Phytosociology and gradient analysis of a subalpine treed fen in Rocky Mountain National Park, Colorado

1996 ◽  
Vol 74 (8) ◽  
pp. 1203-1213 ◽  
Author(s):  
J. Bradley Johnson
Keyword(s):  
Species Composition ◽  
Correspondence Analysis ◽  
Species Distribution ◽  
Gradient Analysis ◽  
Vegetation Type ◽  
Detrended Correspondence Analysis ◽  
Tree Density ◽  
Small Scale ◽  
Groundwater Temperature ◽  
Strong Control

The vegetation of a subalpine fen in Colorado was studied. Insight was sought into the community structure and factors influencing species distribution of a vegetation type heretofore undescribed in the southern Rocky Mountains. A vegetational gradient was evaluated using detrended correspondence analysis (DCA). Four types of vegetation were subjectively defined; these same types were distinguished by the DCA. DCA further revealed marked differences in the vegetation occurring on peat hummocks versus in hollows. Species composition was related to environment using canonical correspondence analysis (CCA). Water-table depth, hummock height, shading, groundwater temperature, and conductivity were significantly correlated with species distribution, accounting for 51% of the total species variance. Univariate regression was used to examine how tree density varied with environment. The above factors, except for shading and conductivity, were also significantly correlated with tree density. It is suggested that the peat hummocks that form on this moderate fen provide an environment similar to that of an ombrotrophic bog and that these "miniature bogs" form in areas unable to support expansive bogs. Further, these hummocks provide small-scale environmental heterogeneity that exerts a strong control over species composition that would not be evident in studies based on samples of a large areal extent. Keywords: Colorado, gradient analysis, ordination, heterogeneity, peatlands, phytosociology.

Indirect gradient analysis of the Mangal formation of Gazi bay (Kenya)

1989 ◽  
Vol 54 ◽  
Author(s):  
H. Beeckman ◽  
E. Gallin ◽  
E. Coppejans
Keyword(s):  
Correspondence Analysis ◽  
Gradient Analysis ◽  
Stomatal Density ◽  
Detrended Correspondence Analysis ◽  
Zonation Pattern ◽  
Mangrove Species ◽  
Indirect Gradient Analysis ◽  
Ordination Method ◽  
Gazi Bay

(1)  Based on vegetation relevés of sample units along transects perpendicular to  the coastline, the mangal ecosystem of Gazi Bay (Kenya) has been  investigated.     (2) An indirect gradient analysis is performed by the ordination method  Detrended Correspondence Analysis.     (3) The first ordination axis can be interpreted in terms of resistance of  the different species to flooding.     (4) A similar zonation pattern is found as described by WALTER &  STEINER (1936).     (5) Zonation is closely connected with morphological and ecophysiological  features of the mangrove species. Therefore stomatal density has been  measured. Sonneratia has by  far the lowest stomatal density, Lumnitzera the highest.

scholarly journals How do plant communities and flower visitors relate? A case study of semi-natural xerothermic grasslands

2013 ◽  
Vol 82 (2) ◽  
pp. 99-105 ◽  
Author(s):  
Damian Chmura ◽  
Paweł Adamski ◽  
Zygmunt Denisiuk
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Plant Communities ◽  
Correspondence Analysis ◽  
Positive Relationship ◽  
Detrended Correspondence Analysis ◽  
Permanent Plots ◽  
Moisture Index ◽  
Rarefaction Analysis ◽  
Flower Visitors

<p>The paper examines the relationships between the species composition of flower visitors and plants in the semi-natural xerothermic grasslands in southern and central Poland. Thirty 10 × 10 m permanent plots were laid out in total, mainly in nature reserves. The vegetation units studied were classified according to the Braun-Blanquet system; these were phytocoenoses of the <em>Festuco-Brometea</em> classes <em>Inuletum ensifoliae</em>, <em>Adonido-Brachypodietum pinnati</em> and the transitional plant community. Entomological research was performed using the Pollard method within the same plots. A particular site was visited only once and different sites were studied between April and August 2008. We applied, among others, co-correspondence-analysis Co-CA, detrended correspondence analysis (DCA) and redundancy analysis (RDA) to investigate the co-occurrence patterns of plants and flower visitors and their biotopic requirements. We found that the species composition of flower visitors cannot be predicted by floristic composition when the duration of the study is restricted to one day (but under similar weather conditions); however, there is a positive relationship between the species richness of insects and plants and a positive relationship between the number of plant species and the abundance of flower visitors. The Ellenberg moisture index and the cover of meadow species significantly explained the species composition of insects. The three various vegetation units and five dominant xerothermic species, i.e. <em>Adonis vernalis</em>, <em>Anemone sylvestris</em>, <em>Inula ensifolia</em>, <em>Linum hirsutum</em> and <em>Carlina onopordifolia</em> that were studied across time differed in the species richness of insects. Our results demonstrate that possible patterns in the species composition and the assembly rules of flower visitors are not apparent when the Pollard method is applied. Based on the data obtained using this method, the flower visiting assemblages seem not to be driven by competition and they primarily show a tendency to co-occur which can be an artifact. A plant-focused method that included a rarefaction analysis yielded more insightful results and shed more light on the differences between the dominant plants that shape the physiognomy of plant communities in a possible pollination specialization.</p>

