scholarly journals History of Canonical Correspondence Analysis

2014 ◽  
pp. 103-118
Keyword(s):  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
History Of

Weed communities associated with arable Saskatchewan farm management systems

2000 ◽  
Vol 80 (1) ◽  
pp. 177-185 ◽  
Author(s):  
J. Y. Leeson ◽  
J. W. Sheard ◽  
A. G. Thomas
Keyword(s):  
Life History ◽  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Management System ◽  
Management Practices ◽  
Farming System ◽  
Management Systems ◽  
Weed Communities ◽  
History Of ◽  
The Impact

The objective of this study was to determine the impact of a range of management systems on weed communities in cropped fields on farms in Saskatchewan. Farms (n = 28) with management systems defined by a combination of different cropping histories and chemical input levels were selected. Fields were surveyed on each farm in 1995, 1996, and 1997 after any post-emergent weed control to ensure that their weed communities reflected the impact of all agronomic management practices typical of the management system. Canonical correspondence analysis was used to determine whether weed communities were significantly correlated with management system after removal of variance due to ecoregion and year. The largest difference in weed communities attributable to farming system was between the systems with annual cropping histories and those that included perennials in the cropping history. Thus, the life history of the weeds reflected the life history of the crops. Herbicide use was correlated with the next largest difference between systems. A significant association between weed communities and different management systems indicates that weed species are being selected for by these systems. If such selection pressure continues, these species may become a threat to the system's sustainability. Key words: Weed communities, chemical input level, cropping history, canonical correspondence analysis, correspondence analysis, farming system

Relationship between Chrysophyte Assemblages and Environmental Variables in Seventy-Two Sudbury Lakes as Examined by Canonical Correspondence Analysis (CCA)

1989 ◽  
Vol 46 (10) ◽  
pp. 1667-1676 ◽  
Author(s):  
Sushil S. Dixit ◽  
Aruna S. Dixit ◽  
John P. Smol
Keyword(s):  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Surface Sediment ◽  
Important Variable ◽  
Great Promise ◽  
Calibration Model ◽  
Ph Indicator ◽  
History Of ◽  
Inferred Ph ◽  
Almost All

Relationship between surface sediment chrysophyte scales and limnological variables in 72 Sudbury lakes was examined using canonical correspondence analysis (CCA). CCA is a recently developed multivariate direct gradient analysis that has many advantages over indirect gradient analyses. Lakewater pH was identified as the most important variable influencing the distribution of scaled chrysophytes in Sudbury lakes. Almost all common chrysophyte taxa can be assigned a pH indicator value. In addition to pH, many chrysophyte taxa are sensitive to metal concentrations. A calibration model was developed to predict chrysophyte inferred pH using CCA. The model proved to be far superior to traditionally used models derived from multiple regression of pH indicator chyrsophyte assemblages. Applicability of the predictive pH equation was examined by reconstructing the recent pH history of Lohi Lake. The study provides compelling evidence that canonical correspondence analysis offers great promise in surface sediment calibration and pH reconstruction studies.

Environmental factors including management practices as correlates of weed community composition in spring seeded crops

1992 ◽  
Vol 70 (10) ◽  
pp. 1931-1939 ◽  
Author(s):  
M. R. T. Dale ◽  
A. G. Thomas ◽  
E. A. John
Keyword(s):  
Community Composition ◽  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Environmental Variables ◽  
Management Practices ◽  
Geographic Region ◽  
Climatic Conditions ◽  
Weed Species ◽  
Weed Communities ◽  
Seed Crops

The relationship between the weed communities and environmental variables such as soil, crop, and management was investigated in two provinces of Canada. The frequencies of weed species were recorded in cereal and oilseed fields in Saskatchewan (2244 fields over 4 years) and Manitoba (864 fields over 3 years), Canada. Information on some of the physical characteristics of the fields and on the management practices imposed on them was also collected, in part by questionnaire. The two kinds of data were ordinated together using canonical correspondence analysis to assess the relationships between the species and the environmental variables. In the Saskatchewan data, there was a clear and consistent separation of the species into groups along an axis correlated with soil zone and the associated climatic gradient. In the Manitoba data, the same groups of species did not separate as clearly or as consistently, although geographic region was a major determinant of the weed communities. The greater variability may be due to the fact that the gradient of soil types is much more restricted in Manitoba and not as closely correlated with climatic conditions. In both provinces, culture practices were less important as correlates of the weed community composition than soil type or, to a certain extent, the previous crop. Key words: canonical correspondence analysis, cereal crops, oil seed crops.

scholarly journals Desmid algae (Charophyta: Conjugatophyceae) of Ekaterinburg, Middle Urals, Russia

2018 ◽  
Vol 55 ◽  
pp. 7-15
Author(s):  
Andrei S. Shakhmatov ◽  
Evgeniy V. Pavlovskiy ◽  
Alexander G. Paukov
Keyword(s):  
Species Composition ◽  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Habitat Preferences ◽  
Water Bodies ◽  
Middle Urals ◽  
The Middle Urals

Species composition of desmid algae and their habitat preferences in water bodies of Ekaterinburg city were studied during the 2013–2017. Thirty-seven species and subspecific taxa which belong to 12 genera and 2 families were identified, of which 17 species are new for the eastern macroslope of the Middle Urals. Canonical correspondence analysis, which was performed to reveal habitat preferences, demonstrates that the majority of analyzed species prefer quarry lakes, ponds and overgrown lake shores, contrary to fens and rivers.

scholarly journals On the Use of Selected Ordination Techniques to Analyze the Parliamentary Election Results

2016 ◽  
Vol 3 (322) ◽  
Author(s):  
Małgorzata Misztal
Keyword(s):  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Redundancy Analysis ◽  
Social Research ◽  
Economic Research ◽  
Parliamentary Election ◽  
Ecological Research ◽  
Parliamentary Elections ◽  
Ordination Techniques ◽  
Election Results

Ordination techniques such as CCA (Canonical Correspondence Analysis) or RDA (Redundancy Analysis) are very popular in ecological research but almost completely unknown in, for example, socio-economic research. The goal of this paper is to concisely organize the concepts and terminology associated with ordination and to present the possibilities of its application in social research with an example of the analysis of the 2015 parliamentary elections results.

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