Nematode communities of Byers Peninsula, Livingston Island, maritime Antarctica

2011 ◽  
Vol 23 (4) ◽  
pp. 349-357 ◽  
Author(s):  
Uffe N. Nielsen ◽  
Diana H. Wall ◽  
Grace Li ◽  
Manuel Toro ◽  
Byron J. Adams ◽  
...  
Keyword(s):  
Community Composition ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Terrestrial Ecosystems ◽  
Nematode Species ◽  
Trophic Group ◽  
Maritime Antarctica ◽  
Nematode Communities ◽  
Livingston Island ◽  
Harsh Conditions

AbstractThe nematode communities of Antarctica are considered simple. The few species present are well adapted to the harsh conditions and often endemic to Antarctica. Knowledge of Antarctic terrestrial ecosystems is increasing rapidly, but nematode communities remain to be explored in large parts of Antarctica. In soil samples collected at Byers Peninsula (Antarctic Specially Protected Area No. 126), Livingston Island we recorded 37 nematode taxa but samples showed great variation in richness and abundance. Nematode richness decreased with increasing soil pH, whereas total abundances, and the abundance of several trophic groups, were greatest at intermediate pH (around 6.5–7). Moreover, the community composition was mainly related to pH and less so to soil moisture. Trophic group, and total nematode, rotifer and tardigrade, abundances were generally positively correlated. Byers Peninsula is thus, by maritime Antarctic standards, a nematode biodiversity hotspot, and the presence of several previously unrecorded genera indicates that nematode species richness in maritime Antarctica is probably underestimated. Our results indicate that abiotic factors influence nematode communities with little evidence for biotic interactions. The unexplained heterogeneity in community composition is probably related to variation in microclimate, vegetation, topography and unmeasured soil properties, but may also be contributed to by biological processes.

scholarly journals Identifying appropriate sampling and modelling approaches for analysing distributional patterns of Antarctic terrestrial arthropods along the Victoria Land latitudinal gradient

2010 ◽  
Vol 22 (6) ◽  
pp. 742-748 ◽  
Author(s):  
Tancredi Caruso ◽  
Ian D. Hogg ◽  
Roberto Bargagli
Keyword(s):  
Abiotic Factors ◽  
Relevant Literature ◽  
Biotic Interactions ◽  
Terrestrial Ecosystems ◽  
Climatic Conditions ◽  
Trophic Levels ◽  
Terrestrial Arthropods ◽  
Victoria Land ◽  
Dispersal Capability ◽  
Modelling Techniques

AbstractBiotic communities in Antarctic terrestrial ecosystems are relatively simple and often lack higher trophic levels (e.g. predators); thus, it is often assumed that species’ distributions are mainly affected by abiotic factors such as climatic conditions, which change with increasing latitude, altitude and/or distance from the coast. However, it is becoming increasingly apparent that factors other than geographical gradients affect the distribution of organisms with low dispersal capability such as the terrestrial arthropods. In Victoria Land (East Antarctica) the distribution of springtail (Collembola) and mite (Acari) species vary at scales that range from a few square centimetres to regional and continental. Different species show different scales of variation that relate to factors such as local geological and glaciological history, and biotic interactions, but only weakly with latitudinal/altitudinal gradients. Here, we review the relevant literature and outline more appropriate sampling designs as well as suitable modelling techniques (e.g. linear mixed models and eigenvector mapping), that will more adequately address and identify the range of factors responsible for the distribution of terrestrial arthropods in Antarctica.

scholarly journals Abiotic factors influence patterns of bacterial diversity and community composition in the Dry Valleys of Antarctica

2020 ◽  
Vol 96 (5) ◽  
Author(s):  
Eric M Bottos ◽  
Daniel C Laughlin ◽  
Craig W Herbold ◽  
Charles K Lee ◽  
Ian R McDonald ◽  
...  
Keyword(s):  
Community Composition ◽  
Bacterial Communities ◽  
Structural Equation ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Equation Modeling ◽  
Dry Valleys ◽  
Physicochemical Variables ◽  
Soil Conductivity ◽  
Community Dissimilarity

