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Multivariate Analysis of Ecological Data. Faculty of Biological Sciences, University of South Bohemia

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... Canopy cover, stream width, depth and water velocity were measured to describe the physical attributes at each site. (Lepš & Šmilauer, 1999;Chen et al., 2016). To reduce the effects of rare species in the model, only those taxa with relative abundances >0.1% were retained in the RDA model (Fu et al., 2014). ...
... To determine the appropriate constrained ordination model for the datasets, I performed a detrended correspondence analysis (DCA; Lepš & Šmilauer, 1999;ter Braak & Šmilauer, 2002). DCA revealed a gradient length of < 3.5 standard unit; hence RDA was conducted (Lepš & Šmilauer, 1999). ...
... To determine the appropriate constrained ordination model for the datasets, I performed a detrended correspondence analysis (DCA; Lepš & Šmilauer, 1999;ter Braak & Šmilauer, 2002). DCA revealed a gradient length of < 3.5 standard unit; hence RDA was conducted (Lepš & Šmilauer, 1999). Significance of the RDA axes was tested with an ANOVA-like permutation test based on a pseudo-F statistic (Oksanen, & ter Braak, 2011). ...
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Agricultural land-use is a leading cause of water quality deterioration, biodiversity loss and impairment of stream functionality. Understanding the mechanisms by which agricultural land-use impair stream ecosystems is important for their effective management, especially in Africa. In this study, a combination of analytical tools, including macroinvertebrate taxonomic- and trait-based community analysis, functional indices, functional feeding groups and stable isotopes were used to investigate the effects of an increasing gradient of agricultural disturbance on the community composition, functional diversity, and food web of aquatic macroinvertebrates in the Kat River. Eight sites grouped into four site categories that represent a decreasing gradient of agricultural pollution (LUC 1< LUC 2 < LUC 3 and LUC 4) were selected. Macroinvertebrates and physiochemical variables and aquatic and terrestrial basal food sources were sampled from the eight sites over four sampling occasions; dry (winter and spring) and wet (summer and autumn) periods using the SASS 5 protocols. The taxonomy-based analysis showed different responses of macroinvertebrates to agricultural disturbance, with taxa such as Lymnaea spp., L. columella, Appasus spp. Biomphalaria spp., Trithemis spp. and Oligochaeta identified as potentially tolerant indicators of agricultural pollution. These taxa were positively correlated with the highly disturbed LUC 1 sites, and increasing levels of NH4-N, NO2-N, temperature and TDS. Conversely, Caenis spp., Afroptilum spp., Pseudocloeon piscis, Pseudocloeon spp., Baeti harrisoni, and Potamonautes spp. were sensitive to agricultural pollution, indicating strong negative associations with LUC 1 sites and NH4-N, NO2-N, salinity, temperature and TDS. Further, a multimetric index (MMI) was developed, validated and applied to assess agricultural disturbance in the Kat catchment. Of the 29 metrics that satisfactorily discriminated the LUC 4 site from the LUC 1, 2 and 3 sites, only eight metrics were non-redundant and integrated into Kat River MMI. The metrics integrated into the final MMI were Decapoda abundance, EPT/Chironomidae abundance, %EPT abundance, %Ephemeroptera abundance, %Caenidae abundance, %Hydropsychidae abundance, %Oligochaeta+chironomidae abundance and Shannon index. The developed MMI proved effective as a biomonitoring tool for assessing the ecological health of agricultural pollution in the Kat River. The trait-based analysis showed that traits such as haemoglobin, spiracle, adult aquatic life stage, active swimming and predatory lifestyle were positively correlated with LUC 1 sites, and were deemed tolerant-trait indicators of agricultural pollution. Shredding, medium body size (>10–20 mm), crawling and a preference for macrophytes were negatively correlated with LUC 1 sites, and were deemed sensitive-trait indicators of agricultural pollution in the Kat River. Functional diversity responded predictably to agricultural pollution, as functional indices such as functional richness, significantly declining along disturbance gradient during the dry and wet periods. The functional feeding group results revealed that gatherers and scrapers dominated in the Kat River, and together represented 0.27–0.43 of the invertebrate composition. Shredders were the lowest represented in the Kat River, with a relative abundance of 0.18. The FFG results showed that filter-feeders and predators increased in abundance along increasing environmental stress gradient, whereas shredders’ abundance decreased along the environmental stress gradient. Analysis of stable carbon (δ13C) and nitrogen (δ15N) isotopes were used to estimate the contributions of aquatic and terrestrial resources to consumers across the four LUC and periods. Carbon contributions, determined using mixing models (Stable Isotope Analysis in R), revealed that consumers assimilated mainly aquatic sources (filamentous algae, macrophytes and biofilms), and this assimilation increased as agricultural disturbance increased across the two seasons. Terrestrial-derived food sources did not show evident variations among the LUCs, but C4 grasses changed along an increasing gradient of agricultural pollution during the two seasons. Further, there was enriched 15N of consumers, especially scrapers, predators and filter-feeders, along the disturbance gradient, whereas that of shredders declined along an agricultural disturbance gradient. NH4-N was the variable that affected consumers δ15N values, indicating a significant positive correlation with δ15N values for the majority of the consumers, especially gatherers, shredders and scrapers. The results of the study highlight the strength of a complementary approach to biomonitoring agricultural pollution in riverine systems. For example, the taxonomic analysis indicated changes in community composition, and the trait-based approach provided insights into the key stressors associated with agricultural pollution as a cause of water quality deterioration. The study contributes significantly to our understanding of riverine ecology in South Africa and, in particular the Kat River, in the context of agricultural pollution, which remains one of the leading causes of pollution of riverine ecosystems.
... Partial redundancy analyses with forward selection (p-RDA FS) was performed for both phytoplankton and zooplankton assemblages. These methods were used because the Detrended Correspondence Analysis (DCA) revealed that the gradient length of the response data was < 3 (Lepš and Šmilauer, 1999). Only those variables that had a variance inflation factor (VIF) less than 20 were considered (Lepš and Šmilauer, 1999). ...
... These methods were used because the Detrended Correspondence Analysis (DCA) revealed that the gradient length of the response data was < 3 (Lepš and Šmilauer, 1999). Only those variables that had a variance inflation factor (VIF) less than 20 were considered (Lepš and Šmilauer, 1999). Two groups of variables were used: natural (including routine environmental variables like temperature, pH, conductivity, or light penetration) and anthropogenic (including BOD 5 , COD, metals, pesticides, and nutrients). ...
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Lowland lotic ecosystems are under increasing pollution pressure. In this study, we analyzed the plankton community responses to environmental changes, including natural ones and those related to anthropogenic activities, to finally determine their optimums in natural conditions. In four dates, seven streams were sampled, and a total of twenty-one physical-chemical variables were measured or estimated (including metals and pesticides). Partial redundancy analyses were performed, as well as, General Linear Models (GLM) considering Reynolds Functional Groups (RFG) for phytoplankton, and families for zooplankton as response variables. Finally, the optimum concentration of these plankton groups was estimated. Results indicated that phytoplankton was dominated by diatoms belonging to functional groups B, C, and TB, being chlorophytes (J) and cyanobacteria (M) the subdominant groups. Zooplankton was dominated by Bdelloidea, Brachionidae, and Copepoda nauplii. For almost all groups of phytoplankton, except M, chemical oxygen demand (COD) and high nutrients concentrations contribute to explain their variations. However, the explanation percentages increased when other variables like temperature and light extinction coefficient were included. For zooplankton, chromium and biochemical oxygen demand (BOD 5) explained variation of almost all groups. Variance explanation of Lecanidae, Gastropodidae, Trochosphaeridae, and Trichocercidae increased when conductivity and pH were included. Finally, both plankton groups had in general high maximum tolerance for COD, BOD5 , and metals concentrations. We conclude that the plankton assemblages of these highly modified lowland streams could tolerate the anthropogenic disturbance, with organic pollution and eutrophication, as the most relevant.
