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Multivariate Analysis of Ecological Data Lsing CANOCO

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... Descriptive statistics were calculated by nematode per taxa and sample, relative to the distribution and number of nematodes observed. The relation between the numbers of nematodes per taxa was first analyzed by correspondence analysis (CA) to identify associations between them without environmental influences (Leps and Smilauer, 1999;Shi, 1993). Canonical correspondence analysis (CCA) was then performed to determine the distribution of nematode taxa in relation to environmental variables, in this case type of soil and grape cultivars. ...
... Relationships between the composition of nematode community and the impact of each on environmental data were investigated by using forward selection of environmental variables in CCA. Environmental variables were added as long as the significance level of the partial Monte Carlo permutation test was below 0.05 (Leps and Smilauer, 1999). To evaluate the effects of both different groups of explanatory variables upon the species data, a variance partitioning procedure was performed to determine the relative contribution (proportion of total variation explained) of each variable set on the total variance and their overlap (Ramette, 2007). ...
... Before evaluating the influence of the environment on the presence of the most important plant-parasitic nematodes in the vineyards, a correspondence analysis (CA) was performed to verify the existence of some gradient and the relation between samples and nematode species. The length of the longest gradient was 3.5, which showed a unimodal answer justifying the posterior use of constrained methods (Leps and Smilauer, 1999). Sample distribution (Fig. 2) shows the relationship between nematode genera and soil samples, and concludes that presence of the nematode species corresponds to all samples and geographical areas. ...
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A survey to detect the presence and distribution of plant-parasitic nematodes in Chilean vineyards was undertaken during the years 2006 and 2007 covering an area of 40000 km2, over 90% of the surface area cultivated with Vitis vinifera L. Descriptive statistics relative to the distribution observed, number of nematodes per taxa and sample was performed. Correspondence analysis and canonical correspondence analysis were performed to determine relations between nematodes taxa with culti- vars and soil type. Twelve nematode genera were extracted from 1818 soil samples, but only four were considered to be highly pathogenic to the crop, Xiphinema spp. (X. index, X. americanum sensu lato), Meloidogyne spp. (M. ethiopica, M. spp.), Mesocriconema (M. xenoplax) and Tylenchulus (T. semipenetrans). The population densities of determined taxa were fairly variable; however, at least one of the species was present in every sample in high density. No correlations between nematode species were observed, nor was there a tendency of two or more nematodes to occur together. The total variance of nematodes was only marginally explained by cultivars and soil with an incidence of 18% and 0.5%, respectively, and an unexplained variation of 81.3%. These data indicated that environmental factors or management practices not measured in the survey greatly influenced nematode populations, and that previous selection of the variables to be evaluated should include some of them, like irrigation, tillage or fertilizers, especially under intensive agriculture.
... In both the unconstrained and constrained methods, we finally selected either an ordination technique for species response to an underlying environmental gradient to be linear (PCA and RDA), or unimodal (DCA and CCA) based on simple criteria. After carrying out DCA on each dataset and checking the length of the largest gradient among the resultant ordination axes, we selected PCA and RDA if the largest gradient was shorter than 2.0, and DCA and CCA if it was larger than 4.0 (Jongman et al., 1995;Lepš and Šmilauer, 2003). Regardless of the length of the largest gradient, we chose DCA over PCA in those cases in which we visually confirmed an artifactual distortion of the ordination diagram due to the arch effect, in which the second axis was an arched function of the first axis (Jongman et al., 1995;Lepš and Šmilauer, 2003). ...
... After carrying out DCA on each dataset and checking the length of the largest gradient among the resultant ordination axes, we selected PCA and RDA if the largest gradient was shorter than 2.0, and DCA and CCA if it was larger than 4.0 (Jongman et al., 1995;Lepš and Šmilauer, 2003). Regardless of the length of the largest gradient, we chose DCA over PCA in those cases in which we visually confirmed an artifactual distortion of the ordination diagram due to the arch effect, in which the second axis was an arched function of the first axis (Jongman et al., 1995;Lepš and Šmilauer, 2003). If necessary, a partial RDA or CCA was carried out using one or several environmental variables as a covariable or covariables in order to help to interpret results obtained by the constrained method. ...