ABSTRACT The Dry Valleys of Antarctica are a unique ecosystem of simple trophic structure, where the abiotic factors that influence soil bacterial communities can be resolved in the absence of extensive biotic interactions. This study evaluated the degree to which aspects of topographic, physicochemical and spatial variation explain patterns of bacterial richness and community composition in 471 soil samples collected across a 220 square kilometer landscape in Southern Victoria Land. Richness was most strongly influenced by physicochemical soil properties, particularly soil conductivity, though significant trends with several topographic and spatial variables were also observed. Structural equation modeling (SEM) supported a final model in which variation in community composition was best explained by physicochemical variables, particularly soil water content, and where the effects of topographic variation were largely mediated through their influence on physicochemical variables. Community dissimilarity increased with distance between samples, and though most of this variation was explained by topographic and physicochemical variation, a small but significant relationship remained after controlling for this environmental variation. As the largest survey of terrestrial bacterial communities of Antarctica completed to date, this work provides fundamental knowledge of the Dry Valleys ecosystem, and has implications globally for understanding environmental factors that influence bacterial distributions.

Short-term effects of forest disturbances on soil nematode communities in European mountain spruce forests

2012 ◽  
Vol 87 (3) ◽  
pp. 376-385 ◽  
Author(s):  
A. Čerevková ◽  
M. Renčo ◽  
L. Cagáň
Keyword(s):  
Dominant Species ◽  
Nematode Species ◽  
Trophic Group ◽  
Soil Samples ◽  
Maturity Index ◽  
Short Term ◽  
Nematode Communities ◽  
Spruce Forests ◽  
Nematode Abundance ◽  
Short Term Effects

AbstractThe nematode communities in spruce forests were compared with the short-term effects of forest damage, caused by windstorm, wildfire and management practices of forest soils. Soil samples were collected in June and October from 2006 to 2008 in four different sites: (1) forest unaffected by the wind (REF); (2) storm-felled forest with salvaged timber (EXT); (3) modified forest affected by timber salvage (wood removal) and forest fire (FIR); and (4) storm-felled forest where timber had been left unsalvaged (NEX). Nematode analysis showed that the dominant species in all four investigated sites were Acrobeloides nanus and Eudorylaimus silvaticus. An increase of A. nanus (35% of the total nematode abundance) in the first year in the FIR site led to the highest total abundance of nematodes compared with other sites, where nematode abundance reached the same level in the third year. In the FIR site bacterial feeders appeared to be the most representative trophic group, although in the second and third year, after disturbance, the abundance of this trophic group gradually decreased. In the NEX site, the number of nematode species, population densities and Maturity Index were similar to that recorded for the FIR site. In EXT and NEX sites, the other dominant species was the plant parasitic nematode Paratylenchus microdorus. Analyses of nematodes extracted from different forest soil samples showed that the highest number of species and diversity index for species (H'spp) were in the REF site. Differences between the nematode fauna in REF and other localities were clearly depicted by cluster analysis. The greatest Structure Index and Enrichment Index values were also in REF. In the EXT site, the number of nematode species, their abundance, H'spp and Maturity Index were not significantly different from those recorded in the reference site.

scholarly journals Geospatial variability of soil CO2–C exchange in the main terrestrial ecosystems of Keller Peninsula, Maritime Antarctica

2016 ◽  
Vol 562 ◽  
pp. 802-811 ◽  
Author(s):  
A. Thomazini ◽  
M.R. Francelino ◽  
A.B. Pereira ◽  
A.L. Schünemann ◽  
E.S. Mendonça ◽  
...  
Keyword(s):  
Terrestrial Ecosystems ◽  
Soil Co2 ◽  
Maritime Antarctica

Environmental–biomechanical reciprocity and the evolution of plant material properties