... We used redundancy analysis (RDA; Canoco 4.5 package; ter Braak and Šmilauer, 2002) to assess correlation between Euphorbia traits in different microhabitats. RDA provides a good estimate of main trends in the data and can be considered an extension of multivariate regression for a multivariate response variable (Lepš and Šmilauer, 2003). The parametric test is replaced by Monte Carlo permutations to overcome problems with distributional characteristics. ...
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Shrubs have positive (facilitation) and negative (competition) effects on understory plants, the net interaction effect being modulated by abiotic conditions. Overall shrubs influence to great extent the structure of plant communities where they have significant presence. Interactions in a plant community are quite diverse but little is known about their variability and effects at community level. Here we checked the effects of co-occurring shrub species from different functional types on a focal understory species, determining mechanisms driving interaction outcome, and tested whether effects measured on the focal species were a proxy for effects measured at the community level. Growth, physiological, and reproductive traits of Euphorbia nicaeensis, our focal species, were recorded on individuals growing in association with four dominant shrub species and in adjacent open areas. We also recorded community composition and environmental conditions in each microhabitat. Shrubs provided environmental conditions for plant growth, which contrasted with open areas, including moister soil, greater N content, higher air temperatures, and lower radiation. Shrub-associated individuals showed lower reproductive effort and greater allocation to growth, while most physiological traits remained unaffected. Euphorbia individuals were bigger and had more leaf N under N-fixing than under non-fixing species. Soil moisture was also higher under N-fixing shrubs; therefore soil conditions in the understory may counter reduced light conditions. There was a significant effect of species identity and functional types in the outcome of plant interactions with consistent effects at individual and community levels. The contrasting allocation strategies to reproduction and growth in Euphorbia plants, either associated or not with shrubs, showed high phenotypic plasticity and evidence its ability to cope with contrasting environmental conditions.
... CCA is an unlinear technique used to relate variation in biotic properties to measured variation of the environment. The constrained ordination axes correspond to the directions of the greatest variability of thedata set that can be explained by the variables (Lepš and Šmilauer, 1999), XL State 2001 program was used to analyze correlation and regression analysis. ...
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Lake Qarun is a closed saline lake in the northern part of El-Fayoum Depression of Egypt. The objective of this work is to give a complete picture of lake biotic factors to alarm on dinoflagellates blooming phenomenon and to compare between chlorophyll a values measured by Fluorometer and Spectrophotometer. Monthly patterns in Chlorophyll a concentrations were measured during the period from May 2015 to April 2016, using two different methods; by fluorometric and spectrophotometric techniques. Phytoplankton species in Lake Qarun are heterogeneously distributed all over the year; dinoflagellates were the main dominant group, chlorophyll a frequently accumulated as distinct peak (336 μgl ⁻¹ ) in July 2015. The phenomenon of dinoflagellated blooming of Prorocentrum micans, Gymnodinium lantzschii and Exuviaell aapora that turning the lake water to brown in colour, is recorded annually. The two methods used in detection of chlorophyll a during this work are accurate and simplified bring the picture in Lake Qarun. Actually, results of fluorometer are more sensitive and higher than those of spectrophotometer. In fact, high salinity, agricultural drainage water from drains and aquaculture activities turned the lake to variable, sensitive aquatic ecosystem, affecting significantly on phytoplankton structure and blooming dynamics determination. There is no record of toxicity effects or mass fish mortality in the lake due to this phenomenon. © 2018, Egyptian Society for the Development of Fisheries and Human Health. All rights reserved.
... Cependant, comme l'écrivent Leps & Smilauer (1999), "It should be noted that the results of numerical classifications are objective in the sense that the same method gives (usually) the same results; however, it should be kept in mind that the results of numerical classifications are dependent on the methodological choices". Et, dans le cas d'un mélange statistique de relevés de diverse nature (relevés trop étendus, complexes, fragmentaires...), l'ordination ne peut aboutir qu'à l'élaboration d'unités virtuelles de végétation sans réalité synécologique (Géhu, 1996). ...
... Statistical analysis. The CA vegetation data analysis was performed using the CANOCO 4.5 statistical software [14]. The transformation of abundance and cover estimation for each species within phytocoenological relevés was performed according to the Van Der Maarel method [15]. ...
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Forest of beech and fir represents a climate-regional vegetation belt, widely present in the Balkans. In Serbia, this community has the widest span on Mt. Goč, but occasionally occurs on different parent rocks as well as on many lower mountains. This paper compares the beech and fir forest on the granodiorite parent rock of Mt. Jastrebac against the same type of forest on the serpentinite parent rock of Mt. Suvobor, in order to determine whether and how the parent rock influences the floristic composition of the studied stands. The analysis included 29 phytocoenological relevés, 20 of them from Mt. Suvobor and 9 from Mt. Jastrebac. Statistical analysis revealed significant differences in floristic composition of studied sites. The beech and fir forest of Mt. Jastrebac has richer floristic composition and a larger number of species of the Central European areal type, which emphasizes a highly mesophilic character of the studied stands. The beech and fir forest of Mt. Suvobor has poorer floristic composition, a larger number of xerophilic species belonging to the sub-Mediterranean areal type, as well as an increased share of chamaephytes and therophytes, which is an indicator of Mt. Suvobor's deficient site conditions. Increased xerophilia of the beech and fir forests on Mt. Suvobor can be explained with the warmth of serpentinite parent rock, as well as with very steep slopes on which the observed stands are located.
... The DCA indicated that unimodal method of ordination was the most appropriate method to analyse our dataset: the longest gradient was larger than 4 standard deviation units (5.5) of species turnover. Use of the linear method would not be appropriate, as the data are too heterogeneous and too many species deviate from the assumed model of linear response (Leps and Smilauer, 1999). Therefore, CCA was chosen as the most suitable method to analyse the data. ...
Article
The fungal diversity in silages for dairy cattle feeding has been assessed by purification and identification of 966 isolates collected in silages during the two 2006 and 2007 winter storage/feed-out periods from farms localized in various geographic regions in Belgium. The relevant fungal species in silos were P. paneum and P. roqueforti (18.2 % and 14.5 % of total isolates, respectively). The proportion between the two species varied significantly from 2006 to 2007 (P<0.05) depending on the type of forage crop. The prevalence of P. paneum in Belgium compared to results in other countries is of major importance due to the mycotoxigenic capacity of this species. Information on numerous aspects of silage making process and silo management showed that neither the crop rotation, the date and weather at harvest, the use of additives, the feeding rate, the type and dimension of silo, the covering used nor the forage chopping length at ensiling could be significantly correlated to the fungal species composition isolated in farm silages. There were also no significant relationships between the chemico-fermentative parameters tested (dry matter, pH, NH3 content, concentration of lactic, acetic and butyric acids) and the fungal species composition in silages. The prevalent fungi were tolerant of the wide ranges of conditions found in the farm silages with year-to-year variations.
