Museums of evolution

The artesian springs on Edgbaston Reserve are strongholds for ancient life, such as the world’s only population of the Red-finned Blue-eye fish. Thanks to a three-part conservation approach, their numbers are beginning to recover.

Edgbaston Reserve in central Queensland is a never-ending expanse of open claypans, cracked earth and beating sun.

It’s one of the last places you’d expect to find permanent water, but tucked away on the eastern side of the reserve, at the base of an escarpment, is the most ecologically diverse freshwater spring complex in Australia.

Here, some 100 springs are home to over a dozen species found nowhere else.

Bush Heritage bought the 8074-hectare Edgbaston Reserve in 2008 to protect its springs, which are fed by water that bubbles up from the Great Artesian Basin (GAB), an ancient aquifer that lies under 22% of Australia.

There are more than 600 GAB springs, but many have been destroyed through pastoralism or mining, or have dried up due to excessive extraction of groundwater from the GAB. The species that rely on these springs are now listed as an endangered community.

“Species have been isolated in these springs for so long that there's been an incredible amount of evolution and development of species,” says Dr Pippa Kern, Bush Heritage Freshwater and Wetlands ecologist.

“The level of diversity that we have in the Edgbaston springs is probably the highest of any springs in the Great Artesian Basin, and that's why this is such an important area for conservation.”

Edgbaston’s springs and the Great Artesian Basin owe their existence to the prehistoric Eromanga Sea that covered much of arid inland Australia about 110 million years ago and laid down the sediment that capped the basin.

Having been isolated in the middle of the outback for millions of years, many plants, invertebrates and fish in Edgbaston’s springs have evolved into species found nowhere else on the planet, making the springs ‘museums of evolution’.

Cue a special little fish that Bush Heritage has been working particularly hard to protect: the Red-finned Blue-eye (Scaturiginichthys vermeilipinnis). These translucent slips of silver with their baby blue eyes and vermillion fins are one of the world’s rarest fish.

First recorded by Europeans in 1990, Red-finned Blue-eyes are only found on Edgbaston Reserve and are listed as ‘critically endangered’.

“There were originally seven populations of Red-finned Blue-eyes. By the time Bush Heritage bought the property, only four remained, but a number of those were already compromised by the invasive Mosquitofish (Gambusia holbrooki).

Now, all but one of those natural populations has disappeared because of the Mosquitofish threat,” says Pippa.

But thanks to a three-part conservation approach, the Red-finned Blue-eye population has slowly begun to recover.

“Over the last decade Bush Heritage has worked to create new translocated populations, taking fish from the one remaining natural population and moving them into springs that are free from the Mosquitofish,” says Pippa.

The next step has been to surround the springs with fences of fine mesh that stop the Mosquitofish from entering the springs. But, most importantly, Bush Heritage has cracked the key to breeding Red-finned Blue-eye in captivity.

Previous attempts by other groups to breed the fish in traditional aquariums had failed: the fish survived, but they didn’t breed. The answer was to create artificial springs that replicate their naturally occurring homes.

This is done by sinking bores that release water into tanks buried in the ground, creating artificial spring wetlands. These captive-bred fish will be translocated into a natural spring to create new wild populations.

It’s been a year since the captive-breeding program kicked off, and two of those translocated populations have already increased from about 50-70 fish to about 100.

The future is now starting to look brighter for this living relic of an ancient past.

Funding for Bush Heritage’s Red-finned Blue-eye projects has been provided by the Mohamed bin Zayed Species Conservation Fund and the Queensland Government Nature Assist Program through an Everyone’s Environment Grant.