Detects compartments
Finds number of compartments, based on multivariate ordination techniques, and labels interactions according to the compartment they belong to.
compart(web)
web: A bipartite interaction web, i.e.~a matrix with higher (cols) and lower (rows) trophic levels.Internal function, to be called by networklevel.
Note that up to (and including) version 0.85 we used a code based on correspondence analysis (see Lewinsohn et al. 2006). This is, however, faulty for webs with many same-linked species. Hence we resorted to a brute-force search for compartments, which is orders of magnitude slower, but at least works correctly. Only in version 1.18 Juan M. Barreneche eventually found a solution that is fast and works with ties!
Returns a list with two entries: - cweb: A matrix similar to web, but now with compartment numbers instead of interaction values.
Lewinsohn, T. M., P. I. Prado, P. Jordano, J. Bascompte, and J. M. Olesen (2006) Structure in plant-animal interaction assemblages. Oikos 113 , 174--184
Juan M. Barreneche jumanbar@gmail.com, but please co-copy comments/questions to package maintainer: Carsten F. Dormann carsten.dormann@biom.uni-freiburg.de
See also networklevel.
# make a nicely comparted web: web <- matrix(0, 10,10) web[1,1:3] <- 1 web[2,4:5] <- 1 web[3:7, 6:8] <- 1 web[8:10, 9:10] <- 1 web <- web[-c(4:5),] #oh, and make it asymmetric! web <- web[,c(1:5, 9,10, 6:8)] #oh, and make it non-diagonal compart(web) # or, standard, use Safariland as example: data(Safariland) compart(Safariland)