scholarly journals Identification of Fine-Scale Marine Benthic Ecoclines by Multiple Parallel Ordination

2014 ◽  
Vol 2014 ◽  
pp. 1-23 ◽  
Author(s):  
Thijs Christiaan van Son ◽  
Rune Halvorsen ◽  
Karl Norling ◽  
Torgeir Bakke ◽  
Maria Kaurin ◽  
...  
Keyword(s):  
Species Composition ◽  
Environmental Variables ◽  
Gradient Analysis ◽  
Detrended Correspondence Analysis ◽  
Natural Ecosystems ◽  
Form Complex ◽  
Indirect Gradient Analysis ◽  
Physical Forcing ◽  
Periodic Hypoxia ◽  
Geomorphological Features

The species-environment relationship is a fundamental structural property of natural ecosystems. Marine sedimentary macrofauna is known to be structured by a range of environmental variables; however, the mechanisms by which environmental variables covary to form complex-gradients (i.e., groups of intercorrelated environmental variables), and how these are related to coenoclines (i.e., gradients in species composition), remain poorly understood. We classified our study area into geomorphological features that were used for stratified sampling of macrofaunal polychaetes, molluscs, and echinoderms. The resulting species-by-site matrix was subjected to indirect gradient analysis by a multiple parallel ordination strategy, using detrended correspondence analysis and nonmetric multidimensional scaling. One major and one minor coenocline were identified. Based on the correlation between complex-gradients and the main coenocline we hypothesise the existence of two ecoclines that we have termedPeriodic hypoxiaandPeriodic physical forcing. We conclude that a combination of recurrent (periodical) and extreme events is likely to determine the variation found in the species composition of marine sedimentary ecosystems. Based on the results of our study, we conclude that indirect gradient analysis is a useful tool for enhancement of our basic mechanistic understanding of the processes governing the compositional structure of marine sediment communities.

scholarly journals Psocid taxocenoses (Insecta: Psocoptera) in the forest ecosystems of the Querci-fageta s. lat. zone in the Western Carpathian Mts. and Polonic subprovincy

2013 ◽  
Vol 61 (3) ◽  
pp. 637-646
Author(s):  
Otakar Holuša
Keyword(s):  
Cluster Analysis ◽  
Czech Republic ◽  
Species Composition ◽  
Correspondence Analysis ◽  
Dominant Species ◽  
Forest Ecosystems ◽  
Detrended Correspondence Analysis ◽  
The Czech Republic ◽  
Vegetation Zones ◽  
Characteristic Species

Structure of psocid taxocenoses (Psocoptera) were intensively studied in forest ecosystems of the Western Carpathian Mts. and Polonic biogeographical subprovincy during 1997–2001 in the Czech Republic. Vegetation tiers (= altitudinal vegetation zones) were used as a study frame. Only a part of material, i.e. individuals that was found in the forest ecosystems of Querci-fageta s. lat. communities (= the 3rd oak-beech vegetation tier) was evaluated for purpose of this work. This vegetation tier is widespread in large part of the Opavská pahorkatina hills, in large parts of Podbeskydská pahorktina hills, in the Bílé Karpaty hills and in the foothills of the Vsetínské vrchy hills. 1201 adults comprising 29 species were found in total in the 3rd vegetation tier. As eudominant species, the following ones were found: Peripsocus subfasciatus, Caecilius flavius and Stenopsocus lachlani, as dominant species, the following ones were found: Philotarsus parviceps and Caecilius piceus. In natural geobiocenoses with the level of naturalness of 1 or 2, the following species were found: as eudominant species: Caecilius flavidus, Peripsocus phaeopterus, as dominant species, the following ones were found: Caecilius piceus, Peripsocus subfasciatus, Philotarsus parviceps and Elipsocus moebiusi. Taxocenoses of psocids were evaluated by Detrended Correspondence Analysis (DCA) and Divisive Cluster Analysis (DvClA). This material was compared to another material gained from various vegetation tiers in the Western Carpathians Mts. The characteristic species composition of psocids in the 3rd vegetation tier was as follows – Elipsocus moebiusi – E. hyalinus – Philotarsus parviceps – Ectopsocus meridionalis – Caecilius flavidus.

