R: Estimate the expected species abundance distribution of both...

expected.SAD.Guilds {GUILDS} | R Documentation

## Estimate the expected species abundance distribution of both guilds using the guilds model, provided theta, alpha_x, alpha_y and J.

### Description

This function estimates the expected species abundance distribution of both guilds using the guilds model, provided theta, alpha_x, alpha_y and J. The expected species abundance distribution is approximated by first drawing px from a beta distribution (equation 4 in Janzen et al. 2014). Then, guild sizes are drawn using equation 3 in Janzen et al. 2014. Because the abundance distributions of the two guilds are independent, the distributions can now be obtained using equation 6 in Etienne and Alonso 2005. Because drawing from the beta distribution and equation 3 is inherently stochastic, this function returns the average over a specified number of replicates.

### Usage

    expected.SAD.Guilds(theta, alpha_x, alpha_y, J, n_replicates = 100)

### Arguments

`theta` | Fundamental biodiversity number theta
`alpha_x` | Dispersal ability of guild X
`alpha_y` | Dispersal ability of guild Y
`J` | Total number of individuals in the local community, e.g. J = Jx + Jy
`n_replicates` | Number of replicates to use to estimate the abundance distributions.

### Value

`guildX` | Vector containing the mean abundances of species in Guild X, binned into log2 bins
`guildY` | Vector containing the mean abundances of species in Guild Y, binned into log2 bins

### Author(s)

Thijs Janzen & Bart Haegeman

### References

Etienne, R.S., & Alonso, D. (2005). A dispersal-limited sampling theory for species and alleles. Ecology Letters, 8(100), 1147-1156.

### Examples

      SADs <- expected.SAD.Guilds(theta = 42, alpha_x = 0.01, alpha_y = 0.1, J = 1000, n_replicates = 3)
      par(mfrow=c(1,2));
      barplot(SADs$guildX,names.arg=0:(length(SADs$guildX)-1),
    	  xlab="Number of individuals (log2)",
    	  ylab="Number of Species",main="Guild X" )

      barplot(SADs$guildY,names.arg=0:(length(SADs$guildY)-1),
    	  xlab="Number of individuals (log2)",
    	  ylab="Number of Species",main="Guild Y" )

[Package GUILDS version 1.4.4 Index]