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Relationships Between Groundwater Characteristics, Vegetation, and Peatland Type in the Hiawatha National Forest, Michigan
Published in Carl C. Trettin, Martin F. Jurgensen, David F. Grigal, Margaret R. Gale, John K. Jeglum, Northern Forested Wetlands, 2018
Gregory M. Kudray, Margaret R. Gale
Detrended correspondence analysis (Hill, 1979) was used to examine the vegetation data. Detrended correspondence analysis (DCA) provides an ordination of plots; each plot is assigned a value along four ordination axes that allows correlations with environmental factors or a visual representation. A DCA ordination was performed with each of the following data sets: vascular plants only, bryophytes only, and vascular plants and bryophytes combined. The vegetation data was presence/absence; no cover values were used. In each ordination, species that occurred in only one plot were eliminated from the vegetation data set. DCA default settings regarding axes resealing and detrending were used. Plot scores from DCA axes were correlated to water chemistry variables using Spearman’s rank order correlation.
Diversity of microbial community structure and their association with phthalic acid esters and physicochemical parameters in informal landfills
Published in Environmental Technology, 2022
Qin Yin, Haihong Yan, Xiaoya Guo, Yu Liang, Xingzhi Wang, Yuegang Nian, Haiyan Wang
Canoco (version 4.5) was conducted to determine the relationships between environmental factors and bacterial community composition. Detrended correspondence analysis (DCA) was initially used to determine a suitable response model for the obtained microbial data. The length of the gradient after DCA was 2.83, which was shorter than the previously reported length of 3.0. Therefore, RDA was conducted to determine how physiochemical factors affect the bacterial community composition. For this, pH, TN, NO3-N, NO2-N, , SUVA254, and moisture content were chosen as the environmental factors for evaluation by automated forward selection and the RDA model to determine which environmental factor exhibited a significant influence on bacterial communities. The sum of all canonical eigenvalues indicated the total variance explained by environmental parameters in the dataset and was 0.365 for the bacterial community. For the variance of the species–environment relationship, the first and second canonical axes explained 34.7% and 56.8% of the total variation, respectively. The RDA results are shown in Figure 7 and revealed a clear relationship between bacterial species and environmental parameters at the phylum level. Redundancy analysis of the relationship between bacterial species and environmental parameters (, TN, pH, moisture content, and SUVA254) is indicated by the red solid lines, whereas the phylum parameters of bacterial species are shown in black solid lines.
Responses of benthic macroinvertebrate communities in tropical Asian streams passing through an industrial zone
Published in Chemistry and Ecology, 2021
Mark Edward Jolejole, Mylene G. Cayetano, Francis S. Magbanua
Spatial and temporal variation in river water quality was determined by performing two-way analysis of variance (ANOVA) in IBM SPSS Statistics 20.0 (IBM Corp., New York, USA). Patterns in water quality (pH, temperature, DO, NH3–N, NO3-–N, PO43-–P, TSS) and benthic macroinvertebrate assemblages were then investigated using ordination analysis. Parameters conductivity, BOD5, Cd and Pb were not included in the analysis due to limited points analysed. Detrended correspondence analysis (DCA) was first performed to determine the ordination method (redundancy analysis (RDA) or canonical correspondence analysis (CCA)) to be used based on the gradient length [28]. Analyses were performed using vegan package [29] in R 3.6.1 [30]. Prior to analysis, fourth-root transformation of abundance data, log-transformation of water quality data and arcsine square root transformation of the proportion data were done [31,32]. Moreover, collinearity was assessed using Spearman rank correlation and collinear variables (|r| > 0.50) [33] were not included in the ordination analysis. The contribution of benthic macroinvertebrates accounting for the dissimilarities between sampling locations and seasons was identified using Similarity Percentages (SIMPER) function in PRIMER 6 (version 6.1.16).
Influence of the conservation status on carbon balances of semiarid coastal Mediterranean wetlands
Published in Inland Waters, 2020
Daniel Morant, Antonio Picazo, Carlos Rochera, Anna C. Santamans, Javier Miralles-Lorenzo, Antonio Camacho
A multivariate analysis (RDA) was performed to reveal the relation between environmental variables and the biological activities (GPP and aerobic respiration separated for both plankton and benthos, helophyte production, and CH4 release). These variables were the maximum water depth (cm), temperature (°C), conductivity (mS cm−1), SRP (µM), NO3− (µM), NH4+ (µM), BOD5 (mg L−1), COD (mg L−1), Chl-a (µg L−1), and OM content in sediment (%). For the RDA, square root transformation was used to normalise the metabolism, and log transformation was used for the environmental data. Because the gradient length of the detrended correspondence analysis (DCA) was between 0.8 and 1.8, we performed a redundancy analysis (RDA). These analyses were performed with the vegan package (Oksanen et al. 2013) in R (R Core Team 2017). Additionally, a 2-way analysis of variance (ANOVA) and honestly significant differences (HSD) Tukey post hoc tests were performed using SPSS Statistics 24 among sampling sites and seasons for the C processes of plankton and benthos, as well as for methanogenesis, to examine if the C rates depend on the conservation status represented by the different study sites. The normality of the distribution and homogeneity of variances were checked. A level of significance of 95% was used.