Finding a compromise between tractability (simplicity) and realism (complexity) has always been at the core of ecological modeling. The introduction of nonlinear interaction processes, such as higher-order interactions and nonlinear functional responses, has reconciled part of this compromise in 2-species models. However, it remains unclear whether this compromise can be extended to multispecies models. Yet, answering this question is necessary in order to differentiate whether the explanatory power of a model simply comes from the general form of its polynomial or from a more realistic description of multispecies systems. Here, we study the expected capacity of complex models (modifications to the LV model with nonlinear functions) in explaining the feasibility of multispecies systems.
Results/Conclusions
We demonstrate that the probability of generating a feasible multispecies system described by a complex model increases as a function of the degree of the polynomial and number of parameters. Specifically, when parameter values are arbitrarily chosen, the probability of feasibility is larger in models with nonlinear functions than with linear functions. However, this increase in probability happens no matter what type of nonlinear mechanism is added. That is, this increase in probability happens regardless of the exact form of the nonlinear function, even when comparing completely opposite mechanisms. Our work can be used to investigate the extent to which a mechanism actually contributes to feasibility more than its expectation, and invites us to reconsider what constitutes a realistic multispecies model.