Spatial and temporal stability of commercial groundfish assemblages off Oregon and Washington as inferred from Oregon trawl logbooks

2000 ◽  
Vol 57 (12) ◽  
pp. 2443-2454 ◽  
Author(s):  
Yong-Woo Lee ◽  
David B Sampson
Keyword(s):  
Correspondence Analysis ◽  
Temporal Stability ◽  
Detrended Correspondence Analysis ◽  
Hierarchical Cluster ◽  
General Linear Model ◽  
Multivariate Methods ◽  
Strongly Correlated ◽  
Study Region ◽  
Spatial And Temporal Characteristics ◽  
Logbook Data

Spatial and temporal characteristics of species compositions for 15 major commercial groundfish species off Oregon and Washington (U.S.A.) were studied using Oregon bottom trawl logbook data from 1987 to 1993. Screening procedures to remove questionable data from the original logbook files resulted in the exclusion of information from 46% of the total available tows. Two multivariate methods, detrended correspondence analysis and Ward's hierarchical cluster analysis, were used to derive species ordinations and groupings. A general linear model developed for the primary detrended correspondence analysis axis scores showed that the species compositions were strongly correlated with depth and minimally correlated with the other environmental variables examined (latitude, month, and year). However, there were distinct seasonal changes in species composition at the shallower depths, consistent with the movement of deepwater species onto the shelf during summer. Annual trends in the species compositions were not evident even though the study region is very dynamic oceanographically and was heavily fished during the study period.

Ordination by detrended correspondence analysis (DCA) of the vegetation of Swartboschkloof, Jonkershoek, Cape Province

Bothalia ◽  
1987 ◽  
Vol 17 (1) ◽  
pp. 121-129 ◽  
Author(s):  
D. J. Mcdonald
Keyword(s):  
Soil Moisture ◽  
Plant Communities ◽  
Correspondence Analysis ◽  
Detrended Correspondence Analysis ◽  
Vegetation Classification ◽  
Environmental Data ◽  
Strongly Correlated ◽  
Intensive Study ◽  
Dca Ordination ◽  
Soil Moisture Status

The data of a Braun-Blanquet vegetation classification was ordinated using detrended correspondence analysis (DCA). This was done at the Fynbos Biome intensive study site, Swartboschkloof, Jonkershoek, to investigate the factors determining the distribution of the plant communities. Superimposition of environmental data on the DCA ordination confirmed the indications of the Braun-Blanquet classification that the distribution of plant communities is most strongly correlated with soil geology and, to a lesser extent, with soil moisture status. The ordination also proved useful for examining the relationships between the transitional communites and the distinct communities of Swartboschkloof.

Gradient analysis of forests of the Sangre de Cristo Range, Colorado

1990 ◽  
Vol 68 (1) ◽  
pp. 193-201 ◽  
Author(s):  
Robert B. Allen ◽  
Robert K. Peet
Keyword(s):  
Correspondence Analysis ◽  
Soil Ph ◽  
Populus Tremuloides ◽  
Environmental Gradients ◽  
Detrended Correspondence Analysis ◽  
Base Saturation ◽  
Strongly Correlated ◽  
Moisture Index ◽  
Compositional Gradient ◽  
Sangre De Cristo

Interrelationships between dominant compositional and environmental gradients were studied using 186 forest stands sampled on the east slope of the Sangre de Cristo Range, Colorado. Detrended correspondence analysis and detrended canonical correspondence analysis were used to analyze indirect and direct gradients, respectively. The dominant compositional gradient was strongly correlated with elevation. Increasing elevation was associated with decreasing soil pH and percent base saturation, and increasing total soil N. Ordination of stands stratified by elevation showed the major compositional gradient within each elevation class was strongly correlated with a topographic moisture index. Most soil variables correlated with this gradient in low and high elevation classes. In mid-elevation forests, a third compositional gradient correlated with soil pH, percent base saturation, and potential solar radiation. In these forests, Pinus contorta and Pseudotsuga menziesii were associated with acidic soils on north-facing slopes, whereas Populus tremuloides and Abies concolor were associated with base-rich soils on south-facing slopes. Ordination axes accounted for least variation in comparatively young mid-elevation forests. A plausible explanation is that the mid-elevation forests represent an unpredictable stage in forest development where competition has not yet had sufficient time to sort species along environmental gradients.