2021 ◽  
Author(s):  
Karl J Niklas ◽  
Frank W Telewski
Keyword(s):  
Physical Environment ◽  
Structural Changes ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Cellular Solids ◽  
Form And Function ◽  
Evolutionary Innovation ◽  
Plant Form ◽  
And Function ◽  
Abiotic Environmental Factors

Abstract Abiotic–biotic interactions have shaped organic evolution since life first began. Abiotic factors influence growth, survival, and reproductive success, whereas biotic responses to abiotic factors have changed the physical environment (and indeed created new environments). This reciprocity is well illustrated by land plants who begin and end their existence in the same location while growing in size over the course of years or even millennia, during which environment factors change over many orders of magnitude. A biomechanical, ecological, and evolutionary perspective reveals that plants are (i) composed of materials (cells and tissues) that function as cellular solids (i.e. materials composed of one or more solid and fluid phases); (ii) that have evolved greater rigidity (as a consequence of chemical and structural changes in their solid phases); (iii) allowing for increases in body size and (iv) permitting acclimation to more physiologically and ecologically diverse and challenging habitats; which (v) have profoundly altered biotic as well as abiotic environmental factors (e.g. the creation of soils, carbon sequestration, and water cycles). A critical component of this evolutionary innovation is the extent to which mechanical perturbations have shaped plant form and function and how form and function have shaped ecological dynamics over the course of evolution.

scholarly journals Soil–landform–plant-community relationships of a periglacial landscape on Potter Peninsula, maritime Antarctica

Solid Earth ◽  
2015 ◽  
Vol 6 (2) ◽  
pp. 583-594 ◽  
Author(s):  
E. L. Poelking ◽  
C. E. R. Schaefer ◽  
E. I. Fernandes Filho ◽  
A. M. de Andrade ◽  
A. A. Spielmann
Keyword(s):  
Climate Change ◽  
Plant Communities ◽  
Terrestrial Ecosystems ◽  
Maritime Antarctica ◽  
Climate Change Effects ◽  
Ornithogenic Soils ◽  
Physical Environmental Factors ◽  
Potter Peninsula

Abstract. Integrated studies on the interplay between soils, periglacial geomorphology and plant communities are crucial for the understanding of climate change effects on terrestrial ecosystems of maritime Antarctica, one of the most sensitive areas to global warming. Knowledge on physical environmental factors that influence plant communities can greatly benefit studies on the monitoring of climate change in maritime Antarctica, where new ice-free areas are being constantly exposed, allowing plant growth and organic carbon inputs. The relationship between topography, plant communities and soils was investigated on Potter Peninsula, King George Island, maritime Antarctica. We mapped the occurrence and distribution of plant communities and identified soil–landform–vegetation relationships. The vegetation map was obtained by classification of a QuickBird image, coupled with detailed landform and characterization of 18 soil profiles. The sub-formations were identified and classified, and we also determined the total elemental composition of lichens, mosses and grasses. Plant communities on Potter Peninsula occupy 23% of the ice-free area, at different landscape positions, showing decreasing diversity and biomass from the coastal zone to inland areas where sub-desert conditions prevail. There is a clear dependency between landform and vegetated soils. Soils that have greater moisture or are poorly drained, and with acid to neutral pH, are favourable for moss sub-formations. Saline, organic-matter-rich ornithogenic soils of former penguin rookeries have greater biomass and diversity, with mixed associations of mosses and grasses, while stable felsenmeers and flat rocky cryoplanation surfaces are the preferred sites for Usnea and Himantormia lugubris lichens at the highest surface. Lichens sub-formations cover the largest vegetated area, showing varying associations with mosses.

scholarly journals Effects of Abiotic Factors on HIPV-Mediated Interactions between Plants and Parasitoids

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
Christine Becker ◽  
Nicolas Desneux ◽  
Lucie Monticelli ◽  
Xavier Fernandez ◽  
Thomas Michel ◽  
...  
Keyword(s):  
Plant Volatiles ◽  
Global Climate ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Green Leaf Volatiles ◽  
Limited Attention ◽  
Emission Rates ◽  
Leaf Volatiles ◽  
Parasitic Hymenoptera ◽  
Growing Conditions