... The names of syntaxa were given based on [11], DCA analysis of vegetation data was done with the help of statistical software CANOCO 4.5 [12]. ...
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This article shows the results of coenological and vital adaptation, and in that regard planned sustainability, of certain species inside artificially-established stands in forests of Hungarian oak and Turkey oak (Quercetum farnetto-cerris Rud. 1949.) on loam soil, located in the forest complex Lipovica near Belgrade. Results of this research have undoubtedly confirmed that cultivating certain species in these parts is worth the effort, since they have shown extreme coenological adaptability and vitality. These species are the English
... Detrended Correspondence Analysis (DCA) is useful for determining similarities between the biological assemblages of sites (Lepš and Šmilauer 1999). DCA was used to check on the viability of using the three different diatom data sets to construct wetland metrics for northern Wisconsin. ...
... All the measured environmental variables were initially used as explanatory variables. However, a forward selection was used to identify the more significant subset of environmental variables, and only those variables that had a variance inflation factor (VIF) less than 20 were finally considered (Lepš & Šmilauer, 1999). ...
Article
Despite the critical importance of zooplankton for many ecological processes, knowledge of its structure and distribution patterns in small streams subject to intensive land uses remains limited. Here we analyzed changes in zooplankton community and composition in 10 sites located in streams from first‐order to sixteenth‐order, according to Shreve´s classification, in a small catchment influenced by intensive agriculture. Using uni and multivariate methods, we investigated the extent to which local scale environmental factors explained the spatial patterns of zooplankton community. We found that environmental conditions of headwaters differed markedly from those of lowland streams, especially with respect to nutrient levels, which were higher in the former than the latter. Zooplankton community was mainly composed by microphagous rotifers, and the overall species composition differed with the stream order. While zooplankton diversity and evenness increased with stream order and correlated negatively with nutrient level, zooplankton abundance and biomass showed the opposite trend. The mechanistic processes creating these patterns remain unknown but are likely linked to the effects of greater water mixing and dilution in lowland streams, as well as ecological processes such as predation and resource diversification. No clear pattern was found for presence or concentrations of pesticides in relation to the stream order. However, water quality seemed to be an important factor influencing zooplankton assemblages, which were significantly associated with pesticides and trophic state variables. Our findings suggest that agricultural pollution is impacting the zooplankton community, which may have implications for the food webs and overall health of the stream systems.
... Avaliamos se o esforço amostral foi suficiente para amostrar a comunidade de anfíbios anuros local construindo uma curva de acumulação, obtida através do índice não-paramétrico Jacknife 1. Para avaliar possíveis associações da abundância e as variáveis climáticas, realizamos análises de regressões linear múltipla, sendo considerados significativos valores de P < 0,05 (ZAR, 1999). As temperaturas médias mensais e a pluviosidade mensal acumulada foram transformadas pela função log10 (x+1), centralizadas e padronizadas, quando necessário (LEPS; SMILAUER, 1999;TER BRAAK, 1995). As análises foram realizadas no software BioEstat 5.3 (AYRES et al., 2007). ...
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Ambientes naturais ou criados pelo homem abrigam uma diversidade biológica ainda não calculada e altamente ameaçada. No presente trabalho, analisamos a artropodofauna edáfica em dois ambientes florestais distintos (bosque de eucalipto e uma área de mata nativa), localizados no município de São José do Cedro/SC. As coletas ocorram no período de maio a dezembro de 2016. Utilizou-se um conjunto 30 armadilhas de queda (pitfall-trap), empregadas em três transectos. Foram coletados 8745 indivíduos distribuídos em 18 táxons, destes 5514 indivíduos (63,05%) na mata nativa (N=19 ordens) e 3231 indivíduos (36,95%) no plantio de eucalipto (N = 15 ordens), sendo que os grupos Hemynoptera, Collembola e Diptera apresentaram as maiores porcentagens de indivíduos coletados respectivamente, 32,9%, 22,4% e 13,9%. A riqueza do plantio de eucalipto e da mata nativa não foi determinado pela temperatura, umidade relativa do ar e pluviosidade. Os resultados apresentados mostram uma grande diversidade de artrópodes de solo abrigados em remanescentes florestais de Mata Atlântica, e que as monoculturas, tais como as plantações de Eucalyptus spp. influenciaram na diminuição da diversidade da artropodofauna.
... DCA revealed that the longest ordination axis was lower than three, which meant that the distribution of the model was linear. Redundancy analysis (RDA) was used due to the fact that the distribution of the model was linear, as described by the statistical method recommended by Lepš and Šmilauer [37]. Statistical significance was tested using a Monte Carlo test with 499 permutations and a selected significance level of 0.05. ...
Article
Primary settling tanks are used to remove solids at wastewater treatment plants and are considered a fundamental part in their joint operation with the biological and sludge treatment processes. The aim of this study was to obtain a greater understanding of the influence of operational parameters, such as surface overflow rate, hydraulic retention time, and temperature, on the removal efficiency of suspended solids and organic matter by the measurement of chemical oxygen demand and biochemical oxygen demand in the primary sedimentation process. The research was carried out in a semi-technical primary settling tank which was fed with real wastewater from a wastewater treatment plant. The physical process was strictly controlled and without the intervention of chemical additives. Three cycles of operation were tested in relation to the surface overflow rate, in order to check their influence on the different final concentrations. The results obtained show that the elimination efficiency can be increased by 11% for SS and 9% for chemical oxygen demand and biochemical oxygen demand, for variations in the surface overflow rate of around ±0.6 m³/m²·h and variations in hydraulic retention time of around ±2 h. The results also show that current design criteria are quite conservative. An empirical mathematical model was developed in this paper relating SS removal efficiency to q, influent SS concentration, and sewage temperature.
... We also performed detrended correspondence analysis to determine whether unimodal or linear ordination techniques would be most appropriate for modeling the relationships between the abundance of each macrobenthos functional group and the environmental variables. This analysis led us to use linear ordination techniques because the gradient length of axis 1 was < 3 (Lepš and Šmilauer, 2003). We used redundancy analysis (RDA; Legendre et al., 2011) to describe the effect of statistically significant environmental parameters on the abundance of the five macrobenthos functional groups, the relationships between the two study areas and the macrobenthos functional groups, and the relationships among the environmental variables. ...
... ‫پبٗ٘ي‬ ‫هتش‬ .‫اػت‬ ‫آصاد‬ ٕ‫دسٗب‬ ‫ػغح‬ ‫اص‬ ‫تش‬ ‫آة‬ ‫ٍضؼ٘ت‬ ٖ‫ثشسػ‬ ‫دس‬ ‫اٗشاى‬ ‫فلَس‬ ٍ ) ( Assadi et al., 1988Assadi et al.,-2012 Lepš & Šmilauer, 1999 ‫ًشم‬ ‫لبلت‬ ‫دس‬ ،) ‫افضاس‬ Canoco ‫ؿذ‬ ُ‫اػتفبد‬ ( Cannon et al.,1998 .) ٍ‫ّشد‬ ‫سٍؽ‬ ُ‫پذٗذ‬ ٍ ّٖ‫گ٘ب‬ ‫پَؿؾ‬ ‫دسن‬ ِ‫ث‬ ُ‫روشؿذ‬ ‫صٗؼت‬ ٕ‫ّب‬ ٖ‫هح٘غ‬ ٖ‫ه‬ ‫ووه‬ ( ‫وٌذ‬ Dalia et al., 2014 ‫اٗي‬ ‫دس‬ .) ...
