IPMpack (version 2.1)

sizeToAge: Estimates size/stage to age relationships

Description

Uses a P matrix and a starting continuous stage value to estimate time to a range of target sizes, from which a size to age pattern can be determined.

Usage

sizeToAge(Pmatrix, startingSize, targetSize)

Arguments

Pmatrix

object of class IPMmatrix describing growth survival transitions.

startingSize

numeric, size at age 1, or size from which age-size relationship is desired.

targetSize

vector of size(s) for which first passage time is required.

Value

timeInYears

Time taken to reach target sizes in unit of the time step of the model.

targetSize

Vector of target sizes.

startingSize

Size at age 1.

References

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

Metcalf, Horvitz, Tuljapurkar & Clark. 2009 A time to grow and a time to die: a new way to analyze the dynamics of size, light, age and death of tropical trees. Ecology 90, p2766-2778.

Cochran & Ellner. 1992. Simple methods for calculating age-based life history parameters for stage-structured populations. Ecological Monographs 62, p345-364.

See for bias in this estimation where variance in growth is small relative to the size range: Zuidema, Jongejans, Chien, During & Schieving. 2010. Integral Projection Models for trees: a new parameterization method and a validation of model output. Journal of Ecology 98, p345-355.

See Also

passageTime

Examples

dff <- generateData()
Pmatrix <- makeIPMPmatrix(minSize = min(dff$size, na.rm = TRUE),
maxSize = max(dff$size, na.rm = TRUE), growObj = makeGrowthObj(dff),
survObj = makeSurvObj(dff))
targetSize <- 8
startingSize <- 0
sizeToAge(Pmatrix, startingSize, targetSize)