Pattern and vegetation–environment relationships in a boreal forested wetland in northeastern Ontario

1995 ◽  
Vol 73 (4) ◽  
pp. 629-637 ◽  
Author(s):  
John K. Jeglum ◽  
Fangliang He
Keyword(s):  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Detrended Correspondence Analysis ◽  
Forested Wetland ◽  
Strongly Correlated ◽  
Loss On Ignition ◽  
Data Set ◽  
Axis I ◽  
Environmental Measures ◽  
Physical And Chemical

A forested wetland data set from northeastern Ontario, consisting of species cover and environmental measures in 43 stands, was analyzed with canonical correspondence analysis. Results showed two main vegetational gradients related to factor complexes of peat depth – moisture (mire margin to mire expanse) and pH–calcium. Stands within each of the vegetation types were positioned closely, and gradients of types were similar to those from earlier analyses, suggesting the validity of a previous classification. Axis I of the ordination was highly related to peat depth, several elements (Al, Fe, and Cu), loss on ignition, bulk density, and water content in peat. Axis II was highly related to loss on ignition, depth of fibric layer, pH, and several elements (Ca, Mg, Mn, and N). The number of species in a plot was strongly correlated to the pH–calcium gradient, whereas vegetation cover was strongly correlated to the peat depth – moisture gradient. Analysis with detrended correspondence analysis gave results very similar to canonical correspondence analysis, suggesting that there was a relatively high correspondence between vegetational and environmental gradients. Environmental measures were partitioned into physical and chemical attributes, to detect the relative contribution to vegetational variation. Both physical and chemical variables were important, and 81% of the variation in vegetation was explained by the environmental measures. Key words: boreal forest, multivariate analysis, Ontario, wetlands, vegetation pattern, diversity.

scholarly journals Identification of the important environmental factors influencing natural vegetation succession following cropland abandonment on the Loess Plateau, China

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10349
Author(s):  
Zhenguo Zhang ◽  
Mingming Wang ◽  
Jikai Liu ◽  
Xinwei Li
Keyword(s):  
Loess Plateau ◽  
Correspondence Analysis ◽  
Classification Tree ◽  
Detrended Correspondence Analysis ◽  
Vegetation Succession ◽  
Natural Vegetation ◽  
Vegetation Types ◽  
The Loess Plateau ◽  
Cropland Abandonment

Identification of typical vegetation succession types and their important influencing factors is an important prerequisite to implement differential vegetation and soil management after land abandonment on the Loess Plateau, China. However, there is no reported study specifically on the identification of vegetation types and their important factors as well as the thresholds of the important factors for classification of the vegetation types, based on the medium- to long-term succession of natural vegetation after cropland abandonment. We collected vegetation and soil data on the natural vegetation with the longest 60-year-old forest communities that developed after cropland abandonment and analyzed the data using two-way indicator species analysis, detrended correspondence analysis, direct canonical correspondence analysis and classification tree model. The vegetation communities were classified into five distinct vegetation types, including Artemisia scoparia, Lespedeza davurica and Stipa bungeana, Artemisia giraldii pamp, Sophora viciifolia, Quercus liaotungensis and Biota orientalis. The years after cropland abandonment and soil C/N were further identified as important factors determining the types of vegetation. Likewise, it was observed that most of the investigated soil nutrient variables and soil texture-related variables improved with the vegetation succession while soil water in the surface layers showed a decreasing trend. These findings may provide an ecological basis for site-specific management of vegetation types after cropland abandonment in the medium-long term on the Loess Plateau. Our results encourage further exploration of vegetation succession and their important factors based on longer periods of vegetation succession after cropland abandonment under more soil and climatic conditions on the mountainous areas as the Loess Plateau.

scholarly journals The vegetation types and management units of Goedverwacht farm in the mixed bushveld of the Northern Province, South Africa

Koedoe ◽  
1997 ◽  
Vol 40 (2) ◽  
Author(s):  
L. Breebaart ◽  
M. Deutschlander
Keyword(s):  
Plant Communities ◽  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Environmental Gradient ◽  
Detrended Correspondence Analysis ◽  
Northern Province ◽  
Computer Programme ◽  
Data Set ◽  
Management Units ◽  
Floristic Data

An analysis of the vegetation of Goedverwacht farm in the mixed bushveld of the Northern Province is presented. Releves were compiled in 33 stratified random sample plots. Eight distinct plant communities were identified by means ofBraun-Blanquet pro-cedures. Detrended correspondence analysis (DCA) was applied to the floristic data set using the computer programme DECORANA (Detrended Correspondence Analysis) to determine a probable environmental gradient and to facilitate in the identification of management units. The computer programme CANOCO (Canonical Correspondence Analysis) was used to apply canonical correspondence analysis (CCA) to the floristic data set. Two management units were determined by means of vegetation ordinations and soil data. A classification, description and ecological interpretation of the plant communities as well as a description of the management units are presented.

scholarly journals A vegetation survey of the Tsitsikamma Coastal National Park

Koedoe ◽  
1989 ◽  
Vol 32 (1) ◽  
Author(s):  
N. Hanekom ◽  
A. Southwood ◽  
M. Ferguson
Keyword(s):  
Correspondence Analysis ◽  
Indicator Species ◽  
National Park ◽  
Detrended Correspondence Analysis ◽  
Indicator Species Analysis ◽  
Vegetation Survey ◽  
Afromontane Forest ◽  
Species Analysis ◽  
North And South

