Chironomus species (Diptera: Chironomidae) in the profundal benthos of Spanish reservoirs and lakes: factors affecting distribution patterns

2000 ◽  
Vol 43 (1) ◽  
pp. 1-18 ◽  
Author(s):  
M. Real ◽  
M. Rieradevall ◽  
N. Prat
Keyword(s):  
Distribution Patterns ◽  
Factors Affecting

scholarly journals Distribution Patterns of Odonate Assemblages in Relation to Environmental Variables in Streams of South Korea

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 152 ◽  
Author(s):  
Da-Yeong Lee ◽  
Dae-Seong Lee ◽  
Mi-Jung Bae ◽  
Soon-Jin Hwang ◽  
Seong-Yu Noh ◽  
...  
Keyword(s):  
Land Use ◽  
Ecosystem Services ◽  
Environmental Factors ◽  
South Korea ◽  
Habitat Heterogeneity ◽  
Environmental Variables ◽  
Environmental Changes ◽  
Distribution Patterns ◽  
Self Organizing Map ◽  
Factors Affecting

Odonata species are sensitive to environmental changes, particularly those caused by humans, and provide valuable ecosystem services as intermediate predators in food webs. We aimed: (i) to investigate the distribution patterns of Odonata in streams on a nationwide scale across South Korea; (ii) to evaluate the relationships between the distribution patterns of odonates and their environmental conditions; and (iii) to identify indicator species and the most significant environmental factors affecting their distributions. Samples were collected from 965 sampling sites in streams across South Korea. We also measured 34 environmental variables grouped into six categories: geography, meteorology, land use, substrate composition, hydrology, and physicochemistry. A total of 83 taxa belonging to 10 families of Odonata were recorded in the dataset. Among them, eight species displayed high abundances and incidences. Self-organizing map (SOM) classified sampling sites into seven clusters (A–G) which could be divided into two distinct groups (A–C and D–G) according to the similarities of their odonate assemblages. Clusters A–C were characterized by members of the suborder Anisoptera, whereas clusters D–G were characterized by the suborder Zygoptera. Non-metric multidimensional scaling (NMDS) identified forest (%), altitude, and cobble (%) in substrata as the most influential environmental factors determining odonate assemblage compositions. Our results emphasize the importance of habitat heterogeneity by demonstrating its effect on odonate assemblages.

scholarly journals Identification of the factors determining the concentration and spatial distribution of Zn, Pb and Cd in the soils of the non-forest Tatra Mountains (southern Poland)

2022 ◽  
Author(s):  
Krystyna Ciarkowska ◽  
Anna Miechówka
Keyword(s):  
Distribution Patterns ◽  
Parent Material ◽  
Tatra Mountains ◽  
Spatial Continuity ◽  
Factors Affecting ◽  
Range Transport ◽  
West Carpathians ◽  
Potential Factors ◽  
Cd Distribution ◽  
Tatra National Park

AbstractWe investigated trace-metal (TM)––Zn, Pb and Cd––concentrations and spatial distributions in the uppermost layers of non-forest soils from Tatra National Park (West Carpathians). We aimed to determine the main factors affecting the distribution of TMs, as well as the risk they posed to the environment. TM concentrations were compared to the target and intervention values established by the Dutch Ministry. Principle component analysis was used to identify the potential factors affecting TM accumulation, with two-factor analysis being applied to further examine the importance of any given factor. To examine the regularity of the TM distribution, semivariograms were created. The semivariograms of Cd and Pb were similar, suggesting a moderate spatial dependence for these metal concentrations, while the Zn variogram indicated a lack of spatial continuity for this metal. We established that the Zn, Pb and Cd exceeded target levels and at some sites, Cd exceeded the intervention values, posing a strong ecological risk to the environment. Our study confirmed that the parent rock was the most important factor affecting the TM accumulation. The carbonate-free soils differed from carbonate soils in the second important factor affecting TM accumulation, for carbonate-free soils it was location when for carbonate soils–TM content in the parent material. The Zn, Pb and Cd distribution patterns indicated that Cd, but also to a lesser degree Pb and Zn, accumulation mainly resulted from long-range transport from industrialised areas, while the Zn concentrations were also affected by local sources, such as the historical mining of Zn ore.