... If necessary, a partial RDA or CCA was carried out using one or several environmental variables as a covariable or covariables in order to help to interpret results obtained by the constrained method. Partial constrained methods enable us to examine effects of environmental variables of interest after partialling out the effect of covariables (Gutiérrez et al., 2003;Lepš and Šmilauer, 2003). We carried out these analyses using CANOCO version 4.5 (ter Braak and Šmilauer, 2002). ...
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Rural biodiversity in East Asia is at risk due to the loss of habitat diversity, and good indicators are needed to evaluate diverse habitats in rural landscapes. We examined whether the higher taxa (classes and orders) of soil invertebrates discriminated among several types of secondary forests such as broad-leaved deciduous forests, conifer forests and bamboo forests, primary forests, grasslands and/or wetlands, better than species assemblages of a well-established indicator, ground beetles (Coleoptera, Carabidae and/or Staphylinidae), in three East Asian regions (Japan, South Korea and the Russian Far East). We collected soil invertebrates with pitfall traps and used community composition and an ordination technique to test their performance as indicators. In Japan, the higher taxa of soil invertebrates discriminated finely among a wide range of habitats, and soil moisture seemed to be an important factor underlying habitat arrangement by these taxa along an ordination axis. While species assemblages of ground beetles detected large faunal differences among grasslands, wetlands and a composite group of three forest-type habitats (oak, conifer and bamboo forests), it failed to discriminate among any of the three forest-type habitats. When the analysis included only these types of forests, ground beetles were found to be able to discriminate finely among them, indicating limited performance in relation to the range of habitats covered. In the other two countries, the higher taxa of soil invertebrates showed a performance similar to that of species assemblages of ground beetles, possibly because of the narrow range of habitats analyzed. We conclude that the higher taxa of soil invertebrates are an effective tool for assessing the diversity of rural habitats across the East Asian region, where taxonomic knowledge at the species level is still insufficient. Our results may be applied broadly to other regions where agricultural intensification and land abandonment have caused quantitative and qualitative changes in rural landscapes.
... As the ordination axes are constrained to be linear combinations of the environmental variables, the relationships between the environmental variables and the response variables can be compared directly. The sites are represented by points in the ordination space, and the species abundances and environmental variables are represented by arrows projecting from the origin [26]. ...
... Species arrows pointing in the same general direction as environmental arrows can be interpreted as correlating well with that variable, and the longer the arrows, the more confidence can be expected in that correlation. The longest environmental arrows allow more confidence in the concluded correlations and indicate a larger effect of that parameter on the total species variation [26]. ...
Article
Testate amoebae play an important role at the very first beginning of succession on land. We used litterbags buried into four different soils to study the early colonization (which occurred within less than 55 days) and establishment of testate amoebae. The litterbag cellulose exposed at the youngest mining site poor in nitrogen and phosphorus was colonized firstly in high abundances, whereas the substrate introduced into the reference sites of undisturbed soil was colonized slowly and in low densities. Besides the (expected) small-sized r-strategists (e.g., Euglypha rotunda, Tracheleuglypha dentata, and Trinema lineare), large-sized K-strategists (e.g., Centropyxis spp., Phryganella acropodia) occurred in remarkably high densities on all sites. Species that colonized the cellulose in high densities (e.g., P. acropodia and T. dentata) were found extremely rarely in the adjacent source substrate and vice versa, stressing the importance of the target substrate quality. In the course of the experiment, the influencing environmental factors became more complex, as shown by redundancy analysis (RDA). Concerning the amoebal community, there was a change from variability to stability, as visualized by cluster analysis. Adjacent litterbags within an investigation site revealed amoebal species and abundances with an increasing similarity during exposition time, whereas the litterbags between the four investigation sites were colonized differently. These observations point to a stochastic (variable) beginning of community assembly, changing to a more deterministic (stable) course. No species replacement has been observed, which is an essential part of most successional theories. Thus, the more flexible concept of "community assembly" should be considered instead of "succession" for protozoa. The stochastic beginning of community assembly and the lack of species replacement are explained by a neutral community model.
