sharx (version 1.0-6)

sie: Small Island Effect (SIE) via Breakpoint Regression

Description

Fit a breakpoint regression model to data to find threshold for the small island effect (SIE) as described in Lomolino...

Usage

sie(S, A, method = "Nelder-Mead", ...)
sieplot(x, add = FALSE, ...)

Value

An S4 object of class 'sie' inheriting from class 'mle'.

Arguments

S

untransformed species richness, vector.

A

untransformed area, vector.

x

a fitted model object of class 'sie'.

method

optimization method.

add

logical, if lines should be added to existing plot (TRUE), or a new plot is to be drawn (FALSE, default).

...

graphical arguments passed to plot.

Author

Peter Solymos

Details

sie fits the breakpoint regression to the data, richness is log(S+0.5) transformed, area is log(A) transformed before analysis. There is a coef, summary, print method for fitted objects.

sieplot plots the observed (transformed) data and the fitted line.

References

Lomolino, M. V., and M. D. Weiser. 2001. Towards a more general species-area relationship: diversity on all islands, great and small. Journal of Biogeography, 28, 431--445.

Examples

data(sardata)
DAT <- sardata$islands[sardata$islands$study=="abbott1978plant",]
(x <- sie(DAT$S, DAT$A))
coef(x)
summary(x)
sieplot(x)