Colonising Strategies and Diapause of Planktonic Rotifers (Monogononta, Rotifera) during Aquatic and Terrestrial Phases in a Floodplain (Lower Oder Valley, Germany)

The floodplains of the River Oder are inundated in winter and spring and are desiccated during summer. The plankton community developing towards the end of winter is dominated by monogonont rotifers. Some species maintain populations on the flooded areas as well as in the remaining permanent waters after flooding. Other species are found during the inundation period only. These species produce drought-resistant diapause stages, beginning at low population densities between 5 to 36 females L–1. Experiments showed that 9 out of 10 species, which were observed to produce resting eggs during the aquatic phase, were able to survive the terrestrial phase through dormancy in the desiccated floodplain soils. Other species colonise the temporarily inundated areas from the permanent waters again during each flooding period.