NvMTriTrophicTable {cheddar}  R Documentation 
Tritrophic statistics.
NvMTriTrophicTable(collection)
collection 
an object of class 
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.
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 2span 

Mean L upper + L lower 

2 x mean link length / mean 2span 

Mean L upper + L lower/ mean 2span 

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. 
Lawrence Hudson
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.
NvMTriTrophicStatistics
, CommunityCollection
data(TL84, TL86, YthanEstuary) collection < CommunityCollection(list(TL84, TL86, YthanEstuary)) table < NvMTriTrophicTable(collection) print(round(table, 2))