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This paper concerns itself with the study of sand beaches of the Boujagh National Park with an area of 3477 ha. The purposes of this study include the determination of the plant species diversity and plant groups. In ad-dition, the determination of the impact of environmental and specific variables on the presence or absence of certain species and their communities is another aim that the study follows. In order to attain those purposes, 52 plots across 6 transects of the district were used. In each plot, the materials were identified and abundance-dominance of species by using Braun-Blanquet criteria were obtained and their life forms were determined according to Raunkiaer clas-sification. To determine the plant groups, a Two-way analysis of significant modified species (Modified TWINSP-AN) was utilized. Detrended Canonical Analysis (DCA) was used to determine factors affecting plant groups. The results showed that four plant groups exist in this district: Convolvulus persicus-Crepis foetida subsp. Foetida grou-p, Argusia sibirica group, Eryngium caucasicum-Juncus acutus group and Rubus sanctus group. The first and seco-nd groups consist of higher percentages of therophytes and spread in areas where the soil contains more sand. Plants in the third and fourth groups spread in areas with stabilized sand and high percentage of silt. DCA analysis results showed that soil factors (texture, OC, Na, K, N, Ca, Mg) have significant relation with plant groups were studied. Among the plant groups, the percentage of silt and sand, species richness and life forms of therophytes and geop-hytes show significant relations. Therefore it can be concluded that these factors affect on the separation and distri-bution of plant groups.
... The ordination method was used to assess the species-environment relationships (Kent & Coker, 1994). Since the species data in this study generally showed a non-linear species response curve, CCA (Canonical Correspondence Analysis) was applied to investigate the vegetation-environment relationships (Lepš & Šmilauer, 1999) using PC-ORD 4 software (McCune &Mefford, 1999) andCanoco 4.5 (ter Braak &Smilauer, 2002). For the application of ordination method, the different measurement units of environmental variables were standardized (ter Braak, 1986). ...
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The genus Cotoneaster is considered an important taxon in the woodlands of the Mediterranean and Irano-Turanian regions. Some species of this genus were reported from the Irano-Turanian alpine woodlands. Irano-Turanian mountainous wood and shrublands have a great importance in terms of water and soil conservation, biodiversity and plant richness. There is a lack of quantitative and qualitative statistics available for many of these ecosystems. This research focused on the ecology and phytosociology of Cotoneaster shrublands in central Alborz (Iran), with emphasis on C. kotschyi, an endemic drought-tolerant species. Data was collected based on the Braun-Blanquet method. TWINSPAN was used to analyse the vegetation data. Species-environment analysis was performed by CCA (Canonical Correspondence Analysis) and one-way ANOVA. Relevés were classified into three distinct groups regarding their floristic composition. By organizing the phytosociological table, a new subassociation was defined and named as Rhamno pallasii-Juniperetum excelsae cotoneastretosum kotschyi subass. nova. This syntaxon is distributed in the range of 2,200–2,430 m a.s.l. between two other groups, i.e. Cotoneastro nummulariis-Juniperetum excelsae and Rhamno pallasii-Juniperetum excelsae. Cotoneaster kotschyi ecologically is near to Rhamnus pallasii which is characteristic for Juniper communities on shallow soils and stony lands. Among the environmental variables, slope, soil texture, pH, lime and saturation percent are the most important distinguishing factors of this subassociation. So, the new syntaxon is found in the habitat with an average slope of 60%, sandy-loam soils and pH and lime percent less than other studied communities. The subassociation cotoneastretosum kotschyi has a higher amount of sand content compared to the other vegetation groups. Cotoneaster nummularius is an indicator of vegetation communities with relatively evolved soils. However, C. kotschyi grows in poor and shallow soils. C. kotschyi is a differential species which indicates the variability between the two main Alpine associations of the Irano-Turanian region. It is an appropriate species for plantation in the semi-arid mountainous areas. The ecological demands and the floristic composition of these plantations are determined in this article.
... CCA was done on abundant bacterial genera (i.e., relative abundance >1 % in at least one sequencing library) and selected environmental parameters (TOC and Fe-extractable fractions). Manual forward selection with Monte Carlo permutation was then performed to determine the significance of the environmental variables with 999 permutations (Lepš and Šmilauer 2003 ). The correlations between TOC and the dominant phyla and genera and diversity indices were determined by Spearman's rank correlation using SPSS (v19, IBM, Armonk, USA). ...
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A small watershed heavily contaminated by long-term acid mine drainage (AMD) from an upstream abandoned coal mine was selected to study the microbial community developed in such extreme system. The watershed consists of AMD-contaminated creek, adjacent contaminated soils, and a small cascade aeration unit constructed downstream, which provide an excellent contaminated site to study the microbial response in diverse extreme AMD-polluted environments. The results showed that the innate microbial communities were dominated by acidophilic bacteria, especially acidophilic Fe-metabolizing bacteria, suggesting that Fe and pH are the primary environmental factors in governing the indigenous microbial communities. The distribution of Fe-metabolizing bacteria showed distinct site-specific patterns. A pronounced shift from diverse communities in the upstream to Proteobacteria-dominated communities in the downstream was observed in the ecosystem. This location-specific trend was more apparent at genus level. In the upstream samples (sampling sites just below the coal mining adit), a number of Fe(II)-oxidizing bacteria such as Alicyclobacillus spp., Metallibacterium spp., and Acidithrix spp. were dominant, while Halomonas spp. were the major Fe(II)-oxidizing bacteria observed in downstream samples. Additionally, Acidiphilium, an Fe(III)-reducing bacterium, was enriched in the upstream samples, while Shewanella spp. were the dominant Fe(III)-reducing bacteria in downstream samples. Further investigation using linear discriminant analysis (LDA) effect size (LEfSe), principal coordinate analysis (PCoA), and unweighted pair group method with arithmetic mean (UPGMA) clustering confirmed the difference of microbial communities between upstream and downstream samples. Canonical correspondence analysis (CCA) and Spearman’s rank correlation indicate that total organic carbon (TOC) content is the primary environmental parameter in structuring the indigenous microbial communities, suggesting that the microbial communities are shaped by three major environmental parameters (i.e., Fe, pH, and TOC). These findings were beneficial to a better understanding of natural attenuation of AMD.
... In order to determine the similarity in the floristic composition between the studied stands, Bray-Curtis cluster analysis (measuring similarity) with the option "Group Average" in BIODIVERSITY PRO (McAleece et al., 1997) was performed. DCA vegetation data analysis was performed using the statistical software CANOCO 4.5 (Lepš and Šmilauer, 1999). The cover-abundance score obtained for each species within a relevé was transformed using the method of Van Der Maarel (Van Der Maarel, 1979). ...
