untb (version 1.7-2)

fisher: Various functionality to implement Fisher's logseries

Description

Various functions connected to Fisher's logseries including creation of synthetic datasets and estimation of Fisher's alpha

Usage

fishers.alpha(N, S, give=FALSE)
fisher.ecosystem(N, S, nmax, alpha=NULL, c=0)

Arguments

N

Size of the ecosystem. In the case of fisher.ecosystem(), the expected size of the ecosystem

S

Number of species in ecosystem

alpha

In function fisher.ecosystem(), Fisher's $alpha$. If not supplied, it will be calculated from N and S.

give

In function fishers.alpha(), Boolean variable with default FALSE meaning to return alpha, and TRUE meaning to return a list containing x and alpha.

nmax

In function fisher.ecosystem(), the maximum number of species abundance classes to consider

c

In function fisher.ecosystem(), the rare species advantage term

Details

Function fishers.alpha() solves for $alpha$ given $N$ and $S$, as per Fisher's table 9, p55.

Given $N$ and $S$ (or $alpha$), function fisher.ecosystem() generates a Fisherian ecosystem with expected size $N$ and expected species count $S$.

References

R. A. Fisher and A. S. Corbet and C. B. Williams 1943. “The relation between the number of species and the number of individuals in a random sample of an animal population”, Journal of Animal Ecology, volume 12, pp 42--58

Examples

 fishers.alpha(N=100000,S=100)
#compare the Table value:
  100000/10^3.95991