Short and dynamic: succession of invertebrate community over a hydroperiod in ephemeral wetlands on arable land

ABSTRACT The temporal dynamics of aquatic invertebrate communities are known to be influenced by the length of hydroperiods, but only temporary wetlands with relatively long hydroperiods have been well studied. By contrast, few studies have focused on ephemeral wetlands, primarily represented by extremely ephemeral rock pools. In Central Europe, many ephemeral wetlands develop spontaneously directly on arable land, often on the sites of former natural wetlands that have been drained and converted to agricultural land. Here, we focused on aquatic invertebrates in 10 ephemeral pools over periods of inundation to desiccation on arable land in southern Moravia. Despite relatively short hydroperiods of 5–11 weeks, we observed significant changes in community composition, including species replacement. Dynamics differed between macroinvertebrates and microcrustaceans and between different macroinvertebrate feeding and dispersal groups. Predation pressure increased over time and was highest during drying. Passive dispersers were most abundant during the middle phase, whereas the abundance of active dispersers increased throughout the hydroperiod. Because no significant effect of any environmental factor was detected on community change, we hypothesized that community dynamics were driven by differences in species traits and biotic interactions rather than by the changing environment. This study fills a knowledge gap on the temporal dynamics of aquatic invertebrate communities in temporary wetlands by investigating wetlands with short, but not extremely ephemeral, hydroperiods.