Fig. 5

Coexistence and bistability propagate from pair to trio, as predicted by assembly rules. a–c Subway maps show pairwise outcome trajectories across changing dilution factor (DF), as explained in Figs. 1 and 3. The fast grower’s line is always plotted above the slow grower’s line. Of the three pairs that make up the community Ea–Pci–Pv, two are coexisting (a, b) and one is bistable (c). d The pairwise assembly rules state that a species will survive in a community if it survives in all corresponding pairs. At DF 10, Ea and Pci coexist, but both are excluded by Pv. The rules correctly predict that Pv will dominate in the trio. Because both species can be excluded in a bistable pair, a bistable pairwise outcome propagates to the trio as more than one allowed state. Each of the bistable species can be seen separately coexisting with Ea at DF 10³, as they do in pairs. The assembly rules failed at DF 10⁵ for three out of four starting conditions: Pci usually goes extinct when it should coexist with Ea. e Three-species competition results are shown in simplex plots. Arrows begin and end at initial and final fractions, respectively. Edges represent pairwise results, and black dots represent trio results