... A significance level of 95% (p < 0.05) was selected. Redundancy analysis (RDA), an ordination method of direct gradient analysis (Lep s and Smilauer, 1999), was performed to search for patterns in the different sets of biological parameters and to assess their relationship with the environmental variables (operational parameters). The biological parameters analysed throughout the whole set of samples were: 1) enzyme activities, 2) presence/absence of band classes in the TGGE profiles, and 3) calculated values of the ShannoneWiener (H 0 ) and functional organisation (Fo) indices. ...
... Among these, TSS concentration had to be removed from the final analysis because of its strong linear correlation with VSS. RDA was chosen as the ordination method after performing a detrended correspondence analysis (DCA) which revealed that all the biological parameters exhibited a linear response to the environmental variables, rather than an unimodal response ( Lep s and Smilauer, 1999). All environmental variables were transformed to log (x þ 1). ...
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A comparative analysis was performed in a pilot-scale membrane bioreactor (MBR) treating urban wastewater supplied with either pure oxygen (O2) or air, to assess the influence of each aeration source on the diversity and activity of the bacterial communities in the sludge. The MBR was operated in three experimental stages with different concentrations of volatile suspended solids (VSS) and temperature, and under both aeration conditions. α-Glucosidases, proteases, esterases and phosphatases were tested as markers of organic matter removal in the sludge, and the diversity of the bacterial community was analysed by fingerprinting (temperature-gradient gel electrophoresis of partially-amplified 16S-rRNA genes). Redundancy analysis (RDA) revealed that temperature and VSS concentration were the only factors that significantly influenced the levels of enzyme activities and the values of both the Shannon-Wiener diversity index (H') and the functional organisation index (Fo), while the bacterial community structure experienced significant changes depending on the aeration source supplied in each experimental stage.
... Multivariate analysis was conducted to find the relationships between hydrographical parameters and copepods abundance, total biovolume and proportions of various sizes in total biovolume and NASS slopes in different eddy phases. Initially, etrended correspondence analysis ( CA) was performed to select the correct ordination methods for the present study (Leps and Smilauer, 2003). The results of the CA shows that the length of the axis was <2; this suggests R A is the proper ordination pattern to explain the interrelationships between the parameters in the present data sets. ...
... The outcome of the R A was presented in the form of Triplot. The total copepods abundance and total biovolume were log-transformed before the R A and significance of the R A tested with Mote-Carlo test (Leps and Smilauer, 2003). ...
Article
The present study addresses the copepods size structure in different phases of a cold-core eddy based on a 17 day time-series measurement (21st February to 8th March 2016) from a coastal site in the western Bay of Bengal during the Spring Intermonsoon (SIM). Copepod size measured using FlowCAM and microscope was converted into biovolumes. Based on the salinity and temperature in discrete depth layers, sampling days were grouped into 3 Phases, pre-eddy (21–24 February), Core-eddy (28 February – 6 March) and transition (25–27 February and 7–8 March). The core-eddy phase was characterised as cool, less oxygenated and nutrient-rich in subsurface layers than pre-eddy and transition. Copepod abundance and total biovolume were relatively high in core-eddy phase compared to other phases. Copepods biovolumes were arranged in 15 size classes. Contribution of each size classes in total biovolume differed between the eddy phases. In total biovolume, smaller copepods (biovolume size class ≤ log2 (−3) mm⁻³) contribution was high (76.84%) in pre-eddy, but larger copepods proportion was high in core-eddy phase. Normalised Abundance Size Spectra (NASS) slope varied from −2.45 to −1.02. Similar to the taxonomic diversity, size diversity also high in core-eddy phase. Relatively flatter slope, high intercept and diversity in core-eddy phase suggest that copepods production and trophic efficiency was substantially increased. In short, copepods taxonomy and their size structure explain, pre-eddy contains the smaller coastal forms and core-eddy have a mixture of smaller coastal, larger oceanic and Oxygen Minimum Zone (OMZ) tolerant forms. Larger oceanic and OMZ tolerant forms in core-eddy phase indicate their entry through the transverse of the offshore formed cold-core eddy in the study site. Slope, intercept of NASS and size diversity captured the copepod species composition and production differences between the eddy phases in terms of abundance. This study suggests plankton size spectra and size diversity can be used as a tool to predict the plankton food web response in the varying environmental conditions. This study is the first of its kind explaining about copepods size structure and size spectrum changes with the hydrographical characteristics in Indian waters.
