.

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