Limnetica 39

Predation pressure from vertebrates can affect the production of aquatic invertebrate resting stages in ponds, but the effects of seasonal predation on the assemblages of their hatchlings remains poorly understood. This study assessed the effects of the presence and density of annual killifish predators on the structure of assemblages of aquatic invertebrate hatchlings, as well as on the density and size of cladoceran eggs in southern Brazil temporary ponds. Dry sediment samples were collected from ponds that differed according to the presence and density of annual fishes, being four ponds without annual fish and four with annual fish at various densities. We detected no difference in density and size of cladoceran eggs between ponds with and without annual fish. Model selection procedures showed that the hatchling assemblage structure (richness, abundance and composition) did not change in relation with fish presence. Nonetheless, richness and abundance of hatchlings was lower in ponds with higher densities of annual fish. Our results suggest a limited effect of annual fish predators on the assemblage structure of resting stages of aquatic invertebrates, which can be related to dietary, ontogenetic and stochastic contingencies associated with populations of annual fish. In particular, the effect of annual fish on aquatic invertebrate hatchlings seemed to be more related with predator density.