NvMTriTrophicTable {cheddar}

N-versus-M tri-trophic statistics

Description

Tri-trophic statistics.

Usage

NvMTriTrophicTable(collection)

Arguments

collection

an object of class CommunityCollection.

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.

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.

Author(s)

Lawrence Hudson

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.

See Also

NvMTriTrophicStatistics, CommunityCollection

Examples

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