Realistic parameter assessment for a well known elephant–tree ecosystem model reveals that limit cycles are unlikely

In 1976 Caughley proposed a simple predator–prey model for elephant–tree dynamics. To our knowledge no-one has attempted to assess this model against real data. The significance of Caughley’s model was to show that limit cycle behavior is possible for the elephant-tree system. Using realistic parameter estimates the paper emphasizes that, in fact, limit cycles are highly unlikely. For a wide range of realistic parameter estimates the model predicts a fixed point equilibrium between elephant and trees. Equilibrium model results are compared to real data for systems where there is a strong dependence between elephant and a dominant tree species. These results compare well giving added confidence in the biological premises of the model. Reasonable variations in parameter values change the equilibrium points in explainable ways. The conclusion is that this model, while crude, is realistic for certain ecological situations and can provide useful insights into such ecosystems.