untb (version 1.6-2)

volkov: Expected frequency of species

Description

Given a community size, biodiversity parameter $\theta$, and an immigration rate $m$, returns the expected frequency of species with $n$ individuals, for $0

Usage

volkov(J, params, bins = FALSE, give = FALSE)

Arguments

J
Size of community
params
A two-element vector with first element interpreted as theta, the Fundamental biodiversity parameter and the second, m, interpreted as the probability of immigration. This argument will accept the output of optimal.params()
bins
Boolean, with default FALSE meaning to return the expected number of species with $1,2,\ldots,J$ individuals, and FALSE meaning to return the binned total, using a Preston-like binning system as used in preston(
give
Boolean, with TRUE meaning to return all the output of integrate(), and default FALSE meaning to return just the value of the integral

Value

  • Returns an object of class phi.

References

I. Volkov and others 2003. Neutral theory and relative species abundance in ecology. Nature, volume 424, number 28.

See Also

phi,preston

Examples

Run this code
volkov(J=21457,c(theta=47.226, m=0.1)) # Example in figure 1 

volkov(J=20,params=c(theta=1,m=0.4))

 data(butterflies)
 r <- plot(preston(butterflies,n=9,orig=TRUE))

 jj <- optimal.params(butterflies)  # needs PARI/GP

 jj <- c(9.99980936124759, 0.991791987473506)

 points(r,volkov(no.of.ind(butterflies), jj, bins=TRUE),type="b")

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