... Data from the survey of species of rhizobacteria was correlated with the variables type of soil, grape cultivar and irrigation water and analysed by redundancy analysis (RDA) performed with CANOCO software, version 4.5 (Leps and Smilauer 1999). ...
Article
Xiphinema index is the most aggressive root parasite affecting vines in Chile, controlled mainly chemically. The aim of this study was to identify rhizobacteria in grapevine roots growing in infested soils and to determine if some of these affect the parasitism caused by the nematode. Rhizobacteria of ungrafted grapevine cultivars from 11 vineyards were isolated using TSBA and identified with FAMEs analysis. The antagonistic effect to X. index of those from soils 1 to 4 was assessed in 500ml pots treating 2months old in vitro plants with a bacterial suspension containing 1 × 106 c.f.u./ml and 400 nematodes, determining after 4months growth nematode populations and root damages. Also culture filtrates were assessed. 400 isolates in 25 genera were obtained from the 11 vineyards. The most frequent species were Pseudomonas putida (35.1%), Escherichia coli (7.6%) and Pseudomonas fluorescens (6.1%). Isolates of soils 1 to 4, show that Bacillus megaterium, B. brevis, Pseudomonas corrugata, P. savastanoi, Stenotrophomonas maltophilia and Serratia plymuthica reduced root damage and suppressed populations, meanwhile strains of B. brevis and Comamonas acidovorans increased plant growth but did not control nematodes. It is concluded that these isolates may be useful in biological control programmes in vineyards. KeywordsRhizobacteria– Vitis vinifera –Biological control–Plant-parasitic nematodes–Roots– Xiphinema index
... The data matrix used for the analysis comprised carbon biomass data of 35 species or phytoplankton groups from 18 quantitative phytoplankton samples. TWINSPAN works with qualitative data (i.e., presence/absence), so quantitative species' carbon biomass data were transformed to qualitative variables called pseudospecies, which are defined by cut-levels of species carbon biomass concentrations (Lepš & Šmilauer 1999). In our analysis, pseudospecies cut-levels were set at 0, 2, 5, 10, 20 and 100 μg C L −1 , representing the whole range of species carbon biomass values. ...
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Seasonal variations in the composition and carbon biomass of diatoms and other phytoplankton groups were analyzed over two years, from December 1996 to January 1999, at a fixed station in Anegada Bay, within the El Rincón estuarine system (38–41°S). Phytoplankton communities characterizing the different seasons were identified by classification and detrended correspondence analyses. Diatom communities were highly speciose, with 117 species recorded during the two-year study. Three diatom species are new records for the Argentinean Sea (i.e., Minidiscus trioculatus (F.J.R. Taylor) Hasle, M. decoratus Chrétiennot-Dinet & Quiroga and Thalassiosira tealata Takano). Phytoplankton taxonomic composition and carbon biomass showed a strong seasonality, with two carbon (C) biomass maxima occurring in summer and winter (maximum concentration: 193 μ g C L). Summer blooms were mainly dominated by tychoplanktonic diatom species (Paralia sulcata (Ehrenberg) Cleve, Rhaphoneis amphiceros (Ehrenberg) Ehrenberg and Delphineis surirella (Ehrenberg) Andrews), probably resuspended from the sediments, and by the pelagic diatom T. hendeyi Hasle & Fryxell. The winter phytoplankton community was characterized by a high number of diatom species and a high carbon biomass of diatom resting spores. The occurrence of the winter bloom seems to be closely associated with the inoculation of the water column by diatom resting spores. Maximum diatom carbon biomass corresponded to periods of increased freshwater inflow, whereas seasonal variations in diatom taxonomic composition may be explained by the life-cycle strategies of the species. The taxonomic composition and temporal succession of phytoplankton communities in Anegada Bay are comparable with previous studies in Blanca Bay, suggesting relatively uniform phytoplankton seasonality over shoals in the El Rincón estuarine system.
