Two types of sudds, organic and plant sudds, form in the back swamp communities of the Maunachira river system in the Okavango Delta. Floating organic sudds, which form as a result of gas production in the benthic detrital aggregate, provide an exposed surface for plant colonization. The sequence of establishment of plants is determined largely by the input of propagules from the surrounding communities after exposure. These sudds are extremely mobile and, as a result of wind action, bank up on the leeward side of water bodies. Hydrology; Aquatic botany.