shuffle.web {bipartite}R Documentation

Shuffle web entries

Description

Shuffles (= relocates) entries in a web matrix whilst maintaining the dimensionality.

Usage

shuffle.web(web, N)

Arguments

web An interaction matrix.
N Number of desired shuffled matrices.

Details

This function is designed to behave similar to r2dtable, i.e. it returns a list of randomised matrices. In contrast to r2dtable is does not keep marginal sums constant!

This function is thought of as a nullmodel for the analysis of bipartite webs. It keeps two web properties constant: The number of interactions and the number of links (and hence connectance). A comparison of shuffle.web- and r2dtable-based webs allows to elucidate the effect of marginal sums.

Value

A list of N randomised matrices with the same dimensions as the initial web.

Note

shuffle.web is not an extremely intelligent nullmodel. You may want to think of a better one for your specific application!

Author(s)

Carsten F. Dormann <carsten.dormann@ufz.de>

References

There is no reference for this specific nullmodel. For a very nice and thorough overview of nullmodels in general see

Gotelli, N. J., and G. R. Graves. 1996. Null Models in Ecology. Smithsonian Institution Press, Washington D.C.

For nullmodels and their application to webs/networks see, e.g.:

Vázquez, D. P., and M. A. Aizen. 2003. Null model analyses of specialization in plant-pollinator interactions. Ecology 84:2493-2501.

Vázquez, D. P., C. J. Melián, N. M. Williams, N. Blüthgen, B. R. Krasnov, and R. Poulin. 2007. Species abundance and asymmetric interaction strength in ecological networks. Oikos 116:1120-1127.

See Also

r2dtable

Examples


data(Safariland)

shuffle.web(Safariland, N=2)


[Package bipartite version 0.5 Index]