Figure 4.
Properties of metacommunities with strong top-down control of colonization. (a) Increasing the efficiency of habitat selection (φ) is detrimental to food chain length (maximum and spatial average) with cTD = −1. Three cases, corresponding to increasing extinction rates (e) are presented. The discontinuous changes in average chain length mirror the discrete changes in maximum food chain length. (b) Increasing the extinction rate (e) can be beneficial to habitat occupancy (qi). Abrupt changes in the curves correspond to discrete changes in the number of trophic levels, top predators being lost as e increases. Beyond the vertical line, only one species persists and top-down effects no longer play any role. Other parameters: μ = 0.1; eTD = 0.01;φ = 0.1.