spectral.radius function

Calculates the spectral radius as a nestedness measurement of a bipartite matrix, possibly with regard to mass action

This function calculates the spectral radius (i.e. the maximum absolute value of the Eigenvalues) of the square adjacency matrix corresponding tp a given bipartite matrix. This may be used as a measure of nestedness as described by Staniczenko et al. (2013). UTF-8

spectral.radius(web, mass.action.norm = FALSE)
  massaction(web)

Arguments

• web: A matrix with lower trophic level species as rows, higher trophic level species as columns and number of interactions as entries.
• mass.action.norm: If TRUE the matrix is normalized for mass action using the massaction() function before calculating the spectral radius.

Massaction

Implementation of mass action calculations based on section 6.2 "Effective abundance, pseudo-inverse and mass action" in the Supplementary Information of Staniczenko et al. (2013).

Returns

The spectral radius (i.e. the largest Eigenvalue) of the square adjacency matrix corresponding to the given bipartite matrix.

References

Staniczenko, P., Kopp, J. & Allesina, S. (2013) The ghost of nestedness in ecological networks. Nat. Commun. 4 , 1391. tools:::Rd_expr_doi("10.1038/ncomms2422")

Author(s)

Tobias Bauer tobias.bauer-2@studium.uni-hamburg.de

Examples

data(bezerra2009, package="bipartite")
  spectral.radius(bezerra2009, mass.action.norm = TRUE)