Pans are isolated, shallow depressions that are endorheic in nature. Because of the natural hydrological functioning of pans, these systems are usually restricted to arid regions and complete desiccation occurs seasonally. In the eastern provinces of South Africa many pans are perennial in nature often remaining inundated for several years. A study of the aquatic invertebrate community structure of selected perennial pans indicated that when these systems undergo complete desiccation, the communities are comparable to the communities of ephemeral ecosystems. During these periods the community displays normal succession patterns with branchiopod crustacean dominating the community structure a few weeks after inundation. These perennial ecosystems are comparable to similar habitats around the world but are under increasing threat due to an increase in mining and agricultural activities within the study area.