In contrast to constitutively emitted plant volatiles (PV), herbivore-induced plant volatiles (HIPV) are specifically emitted by plants when afflicted with herbivores. HIPV can be perceived by parasitoids and predators which parasitize or prey on the respective herbivores, including parasitic hymenoptera. HIPV act as signals and facilitate host/prey detection. They comprise a blend of compounds: main constituents are terpenoids and “green leaf volatiles.” Constitutive emission of PV is well known to be influenced by abiotic factors like temperature, light intensity, water, and nutrient availability. HIPV share biosynthetic pathways with constitutively emitted PV and might therefore likewise be affected by abiotic conditions. However, the effects of abiotic factors on HIPV-mediated biotic interactions have received only limited attention to date. HIPV being influenced by the plant’s growing conditions could have major implications for pest management. Quantitative and qualitative changes in HIPV blends may improve or impair biocontrol. Enhanced emission of HIPV may attract a larger number of natural enemies. Reduced emission rates or altered compositions, however, may render blends imperceptible to parasitoides and predators. Predicting the outcome of these changes is highly important for food production and for ecosystems affected by global climate change.

scholarly journals Rewetting of Three Drained Peatlands Drives Congruent Compositional Changes in Pro- and Eukaryotic Soil Microbiomes Through Environmental Filtering

2019 ◽  
Author(s):  
Micha Weil ◽  
Haitao Wang ◽  
Mia Bengtsson ◽  
Daniel Köhn ◽  
Anke Günther ◽  
...  
Keyword(s):  
Community Composition ◽  
Ecosystem Respiration ◽  
Abiotic Factors ◽  
Environmental Filtering ◽  
Network Analyses ◽  
Respiration Rates ◽  
Control Community ◽  
Methane Fluxes ◽  
Compositional Changes ◽  
Shed Light

AbstractDrained peatlands are significant sources of the greenhouse gas (GHG) carbon dioxide. Rewetting is a proven strategy to protect carbon stocks; however, it can lead to increased emissions of the potent GHG methane. The response to rewetting of soil microbiomes as drivers of these processes is poorly understood, as are biotic and abiotic factors that control community composition.We analyzed the pro- and eukaryotic microbiomes of three contrasting pairs of minerotrophic fens subject to decade-long drainage and subsequent rewetting. Also, abiotic soil properties including moisture, dissolved organic matter, methane fluxes and ecosystem respiration rates.The composition of the microbiomes was fen-type-specific, but all rewetted sites showed higher abundance of anaerobic taxa compared to drained sites. Based on multi-variate statistics and network analyses we identified soil moisture as major driver of community composition. Furthermore, salinity drove the separation between coastal and freshwater fen communities. Methanogens were more than tenfold more abundant in rewetted than in drained sites, while their abundance was lowest in the coastal fen, likely due to competition with sulfate reducers. The microbiome compositions were reflected in methane fluxes from the sites. Our results shed light on the factors that structure fen microbiomes via environmental filtering.

scholarly journals Application of PCR-DGGE method for identification of nematode communities in pepper growing soil

2016 ◽  
Vol 7 (1) ◽  
pp. 9-14
Author(s):  
Duong Duc Hieu
Keyword(s):  
Maximum Likelihood ◽  
Community Sample ◽  
Nematode Species ◽  
Viet Nam ◽  
Soil Nematode ◽  
Nematode Communities ◽  
Maximum Likelihood Tree ◽  
Relationship Of ◽  
First Time ◽  
Soil Nematode Communities

