Western Swamp Tortoise Conservation
(1) - (3) © Perth Zoo
To breed and reintroduce western swamp tortoises into their former range in Australia
The western swamp tortoise or short-necked freshwater tortoise (Pseudemydura umbrina) is Australia's most critically endangered reptile. The western swamp tortoise has only been recorded in scattered localities in a narrow, 3–5 km strip of the Swan Coastal Plain in Western Australia. It is believed that their original habitat was in the clay soil areas of the Swan Valley to the north of Perth. This area was one of the first to be developed for agriculture after the arrival of European settlers in 1829.
The western swamp tortoise lifecycle requires shallow winter and spring wet ephemeral swamps with clay or clay overlay with sand substrates. The small remaining areas of this specialised habitat are close to urbanisation. Between 1963 and 2001, the numbers of these tortoises known to be alive in the wild fluctuated between 40 and 120. Without a recovery programme and significant efforts to restock the population this tortoise would likely have become extinct.
In 1988, a captive breeding programme was initiated by Dr Gerald Kuchling from the University of Western Australia and was taken over by Perth Zoo in 1989. A Recovery Team was established in 1990. In July 1991, responsibility for captive breeding passed from the Western Swamp Tortoise Captive Breeding Project Management Committee to Perth Zoo.
A number of management tools were developed to ensure successful breeding. The diet was re-evaluated and a special ‘pudding' developed, consisting of marron, rats, fish, beef heart and vitamin and mineral supplements in gelatine. This diet improved the condition of the females that started to ovulate. Over the years, genetic management has been a critical factor due to the small size of the original population.
One of the key factors in breeding western swamp tortoises is to allow them to aestivate. This happens naturally in the wild from November to June each year (though the exact time frame varies with the amount of rain and time of year the region receives the rainfall). Perth Zoo encourages this natural behaviour as it is essential for breeding. When the tortoises reach 100 g in weight (about three years of age), they are released into managed wild habitats by the Western Australian Department of Environment and Conservation.
In combination, these tools have resulted in a very successful breed-for-release programme. Since 1988, Perth Zoo has bred more than 800 western swamp tortoises of which more than 500 have been released (figures as at 2011).
WAZA Conservation Project 05028 is implemented by Perth Zoo in partnership with the Western Swamp Tortoise Recovery Team members, with input from Dr Gerald Kuchling of the Western Australian Department of Environment and Conservation, the World Wildlife Fund and Friends of the Western Swamp Tortoise. The indigenous company, Boola Wongin Nursery, also supports and promotes the programme. Adelaide Zoo has begun development of a second insurance population to ensure that all the western swamp tortoise 'eggs' are not in one basket.
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(1) - (3) © Perth Zoo