ecostudy-package: Ecology teaching package

In jarioksa/ecostudy: Ecology Teaching Package

Ecology teaching package

Description

Functions to aid understanding ecological models for Ecology 101 level. The package is designed to support Krebs (2009), but because it covers the most basic models, it probably suits for any other similar textbook. The primary usage was to draw graphics for my basic ecology lectures, but many functions can be used for other teaching or studying purposes.

Details

The package contains basic ecological models for population dynamics of single species and two-species interactions. The models include:

• Population growth: logistic model (poplogist), stochastic logistic growth (ranlogist), Ricker model (ricker), Milne's stochastic ceiling model (ranmilne).

• Competition: Lotka-Volterra model (lotkacomp), Tilman's resource competition model (tilman).

• Predator–Prey relationship: Lotka-Volterra model in its basic form (lotkaprey), and the model with density dependent prey (lotkapreyK), Rosenzweig–MacArthur model (rmprey).

The functions were originally written to draw graphics for my lecture slides, and therefore their user interface often is restricted (contributions are welcome). Most functions work so that the the basic function sets up the model, plot draws the zero isoclines and other static structures but no population trajectories. The population trajectories can be found with a new S3 generic function traj in the package, and lines function normally adds the trajectories to the basic plot.

Most functions are based on the primer package (Stevens 2009), and even other functions are modelled similarly. The models are set up as differential equations, and numerical integration is used to find the trajectories (function ode of the deSolve package).

Author(s)

Jari Oksanen <[e-mail]>

Maintainer: Jari Oksanen <[e-mail]>

References

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

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

See Also

primer.

Examples

## A typical usage: Lotka-Volterra competition
mod <- lotkacomp(1.2, 1.1, 50, 50)
## The static model
mod
summary(mod)
plot(mod)
## Species trajectories
tr <- traj(mod, N1 = 20, N2 = 4, r1 = 0.3, r2 = 1)
plot(tr)
## Plot species trajectories
plot(mod)
lines(mod, N1 = 20, N2 = 4, r1 = 0.2, r2 = 1)

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