... TGGE banding patterns generated by Gel Compar II were converted to a binary matrix by scoring bands (=species) as present (1) or absent (0), and this matrix was used for CCA without transformation. CCA was chosen as ordination method after initial evaluation of species data by detrended correspondence analysis (DCA), which revealed that they exhibited a unimodal, rather than linear, response to the environmental variables [22]. The operational variables tested were hydraulic retention time (HRT) and TSS concentration in the sludge. ...
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A bacterial strain, designated strain LP01T, was isolated from a lab-scale microcosm packed with a mixture of soil and sewage sludge compost designed to study the evolution of microbial biodiversity through the time. The bacterial strain was selected for its potential ability to store polyhydroxyalkanoates (PHAs) as intracellular granules. The cells were aerobic, Gram-negative, non-endospore forming motile rods. Phylogenetically was classified within the genus Massilia as its 16S rRNA gene sequence had a similarity of 99.2% with respect to the type strains of Massilia albidiflava DSM 17472T and Massilia lutea DSM 17473T. DNA-DNA hybridization showed low relatedness of strain LP01T with other, phylogenetically related Massilia species. It contained Q-8 as predominant ubiquinone and possessed summed feature 3 (C16:1ω7c and/or iso-C15:0 2OH) as the major fatty acids. It was found to contain low amounts of the fatty acids C18:0 and C14:02-OH, feature that served to distinguish it from its closest phylogenetic relatives of the genus Massilia. The DNA G+C content was 66.0 mol%. Phylogenetic, phenotypic and chemotaxonomic data obtained in this study suggest that strain LP01T represents a novel species of the genus Massilia, for which the name Massilia umbonata sp. nov. is proposed. The type strain is LP01T (= CECT 7753T = DSM 26121T).
... DCA revealed the longest ordination axis to be less than three, and so the distribution of the model was linear. Redundancy analysis (RDA) was therefore used as the statistical method recommended for gradients with a linear response (Lepš and S ˇ milauer 1999). Statistical significance was tested using a Monte Carlo permutation test with 499 permutations. ...
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Wastewater treatment using moving bed membrane bioreactor technology was tested with real urban wastewater at a pilot plant, combining moving bed treatment as a biological process with hybrid biomass (suspended and fixed) and the advantages of a membrane separation system. The evolution of the kinetic constants of the hybrid biomass and organic matter removal were studied in a pilot plant under different operational conditions, by varying hydraulic retention time (HRT), mixed liquor suspended solids (MLSS) and temperature, and considering the attached biomass of the carrier and the dispersed biomass of the flocs to reproduce real treatment conditions. The rates of organic matter removal were 97.73 ± 0.81 % of biochemical oxygen demand (BOD5), 93.44 ± 2.13 % of chemical oxygen demand (COD), 94.41 ± 2.26 % of BOD5 and 87.62 ± 2.47 % of COD using 24.00 ± 0.39 and 10.00 ± 0.07 h of HRT, respectively. The influence of the environmental variables and operational conditions on kinetic constants was studied; it was determined that the most influential variable for the decay coefficient for heterotrophic biomass was HRT (0.34 ± 0.14 and 0.31 ± 0.10 days−1 with 10.00 ± 0.07 and 24.00 ± 0.39 h of HRT, respectively), while for heterotrophic biomass yield, this was temperature (0.61 ± 0.04 and 0.52 ± 0.06 with 10.00 ± 0.07 and 24.00 ± 0.39 h of HRT, respectively). The results show that introducing carriers in an MBR system provides similar results for organic matter removal, but with a lower concentration of MLSS.