scholarly journals Composition and diversity of psocid (Insecta: Psocoptera) taxocoenoses in forest ecosystems of the Abieti-fageta s. lat. zone in the Western Carpathian Mts.

2009 ◽  
Vol 55 (No. 4) ◽  
pp. 184-192 ◽  
Author(s):  
O. Holuša
Keyword(s):  
Cluster Analysis ◽  
Species Composition ◽  
Correspondence Analysis ◽  
Dominant Species ◽  
Forest Ecosystems ◽  
Forest Type ◽  
Detrended Correspondence Analysis ◽  
Vegetation Zones ◽  
Characteristic Species

Psocid (Psocoptera) taxocoenoses were studied in forest ecosystems of the Western Carpathian Mts. in 1997–2001. As a study frame, vegetation tiers (VT = altitudinal vegetation zones) of geobiocoenological or forest-typological system were used. Lower units of forest typological system (forest type complexes) were used for the classification of ecological conditions and the material found in forest ecosystems of <I>Abieti-fageta</I> s. lat. communities (5<sup>th</sup> fir-beech VT) was evaluated in detail. This VT is the most widespread in the regions under study (the Moravskoslezské Beskydy Mts., the Vsetínské vrchy Hills and Javorníky). 2,023 adults comprising 28 species were found in the 5<sup>th</sup> VT. <I>Caecilius burmeisteri</I> was found as eudominant species; <I>Philotarsus picicornis, Caecilius flavidus</I> and <I>Peripsocus subfasciatus</I> were found as dominant species. In natural geobiocoenoses with the level of naturalness 1 or 2, the following species were found: <I>Mesopsocus unipunctatus, Caecilius flavidus</I>, and <I>Caecilius burmeisteri</I> as eudominant and <I>Caecilius despaxi</I> as dominant. Taxocoenoses of psocids were evaluated by Detrended Correspondence Analysis (DCA) and Divisive Cluster Analysis (DvClA). The axes were interpreted in DCA-analysis as follows: the <I>x</I>-axis denotes the influence of VTs and the <I>q</I>-axis refers to the influence of hydricity. This material was compared with other material obtained from various vegetation tiers in the Western Carpathians Mts. The characteristic species composition of psocids in the 5<sup>th</sup> VT was as follows: <I>Caecilius flavidus – C. burmeisteri – C. despaxi – Metylophorus nebulosus – Philotarsus picicornis</I>.

Significance of current velocity gradients for distribution patterns of charophytes versus mosses and vascular plant communities in a lowland stream

2015 ◽  
Vol 44 (2) ◽  
Author(s):  
Emilia Jakubas ◽  
Maciej Gąbka
Keyword(s):  
Species Composition ◽  
Correspondence Analysis ◽  
Current Velocity ◽  
Vascular Plants ◽  
Vascular Plant ◽  
Detrended Correspondence Analysis ◽  
Water Current ◽  
Chara Vulgaris ◽  
Lowland Stream ◽  
Chara Globularis

AbstractThe study focused on the relationships between charophytes and the surrounding species composition and environmental factors in a lowland stream (Flinta stream, Western Poland). A total of 32 vegetation plots (4 m × 4 m) and 13 environmental variables were tested. Detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) were used to describe the relationships between the species composition and the selected variables. Dominance curves of aquatic plants, response curves (GAMs model) of charophytes and other macrophytes to the velocity gradient (the most important environmental factor, the Monte Carlo test) were prepared. In this study, 2 species of charophytes were recorded: Chara vulgaris and Chara globularis and 5 other co-occurring macroscopic algae, 2 mosses and 10 vascular plants. In the studied stream, charophytes occupied the separate niche. Chara vulgaris stands with moss vegetation were found in stream sections with the highest velocity of the water current (0.29 m s-1 mean), and the Chara globularis (with dominant Potamogeton species), preferred sections with the smallest water current velocity (0.19 m s-1 mean).Charophytes seem to respond to ecological gradients differently from mosses and vascular plants. These differences are related to current velocity, pH, conductivity and organic matter in bottom sediments, and to the niche differentiation associated with them.