Quantification of motility of carabid beetles in farmland

2015 ◽  
Vol 105 (2) ◽  
pp. 234-244 ◽  
Author(s):  
A.B. Allema ◽  
W. van der Werf ◽  
J.C.J. Groot ◽  
L. Hemerik ◽  
G. Gort ◽  
...  
Keyword(s):  
Field Experiment ◽  
Diffusion Theory ◽  
Meta Analysis ◽  
Arable Land ◽  
Distribution Patterns ◽  
Carabid Beetles ◽  
Factors Affecting ◽  
Crop Field ◽  
Pterostichus Melanarius ◽  
Time Frames

AbstractQuantification of the movement of insects at field and landscape levels helps us to understand their ecology and ecological functions. We conducted a meta-analysis on movement of carabid beetles (Coleoptera: Carabidae), to identify key factors affecting movement and population redistribution. We characterize the rate of redistribution using motility μ (L2 T−1), which is a measure for diffusion of a population in space and time that is consistent with ecological diffusion theory and which can be used for upscaling short-term data to longer time frames. Formulas are provided to calculate motility from literature data on movement distances. A field experiment was conducted to measure the redistribution of mass-released carabid, Pterostichus melanarius in a crop field, and derive motility by fitting a Fokker–Planck diffusion model using inverse modelling. Bias in estimates of motility from literature data is elucidated using the data from the field experiment as a case study. The meta-analysis showed that motility is 5.6 times as high in farmland as in woody habitat. Species associated with forested habitats had greater motility than species associated with open field habitats, both in arable land and woody habitat. The meta-analysis did not identify consistent differences in motility at the species level, or between clusters of larger and smaller beetles. The results presented here provide a basis for calculating time-varying distribution patterns of carabids in farmland and woody habitat. The formulas for calculating motility can be used for other taxa.

scholarly journals Changes in paleo-circulation and the distribution of ammonite faunas at the Coniacian–Santonian transition in central Poland and western Ukraine

2016 ◽  
Vol 66 (1) ◽  
pp. 107-124 ◽  
Author(s):  
Zbyszek Remin ◽  
Michał Gruszczyński ◽  
Jim D. Marshall
Keyword(s):  
Cold Water ◽  
Sea Water ◽  
Circulation Model ◽  
Distribution Patterns ◽  
Low Latitude ◽  
Factors Affecting ◽  
The North ◽  
Oxygen Stable Isotopes ◽  
Western Ukraine ◽  
Tectonic Movements

Abstract Ammonite distribution patterns and carbon and oxygen stable isotopes from the Lipnik-Kije (Poland) and Dubovcy (Ukraine) sections allow us to propose a model of sea water paleo-circulation in central Europe for the Coniacian- Santonian interval. The tectonic evolution of the south-eastern part of Poland, and expansion of the Krukienic Island areas, appears to have been one of the most important factors affecting paleotemperatures and the distribution of ammonite faunas in the shallow, epicontinental sea in this part of Europe. In the Lipnik-Kije section, low-latitude Tethyan ammonites, especially of the genera Nowakites, Parapuzosia and Saghalinites, are mixed with the cold water loving ammonite genus Kitchinites in the Lower Santonian. In the Dubovcy section (western Ukraine), Tethyan ammonites disappear abruptly in the earliest Santonian, giving place to temperate ammonites of the Kitchinites group in the early Early Santonian and to Boreal belemnites of the genus Gonioteuthis in the Middle and Late Santonian. Despite evidence for the effects of diagenesis in both sections, bulk-rock δ18O records from the limestones support higher seawater paleotemperatures in the Polish sea and cooler conditions in the western Ukraine. The proposed paleo-circulation model and paleotemperature distribution across Europe is supported independently by changes in faunal and nannoflora evidence (ammonites, foraminifera and nannoplankton), and rather unexpectedly with the bulk δ18O data. These data allow the recognition of the end-Coniacian-Early Santonian cooling event, resulting from cold currents flowing from the north, which is traceable, with different magnitude, in several European sections. Facies changes in both sections are related to the input of terrigenous material, and linked to Subhercynian tectonic movements which affected the eastern (Ukrainian) and central (Holy Cross) segment of the Mid Polish Trough at different times. Uplift and sediment input moved westwards through time. Clastic input is detectable at the Coniacian-Santonian boundary in the Ukrainian segment. Similar facies changes reached the Holy Cross segment in Poland distinctly later, somewhen in the Middle Santonian. It is likely that tectonics together with paleo-circulation changes markedly restricted or even cut-off the western Ukraine area from Tethyan ocean influences in the Early Santonian.

scholarly journals Differentially Amplified Repetitive Sequences Among Aegilops tauschii Subspecies and Genotypes

2021 ◽  
Vol 12 ◽  
Author(s):  
Rahman Ebrahimzadegan ◽  
Fatemeh Orooji ◽  
Pengtao Ma ◽  
Ghader Mirzaghaderi
Keyword(s):  
Dna Sequences ◽  
Tandem Repeats ◽  
Repetitive Sequences ◽  
Aegilops Tauschii ◽  
Distribution Patterns ◽  
Snp Analysis ◽  
Specific Sequence ◽  
Factors Affecting ◽  
Illumina Sequence ◽  
Species Specific