... Figures were made using the software of SigmaPlot in version 10.0. In order to test the combined contribution of biophysical variables to the variability of R 10 and Q 10 , redundancy analysis (RDA) [25] was conducted with R 10 and Q 10 as dependent variables and with selected biophysical variables, i.e. DBH, soil pH, variances in soil bulk density, soil TN and soil pH, as explanatory variables. ...
Article
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The basal respiration rate at 10°C (R10) and the temperature sensitivity of soil respiration (Q10) are two premier parameters in predicting the instantaneous rate of soil respiration at a given temperature. However, the mechanisms underlying the spatial variations in R10 and Q10 are not quite clear. R10 and Q10 were calculated using an exponential function with measured soil respiration and soil temperature for 11 mixed conifer-broadleaved forest stands and nine broadleaved forest stands at a catchment scale. The mean values of R10 were 1.83 µmol CO2 m(-2) s(-1) and 2.01 µmol CO2 m(-2) s(-1), the mean values of Q10 were 3.40 and 3.79, respectively, for mixed and broadleaved forest types. Forest type did not influence the two model parameters, but determinants of R10 and Q10 varied between the two forest types. In mixed forest stands, R10 decreased greatly with the ratio of coniferous to broadleaved tree species; whereas it sharply increased with the soil temperature range and the variations in soil organic carbon (SOC), and soil total nitrogen (TN). Q10 was positively correlated with the spatial variances of herb-layer carbon stock and soil bulk density, and negatively with soil C/N ratio. In broadleaved forest stands, R10 was markedly affected by basal area and the variations in shrub carbon stock and soil phosphorus (P) content; the value of Q10 largely depended on soil pH and the variations of SOC and TN. 51% of variations in both R10 and Q10 can be accounted for jointly by five biophysical variables, of which the variation in soil bulk density played an overwhelming role in determining the amplitude of variations in soil basal respiration rates in temperate forests. Overall, it was concluded that soil respiration of temperate forests was largely dependent on soil physical properties when temperature kept quite low.
... W celu porównania ogólnego udziału chrobotków w klasach wieku drzewostanu dla każdej klasy obliczono średnią liczbę gatunków z rodzaju Cladonia oraz ich średnie pokrycie. Przy oblicza− niu średniego pokrycia dla stopni ilościowości (5, 4, 3, 2, 1, +, r) przyjęto średnie procentowe pokrycie (równe odpowiednio: 87,5, 62,5, 37,5, 17,5, 5,0, 0,5 i 0,1) [Pawłowski 1972; Lepš, Šmilauer 1999]. Istotność różnic między średnimi zbadano testem Kruskala−Wallisa oraz testami porównań wielokrotnych [Stanisz 2006]. ...
... The phytosociological data were analyzed using the modified TWINSPAN method (Hill 1979;Roleček et al. 2009) embedded in the JUICE 7.0 program (Tichý 2002). TWINSPAN analysis is one of the most popular classification methods used in plant community ecology ( Lepš and Šmilauer 1999). In this method, relevés are compared based on presence or absence of species. ...
Article
Bazdid Vahdati F, Saeidi Mehrvarz Sh, Naqinezhad A, Gholizadeh H. 2014. How plant diversity features change across ecological species groups? A case study of a temperate deciduous forest in northern Iran. Biodiversitas 15: 31-38. Species diversity is one of the most important indices for evaluating the stability and productivity of forest ecosystems. The aim of this research was to recognize ecological species groups and to determine the relationship between environmental variables and the distribution of ecological species groups. For this purpose, 25 400-m 2 relevés were sampled using the Braun-Blanquet method. Vegetation was classified using modified Two-Way Indicator Species Analysis (TWINSPAN) and resulted in three ecological species groups. Different species diversity indices were applied to quantify diversity of these species groups. ANOVA and Duncan’s tests indicated that all species and environmental variables except altitude changed significantly across the species groups. The results also showed that the group located in the northern aspect and on low slopes had the highest diversity indices compared with groups located in dry aspects and on high slopes. In reality, abundant precipitation (northern aspect) and soil enrichment (low slopes) are principal factors that provide suitable conditions for plant growth and species diversity. Thus, the study of diversity changes in ecological species groups can result in an ecologically precise perspective for managing forest ecosystems.
