EcoTroph (version 1.3)

saturation: Sigma Saturation Function

Description

This function enables an other calculation for the sigma of the create.smooth function. Sigma is calculated on the base of a saturation function reflecting a biological reasoning about the variability of the TL within the trophic classes: The variability increases with the TL and reaches a plateau after a certain TL.

Usage

saturation(sigma_inf = NULL, coeff = NULL, pas = NULL)

Arguments

sigma_inf

defines the value of the curve's plateau.

coeff

defines the value of the slope.

pas

defines the splitting of the TL classes.

Value

• saturation returns a vector of values for the sigma used in the create.smooth function.

Details

By default sigma is calculated using a lognormal function. This function enables an other user choice reflecting a different reasoning.

References

Gascuel et al. (2009) EcoTroph (ET): a trophic level based software for assessing the impacts of fishing on aquatic ecosystems.

See Also

create.smooth function to create the Smooth, plot_smooth to plot the smooth function, Transpose to calculate the data transposition into trophic spectra, plot_Transpose to plot the trophic spectra.

Examples

plot(saturation())
lines(saturation(0.2))
text(48,0.18,"sigma_inf=0.2")
lines(saturation(coeff=0.5))
text(48,0.35,"coeff=0.5")