NvMTriTrophicTable: N-versus-M tri-trophic statistics

Description

Tri-trophic statistics.

Usage

NvMTriTrophicTable(collection)

Value

A data.frame with a column per community and the rows

Mean link length
Mean L upper
Mean L lower
2 x mean link length
Mean 2-span
Mean L upper + L lower
2 x mean link length / mean 2-span
Mean L upper + L lower/ mean 2-span
Mean count chain length
Mean count chain length x mean link length
Community span
Mean count chain length x mean link length / community span
Mean sum chain lengths
Mean chain span
Mean chain span / community span
Mean sum chain lengths / mean chain span
Mean sum chain lengths / community span
L: number of trophic links after removals.
S^2: number of nodes squared after removals.
L/S^2: directed connectance links after removals.
L/S: linkage density after removals.
L: number of trophic links before removals.
S^2: number of nodes squared before removals.
L/S^2: directed connectance links before removals.
L/S: linkage density before removals.

Arguments

collection: an object of class CommunityCollection.

Author

Lawrence Hudson

Details

Returns a data.frame that contains the same statistics presented in Table 1 on Cohen et al 2009 PNAS. The function removes nodes lacking body mass (M) and/or numerical abundance (N), cannibalistic links and isolated nodes from each community. The last eight rows of the table contain four network statistics both with and without these removals.

References

Cohen, J.E. and Schittler, D.N. and Raffaelli, D.G. and Reuman, D.C. (2009) Food webs are more than the sum of their tritrophic parts. Proceedings of the National Academy of Sciences of the United States of America 106, 52, 22335--22340.

Examples

Run this code

data(TL84, TL86, YthanEstuary)
collection <- CommunityCollection(list(TL84, TL86, YthanEstuary))
table <- NvMTriTrophicTable(collection)
print(round(table, 2))

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