Conservation of the Western Swamp Tortoise

Why Did the Turtle Cross the Road?

It’s a rhetorical question, but we should be thankful that this particular turtle did cross the road. The road in question was in Bullsbrook, nowadays a northern suburb of Perth in Western Australia. It was a misty morning in 1953, when Arthur Gates saw and picked up a small tortoise that was crawling across the road and away from a swamp on his farm. Arthur, in turn, gave his find to a schoolboy and keen naturalist Robert Boyd.

So began a journey of rediscovery of a species that had flickered across the consciousness of natural science. Robert took his turtle to Perth’s Wildlife Show and asked local experts to identify his tortoise. The initial assumption was that it was a Long Necked Swamp Tortoise, but as Robert pointed out, his tortoise had a short-neck! There was further excitement, discussion and research which led to Robert’s tortoise being donated to the Western Australian Museum, and then cumulating in it being a nominated as a new species.

This species we now know as the Western Swamp Turtle or sometimes as the Western Short-necked Turtle. The “new species” was announced to the world, only for this assertion to be successfully challenged as a rediscovery of a specimen collected by Austrian botanist and zoologist J.A. Ludwig Preiss during an expedition to Western Australia which ran from 1839 to 1841. Ludwig donated his specimen to the Vienna Museum of Natural History; simply labelling it ‘New Holland ¹’ to indicate that it was collected from what we now know as Western Australia. Much later, in 1901 it was given its scientific name Pseudemydura umbrina, by which it is still known today. The Western Swamp Turtle is the only living species of the genus Pseudemydura, with only minimal differences from species of the Miocene period ² . The Western Swamp Turtles’ lineage goes back over 20 million years and today it is finally teetering on the brink of its extinction.

So where was the Western Swamp Turtle hiding for the years between the collection by Preiss and Boyd? This fresh water turtle has a shell that measures up to 155mm, so you’d think it wouldn’t go unnoticed. The Short-necked frequents shallow swamps, which dry out from the late spring until autumn. During the dry season it aestivates ³ until the wet season returns. The turtles’ aestivation is spent in holes underground or buried under deep leaf litter. While the only other freshwater turtle in Western Australia, the Long Necked Swamp Tortoise, is a yearlong resident of permanent swamps, the Western Swamp Turtle was only likely to be seen at winter and spring time.

It is likely that the decline of the Western Swamp Turtle is mainly due to the draining of the seasonal swamps for clay extraction, agriculture in general and potato farming in particular. Indeed, prior to its rediscovery, farmer Arthur Gates and his brother had planned to drain the remaining seasonal swamps on their land. The Western Swamp Turtle only feeds underwater. Any prolonged period of drought, puts the Western Swamp Turtle at risk as the ephemeral swamps may not be re-established in the autumn. So whether these ephemeral swamps are drained or don’t reappear due to a drought, the outcome is the same; starvation for the turtle.

Predation is also a problem for this tortoise. Alien, that is introduced and non-native, species such as rats, foxes and feral cats are known to eat the turtles’ eggs. Western Swamp Turtles are thought to live for up to 100 years, but these tortoises don’t reach sexual maturity until about 15 years and then lay only relatively small clutches of 3 to 5 eggs. Thus, even if breeding recovered naturally, these turtles are going to require many years to mature and breed before their population recovers and becomes self sustaining.

Following the (re)discovery of the Western Swamp Turtle a search for more individuals began. Two small populations were discovered in the shallow swamps in the Swan Valley near Perth. The population was estimated to be around 100. Work began on establishing two reserves; this required fund raising, buying and then fencing the land to protect the turtles from predation. There was a public appeal for money, support from the government and the generosity of the Gates’ family, which together led to purchase of the land. Because some of the seasonal swamps could extend beyond the fenced perimeter of the Reserves and to allow the turtles to forage in nearby swamps, tortoise-friendly doors were included in the fence. By 1963 the two Reserves were established and the combined population was estimated at 200 to 250 individuals.

Perth Zoo took some specimens for breeding in 1964 and between 1966 and 1977, 26 turtles hatched. This progress was wiped out overnight, when all Perth Zoo’s Western Swamp Turtles were stolen! It’s been reported that in 1978 a pair of these turtles had been smuggled to Germany and were sold for the equivalent of $5000.

Concern mounted as by 1985 the population at one of the reserves was down to 30 to 50 individuals and plans were laid to formally establish a captive breeding programme, initially at the University of Western Australia and then transferring to Perth Zoo in 1989. The Zoo was supported by funding from WWF-Australia, CALM ⁴ and Perth Zoo itself. The team, lead by Dr Gerald Kuchling, (University Western Australia) at Perth developed a ‘special pudding’ based on the carnivorous menu of the wild turtles and supplemented with minerals and vitamins and this in turn led to improved ovulation of the female turtles. Genetic management has been a key factor in sustaining and expanding the numbers of these turtles.

By 1992 a Recovery Plan for the Western Swamp Turtle had been formulated and 1994 saw the re-introduction of captive bred tortoises into one of the Reserves. As of 2000, a wild population was established in a third nature reserve. Since 1988, Perth Zoo has bred more than 700 Western Swamp Tortoises, with 500 released into various sites, including the three nature reserves.

So this short-necked turtle had disappeared from view for more than century, yet it was living on the fringes of a major city and could so easily have become permanently extinct had it not been for farmer Gates picking one up as it crossed the road that ran through his farm. Today, the Western Swamp Turtle holds the title as Australia’s rarest reptile and owes its existence today to the intervention of, among others, Perth Zoo.

David Lomas, 2012

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