Sampling plots (5 m x 10 m in fynbos, 10 m x 10 m in forest) were analysed in the littoral, coastal escarpment, and north and south facing inland escarp- ment zones of 17 transect sites along the length of the Tsitsikamma Coastal National Park. Cover- abundance values were estimated for each species in the sampling plots. A detrended correspondence analysis (using CANOCO) and a two way indicator species analysis (TWINSPAN) were carried out on these data to determine the communities sampled. The vegetation of the park was classified into an Afromontane Forest, a Littoral Herbland and two Mesic Mountain Fynbos Communities. The distribution and extent of these communities were determined and their conservation discussed.

scholarly journals Global Jurassic floras and climate

1992 ◽  
Vol 6 ◽  
pp. 320-320
Author(s):  
Jiping Yao
Keyword(s):  
Correspondence Analysis ◽  
Late Jurassic ◽  
Regression Line ◽  
Detrended Correspondence Analysis ◽  
Climatic Changes ◽  
Temperate Climate ◽  
Fossil Plants ◽  
Generic Level ◽  
Strong Basis ◽  
The Earth

The present day vegetation types on the earth are to a large extent controlled by climatic conditions that are mainly reflected in variations in moisture availability and temperature through the annual cycle. Therefore, fossil plants can be used as a tool to elucidate both spatial and temporal climatic changes. The global climates of the Jurassic can be interpreted with fossil floras because many parts of world have yielded abundant floral localities. Those records not only provide a strong basis for the qualitative depiction of vegetation patterns, but also provide quantitative data for the reconstruction of paleophytogeographic provinces and climatic changes. The computer program known as “Detrended Correspondence Analysis” written by Hill (1979) was used in this study. The floral data for this quantitative approach was assembled at the generic level mainly from the published literature. By definition, it is a method based on ordination scores, that is, the species ordination scores are averages of the sample ordination scores, and vice versa.The scatter diagrams of the first two axes of genera and sample sites derived by detrended correspondence analysis were obtained for the intervals of Early, Middle, and Late Jurassic. The gradient variations of both genera and sample sites are reflected by the scores along axis 1 and 2 because axis 1 and axis 2 maximize the correlation of species and sample sites according to this technique. In the ordination score diagrams, the genera in similar climatic environments and the sample sites in similar paleogeographic regions are relatively close to each other along axis1 and axis2.One of characteristics of the Jurassic vegetation is the taxonomic stability through the period compared with other periods of time. Therefore, the generic scores of axis1 for the Early and Middle, Middle and Late, and Early and Late Jurassic can be plotted against each other. The regression line can be used to assign the scores to the ordered genera. This is the technique used to complement the ordered genera from the gradient score diagrams and to eliminate the effect of some local genera. The genera adjacent to the regression line can be reliably used to reflect climatic gradients. The gradient changes were used to define biomes and to determine phytogeographic patterns on a global scale.The quantitative analysis clearly shows that the use of floral data can achieve fast and satisfactory results in paleoclimatic studies of the Jurassic. For example, the cool-wet temperate climate is reflected by a ginkgophyte dominated deciduous flora, such as Ginkgo, Czekanowskia, Phoenicopsis, and Baiera, whereas the subtropical warm and drier climate is represented by cycad dominated floras, such as Anomozamites, Nilssonia, Pterophylum, Ptilophyllwn, Ctenis, and Otozamites. The general conclusion of earlier workers that Jurassic floras were especially uniform through the earth is true in the relative sense only, and the ordination study allows for the subdivision of the rather shallow gradients that do exist.

scholarly journals Multivariate analysis of the hunting tactics of Kalahari leopards

Koedoe ◽  
1997 ◽  
Vol 40 (1) ◽  
Author(s):  
J. Du P. Bothma ◽  
N. Van Rooyen ◽  
E.A.N. Le Riche
Keyword(s):  
Multivariate Analysis ◽  
Field Study ◽  
Correspondence Analysis ◽  
Detrended Correspondence Analysis ◽  
Prey Type ◽  
Data Sets ◽  
Male And Female ◽  
Sandy Substrate ◽  
Hunting Tactics

The hunting tactics of male and female leopards in the southern Kalahari were analysed for prey-specific patterns. The field study was based on tracking leopard spoor in the sandy substrate of the Kalahari. Visual profiles for each type of prey were compiled for various facets of hunting. Data sets were analysed further, using Correspondence Analysis and Detrended Correspondence Analysis. The results indicate that multivariate analysis can be used to demonstrate prey-specific hunting tactics in Kalahari leopards. In using a scarce prey base, Kalahari leopards seem to be number maximisers as they are unselective of prey type, age or sex. The presence of prey-specific hunting tactics may indicate a move along a continuum towards some degree of energy maximisation.

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