Genomic repetitive sequences commonly show species-specific sequence type, abundance, and distribution patterns, however, their intraspecific characteristics have been poorly described. We quantified the genomic repetitive sequences and performed single nucleotide polymorphism (SNP) analysis between 29 Ae. tauschii genotypes and subspecies using publicly available raw genomic Illumina sequence reads and used fluorescence in situ hybridization (FISH) to experimentally analyze some repeats. The majority of the identified repetitive sequences had similar contents and proportions between anathera, meyeri, and strangulata subspecies. However, two Ty3/gypsy retrotransposons (CL62 and CL87) showed significantly higher abundances, and CL1, CL119, CL213, CL217 tandem repeats, and CL142 retrotransposon (Ty1/copia type) showed significantly lower abundances in subspecies strangulata compared with the subspecies anathera and meyeri. One tandem repeat and 45S ribosomal DNA (45S rDNA) abundances showed a high variation between genotypes but their abundances were not subspecies specific. Phylogenetic analysis using the repeat abundances of the aforementioned clusters placed the strangulata subsp. in a distinct clade but could not discriminate anathera and meyeri. A near complete differentiation of anathera and strangulata subspecies was observed using SNP analysis; however, var. meyeri showed higher genetic diversity. FISH using major tandem repeats couldn’t detect differences between subspecies, although (GAA)10 signal patterns generated two different karyotype groups. Taken together, the different classes of repetitive DNA sequences have differentially accumulated between strangulata and the other two subspecies of Ae. tauschii that is generally in agreement with spike morphology, implying that factors affecting repeatome evolution are variable even among highly closely related lineages.

The Influence of Nonhomogeneous Interlayer Stiffness on Dynamic Response of Orbit-Girder System under Moving Load

2021 ◽  
pp. 2250004
Author(s):  
Shaohui Liu ◽  
Lizhong Jiang ◽  
Wangbao Zhou ◽  
Yuntai Zhang ◽  
Yulin Feng ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Boundary Conditions ◽  
Moving Load ◽  
Distribution Patterns ◽  
Stiffness Degradation ◽  
Factors Affecting ◽  
Nonlinear Fitting ◽  
Fourier Series Method ◽  
Stiffness Distribution ◽  
Peak Value

Based on the finite Fourier series method and the principle of energy variation, a method for calculating the dynamic response of an orbit-girder system is proposed, which is suitable for general spring boundary and nonhomogeneous interlayer stiffness distribution. Two numerical examples are given to verify the effectiveness of the proposed method under different moving load speeds and different stiffness distribution patterns. Based on this method, the influence of boundary conditions, interlayer stiffness degradation mode and degradation amplitude as well as the motion load on the dynamic response of the orbit-girder system is analyzed. A formula for calculating the peak value of additional dynamic response caused by interlayer stiffness degradation is proposed based on the nonlinear fitting method, and the factors affecting the additional response are analyzed. Results show that the variation of boundary conditions does not affect the additional dynamic response of the orbit-girder system. The mode of interlayer stiffness degradation and the degree of nonhomogeneous distribution have a significant influence on the peak of additional dynamic response. The additional dynamic response peak value of the orbit-girder system increases significantly with an increasing degree of nonhomogeneous degradation of the interlayer stiffness. The orbit-girder system has multiple critical speeds under the action of moving load. The magnitude of moving load has an important effect on the additional response peaks of the orbit-girder system. The additional response peaks increase approximately linearly with the increase of the motion load.

scholarly journals Features of the structural phase state of a weld produced by electron-beam welding in the submicrocrystalline grade 2 titanium alloy

2018 ◽  
Vol 143 ◽  
pp. 03011
Author(s):  
Kirill Kurgan ◽  
Vasily Klimenov ◽  
Anatoly Klopotov ◽  
Sergey Gnyusov ◽  
Yuri Abzaev ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Electron Beam ◽  
Heat Affected Zone ◽  
Electron Beam Welding ◽  
Structural Phase ◽  
Weld Zone ◽  
Distribution Patterns ◽  
High Concentration ◽  
Factors Affecting ◽  
Microhardness Distribution

This paper presents the results of structural studies for a welded joint of the Grade 2 titanium alloy in submicrocrystalline and microcrystalline states produced by electron beam welding when joining 2-mm-thick plates. Microhardness distribution patterns of the Grade-2 titanium alloy in micro- and submicrocrystalline states are identified in the weld zone and heat-affected zone. These patterns reflect a difference in structural phase states. It is assumed that one of the key factors affecting both the structural state and microhardness distribution in the weld zone and heat-affected zone during electron-beam welding is high concentration of oxygen atoms embedded into the crystal lattice of α–Ti-based solid solution.

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