calc_r: Intrinsic Rate of Increase r

In insectecol: Insect Ecology Data Analysis Toolkit

Intrinsic Rate of Increase r

Description

The intrinsic rate of increase (instantaneous rate of natural increase): the positive root of the Euler-Lotka equation sum over x of l_x * m_x * exp(-r * x) = 1, where x runs over the age classes (days) starting at 1. The root is located with the bisection method on the interval [0, 1] (tolerance 1e-6, at most 100 iterations).

Usage

calc_r(lt, lx = NULL, mx = NULL)

Arguments

lt	A life_table object returned by lifeTable_read.
lx	Optional; the result of calc_lx.
mx	Optional; the result of calc_mx. Supplying them avoids recomputing.

Value

A single numeric value: the intrinsic rate of increase r (per day).

References

Birch, L. C. (1948) The intrinsic rate of natural increase of an insect population. Journal of Animal Ecology 17(1), 15-26.

See Also

calc_lambda, calc_T

Examples

f <- system.file("extdata", "lifetable_example.csv", package = "insectecol")
lt <- lifeTable_read(f)
calc_r(lt)

insectecol documentation built on Oct. 5, 2026, 5:08 p.m.