Dinner Plate Turtle (Chelodina steindachneri) – an arid zone specialist

Western Australian freshwater turtles can be divided into two groups based on their geographical distribution: central and southern (Chelodina oblonga, C. steindachneri, Pseudemydura umbrina) and tropical (C. burrungandjii, C. rugosa, Elseya dentata, Emydura victoriae, E. australis) (Georges 2008). Temperate zone species mostly nest in spring, with hatchlings emerging in early summer (Legler and Georges 1993). These species generally lay their eggs in sand adjacent to the water ways they inhabit. Tropical species are more flexible when they lay their eggs and they generally select nest sites beyond those areas that will be flooded in the wet season (Legler and Georges 1993).

Chelodina steindachneri (Plate 1) is found in many of the ephemeral rivers of the mid-west, Murchison, Pilbara and Sandy Deserts from the Irwin River in the south to the De Grey River in the Pilbara. Like most Chelidae it lays white soft-shelled eggs in a burrow it digs in the ground. Baby turtles hatch and dig their way to the surface and are a replica of the adult form. Figure 1 below shows the data from the Department of Parks and Wildlife NatureMap website and shows the location of the Departments C. steindachneri records and the drainage systems in which they are found. It is apparent that are some stage in the past that these turtles have been able to move between drainage systems.

Plate 1. Dinner Plate Turtle	Figure 1. Records of Dinner Plate Turtles from NatureMap showing drainage systems

We have recorded C. steindachneri in multiple locations across WA. Three are particularly interesting because of their remoteness. There is a tiny ephemeral creek midway between Paynes Find and Sandstone that crosses the gravel road. We encountered them in the creek after heavy rain. We also recorded them in a creek that runs east from a rocky breakaway about 80km north of Laverton. This creek holds water for an extended period after rain. Both of these creeks drain internally and are not connected to a major river system, so it is likely that they have persisted in these areas for a very long time. We also found one crossing the road that runs north from Wittenoom within a couple of kilometres of the Fortescue River. It was located in a barren open landscape with few trees and the grasses had dried and been burnt. It had clearly walked at least 1km from the water.

Dinner Plate Turtles aestivate in the ground during the dry periods and come to the surface after heavy rain. Like most freshwater turtles they forage on insects, small vertebrates and vegetation. They can be found in the ephemeral rivers, and are occasionally seen travelling overland, most probably from one water body to another. When picked up, particularly in a terrestrial environment, they will generally have a full bladder which they are happy to empty on the captor.

Turtles can be trapped (Iverson 1979, de Lathouder 2007) and caught with a net or grasp by hand (Chaney and Smith 1950, Ream and Ream 1966). Traps are generally classed as either underwater or basking traps. Underwater traps include hoop traps (Legler 1960, Iverson 1979, Kennett 1992), trammel nets (Vogt 1980), fyke nets and cathedral traps (Kuchling 2003). Basking traps are rarely used in WA. All traps have a section that remains above the water and most use a bait to attract turtles.

Kuchling’s (2003) cathedral trap is collapsible, has two elongated entrances and can be adapted for any depth of water (see Plates 2 and 3), however, the vertical cylindrical netting has a propensity to become twisted when it catches numerous individuals; therefore in this circumstance it needs to be cleared more frequently (e.g. every 12 hrs). Entry slits to this trap can be adjusted to reduce the possibility of species known to escape traps from getting out.

Plate 2. Kuchlings cathedral turtle trap (Photo G. Kuchling)	Plate 3. Float for Kuchlings cathedral turtle trap (Photo G. Kuchling)

Their tracks are often seen in the creek and river beds of the Gascoyne, Murchison and Pilbara drainage basins, as individuals move from one pond to the next. But because they are seldom seen, many observers confuse their tracks with other vertebrates because they forget that they are present in the landscape. Their track is reasonably distinctive as the rear foot is almost placed in the print of the front foot (Plate 4). They lift their body off the ground when walking, so there are two parallel lines of tracks with limited or no body or tail drag mark.

We have also used seine nets to catch freshwater turtles, but they are easily snagged, so you can spend more time untangling the net that you do catching turtles. In clear water, it is often possible to see C. steindachneri (Plate 5) and catch turtles by hand while walking or swimming in relatively shallow water.

Plate 4. Dinner Plate Turtle tracks	Plate 5. Dinner Plate Turtle in an emphemeral pond

Reference

Chaney, A. H. and C. L. Smith. 1950. Methods for collecting map turtles. Copeia 1950:323-324.

de Lathouder, R. 2007. Assessing the abundance of freshwater turtles in an urban landscape: A comparison of trapping and observational techniques. Griffith University Brisbane, Queensland.

Georges, A. 2008. Freshwater Turtles of Tropical Australia Compilation of Distributional Data. Applied Ecology, University of Canberra, Canberra.

Iverson, J. B. 1979. Another inexpensive turtle trap. Herpetological Review 10:55.

Kennett, R. 1992. A new trap design for catching freshwater turtles. Wildlife Research 19:443-445.

Kuchling, G. 2003. A new underwater trap for catching turtles. Herpetological Review 34:126-128.

Legler, J. M. 1960. A simple and inexpensive device for trapping aquatic turtles. Proceedings of the Utah Academy of Science, Arts and Letters 37:63-66.

Legler, J. M. and A. Georges. 1993. Family Chelidae.in C. J. Glasby, G. J. B. Ross, and P. L. Beesley, editors. Fauna of Australia. Vol 2A Amphibia and Reptilia. Australian Government Publishing Service, Canberra.

Ream, C. and R. Ream. 1966. The influence of sampling methods on the estimation of population structure in painted turtles. American Midland Naturalist 75:325-338.

Vogt, R. C. 1980. New method for trapping aquatic turtles. Copeia 1980:368-371.