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Dear members, I am performing multivariate analysis on marine benthic populations using R. At first glance I found ca and VEGANO packages to be the suitable for the task, but neither has incorporated Detrended Canonical Correspondence Analysis (DCCA), which is just the method I want to apply on my data. I've looked for alternative packages containing the method, but my suspicion is that

Hi, I hope someone knows the answer to this or has a real good reference about it (I am using Legendre & Legendre, Numerical Ecology, 1998).... My data is a data.frame with locations as rows and vegetation assemblages / species as columns. I've done a PCA, a correspondance analysis (CA) using ca in ca package and a detrended correspondance analysis (DCA) using decorana from vegan package.

Dear all, I'm performing a detrended correspondence analysis on vascular plant community data (296 species), and I have a question on the species scores projected in the ordination diagram. When I run a ordiplot all species are projected in the output graph, but I'd like to restrict the number of species plotted in the final graph. Some species are so rare in the data, that no relevant

Dear R-Help Does "The R Package for Multivariate and Spatial Analysis Version 4.0 (Casgrain and Legendre, 2001)" exist on CRAN and under what name? It supposedly has a chronological clustering program ,CHRONO, that I would like to use. Alternatively, I would ask if there is a R based program that performs chronological clustering? Thanks Alex Alex Hanke Department of Fisheries and

Hi During using the R(vision 2.0.1), I meet a problem. I would like to do the Multiple Correspondence Analysis, but when I use the "< mca(lf, nf = 2, abbrev = FALSE)", the sentence "Error: couldn't find function 'mca'" will appear. So, please tell me how can I use the "mca()", thanks! Any help appreciated....

I stumbled across this link and was wondering if this has any relation to the R project. http://www.fas.umontreal.ca/BIOL/Casgrain/en/labo/R/index.html -jennifer ----------------------------------- J. Steinbachs, Ph.D. Computational Biologist http://compbiology.org ----------------------------------- -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing

Hi all, I have site data with plant species cover and am looking for trends. I'm kind of new to this, but have done lots of reading and can't find an answer. I tried decorana (I know it's been replaced by ca.) and see a trend, but I'm not sure what it means. Is there a way to get the loadings/eigenvectors of the axes (like in PCA)? Is there a way to do this with rda() too? How

Hi After trying a simple decorana analysis (from the vegan package) on a simple data frame which contains no NA's the following error was returned: > tt_decorana(covN) Error in decorana(covN) : NA/NaN/Inf in foreign function call (arg 1) Have any vegan users come across this error and know what can be done about it? Cheers, J

Hi All, Thanks for you help, I have loaded the library MASS to call the mca. But when I want to do the mca, there is another problem, for example -------- -------- > leaf <- read.table("C:/Documents and Settings/wxh-c/×ÀÃæ/1.txt", + col.names=c("size","texture"),header=TRUE) > leaf size texture 1 3 3 2 2 2 3 3 2 4 3

Hi, I'm trying to find out what threshold of indicator value in labadsv should be used to accept a specie as an indicator one? So far I assumed that indval=0.5 is high enough to avoid any mistakes but it was based only in my intuition. I'd be greatful for any advise best regards Agnieszka

Dear R-users I applied vegan's varpart function to partition the effects of explanatory matrices. Adj. R square for the unique fraction [a] is 0.25. Does anyone know why the decomposition by hand using rda gives me a different result for [a] (constrained proportion is 0.32)? I used cbind() for the conditional fractions, but it should be similar to condition()? Thanks very much

Hi, I'd like to perform Dufrene-Legendre Indicator Species Analysis for a multivariate regression tree. However I have problems with arguments of duleg(veg,class,numitr=1000)function. How to obtain a vector of numeric class memberships for samples, or a classification object returned from mvpart? thanks in advance -- Best regards, Agnieszka Strzelczak

Hello, I've got a small dataset on box turtle shell measurements that I would like to perform a detrended correspondence analysis on. I thought that it would be interesting to examine the morphometrics for each species in the area of overlap and in areas where neither species occurs.  I've taken a look at the dune and dune.env datasets in vegan. Using the str() command gives me  >

I am trying to use the cca/rda/capscale functions in vegan to analyse genetic distance data ( provided as a dist object calculated using dist.genpop in package adegenet) with geographic distance partialled out ( provided as a distance object using dist function in veganthis method is attempting to follow the method used by Geffen et al 2004 as suggested by Legendre and . FORTIN (2010). I

Can anyone point me in the right direction of figuring out what downweight() is doing? I am using vegan to perform CCA on diatom assemblage data. I have a lot of rare species, so I want to reduce the influence of rare species in my CCA. I have read that some authors reduce rare species by only including species with an abundance of at least 1% in at least one sample (other authors use 5% as a

Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on hypatia.math.ethz.ch X-Spam-Level: **** X-Spam-Status: No, hits=4.2 required=5.0 tests=MSGID_FROM_MTA_HEADER,RCVD_IN_BL_SPAMCOP_NET autolearn=no version=2.63 Dear r-help list, my question is about ordination technics:

Please could you help me to find a package to apply a depth-constrained cluster analysis on palaeoecological data (in order to zone subfossil diagram)? Thanks, Dr. Emmanuel GANDOUIN Université d'Aix-Marseille 3 Institut Méditerranéen d'Ecologie et de Paléoécologie UMR CNRS 6116 Europôle Méditerranéen de l'Arbois, Bat. Villemin, BP 80 13545 Aix-en-Provence cedex 4 04 42 90 84 40

I am trying to find the percentage of the parameters explaining the bacterial community composition. I have one data matrix with relative abundance of OTUs and one with environmental parameters. I used varpart in vegan package but the values in the venn diagram is bigger than 100% in total.How is it possible? What might be the reason? Thank you library(vegan) gotud <-

Hi all, as I am trying to move slowly from just "working" to "good" code, I'd like to ask if there's a smarter way than using a for-loop in tasks like the example below. I need to obtain the extrema of the cumulated sum of a detrended time series. The following code is currently used, please have a look at the comments for my questions and remarks: system.time({ X

I frequently use hclust on a similarity matrix. In R only a distance matrix is allowed. Is there a simple reliable transformation of a similarity matrix that will result in a distance matrix making hclust work the same as S-Plus with a similarity matrix? Venables & Ripley 3rd edition implies that a simple reversal of values will suffice. Thanks -Frank -- Frank E Harrell Jr