lvcomp2: Two Species Lotka-Volterra Competition
In primer: Functions and Data for the Book, a Primer of Ecology with R

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

System of ordinary differential equations for two species Lotka-Volterra competition. For use with ode in the deSolve package.

1	lvcomp2(t, n, parms)

`t`	Times points that will return N.
`n`	a vector of length two for the population sizes at time = t.
`parms`	vector or list of model parameters (see details below).

The parameters include r1, r2, a11, a12, a21, a22 with the usual meanings. Here the a's are the per capita effects which determine K (a11 = 1/K).

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

Hank Stevens <HStevens@muohio.edu>

Lotka, A.J. (1956) Elements of Mathematical Biology. Dover Publications, Inc.

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

lvcomp3, lvcompg, clogistic

## The function is currently defined as
function (t, n, parms)
{
    with(as.list(parms), {
        dn1dt <- r1 * n[1] * (1 - a11 * n[1] - a12 * n[2])
        dn2dt <- r2 * n[2] * (1 - a22 * n[2] - a21 * n[1])
        list(c(dn1dt, dn2dt))
    })
  }
library(deSolve)
parms <- c(r1 = 1, r2 = 0.1, a11 = 0.2, a21 = 0.1, a22 = 0.02, a12 = 0.01)
initialN <- c(1, 1)
out <- ode(y = initialN, times = 1:100, func = lvcomp2, parms = parms)
matplot(out[, 1], out[, -1], type = "l")