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.
4. Page 98 top of 2nd column in the formula P_i should be p_i (change case of P to p)
5. Not an error per se but to be more clear, in Figure 6.7 the the X-axis represents total time (travel+time foraging in the patch). Time foraging in the patch starts at 0 at the vertical black bar and increases towards the right.
6. Page 105, last paragraph left column, says Figure 6.7C references Type II vs Type III functional response, but it does not. Figure 6.7C shows differences between foraging in high quality vs low quality patches.
7. Page 110 left column line 12, "risker" should be "riskier"; Page 112 left column 6th line "inividual" should be "an individual"
8. Page 124, 1st full paragraph "“If we assume that the consumer population experiences some per capital density-independent mortality rate m (represented by the horizontal line in Figure 7.3A..." should reference Figure 7.4A, not 7.3A
9. Page 22 in box, the formula for Shannon diversity, H, should have a minus sign ("-") in front as in H=-sum(p_i ln p_i)
10. Page 98, top of second column P_i should be lower case p_i
11. Caption Figure 6.7 - note that Travel time runs in reverse (from right to left) from the vertical black line
12. Page 110, first seciton of first column: "risker" should be "riskier"
13. Page 112, first column, line 6: "individual" should be "individuals"