It’s no small task. Edgbaston’s spring complex spans 6km from north to south and 2km across. The springs themselves range in size from small puddles to reservoirs the size of a football field, and new springs are popping up all the time.
A paper published last year found that the Edgbaston springs have trebled in size over the last decade as water pressure in the Great Artesian Basin rises due to the Queensland government’s bore-capping scheme. This has added another layer of not just complexity, but also urgency to Bush Heritage’s work.
With the LiDAR mapping already complete, Dean hopes to begin construction on the new barriers in early 2024. When that happens, it won’t just be the Red-finned Blue-eye that see the benefits. Many other endemic species call the Edgbaston springs home, too: the Edgbaston Goby, a dozen snails, a flatworm, a shrimp, an amphipod, a dragonfly and many plants.
All are impacted by the presence of Gambusia, which occupy the ‘Goldilocks zone’ of life in the springs. This is the area between the spring vents that millennia-old, deoxygenated water from the Great Artesian Basin bubbles to the surface and the outer periphery, which is oxygenated, and also more exposed to the extreme temperature fluctuations of the arid environment.
Long-term, Bush Heritage’s vision is to remove Gambusia from Edgbaston entirely. Starting in the northern, ‘upstream’ cluster of springs, Dean and the team will slowly work their way downstream – eradicating Gambusia and constructing barriers as they go until Gambusia are pushed off the reserve’s southern boundary.
“I can envisage the great Gambusia wall,” he says. “It might take a decade, two decades or even 50 years, but if we keep pushing them south, eventually we’ll have none left on the reserve.”
Bush Heritage gratefully acknowledges funding from WIRES National Grants Program which has made LiDAR mapping at Edgbaston Reserve possible.