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Novaković-Vuković et al.: Floristic composition of black pine forests on serpentinite in the territory of Serbia and Bosnia and Herzegovina (B&H)-4999-APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH 17(2):4999-5010. Abstract. Black pine forests of the Western Balkans constitute a significant complex of azonally and orographically-edaphically conditioned forests, on the ophiolite massifs of central and eastern Bosnia, as well as western and, to a certain extent, central Serbia. CA and Cluster analysis showed that there was no overlap in the floristic composition, which means that there are significant differences between the studied stands. Stands in Bosnia and Herzegovina (B&H) are floristically richer with 152 taxa recorded, while stands in Serbia had 82 taxa recorded. On the territory of B&H, communities grow under the conditions of maritime and humid climate; while in Serbia they grow in continental climate with less rainfall and significant exposure to sub-Mediterranean weather. In black pine forests in B&H two types of soil were described: eutric humus-siliceous, and brown soil on serpentinite; while in Serbia, there was only one type-eutric humus-siliceous. No significant differences were found in the spectrum of life forms. In the spectrum of floral elements, mesophilic floral elements (Central and Sub-Atlantic) were dominant on the territory of B&H; while stands in Serbia, were richer in xerophilous floral elements (Mediterranean, Balkan, Balkan-Apennine). Shannon-Wiener index and evenness index showed higher values in B&H.
... The ordination methods used included detrended correspondence analysis (DCA), principal components analysis (PCA), and redundancy analysis (RDA). DCA revealed that the length of gradient of each axis was <3 and, therefore, linear models (PCA and RDA) were used for data analysis (Lepš & šmilauer, 1999). ...
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Encroachment of woody plants has been among the major threats to the livelihoods of Borana pastoralists and their ecosystem. An approach that integrated vegetation survey and pastoralists’ perception was followed to study the impacts of encroachment of woody plants in the Borana lowlands, Ethiopia. Density of woody species was determined in 192 plots of 500 m2. Canopy cover of woody plants was estimated in 123 quadrates of 400 m2. Pastoralists’ perception was assessed through group discussions and a semi-structured questionnaire. Results showed that plant density was 3014 woody plants ha)1. Cover of woody plants was 52%, indicating an increasing trend from £40% cover reported in the early 1990s. It was concluded that the increase of woody plants density and cover has crossed the critical threshold and has entered into the encroached condition. Principal components analysis (PCA) and redundancy analysis (RDA) also showed that woody plants were negatively correlated with herbaceous biomass. Commiphora africana, Acacia melliphera, A. drepanolobium, A. brevispica and Lannea rivae were among the dominant encroachers. RDA revealed that soil nutrients were positively correlated with woody plants density and cover. The pastoralists perceived that encroachment of woody plants had decreased the production of their grazingland. A ban on fire was perceived as the major factor that caused encroachment of woody plants. Re-utilization of fire and strengthening of traditional rangeland management strategies are recommended.
... The first axis explained 90.1 % of the total variance for species data. In Fig. 5, the species are shown by points, and the environment variables are shown as vectors, arrowheads indicating the direction in which the value of environmental variable increases (Lepš & Šmilauer 1999). Species plotted close to the vectors have a strong relationship with them. ...
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In the actual context of global climatic and environmental changes, two endemic species for the Carpathians – Platynus glacialis Reitter, 1877 and Pterostichus pilosus wellensii (Drapiez, 1819), previously localized in and characteristic for two different mountain habitats (rocky areas in alpine to subalpine zone, respectively high altitude mountain forests), were found cohabiting, in large numbers, in the screes of subalpine zone. The bibliographical sources compiled with our field records revealed that both species have disjunct distributions. The effect of environmental variables (temperature, relative humidity and depth) on their populations was tested in this new type of habitat, where these two species were found coexisting. The statistical analysis of data gathered during a two years period, indicated that each species uses the scree habitat in different way, mainly depending on the exterior temperature variations, emphasizing the ecological importance of this habitat for species conservation. A distribution map of both species is given.
... For the CCGS Hudson AZMP cruise, nutrient samples were also collected directly from the Niskin bottles and frozen at −20°C until analysis by colorimetric techniques using a segmented-flow autoanalyzer (Technicon AutoAnalyzer II) at the Bedford Institute of Oceanography (Mitchell et al., 2002; Li et al., 2010). The values for silicate concentrations at the Amundsen Gulf station 405b 19 May 2008 and 405-10a 21 July 2008 were missing, and inferred from averages of all silicate values from the same depth in the Arctic samples (Lepš and Šmilauer, 2003). Both of these stations were weighted less (0.85) during the statistical analyses. ...
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The marine planktonic diatom order Thalassiosirales are used as climate proxies with reported characteristic temperate and Polar species. However, a systematic analysis of the genetic variability and species limits is lacking. Here, we combined molecular and morphological approaches to identify Thalassiosirales from 7 Beaufort Sea sea-ice samples and 27 water-column samples collected from across the Canadian Arctic at different times of the year and the Scotia Shelf, North Atlantic in spring. While many species were found in both oceanic regions, there were two distinct Thalassiosirales communities: the first from sea ice and ice-influenced water columns and the second Arctic late summer and North Atlantic spring communities. Thalassiosirales formed genetically coherent Boreal-Arctic meta-communities, inclusive of intra-specific variants. Genetic similarity between the Arctic and North Atlantic meta-communities would be reinforced by counter-clockwise dominant surface current systems. Local patterns of spatial and temporal distributions of planktonic thalassiosiroids were best explained by latitudinal gradients and phosphate and silicate concentrations, suggesting that climate-mediated changes in Arctic and North Atlantic hydrography could have a marked effect on species distribution. Our analysis also revealed a need for taxonomic revision of several species complexes reported from the region before they can be reliably used as bio-indicators.
... This approach replicates aspects of the methodology devised by Carrott and Kenward (2001) and Kenward and Carrott (2006) to analyse British archaeoentomological assemblages. Detrended Correspondence Analysis revealed that the dataset was following a linear response model (ter Braak, 1995; Lepš & Šmilauer, 2003) so CANOCO 4.5 (ter Braak & Šmilauer, 2002) was used to conduct Principal Component Analysis (PCA). The results are presented so that the axis x represents the component (or environmental variable) that explains the most variation, and the axis y, the second component in importance. ...
Article
1. Subfossil beetle remains from archaeological sites have proven invaluable for examining past living conditions, human activities, and their impacts on landscapes and ecosystems. 2. In Iceland, specific economic practices (e.g. land management and natural resource exploitation) and major historical events (i.e. colonisation, economic intensification and commercialisation, and urbanisation) have affected local environments and left recognisable traces in the beetle subfossil record. 3. Understanding the ecology of synanthropic beetles is crucial if they are to be employed in high-resolution reconstructions of past lifeways and their ecological impacts, yet, because buildings’ interiors are rarely the object of systematic entomological research, the ecological requirements of many such species are poorly understood. 4. A survey was conducted of live and dead beetle faunas from habitats that have so far been largely neglected by entomological research: stable manure and stored hay inside farm buildings, two key facets of a northern European pastoral economy. 5. The present results clarify the ecological requirements of some under-studied synanthropic beetles and the processes by which their exoskeletons may become incorporated into the archaeological record while also producing new records of exotic species recently introduced to Iceland. 6. This paper provides crucial guidance for the interpretation of archaeological beetle assemblages and highlights the potential of further investigations of indoor insect faunas for clarifying the causes, processes, and ecological impacts of recent bio-invasions.
... The Detrended Correspondence Analysis (DCA) is a type of indirect ordination analysis. It identifies the configuration of samples in the ordination space so that the distance between samples corresponds best to the dissimilarities of their species composition (Lepš and Šmilauer, 1999;Šmilauer and Lepš, 2014). The DCA in the Canoco 5 software (Ter Braak and Smilauer, 2012) was utilized to reveal similarities in woody species compositions among the five sites. ...
