extinction | R Documentation |
Following (how I remember) the paper of Memmott et al. (2004), this function deletes a column (e.g. pollinator) or row (e.g. plant). Only a helper function for second.extinct
, really.
extinction(web, participant = "both", method = "random", ext.row=NULL,
ext.col=NULL)
web |
A matrix representing the interactions observed between higher trophic level species (columns) and lower trophic level species (rows). Usually this will be number of pollinators on each species of plants or number of parasitoids on each species of prey. |
participant |
Which level of participant to remove: lower removes a row, higher removes a row, both randomly picks either row or column. |
method |
Determines sequence of extinctions: random removes a random participant, while abundance removes the least abundant species first. external will use the externally provided vector to determine extinction sequence. |
ext.row |
Optional vector giving the sequence in which lower-level species are to be deleted. |
ext.col |
Optional vector giving the sequence in which higher-level species are to be deleted. |
In itself rather useless. Called repeatedly by second.extinct
to build an extinction sequence and accordingly a sequence of secondary extinctions.
Returns the same matrix that was given as object, just with one row or column being turned into zeros.
Carsten F. Dormann
Memmott, J., Waser, N. M. and Price, M. V. 2004 Tolerance of pollination networks to species extinctions. Proceedings of the Royal Society B 271, 2605–2611
second.extinct
## Not run:
data(Safariland)
(w <- extinction(Safariland, participant="lower", method="abun"))
empty(w, count=TRUE)
## End(Not run)
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