The impact of inundation was studied on two marine littoral collembolan species: Isotoma viridis and Hypogastrura viatica. The unwettable integument causes the collembolans to drift on the water surface during inundation. When trapped under water they try to climb up from below the water level. Their survival on the water surface is higher than under water.
H. viatica, occurring in a habitat that is inundated relatively frequently and over a long time, had a greater ability to survive on the water surface than I. viridis.
The mortality on the water surface was caused by starvation. A strong correlation between the mortality and the metabolic rate was shown. The highest mortality was found at lower salinities, where oxygen consumption of the animals is highest. The metabolic rate and mortality was lower at salinities up to 75% S.W. At 100% S.W. there was again a rise in metabolic rate and mortality. This is probably due to energy-demanding processes concerning internal osmotic and ionic regulation.
After flooding, transport by sea currents can play a role in the distribution of the species. Reproductive synchronization after inundation is considered to be a mechanism for restoring a disturbed population.
