[R-sig-eco] null model for testing nestedness

v_coudrain at voila.fr v_coudrain at voila.fr
Tue Sep 24 20:07:58 CEST 2013


Dear all, 
I would like to implement a null model to test if nestedness of a matrix departs from chance. There is an example in package "bipartite" with the function "nullmodel":

obs <- unlist(networklevel(web, index="weighted NODF"))
nulls <- nullmodel(web, N=100, method=1)
null <- unlist(sapply(nulls , networklevel, index="weighted NODF"))

This works well, however, I have the impress that prior to apply the function "networklevel", the initial matrix is being reordered to achieve maximal packing. 
However, I don't want my matrix to be reordered, but I did not manage to find how to specify it. In the package vegan, there is the function nestednodf with the 
option "order=FALSE", but I could not implement a null model based on this function (because the output contain multiple attributes).

Any help welcomed


___________________________________________________________
Quiz TV : Vous êtes fan de la série "Friends" ? 5 questions ici http://tv.voila.fr/quiz/quiz-special-friends_14538959.html



More information about the R-sig-ecology mailing list