Sensitivity of freshwater turtle eggs to experimental flooding reiterates conservation concerns in impounded waterways

Context Flooding of freshwater turtle eggs has been identified as a threatening process that could negatively affect freshwater turtle population function. Aims Experiments were conducted to identify the effects of inundation of Emydura macquarii krefftii eggs in response to (1) duration and (2) timing on hatching success of eggs and hatchling phenotypes as measures of both direct and indirect impacts. Methods Four treatments of eggs, namely, control (no submersion time), 30 min of submersion, 1 h of submersion and 6 h of submersion, were tested by flooding at nine periods during incubation (within the first 24 h, then every week following). Key results Inundation for any length of time caused a significant increase in egg mortality compared with zero inundation with control eggs. The developmental age at which inundation treatments were applied also had a significant effect on hatching success. Conclusion It is concluded that E. m. krefftii eggs are very sensitive to even brief episodes of inundation, especially within the first 24 h of incubation. Implications It is expected that the eggs of other turtle species that have a brief post-oviposition embryonic diapause will exhibit similar sensitivities to inundation.