... The Principal Component Analysis (PCA) was applied in order to determine soil substitute parameters that influenced the Sinapis alba development. The analysis was performed using the CANOCO package and the variables data were transformed using log (x + 1) prior to the analysis response [37]. ...
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The main purpose of this paper was to outline a novel approach for the use of industrial by-products generated in coal mines and coal-fired power plants as the components for artificial soils. Several coal combustion by-products, coal mine waste and organic waste materials were tested at laboratory scale for use in the reclamation of areas degraded by coal mining activity. The role of artificial soils was the land rehabilitation of the high acidic waste heap. The results revealed that the amounts of organic matter (14.87–25.01%) and nutrients in the soil substitutes were sufficient to support plant growth, i.e., N (0.37–0.51%), P (0.23–0.47%), K (1.78–3.17%), Ca (4.93–8.39%) and Mg (1.16–1.71%). A phytotoxicity test using white mustard (Sinapis alba) seeds under laboratory conditions showed good germination results (56–66%) for three soil substitutes that did not contain fly ash from biomass combustion, compared to the reference soil (84%). The relationships established for the aqueous leachate parameters of soil substitutes vs. the Sinapis alba germination revealed negative correlations with electrical conductivity (r = −0.88), SO42− (r = −0.91) and Cl− (r = −0.70) ions; the two latter ones were responsible for the salinity which hampered the germination process of the soil substitutes. Moreover, quite similar correlations were obtained between the germination of Sinapis alba and the trace elements of the soil substitutes: Fe (r = −0.69), Cd (r = −0.72), Cu (r = −0.80), Pb (r = −0.78) and Zn (r = −0.74). However, negative and significant correlations in aqueous leachates were shown only with Ni concentration (r = −0.73). The relevance of these results for the effect of salinity on germination and the early growth of S. alba was discussed in detail and was confirmed with the Principal Component Analysis (PCA). The study proved that the physicochemical characteristic of recycled wastes exhibited their potential usefulness for the reclamation of affected areas such as mine waste heaps.
... In addition, a discriminant analysis (DA), using three different groups of sites depending on their degree of contamination in order to test which biomarker responses significantly contributed towards discriminating sites between these three groups, and the ordination technique of redundancy analysis (RDA), using forward selection of explanatory variables in order to test which contaminants had a significant effect on the observed biomarker responses were performed to evaluate the response of biomarkers to chemical analyses. Data were centred and standardised before analysis (Leps and Smilauer, 1999). The significance of the relationships between biomarker responses and contaminant body burdens were tested using a global Monte Carlo permutation test. ...
Article
Contaminant effects on defence responses of ecologically and economically important organisms, such as the Pacific oyster Crassostrea gigas, are likely to influence their ability to resist infectious diseases, particularly at the young stages. The aim of this study was to explore the potential relationships between organic contaminants accumulated in the soft tissues of juvenile oysters, defence responses and physiological condition. Oysters were transplanted during summer and winter periods in different sites in the Marennes-Oléron Bay, the first area of oyster production in France, and in the Gironde Estuary, the biggest estuary in Occidental Europe. Amongst the battery of biochemical and physiological biomarkers applied in the present work [superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), malondyaldehyde (MDA), catecholase, laccase and lysozyme in gills, digestive glands, mantle and haemolymph, glycogen, proteins and lipids in the digestive gland and the condition index at the whole-organism level], MDA and lysozyme in the digestive gland and SOD, GPx and laccase in plasma contributed in order to significantly discriminate the sites in which oysters bioaccumulated different levels of heavy polycyclic aromatic hydrocarbons (HPAHs), polychlorobiphenyls (PCBs), polybromodiphenylethers (PBDEs), dichlorodiphenyltrichloroethanes (DDTs) and lindane. These results strengthen the hypothesis that it is possible to differentiate sites depending on their contamination levels and biological effects by carrying out studies with transplanted juvenile oysters. In addition, correlations were found between antioxidant and immune-defence responses, and PAH and DDT body burdens in the first area of oyster production in France (the Marennes-Oléron Bay) and where considerable oyster mortalities have been reported. This result suggests that the presence of organic chemical contaminants in the Marennes-Oléron Bay may influence defence responses in juveniles of C. gigas, and, therefore, could influence their ability to resist infectious diseases.
