By determining the colonisation and re colonisation potential of each species under semi natural conditions, this project will provide informative data for conservation planning such as predicting the impact of future flow reduction in the Murray Darling Basin on the persistence of freshwater turtle populations. The significance of dams and weirs as barrier to dispersal will also be investigated, and the size and age structure of populations within one of the catchments will be estimated (mark recapture method), providing currently lacking information on population health for each species within an upper section of the Murray Darling Basin.