Littoral zone provide habitats for dormant stages of cladocerans in tropical lakes

Abstract

Abstract There is still a lack of fundamental knowledge about the dormant egg bank in the littoral zone, as much of the existing knowledge comes from studies conducted in the pelagic zone. In this study, we compared the diversity and composition of active cladocerans collected from the water column with cladocerans hatching from sediment and macrophyte roots containing dormant egg banks, all collected from the littoral zone of four tropical lakes. Two hypotheses are tested: (1) dormant assemblage will have highest diversity than active assemblage, and (2) pelagic taxa integrate the variability of both active and dormant assemblage in the littoral zone. Dormant assemblages hatchlings from macrophytes contributed less than 2% of the total assemblage numerical abundance, which was too low to undertake any ecologically meaningful analyses. However, dormant assemblage hatchlings from sediment samples showed the highest diversity for two of the four lakes studied, partially supporting our first hypothesis. Our results revealed that pelagic species (Bosminopsis, Ceriodaphnia, and Diaphanosoma) contributed half of the total species richness of active and dormant assemblages in all four lakes. These findings provide new insights into how the littoral zone of shallow lakes with well-developed macrophyte stands can offer a habitat for persistent dormant egg banks of certain pelagic cladocerans. Our increasing understanding of the interaction between dormant banks and active assemblages can be used to predict the dynamics of the zooplankton and develop restoration programs in lakes affected by climate change, such as extreme drought or human land and water use.