A Graphical Display of Large Correlation Matrices

Murdoch, Duncan J.; Chow, Elizabeth

doi:10.1080/00031305.1996.10474371

Cited by 104 publications

(62 citation statements)

References 4 publications

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“…The correlation plot was drawn with the corrplot package [25,26]. A detrended correspondence analysis (DCA) was performed with the software Past version 2.17c [27] on the overall plot-by-species (abundance) dataset to observe the ecological gradient length [28], so as to detect any species associations between sites and/or years.…”

Section: Resultsmentioning

confidence: 99%

Disentangling the Effects of Tillage Timing and Weather on Weed Community Assembly

et al. 2017

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Abstract:The effect of tillage timing on weed community assembly was assessed at four locations in the Northeastern United States by tilling the soil every two weeks from April to September and quantifying the emerged weed community six weeks after each tillage event. Variance partitioning analysis was used to test the relative importance of tillage timing and weather on weed community assembly (106 weed species). At a regional scale, site (75.5% of the explained inertia)-and to a lesser extent, timing-of tillage (18.3%), along with weather (18.1%), shaped weed communities. At a local scale, the timing of tillage explained approximately 50% of the weed community variability. The effect of tillage timing, after partitioning out the effect of weather variables, remained significant at all locations. Weather conditions, mainly growing degree days, but also precipitation occurring before tillage, were important factors and could improve our ability to predict the impact of tillage timing on weed community assemblages. Our findings illustrate the role of disturbance timing on weed communities, and can be used to improve the timing of weed control practices and to maximize their efficacy.

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Section: Resultsmentioning

confidence: 99%

Disentangling the Effects of Tillage Timing and Weather on Weed Community Assembly

et al. 2017

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“…The C-H pseudo-F statistic (Caliński and Harabasz 1974) and the sum of significant indicator values (see below) were used as criteria for choosing an optimal clustering solution. To facilitate the interpretation of ordinations, 95% confidence ellipses (Murdoch and Chow 1996) based on the standard deviations of site scores were calculated for each community type as defined by k-means partitioning and displayed in the ordination plots. Species characteristic for a particular group were identified using indicator species analysis (Dufrêne and Legendre 1997).…”

Section: Species Compositionmentioning

confidence: 99%

The Importance of Local and Regional Factors on the Vegetation of Created Wetlands in Central Europe

et al. 2011

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We assessed the relative importance of regional and local processes to wetland plant diversity in created depressional wetlands in Central Europe (Košské mokrade wetlands, central Slovakia). Twelve wetlands were sampled for vegetation, water chemistry, morphological, and hydrological data in 2008. A total of 39 plant species were found in the wetlands, dominated by Typha latifolia L. The results support the hypothesis that local environmental variables affect both species diversity and composition. Wetland plant diversity was negatively related to electrical conductivity, with a model significantly explaining 34.4 and 31.9% of the variance in species richness and Shannon diversity, respectively. Similarly, species composition was significantly related to local characteristics. A model relating species abundance data to local conditions explained 47.6% of the variation by age ("pure" effect=18.2%), water depth (15.1%), and conductivity (12.2%). Using measures of connectivity among wetlands, we did not find any significant relationships between plant communities and regional variables. Nevertheless, floristic data revealed significant small-scale (0-500 m) positive autocorrelation, indicating that wetlands in near proximity are more similar in species composition than more distant wetlands. This may suggest that the composition of nearby wetlands plays a role in shaping local communities.

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“…The key consideration here is that the compact presentation must specify, as closely as possible, the original concrete matrix with its fixed size. Thus, for example, from matrix (1) in Section 2 we should calculate matrix (3). For each region, we know the cell locations and the vertices of the region, whatever the dimensionality of the regions.…”

Section: Compute Compact Representationmentioning

confidence: 99%

“…Our work is related to work by Murdoch and Chow [3] who abstract large matrices that occur in statistical analysis to prepare them for easier display both on screen and in print formats such as postscript. Their emphasis is not so much on determining accurate numerical relationships between the single elements as on identifying possible relations and gaining an impression of whether they are significant.…”

Section: Introductionmentioning

confidence: 99%

Abstracting symbolic matrices

Almomen

Sexton

Sorge

2012

Ann Math Artif Intell

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We present a procedure that allows the abstraction of elements in concrete symbolic matrices to obtain a more compact representation employing ellipses in order to expose homogeneous regions present in a matrix. We furthermore extend that procedure to allow for generalisations of concrete matrices to an abstract form that enables us to determine the generic type of a given matrix. The presented algorithms employ artificial intelligence techniques such as pattern recognition and constraint solving.

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A Graphical Display of Large Correlation Matrices

Cited by 104 publications

References 4 publications

Disentangling the Effects of Tillage Timing and Weather on Weed Community Assembly

Disentangling the Effects of Tillage Timing and Weather on Weed Community Assembly

The Importance of Local and Regional Factors on the Vegetation of Created Wetlands in Central Europe

Abstracting symbolic matrices

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