5 – Turtles of Cooper Creek – life in the slow lane 59 they are sexually mature, and then they reallocate resources into maintenance and reproduction. Growth slows dramatically at maturity and body sizes are limited by this dynamic partitioning (Georges 1985). In the boom–bust Cooper Creek, resources bounce between severe depletion and plenty. During the bust times, Cooper Creek turtles direct their resources almost entirely to maintenance, sometimes even surviving in the mud (Fig. 5.4). Similarly, eastern long-necked turtles in wetlands near Jervis Bay in New South Wales partition their resources (Kennett and Georges 1995). In the boom times, there is abundant food, probably allowing Cooper Creek turtles to direct their energy to maintenance, reproduction and growth in a way not possible in more stable systems. This allows them to grow to be giants, albeit sporadically, throughout their lives. The pressures of booms and busts and these life history tactics mean that populations of Cooper Creek turtles vary in a fascinating way, along the waterholes of Cooper Creek. Juveniles and adult males and females can be distinguished (Georges et al. 2006). The Fig. 5.4. During bust periods, turtles in Cooper Creek can die when waterholes dry up. Some individuals can survive briefly by seeking refuge in the mud, such as this Cooper Creek turtle from Lake Dunn, but they soon die (photo, J. Cann).
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