Calculates variation in life expectancy in a discretely stochastic environment.

Description

Provided a P matrix, defining survival transitions across size, this function provides a vector with variance in life expectancy in units of the time-step used, for each of the size bins.

Usage

varLifeExpect(IPMmatrix)

Arguments

Value

a vector of variance in life expectancies each corresponding to Pmatrix@meshpoints.

Author(s)

C. Jessica E. Metcalf, Sean M. McMahon, Roberto Salguero-Gomez, Eelke Jongejans & Cory Merow.

References

Caswell, 2001. Matrix population models: analysis, construction and interpretation. 2nd ed. Sinauer. p110-132.

Cochran & Ellner. 1995. Simple methods for calculating age-based life history parameters for stage-structured populations. Ecological Monographs 62, p345-364.

Tuljapurkar & Horvitz, 2006. From stage to age in variable environments. Life expectancy and survivorship. Ecology 87, p1497-1509.

See Also

meanLifeExpect, makeIPMPmatrix

Examples

# With a single continuous (e.g. size) stage
dff <- generateData()
Pmatrix <- makeIPMPmatrix(minSize = min(dff$size, na.rm = TRUE), 
maxSize = max(dff$size, na.rm = TRUE), growObj = makeGrowthObj(dff), 
survObj = makeSurvObj(dff))
vle <- varLifeExpect(Pmatrix)

plot(Pmatrix@meshpoints, vle, ylab = "Variation life expectancy", 
xlab = "Continuous (e.g. size) stage", type = "l", ylim = c(0,max(vle)))

Results

R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

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Type 'demo()' for some demos, 'help()' for on-line help, or
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> library(IPMpack)
Loading required package: Matrix
Loading required package: MASS
Loading required package: nlme
> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/IPMpack/varLifeExpect.Rd_%03d_medium.png", width=480, height=480)
> ### Name: varLifeExpect
> ### Title: Calculates variation in life expectancy in a discretely
> ###   stochastic environment.
> ### Aliases: varLifeExpect
> 
> ### ** Examples
> 
> # With a single continuous (e.g. size) stage
> dff <- generateData()
> Pmatrix <- makeIPMPmatrix(minSize = min(dff$size, na.rm = TRUE), 
+ maxSize = max(dff$size, na.rm = TRUE), growObj = makeGrowthObj(dff), 
+ survObj = makeSurvObj(dff))
> vle <- varLifeExpect(Pmatrix)
> 
> plot(Pmatrix@meshpoints, vle, ylab = "Variation life expectancy", 
+ xlab = "Continuous (e.g. size) stage", type = "l", ylim = c(0,max(vle)))
> 
> 
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>