scholarly journals Vegetation-environment relationships in a catchment containing a dambo in central Zimbabwe

Bothalia ◽  
2001 ◽  
Vol 31 (1) ◽  
pp. 135-143 ◽  
Author(s):  
I. Mapaure ◽  
M. P. McCartney
Keyword(s):  
Species Composition ◽  
Species Distribution ◽  
Southern Africa ◽  
Environmental Variables ◽  
Small Scale ◽  
Plant Water ◽  
Vegetation Composition ◽  
Vegetation Map ◽  
Small Catchment ◽  
Detailed Classification

Seasonally saturated wetlands, known as dambos. are a common landscape element throughout much of southern  Africa. The diversity of species composition within catchments containing dambos is widely attributed to hydrological conditions, but plant-water relationships are poorly established. In this paper a detailed classification and a vegetation map are presented for a small catchment in central Zimbabwe containing a dambo. Canonical Correspondence Analysis has been applied to explore the link between vegetation composition and environmental variables. This confirms that water is a key influence in species distribution and small-scale patterning of vegetation within the catchment.

Impact of small-scale variability of soil pH on the vegetation composition in a mixed hardwood stand, East-Flanders Belgium

2000 ◽  
Vol 65 ◽  
Author(s):  
GH. Zahedi ◽  
N. Lust ◽  
M. Van Meirvenne ◽  
L. Nachtergale ◽  
B. Muys
Keyword(s):  
Soil Ph ◽  
Spatial Dependence ◽  
Ph Value ◽  
Vegetation Type ◽  
Detrended Correspondence Analysis ◽  
Forest Vegetation ◽  
Kriging Interpolation ◽  
Small Scale ◽  
Vegetation Composition ◽  
Raster Image

1 Soil  pH of the forest stand varies widely for the different depths and is very  important in    determining the forest vegetation types. Main aim of the study was to  examine the    correspondence between forest vegetation composition and small-scale  heterogeneity in pH    by several statistical methods.    2 Ordination using DCA (Detrended Correspondence Analysis) found clear  distinction in the    vegetation structure and pointed pH differences as the main factor  explaining the variability    (Eigenvalue= 0.76 for the first three axis).    3 Clustering analysis by TWINSPAN resulted into four major vegetation  groups. Most of these    divisions were explained by differences in pH.    4 The spatial dependence of the pH at ectorganic and top mineral layers was  examined by    geostatistics analysis. All variograms showed a similar well-defined  structure. The structure    of variograms accounted for 95 - 100 % of the spatial dependence for the pH  at all depths.    All variograms represented the same range of 50 m for the pH at ectorganic  horizons, but the    distance of 65 and 72 m was calculated respectively for the pH at 0 - 5 and  5 -15 cm depth.    All variograms increased to the maximum lag over which they were  calculated.    5 The raster image of pH variability resulting from Kriging interpolation  coincided significantly    with the raster image of vegetation composition. It was concluded that it  is possible to predict    the pH value based on the vegetation composition or vice versa. Predicting  the vegetation    type from pH value is only possible for the range of the distance of the pH  variogram.

Species composition of demersal fish in the Rockall Trough, north-eastern Atlantic, as determined by different trawls

1992 ◽  
Vol 72 (1) ◽  
pp. 213-230 ◽  
Author(s):  
J. D. M. Gordon ◽  
O. A. Bergstad
Keyword(s):  
Species Composition ◽  
Continental Slope ◽  
Correspondence Analysis ◽  
Detrended Correspondence Analysis ◽  
Demersal Fish ◽  
Depth Zone ◽  
North Eastern ◽  
Rockall Trough

The variation in species composition of continental slope fishes as determined by the catches of different trawls towed either on single or paired warps was analysed by Detrended Correspondence Analysis (DCA). The catches of two trawls, a semi-balloon trawl (OTSB) and a Granton trawl (GT) were very similar when towed on paired warps. Significant differences were found between the catches of the OTSB trawl towed on single and paired warps. The DCA effectively provided information on the important gradients, e.g. depth, trawl type, and indicated which species were most abundant in the different depth zones and trawl types. Detailed accounts of the abundance and biomass of different species by trawl type and depth zone are given and the observed pattern of distribution discussed.

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