| Degree {cheddar} | R Documentation |
Node degree
Description
The number of trophic links in to and out of nodes in a
Community.
Usage
Degree(community)
InDegree(community)
TrophicGenerality(community)
NumberOfResources(community)
OutDegree(community)
TrophicVulnerability(community)
NumberOfConsumers(community)
NormalisedTrophicGenerality(community)
NormalisedTrophicVulnerability(community)
Arguments
community |
an object of class |
Details
InDegree and OutDegree return the number of trophic
links in-to and out-of each node. Degree returns InDegree +
OutDegree. TrophicGenerality and NumberOfResources
are synonyms for InDegree. TrophicVulnerability and
NumberOfResources are synonyms for OutDegree.
NormalisedTrophicGenerality and NormalisedTrophicVulnerability
return the containing the number of resources and consumer of each node,
normalised with respect to LinkageDensity. The mean of the values
returned by both NormalisedTrophicGenerality and
NormalisedTrophicVulnerability is 1, making their standard
deviations comparable across different food webs.
Value
A vector of length NumberOfNodes.
Author(s)
Lawrence Hudson
References
Williams, R.J. and Martinez, N.D. (2000) Simple rules yield complex food webs. Nature 404, 180–183.
See Also
Community, NumberOfNodes,
LinkageDensity, DirectedConnectance,
DegreeDistribution
Examples
data(TL84)
d <- Degree(TL84)
i <- InDegree(TL84)
o <- OutDegree(TL84)
# This equality is always TRUE for all food webs
all(d == i+o)
ntg <- NormalisedTrophicGenerality(TL84)
mean(ntg) # Equals 1
ntv <- NormalisedTrophicVulnerability(TL84)
mean(ntv) # Equals 1