cheddar (version 0.1-639)

TrophicSpecies: Trophic species

Description

A function that computes trophic species numbers.

Usage

TrophicSpecies(community, include.isolated=TRUE)

Value

A vector of length NumberOfNodes.

Arguments

community

an object of class Community.

include.isolated

if TRUE then nodes for which IsIsolatedNode is TRUE are given their own trophic species number. If FALSE the isolated species are assigned a trophic species of NA.

Author

Lawrence Hudson

Details

Returns a vector containing the trophic species number of each node in the community. Nodes with identical sets of prey and predators are given the same trophic species number.

References

Briand, F. and Cohen, J.E. 1984 Community food webs have scale-invariant structure Nature 307, 264--267.

Pimm, S.L. and Lawton, J.H. and Cohen, J.E. 1991 Food web patterns and their consequences Nature 350, 669--674.

Williams, R.J. and Martinez, N.D. 2000 Simple rules yield complex food webs 404, 180--183.

Jonsson, T. and Cohen, J.E. and Carpenter, S.R. 2005 Food webs, body size, and species abundance in ecological community description. Advances in Ecological Research 36, 1--84.

See Also

Community, IsIsolatedNode, NPS, LumpTrophicSpecies, NumberOfNodes

Examples

data(TL84)

# Isolated nodes assigned their own trophic species number
TrophicSpecies(TL84)

# Isolated nodes assigned a trophic species of NA
TrophicSpecies(TL84, include.isolated=FALSE)

# Compare including and excluding isolated nodes
NPS(TL84, list(TS1='TrophicSpecies', 
               TS2=list('TrophicSpecies', include.isolated=FALSE), 
               Iso='IsIsolatedNode'))