lotkacomp: Lotka-Volterra Competition Model

In jarioksa/ecostudy: Ecology Teaching Package

Lotka-Volterra Competition Model

Description

Lotka-Volterra competition model for two species.

Usage

lotkacomp(alpha, beta, K1, K2)
## S3 method for class 'lotkacomp'
plot(x, arrows = 9, ...)
## S3 method for class 'lotkacomp'
lines(x, N1 = 1, N2 = 1, r1 = 0.2, r2 = 0.2, ...)
## S3 method for class 'lotkacomp'
traj(x, N1 = 1, N2 = 1, r1 = 0.2, r2 = 0.2,
    time = 100, step = 1, ...)
## S3 method for class 'lotkacomp'
summary(object, digits = max(3, getOption("digits") - 3), ...)

Arguments

alpha, beta	Competition coefficients.
K1, K2	Carrying capacities.
x, object	A lotkacomp result object.
arrows	Number of arrows drawn to show the area where species increases.
N1, N2	Initial population sizes.
r1, r2	Population growth rates.
time, step	Total time and length of single time step in the trajectories.
digits	Number of digits in the printed output.
...	Other parameters passed to functions.

Details

Function lotkacomp sets a Lotka-Volterra competition model (Krebs 2009, p. 165–169). The implementation is based on Stevens (2009). Function plot draws a phase graph. Function lines adds species trajectory to the phase graph, and traj extracts the population trajectories. Use plot.traj to display the population sizes against time. The summary gives the winner of the competition and the outcome population sizes.

Value

Function lotkacomp returns a Lotka-Volterra competition object.

Author(s)

Jari Oksanen

References

Krebs, C. J. (2009) Ecology. Benjamin Cummings. 6 ed., 655 p.

Stevens, M.H.H. (2009) A Primer of Ecology with R. Springer.

Examples

mod <- lotkacomp(0.8, 0.6, 20, 20)
plot(mod)
## Add trajectory line and starting point
lines(mod, 1, 1, col="green", lwd=2)
points(1, 1, pch=16, col="green")
## Plot populations against time
plot(traj(mod, 1, 1))
## Textual output
mod
summary(mod)

jarioksa/ecostudy documentation built on June 27, 2022, 6:03 a.m.