Article
Cemeteries harbor and protect the diversity of forest species in urban areas. Inventories of species contribute to a valuable understanding of the indigenous biodiversity within the cemeteries. The goal of this study was to compare the composition of tree and shrub species in cemeteries belonging to the Muslim, Christian and Jewish communities in Istanbul, Turkey. Five cemeteries (Karacaahmet - Muslim; Zincirlikuyu - Muslim; Şişli - Greek Orthodox; Balıklı - Armenian; Hasköy - Jewish) were analyzed to identify and interpret similarities in the density of floral species. The importance of preserving some of these species due to their rarity or threat level was established. Effects of management practices among the selected cemeteries were also encountered. Abies nordmanniana subsp. bornmuelleriana, Viburnum tinus, Fraxinus ornus Cerasus mahaleb, Euonymus latifolius and Liquidambar orientalis were important threatened species. Each of the five cemeteries exhibit different vegetation characteristics and species important to the individual religious traditions. The most widespread species at Karacaahmet were Cupressus spp. (46%) and Pistacia terebinthus (15%). At Zincirlikuyu, tree species were almost identical to those at Karacaahmet and included Cupressus spp. (34%) and Pinus spp. (18%). Tree species identified at Şişli included Cupressus spp. (43%) and Buxus sempervirens (16%). At Balıklı, Rosa spp. (46%) was widespread over the entire site. Cupressus spp. (19%) and Euonymus japonica (15%) were the most widespread tree species at Balıklı. Finally, the most prevalent species at Hasköy were Ligustrum lucidium (35%), and Euonymus japonica (18%). The Karacaahmet and Zincirlikuyu exhibited the diversity of plant species. They were followed by Balıklı, Şişli, and Hasköy, respectively. The density of plant species was highest at Zincirlikuyu, followed by Karacaahmet, Hasköy, Şişli, and Balıklı. A centralized system of management that recognizes and respects the differences in religious beliefs, cultures, and site conditions could be beneficial for the Istanbul cemeteries which are natural and cultural heritage bridges from the past to the future.
... Detrended Correspondence Analysis (DCA) was performed to detect the length of the environmental gradient. After DCA, Canonical Correspondence Analysis (CCA) was performed because the dataset was relatively heterogeneous and, therefore, the length of ordination axes in DCA was relatively long (Lepš and Šmilauer, 2003). ...
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The present study provides an analysis of the soil and vegetation composition at 10 sites in Wadi El Rayan Protected Area and concentrates on the environmental factors that affect plant species distribution. A total of 17 vascular plant species belonging to 13 botanical families was recorded. Poaceae, Chenopodiaceae, and Zygophyllaceae were the largest families identified. Chorological analysis revealed that 47% of the studied species are Pluri-regional, 41% are Bi-regional and 12% are Mono- regional. The recorded species extend their distribution all over the Saharo-Arabian (33%) followed by Irano-Turanian (24%), Mediterranean (22%), Palaeotropical (8%), Sudano-Zambezian (5%), Neotropical (5%), and Euro-Siberian (3%). The life-form spectrum revealed that the phanerophytes (35%) and geophytes helophytes (23%) are the most frequent, followed by chamaephytes (18%), therophytes (12%), hemicryptophytes (6%), and helophytes (6%). The dominant species were Phragmites australis, Tamarix nilotica and Zygophyllum album; while the co-dominant species were Juncus rigidus, Nitraria retusa, Alhagi graecorum, Typha domingensis, Zygophyllum coccineum and Eucalyptus camaldulensis. Variation in species diversity among different locations were evident, the Northeast of the Lower Lake(9 species), followed by the Southwest of the Lower Lake and the Northeast of the Upper Lake(6 species each) showed highest species richness, while the Southeast of the Lower Lake showed the lowest recorded species richness (one species). Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) Ordination techniques were used to examine the relationship between the vegetation and soil parameters; pH, electric conductivity, CaCO3, organic matter and relative concentrations of cations.CCA analysis showed positive correlations of species and sites along the most important ecological gradients. Both ordination techniques clearly indicated the importance of these ecological factors on the distribution of the vegetation pattern in the area. © 2016 Jordan Journal of Biological Sciences. All rights reserved.
... First of all, transformation of quantity and coverage ratings for each type within the phytocoenical relevés was carried out following the Van Der Maarel method [16]. CA vegetation data analysis was conducted using the statistical software CANOCO 4.5 [17]. To determine the similarity of floristic composition between the a high level of presence, however, the spring aspect of this analysis is characterized by stands, the Bray-Curtis cluster analysis (measuring similarity) with the option "Complete Link" in Biodiversity pro [18] was performed. ...
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This paper presents a comparison of the floris-tic compositions of two communities of Greek maple (Acer heldreichii Orph.), which are endemic to the Balkan and a tertiary relict. The analysis consists of nine phytocoenological relevés made in the forest of beech and Greek maple (Acer heldreichii-Fagetum Jov.1957) and four phytocoenological relevés made in a high mountainous beech forest (Fagetum altimontanum moesiacum Jov.1985) on Mount. Jastrebac, Serbia. CA floristic analysis of the data collected showed that the forest of beech and Greek maple is characterized by floristic poverty , where edificators are dominant (Acer hel-dreichiii, Fagus moesiaca (Fagus sylvatica L. (incl. F. moesiaca)) and also Rubus hirtus, Athyriumfilix-femina, Anemone nemorosa. The high-mountainous beech forest is a lot richer in terms of floristic composition and contains species that are characteristic of the Fagion moesiacae alliance, which can be found at lower altitudes: Asperula odorata, Sambucus racemosa, Mercurialis perennis, Polygonatum verticillatum, Fraxinus excelsior. The diversity index (Shannon Wiener index) shows a higher value in the high mountainous beech forest than in the forest of beech and Greek maple, which was to be expected since the forest of beech and Greek maple has a greater number of species per phytocoenological relevé. The evenness index (Evenness index) also shows a higher value in the forest of beech and Greek maple. There is a nearly proper spatial distribution of plant species in this community. In both researched communities, blackberry (Rubus hirtus) prevents the natural re-generation of forests, thus special attention must be paid to the preservation of the gene pool, as well as forest floristic diversity of this important endemic and rare species.
... First, the transformation estimates of abundance and coverage for each species within the phytocoenological relevés were performed by the Van Der Maarel method [13]. CCA analysis of ecological-vegetation data was performed with the help of statistical software CANOCO 4.5 [14]. Monte Carlo permutation test was used to determine the significance of worth (eigenvalue) with appropriate CCA axes. ...
