The Intermediate Disturbance Hypothesis of Species Coexistence Is Based on Patch Dynamics

The 'Intermediate Disturbance Hypothesis' (IDH) is one mechanism suggested to explain indefinite species coexistence. Hutchinson's original concept of the IDH was of a mechanism based on patch dynamics, and logical consideration shows that IDH works only if interpreted this way. Dependence on patch dynamics distinguishes IDH from Gradual Climate Change (GCC), though they are distinct also in terms of premature death of individuals, species selectivity, and the suddenness and transience of the perturbation. The application of the concepts of 'disturbance' and of IDH to phytoplankton communities is questioned.