Correction for slope of settler-recruit relationship

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Description

This function corrects the slope of the settler-recruit curve so that the collapse point of the spatially-explicit population model corresponding to the connectivity matrix agrees with that of the global non-spatially-explicit model. Uses the method in White (2010).

Usage

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settlerRecruitSlopeCorrection(conn.mat, slope = 1, natural.LEP = 1,
  critical.FLEP = 0.35, use.arpack = TRUE)

Arguments

conn.mat

a square connectivity matrix.

slope

slope at the origin of the settler-recruit relationship. Only interesting to fix this argument if it is a vector of length = dim(conn.mat)[2] (i.e., if the slope varies among sites and one wants to globally scale all slopes so that the collapse point matches the global collapse point).

natural.LEP

value of lifetime-egg-production (LEP), also known as eggs-per-recruit, in the absence of fishing. Can be a vector of length = dim(conn.mat)[2]. Defaults to 1.

critical.FLEP

Fraction of natural.LEP at which collapse occurs. Defaults to 0.35.

use.arpack

Boolean determining if calculation is to be done with arpack function from the igraph package. This is much quicker for large matrices, but requires igraph. Defaults to TRUE, but will use eigen instead if igraph is not found.

Value

The slope argument corrected so that collapse happens when LEP is critical.FLEP * natural.LEP.

Author(s)

David M. Kaplan dmkaplan2000@gmail.com

References

White, J. W. 2010. Adapting the steepness parameter from stock-recruit curves for use in spatially explicit models. Fisheries Research, 102: 330-334.

See Also

See also eigs, arpack

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