This web page contains dynamic models to enhance the book Community Ecology (2nd Edition) by Gary Mittelbach & Brian McGill

Quick links to models

• Predator-prey Models
• Lotka Volterra Competition Models
• Two species/one resource consumer-resource exploitation competition model
• Two species/two resource consumer-resource exploitation competition model
• Tri-trophic (Oksanen) Model
• Neutral model simulation

Errata

Although we've made every effort to have the book be error free, we're sure we missed a few. As we discover errors, we will list them here. If you suspect there may be an error please email Brian McGill

1. On page 163 the equations showing how the Lotka-Volterra equations can be extended to a mutualism seem to erroneously introduce a 3rd species with the subscript "3". Should be as below:

   Competition \begin{gather*} \frac{dN_1}{dt} = r_1 N_1 \left( \frac{K_1 - N_1 - \alpha_{12} N_2}{K_1} \right) \\ \frac{dN_2}{dt} = r_2 N_2 \left( \frac{K_2 - N_2 - \alpha_{21} N_1}{K_2} \right) \end{gather*}

   Mutualism \begin{gather*} \frac{dN_1}{dt} = r_1 N_1 \left( \frac{K_1 - N_1 + \alpha_{12} N_2}{K_1} \right) \\ \frac{dN_2}{dt} = r_2 N_2 \left( \frac{K_2 - N_2 + \alpha_{21} N_1}{K_2} \right) \end{gather*}

2. Section subheading page 145, twice on top left of page 146, once on page 149 left column, and possibly elsehwere in that section all mistakenly refer to the criterion α_jj>α_ji. It should instead be α_jj>α_ij (i.e. subscripts on second α are reversed). So in words it should say the effect of species j on itself is greater than the effect of species j on species i.
3. The trajectory (black dashed line) in Figure 5.7a is drawn incorrectly. It should NOT go straight through and out the equilibrium. It should spiral around and in towards the equilibrium.