Figure 5.

Modeling resources explicitly. The adapted Tilman model also can show behavior akin to that observed. (A) Two weak competitors pitted against each other, as in Fig. 3B. (B) A weak competitor pitted against a strong competitor with the weaker population making up 90% of immigrants. As we observed (Fig. 3C), the weaker competitor initially predominates, but as resources become in short supply, the superior competitive ability of the population making up 10% of immigrants is manifested in its predominance. The model is the second set of equations in the text, X₁ represented by the solid line X₂ by the dashed line and resources, R, by the dotted and dashed line. Parameter values are: r_B = 0.8, K_B = 2.6, f = 0.5, n = 0.1, r₁ = r₂ = 0.85, k₂ = 90, m = 0.25, a = 0.1, S = 100, g = 2; in A k₁ = 90 and in B k₁ = 30.