Dear Lists, At several stations distributed regularly in space[1], we sampled repeatedly (4 times) the abundance of organisms and measured environmental parameters. I now want to compare the spatial distribution of various species (and test wether they differ or not), or to compare the distribution of a particular organism with the distribution of some environmental variable. Syrjala's test[2] seems to be appropriate for such comparisons. The hamming distance is also used (but it is not associated with a test). However, as far as I understand it, Syrjala's test only compares the distribution gathered during one sampling event, while I have four successive repeats and: - I am interested in comparing if, on average, the distributions are the same - I would prefer to keep the information regarding the variability of the abundances in time, rather than just comparing the means, since the abundances are quite variable.
Therefore I have two questions for all the knowledgeable R users on these lists: - Is there a package in which Syrjala's test is implemented for R? - Is there another way (a better way) to test for such differences? Thank you very much in advance for your help. [1] http://jo.irisson.free.fr/work/research_tetiaroa.html [2] http://findarticles.com/p/articles/mi_m2120/is_n1_v77/ai_18066337/pg_7 Jean-Olivier Irisson --- UMR 5244 CNRS-EPHE-UPVD, 52 av Paul Alduy, 66860 Perpignan Cedex, France +336 21 05 19 90 http://jo.irisson.free.fr/work/ ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
