Habitat utilization and its relationship to growth and reproduction of the eastern long-necked turtle, Chelodina longicollis (Testudinata: Chelidae), from Australia

Chelodina longicollis occupies a wide range of ephemeral and permanent waters in the Jervis Bay Territory of coastal New South Wales. As ephemeral waters dry up during periods of low rainfall, which may span several years, the turtles retreat to the refuge of two permanent dune lakes. High population densities in these lakes coupled with low productivity lead to a sharp decline in growth, and reproduction ceases almost entirely. Differences between the lakes in the growth rates and body conditions of turtles coincide with differences in food availability. When rainfall increases, the turtles disperse once more to the ephemeral swamps where they growth faster and are in better condition; and reproductive output is considerably greater than in the permanent water. The propensity of the species for overland migration following rain is explained by the advantages of colonizing highly productive ephemeral waters, reinforced by the severe disadvantages of remaining in the permanent water of overcrowded drought refuges. -Authors