Creating a stable ecosystem from scratch doesn’t sound like an easy task: populations of interdependent species have to be carefully balanced to ensure coexistence and avoid extinctions. And the more species to juggle, the harder it gets —increasing the complexity of ecosystems makes them inherently less stable. But then why are ecosystems in nature so wonderfully diverse? Network models are seemingly unhelpful on this front, as large food webs are stable only when parameters are fine-tuned — an unrealistic expectation for real ecosystems.
With a change of perspective, Carlos A. Serván and colleagues have now provided a solution to this problem. They demonstrated that a stable equilibrium comprising many coexisting species can be easily achieved by letting population dynamics prune a much larger pool of species. Interaction parameters influence the share of species that survive, whereas the underlying structure of the interaction network was found to have very little effect. It looks like the key to populating a desert island may just be to bring enough species along.