scheffer: A resource-based model of alternative stable states
In primer: Functions and Data for the Book, a Primer of Ecology with R

Description Usage Arguments Value Author(s) References See Also Examples

A model of floating vs. submerged plant dominance in shallow aquatic systems, after Scheffeer et al. (2003). For use with ode in the deSolve package. Floating plants are better competitors for light, as long as submerged plants cannot drive down nitrogen levels.

1	scheffer(t, y, p)

`t`	the time point for a realization of the integration.
`y`	the vector of populations, at each time t.
`p`	a vector or list containing the necessary parameters.

Returns a list of length one which is the vector of the rates of increase (required by ode).

Hank Stevens <HStevens@muohio.edu>

Scheffer, M., Szabo, S., Gragnani, A., van Nes, E.H., Rinaldi, S., Kautsky, N., Norberg, J., Roijackers, R.M.M. and Franken, R.J.M. (2003) Floating plant dominance as a stable state. Proceeding of the National Academy of Sciences, U.S.A., 100, 4040–4045.

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

lvcompg, igp

p <- c(N=2.5, as=0.01, af=0.01, b=0.02, qs=0.075, qf=0.005,
       hs=0, hf=0.2, ls=0.05, lf=0.05, rs=0.5, rf=0.5, W=0)
t <- 1:200
Initial <- c(F=10, S=10)
S.out1 <- ode(Initial, t, scheffer, p)
matplot(t, S.out1[,-1], type='l')
legend('right', c("F", "S"), lty=1:2, col=1:2, bty='n')