... Cyanobacterial abundance and MC concentration were included in the RDA as dependent (response) variables, while environmental factors and Chl-a were treated as independent (explanatory) variables. RDA was chosen after confirming through a preliminary detrended analysis of correspondence (DCA) that the length of ordination axes in DCA was less than 3 (Jan and Petrš 2003). Before the analysis, both species data and environmental variables except pH were log (X + 1)-transformed to reduce the effect of high values (ter Braak and Šmilauer 2002). ...
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The composition and abundance of cyanobacteria and their toxins, microcystins (MCs), and cylindrospermopsins (CYN) were investigated using samples collected at monthly intervals from the Amudde side of Koka Reservoir from May 2013 to April 2014. Cyanobacteria were the most abundant and persistent phytoplankton taxa with Microcystis and Cylindrospermopsis species alternately dominating the phytoplankton community of the reservoir and accounting for up to 84.3 and 11.9% of total cyanobacterial abundance, respectively. Analyses of cyanotoxins in filtered samples by HPLC-DAD and LC-MS/MS identified and quantified five variants of MCs (MC-LR, MC-YR, MC-RR, MC-dmLR, and MC-LA) in all samples, with their total concentrations ranging from 1.86 to 28.3 μg L-1 and from 1.71 to 33 μg L-1, respectively. Despite the presence and occasional abundance of Cylindrospermopsis sp., cylindrospermopsin was not detected. Redundancy analysis (RDA) showed that the environmental variables explained 82.7% of the total variance in cyanobacterial abundance and microcystin concentration. The presence of considerably high levels of MCs almost throughout the year represents a serious threat to public health and life of domestic and wild animals.
... The calculations were performed using the Canoco 4.0 software package (Jongman et al., 1995;Lepš and Šmilauer, 1999;Lepš and Šmilauer, 2003).The results of CCA are displayed in an ordination diagram, where the axis 1 and 2 indicate months, together with the vectors of sampling sites and environmental factors. The high eigenvalue with 9.787 explained the variance of the station group where the sampling was performed each month with environmental gradients. ...
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... To explain the distribution of Mochokidae fish species in Malebo Pool, data on specific abundances and environmental variables were subjected to multivariate statistical analyses using Canoco for Windows software (Lepš and Šmilauer 1999;Ter Braak and Smilauer 2002). These data were first log-transformed, log(x + 1), and then a series of redundancy analyses (RDAs) were performed using these species abundance matrices and environmental variables. ...
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... Nustatytas rūšių išsidėstymas ordinatinėje erdvėje, priklausomai nuo aplinkos veiksnių. Šiuo metodu nustatyti ryšiai tarp augalų rūšių, įvertintas dažnumas atsižvelgiant į jų gausumą ( Jongman et al., 1987;Okland, 1990;Kent, Coker, 1992;Lepš, Šmilauer, 1999;Lepš, Šmilauer, 2014). Statistiniam patikimumui (p) tarp kintamųjų rodiklių (dirvožemio cheminių savybių, drėgnumo, medyno dendrometrinių rodiklių) ir tiriamųjų rūšių nustatyti naudotas Monte Karlo 4999 permutacijų testas ( Jongman et al., 1987;Socal, Rolhf, 1997;Lepš, Šmilauer, 2014). ...
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