Soil nematodes play an important role in indication for assessing soil environments and ecosystems. Previous studies of nematode community analyses based on molecular identification have shown to be useful for assessing soil environments. Here we applied PCR-DGGE method for molecular analysisoffive soil nematode communities (designed as S1 to S5) collected from four provinces in Southeastern Vietnam (Binh Duong, Ba Ria Vung Tau, Binh Phuoc and Dong Nai) based on SSU gene. By sequencing DNA bands derived from S5 community sample, our data show 15 species containing soil nematode, other nematode and non-nematode (fungi) species. Genus Meloidogyne was found as abundant one. The genetic relationship of soil nematode species in S5 community were determined by Maximum Likelihood tree re-construction based on SSU gene. This molecular approach is applied for the first time in Vietnam for identification of soil nematode communities. Tuyến trùng đất đóng vai trò chỉ thị quan trọng trong công tác đánh giá môi trường và hệ sinh thái đất. Các nghiên cứu trước đây đã cho thấy lợi ích của việc phân tích cộng đồng tuyến trùng đất bằng định danh sinh học phân tử đối với việc đánh giá môi trường đất. Ở đây, chúng tôi ứng dụng phương pháp PCR-DGGE dựa trên gene SSU để phân tích năm (ký hiệu từ S1 đến S5) cộng đồng tuyến trùng đất thuộc các vùng trồng chuyên canh cây hồ tiêu ở miền nam Việt Nam (Bình Dương, Bà Rịa Vũng Tàu, Bình Phước và Đồng Nai). Bằng cách giải trình tự các vạch của mẫu tuyến trùng S5, kết quả cho thấy cộng đồng tuyến trùng này có 15 loài gồm nhóm tuyến trùng đất, nhóm các loại tuyến trùng khác và nhóm không phải tuyến trùng (nấm) và trong đó Meloidogyne là giống ưu thế. Mối quan hệ di truyền của các các loài tuyến trùng đất thuộc cộng đồng S5 được xác định bằng việc thiết lập cây phát sinh loài Maximum Likelihood dựa trên gene SSU. Đây là nghiên cứu đầu tiên ở Việt Nam sử dụng kỹ thuật PCR-DGGE để phân tích các cộng đồng tuyến trùng đất trồng hồ tiêu.

Impact of biochar amendment on soil nematode communities in a West African rain-fed rice cropland

Nematology ◽  
2021 ◽  
pp. 1-12
Author(s):  
Segun O. Oladele ◽  
Adebayo Adeyemo ◽  
Moses Awodun ◽  
Ajoke Adegaye ◽  
Mariko Ingold
Keyword(s):  
Trophic Group ◽  
West African ◽  
Nematode Population ◽  
Available Phosphorus ◽  
Soil Nematode ◽  
Trophic Groups ◽  
Nematode Communities ◽  
Study Results ◽  
Inorganic Fertiliser ◽  
Plant Parasitic

Summary Nematode population and diversity in a West African rain-fed rice cropland amended with biochar (B), biochar plus inorganic fertiliser (B + NPK), inorganic fertiliser (NPK) and control (CK) without amendments were investigated in a 3-year field study. Results demonstrated that significant differences exist between treatments and years of study for total nematode population and nematode trophic groups. Total nematode density, nematode trophic group (bacterivore and plant-parasitic) density were increased and dominant in B + NPK compared with CK after 3 years. Relative abundance of nematode genera according to trophic group across treatments showed Hirschmanniella (23%) as the dominant plant parasites in NPK, and Heterocephalobus (27%), Aphelenchoides (22%) and Eudorylaimus (9%) as dominant bacterivores, fungivores and omnivores-predators, respectively, in B + NPK. Trophic group indicators showed that the fungivore plus bacterivore to plant-parasitic ratio (73%) was significantly increased by B + NPK treatment in comparison to CK. Conversely, treatments exerted no significant effect on the fungivore to bacterivore ratio (F/B) throughout the period of study, which implies less disturbance and adverse impact of biochar on nematode communities. Apart from treatments and environmental factors, changes in nematode trophic groups were strongly related to soil chemical properties, such as soil pH, total nitrogen and available phosphorus, which shows their influence on soil nematode community. Our result shows the positive effect of integrated addition of biochar and inorganic fertiliser in balancing nematode diversity and building a resilient soil ecosystem in a low input rain-fed rice cropping system.

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