isolate(a, size = no.of.ind(a), replace = TRUE)
TRUE
meaning to
sample individuals from the metacommunity with replacement and
FALSE
meaning to sample without replacement. See details
sectioncount
objectreplace
to default TRUE
is much
faster.The canonical example is given by Leigh et al 1993, in which islands were isolated from the mainland by rising waters. The trees on the islands were held to be a randomly drawn sample from the metacommunity.
Given that the usual usage of this function is to generate a plausible
ecosystem under such a scenario, one would have a hard time justifying
the use of replace=TRUE
as it allows (for example) a singleton
metacommunity species to have multiple representatives in the returned
ecosystem.
However, for large metacommunities and small subsamples, the distinction
between replace=TRUE
and replace=FALSE
is small.
a <- rand.neutral(1000,10)
no.of.spp(a)
no.of.spp(isolate(a))
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