|Not megafauna, but charismatic... and needing friends|
|Written by Alex Stone|
With only around 300 alive, the Western Swamp Tortoise remains Australia’s most endangered reptile. But recent achievements by the Recovery Team offer some hope for their future…
They’re not warm, furry or cuddly in any conventional sense. They have appealing eyes, but not of the baby type. A sharp beady stare is closer to the mark – but some might say a smiling look. And then some might say that attitude is entirely warranted.
The more you get to know them, the more you’re enchanted by them. Even if it does require some measure of eccentricity.
These wee critters need all the friends they can get – we’re talking about the 300 or so Western Swamp Tortoises left alive in the world.
They are some rather unique individuals. These few Western Swamp Tortoises are the only representatives of a single species, within a single genus, within a single subfamily. What’s more they belong to an ancient order, older than the dinosaurs.
And right now, they’re restricted to two tiny islands (and maybe a third) in the vast sea of land that is the Australian continent, plus to two Australian zoos.
The Western Swamp Tortoise is Australia’s most endangered reptile. About half are in a breeding-for-release programme at Perth Zoo, and half at Twin Swamps and Ellenbrook Reserves just north of the city. The tiny reserves are both protected by predator-proof fences, and represent the last remaining natural habitat of the tortoises.
In the past few years, Western Swamp Tortoises have been released at another reserve further north near Mogumber, but this site is not as intensively managed and has no predaotor-proof fencing. A bushfire contributed to a high mortality in the third year, but now it appears a greater percentage of the released animals are surviving. And recently Adelaide Zoo took some Western Swamp Tortoises into their care.
Trouble is, in historic times the Western Swamp Tortoise only had a tiny geographic range, being confined to the Swan Coastal Plain north of Perth. They have specific real estate requirements, insisting on living in non-perennial shallow swamps with a clay base, where so much of the surrounding land is predominantly sand.
They’ve seen most of this habitat disappear – these small areas of clay have fertile soil and have been cleared for agriculture and have been mined for the making of bricks. Large tracts of their land have also been subsumed by Perth’s urban sprawl. However, some habitat remains within the boundaries of Perth’s International Airport.
Then the tortoises have a slow and unusual reproductive cycle, which has confused researchers for many years. Turns out they aestivate – it’s like hibernation, but instead, they do it in the heat of summer, in shallow tunnels or under bush litter. This puts them at risk of bushfires, and being snapped up by predators, both native (ravens) and introduced (rats, cats and foxes). And their hatchlings, which appear in autumn, are further made vulnerable by the increasing unreliability of WA’s winter rainfall.
Western Swamp Tortoises have a fascinating history, long believed extinct.
They were ‘rediscovered’ by a schoolboy in the early 1950’s. He found this tortoise he didn’t recognise, crossing the road in Upper Swan (the area also supports the common long-necked tortoise).
Up till then, the species was known only from a single preserved specimen collected somewhere in WA in 1839, and languishing half-forgotten in a museum in Vienna, Austria. That was how Gerald Kuchling first encountered the tortoise.
At one point in the late 1980s, the species was down to less than 50 animals, almost all in the care of their new champion Kuchling. There was a wild population of about eight breeding adults plus about 20 juveniles at Ellen Brook in 1980 which increased to about 20 breeding adults and 34 juveniles by 1990, and less than 10 breeding adults at Twin Swamps in 1980.
But once their specific habitat requirements and unusual breeding habits became better understood, their numbers have risen steadily as a result of Kuchling’s research, Perth Zoo’s breeding-for-release programme, and protection and management of habitat areas including the removal of feral predators like the fox and rat by the Department Conservation and Land Management (CALM) with assistance from and the members of the Western Swamp Tortoise Recovery Team.
A Friends of the Western Swamp Tortoise Group has recently been formed, to support CALM and the Recovery Team in a volunteer capacity.
But the big news this year was the extraordinary output of 75 hatchlings at the Perth Zoo. This allowed 54 animals to be released into the wild at the reserves.
Perth Zoo has successfully bred 590 western swamp tortoises since 1990 and has provided 316 tortoises for release in that time.
The Australasian Regional Association of Zoological Parks and Aquaria awarded the Zoo the 2005 In situ Conservation Award in recognition of its efforts to saving the Western Swamp Tortoise.
So, things might be looking up for the not-exactly-charismatic, not-quite-megafauna western swamp tortoise. Still, the species needs all the help it can get – and perhaps a bit of good luck too.