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The mountain beech forest represents a vast climate-regional belt of vegetation in Serbia, as well as the most economically important forest type, and takes up a significant area in Serbia and Montenegro. This paper focused on a comparison of the floristic composition of a typical mountain beech forest in Serbia and Montenegro in order to determine the differences between the investigated stands. A total of 12 phytocoenological relevés were analyzed; 7 on Jastrebac (Serbia) and 5 on Biogradska Gora (Montenegro). CCA analysis showed that significant differences are present among the studied stands. Phytocoenological relevés from Montenegro correlated with altitude and assembly, while relevés from Serbia have a correlation with slopes. Differences in floristic composition are mostly due to various tree layering. Stands on Mt. Jastrebac are dispersed, which allow the penetration of light on the terrestrial flora, leading to weed growth. The composition of tree layers is quite dense on Biogradska Gora, thus the shrub layer is poor, whereas terrestrial flora is mainly comprised of species that thrive in areas of little light (sciophytes). In the spectrum of floral elements, species of Central European areal type dominate both sites, which expressed extreme mesophilic characteristics of researched stands. In the spectrum of life forms on Mt. Jastrebac, phanerophytes are dominant due to the large number of species in the tree and shrub layer, while geophytes are dominant on Biogradska Gora as a result of dense tree layering, therefore, the ground flora consists of species that can complete the reproductive cycle before trees begin to bloom. KEYWORDS: beech forest, floristic composition, Serbia, Montenegro
... 8&8.78.(&1 &3&1;7.7 First, the transformation estimates of abundance and coverage for each species within the phytocoenological relevés were performed by the Van Der Maarel method [13]. CCA analysis of ecological-vegetation data was performed with the help of statistical software CANOCO 4.5 [14]. Monte Carlo permutation test was used to determine the significance of worth (eigenvalue) with appropriate CCA axes. ...
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The mountain beech forest represents a vast climate-regional belt of vegetation in Serbia, as well as the most economically important forest type, and takes up a significant area in Serbia and Montenegro. This paper focused on a comparison of the floristic composition of a typical mountain beech forest in Serbia and Montenegro in order to determine the differences between the investigated stands. A total of 12 phytocoenological relevés were analyzed; 7 on Jastrebac (Serbia) and 5 on Biogradska Gora (Montenegro). CCA analysis showed that significant differences are present among the studied stands. Phytocoenological relevés from Montenegro correlated with altitude and assembly, while relevés from Serbia have a correlation with slopes. Differences in floristic composition are mostly due to various tree layering. Stands on Mt. Jastrebac are dispersed, which allow the penetration of light on the terrestrial flora, leading to weed growth. The composition of tree layers is quite dense on Biogradska Gora, thus the shrub layer is poor, whereas terrestrial flora is mainly comprised of species that thrive in areas of little light (sciophytes). In the spectrum of floral elements, species of Central European areal type dominate both sites, which expressed extreme mesophilic characteristics of researched stands. In the spectrum of life forms on Mt. Jastrebac, phanerophytes are dominant due to the large number of species in the tree and shrub layer, while geophytes are dominant on Biogradska Gora as a result of dense tree layering, therefore, the ground flora consists of species that can complete the reproductive cycle before trees begin to bloom.
... The plant community types were recognized using Agglomerative hierarchical cluster analysis. Communities were �����= on the basis of quadrats grouping by similarity [38,39]. Agglomerative hierarchical cluster analysis revealed that there ...
... Prior to this analysis, individual densities of species were log-transformed and Variance Inflation Factors (VIFs) were inspected in environmental data. High values for the VIF ( > 20) indicated multicollinearity between some variables, and this should be avoided from set of the environmental variables ( Lepš and Šmilauer, 1999 ). The VIF values were re-calculated in process of the step by step removing the variables and the variables with VIF > 20 were omitted from further multivariate analyses. ...
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Rivers and streams possess many characteristics that result from features of their surrounding landscape, e.g. from climate conditions, superficial lithology, soil profile, topography, vegetation cover, and human activities as well. In this study, we determined the impact of superficial geology and catchment land use, as the key landscape drivers affecting the physico-chemical and biological conditions in stream ecosystems, on the structure and values of selected ecological metrics relating to stonefly assemblages. In order to achieve this goal, we sampled 10 mid-sized submountain Carpathian streams flowing through two different geological bedrocks and draining the catchment areas with different dominant land use. As a consequence, these differences, we analyzed together 16 physico-chemical and biological parameters of stream environment. Our results demonstrate that 4 environmental parameter (particulate organic matter, transported inorganic matter, phosphorus and silicon ions), reflecting difference in superficial geology and landuse of the catchment area, played a significant role in the structuring of stonefly assemblages. We also found that catchment land use had an impact on values of the SAS and Saprobic indices as well as on the proportion of Leuctridae/Nemouridae and Brachyptera species in stonefly assemblages. The difference in catchment geology were reflected in values of total species richness and in the proportion of Leuctridae/Nemouridae and Brachyptera species as well.
... A set of species weights (on the right side of the diagram) shows the affinity of each species to the community response pattern offered by the PRC model (Leps and Smilauer, 2003 for further details). The higher the species weight, the stronger the species response to treatment. ...
Article
Determining the resistance and resilience of resources and benthic invertebrates connected to instream refuges and species re-colonization in post-flood periods may help to elucidate mechanisms behind community recovery. This experiment simulated flow pulses in a small temporary stream in an extremely wet year, using upstream control and downstream flooded reaches at three sites in order to assess community resistance and resilience (benthos and drift), and analyse resources (periphyton and benthic organic matter) and invertebrates at pre- and post-flood time periods. The hyporheos was sampled in order to explore species exchanges with benthos. Fewer resources and benthic invertebrates at the beginning of the experiment were found than in previous studies when base flow conditions prevailed. Resource stocks and benthic invertebrates showed high resistance to the flow pulse. Interestingly, there was low resilience of benthic organic matter to natural seasonal flooding. Chlorophyll a did not recover after experimental floods; instead, it was reduced after floods, despite the more benign flow conditions and non-limiting irradiance levels, pointing to top-down control by consumers. Additionally, the experimental flood significantly disturbed only the invertebrate composition in the groundwater-fed stream, which was inhabited by the fewest adapted-to-flood-disturbances macroinvertebrates. Despite the low resilience observed, richness and densities of benthos increased during the study, evidencing progressive colonization. Around 50–60% of macroinvertebrates were present in both benthos and hyporheos. Richness increased after flooding, suggesting that the hyporheic zone could be the main source of colonizers. Three species traits characterized the hyporheos: small size, cocoons and feeders of microorganisms within the fine sediment matrix. The main results indicate that longer-than-normal flood periods in early spring may constrain invertebrate succession before the next summer drought in temporary streams. This study underscores the importance of hyporheic fauna as a significance source of colonizers, highlighting the importance of connectivity to the groundwater.
... Els resultats obtinguts van servir de guia per orientar els projectes de restauració ecològica actuals i futurs al Ter, com a exemple dels sistemes fluvials mediterranis del sud-oest d'Europa. Per relacionar la distribució per ambients de les espècies i les variables estructurals del medi representades per l'anàlisi factorial es va utilitzar l'anàlisi parcial de redundàncies (APR o RDA en terminologia anglesa), una forma constreta de l'ACP (Leps & Smilauer, 1999). Permet distingir gradients estructurals entre l'hàbitat i els grups d'organismes, però assumeix que les respostes de les espècies a les variables ambientals segueix una distribució lineal i no unimodal, com en el cas de l'anàlisi canònica de correspondències (ACC), que és el test de referència. ...
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The chapter has been published in the book of the EU Interreg IVB Sudoe RICOVER project, that was based on the development of joint strategies for the protection and restoration of rivers, which play such an important role in ecosystems.
... Statistical analysis. The CA vegetation data analysis was performed using the CANOCO 4.5 statistical software [12]. The transformation of abundance and cover estimation for each species within phytocoenological relevés was performed according to the Van Der Maarel method [13]. ...
