[R] Quantile regression - violation of independence

I am trying to perform quantile regression (using quantreg package) and I am particularly interested to know whether the technique requires independence of observations. I am an ecologist and, in particular, I collected data of abundance of a species in 15 location around an island. In each l

[R] ctree - party package multivariate response variables

Hi, I have a problem with ctree of party package. I have data on distribution of more than one species (about 50 species) and I would like identify the relation of this multivariate object (species distribution) with a number of explanatory variables. rs is the name of my dataframe containing the