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Beech-fir forests comprise distinctly formed climate-regional vegetation belt on West Balkans. They are registered on various geological substrates: acidic, alkaline, ultra-alkaline; and on various types of soil: from humus-accumulative (mul-ranker), to brown (eutric), lessive soils and diluvium. These forests are highly productive on most localities and represent the most stable type of forest on Dinarides. Aim of this research was to gather floristic data which would aid in clearer eco-vegetational differentiation of these forests by comparing their floris-tic composition. Phytocoenological relevés from Jastrebac, Maljen and Suvobor (Serbia), as well as relevés from beech-fir virgin forest community on Biogradska Gora (Montenegro) were analyzed. CA analysis showed clear differentiation of phyto-coenological relevés and species depending on locality and geological substrate. Forests of beech and fir on granodiorite of Jastrebac are characterized by presence of typical fagetal species: Ulmus glabra, Tilia platyphyllos, Asperula odorata, Asa-rum europaeum. Beech and fir forests on serpentin-ite of Suvobor and Maljen are characterized by poorer floristic composition and presence of xero-philic species, as well as species typically found in oak and pine forests (Quercus dalechampii, Fraxi-nus ornus, Daphne blagayana). Floristic composition of beech and fir communities on eruptives of Biogradska Gora differ significantly compared to localities in Serbia. They are found on higher altitudes , and contain typical beech-fir forest species as well as high-mountain species: Paris quadrifolia, Senecio nemorensis, Sanicula europaea, Rubus idaeus, Actaea spicata, etc. Forests of beech and fir on Jastrebac and Biogradska Gora contain more floral elements characteristic for humid areas, as opposed to beech and fir forests of Maljen and Suvobor, which feature more xerophilic elements. Highest values of Shannon Wiener index are on Biogradska Gora, where highest species count had been registered. Evenness index is highest on Maljen, which indicates that plant species there have most favorable spatial distribution.
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Macroinvertebrates are widely used as indicators to detect and assess anthropogenic impacts on freshwater ecosystems. However, despite being considered useful in indicating effects of environmental change in alpine catchments, little is known about species preferences for local conditions in such environments. In exploring the occurrence of 59 taxa within the dipteran family Chironomidae in relation to key-environmental variables in alpine and sub-alpine streams, we showed that sediment load, water temperature, periphyton density, and fine particulate organic matter mostly explain assemblage structures. Two-way-cluster analyses identified stream-type specific assemblages, indicator value analysis defined indicator species for glacial and non-glacial streams, and weighted averaging regression models confined preferences for local environmental conditions by summing their optima and tolerance widths regarding environmental key factors. The definition of habitat requirements identified stenoecious taxa with preferences for high and low values of respective variables thus identified most suitable indicators for future studies. Our work reveals manifold preferences within the dominant benthic invertebrate family, underlines their enormous potential for monitoring purposes, and is a step forward in better understanding ecosystem properties and biodiversity. Fundamental requirements for these kinds of indicative traits, essential to understand cause–effect relationships in environmental change issues, are a robust taxonomy and a comprehensive set of physical and chemical data.
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Abstract: In order to determine whether using indicators of zooplankton diversity and macrophyte parameters (density and biomass) could be a useful tool for diagnosing the water quality of ponds we hypothesised that in various trophic types of shallow water bodies parameters of a macrophyte habitat will reflect zooplankton diversity. Thus, 439 stations (open water, helophytes, elodeids) were studied among 274 pastoral ponds (mid-west Poland). In each trophic state of waters a key predictor of zooplankton diversity was biomass of macrophytes attributed to a variety of ecological types or various species of macrophytes. A shift from the high importance of elodeids (e.g. Myriophyllum, Ceratophyllum demersum) in structuring zooplankton diversity in mesotrophic waters to helophytes (Typha angustifolia, Phragmites australis, Schoenoplectus lacustris) in hypereutrophic ponds was recorded. Hypereutrophy proved to be extremely unfavourable for zooplankton, as reflected in its lowest diversity; rotifers reached their optimum in eutrophy and crustaceans in mesotrophy. Adverse environmental conditions in hypereutrophic waters caused the elimination of macrophyte-dominated refuges, thereby lowering the macrophyte-site share, which ranged from 47% in eutrophy, 40% in mesotrophy to only 20% in hypereutrophy. Therefore, we assume that zooplankton diversity and macrophyte occurrence can be used for quality assessment of small water bodies.
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The present study was conducted in the Ramnagar Forest Division of Uttarakhand. Total 45 quadrats were laid by nested quadrat method for the phytosociological and ordination analysis of herb, shrub and tree layers. The data collected from the field was analyzed for frequency, density and abundance and finally importance values index (IVI) was calculated for all the species. The results of the study shows that Sal (Shorea robusta) was the most dominant plant species with 117 tree ha–1 density, 48.05 cm diameter and highest importance value (112.37) at tree layer and moderate contributor at shrub (IVI, 33.22) and herb (IVI, 32.94) layers. M. velutina with average diameter of 7.46 cm and density, 733 trees ha–1, was the other important species of the forest. The Principle Component Analyses (PCA) of the species shows that M. velutina was negatively associated with S. robusta, Anogeissus latifolia, Mallotus philippensis and Holarrhena antidysenterica and positively associated Cassia fistula and Diospyros melanoxylon. Population structure of the dominant species shows that S. robusta has started reviving from the losses due to mortality and it will start dominating these forests, once again, in near future.
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To assess the impact of antimony (Sb) on microbial community structure, 12 samples were taken from an Sb tailings pile in Guizhou Province, Southwest China. All 12 samples exhibited elevated Sb concentrations, but the mobile and bioaccessible fractions were small in comparison to total Sb concentrations. Besides the geochemical analyses, microbial communities inhabiting the tailing samples were characterized to investigate the interplay between the microorganisms and environmental factors in mine tailings. In all samples, Proteobacteria and Actinobacteria were the most dominant phyla. At the genus level, Thiobacillus, Limnobacter, Nocardioides, Lysobacter, Phormidium, and Kaistobacter demonstrated relatively high abundances. The two most abundant genera, Thiobacillus and Limnobacter, are characterized as sulfur-oxidizing bacteria and thiosulfate-oxidizing bacteria, respectively, while the genus Lysobacter contains arsenic (As)-resistant bacteria. Canonical correspondence analysis (CCA) indicates that TOC and the sulfate to sulfide ratio strongly shaped the microbial communities, suggesting the influence of the environmental factors in the indigenous microbial communities.
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Habitat fragmentation is a topic widely studied in ecology; however, its effects on the assemblage of the order Scorpiones is less well understood. Aiming to fill this gap, this study assessed the effect of fragmentation on the assemblage of these arachnids in 12 Brazilian Atlantic forest fragments. Five environmental variables were measured (depth and dry mass of litter, understory density, canopy openness, and diameter at breast height of the trees), and the fragment area, vegetation cover, connectivity and elevation assessed. The animals were collected during the dry season and, identified at night with the use of ultraviolet light lamps. The analyzed scorpion assemblage in the landscape was characterized by the species Tityus pusillus, T. stigmurus, T. neglectus, T. brazilae, and Ananteris mauryi, with a maximum of three species co-occurring per fragment. Only the fragment size and the dry mass of litter showed a positive relationship with the composition of scorpions. These results suggest that the habitat of scorpions responds to environmental attributes and landscape metrics at both higher (fragment size) and lower (leaf litter) scales. Our study was able to expand our knowledge of how scorpions respond to habitat changes in the Atlantic Forest. We conclude that fragmentation and habitat quality are determining factors for the assemblage of these arachnids.
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