Bush Heritage ecologist Paul Foreman reveals the remarkable biodiversity of Edgbaston Reserve in Queensland.
Artesian spring on Edgbaston Reserve, Qld. Photo Wayne Lawler/ EcoPix.
It’s easy to think that we know everything there is to know about the world. Each country has been mapped, every ‘lost tribe’ discovered. And yet you often hear observations like this one, from the Convention on Biological Diversity:
‘Globally, around 1.75 million species have been described and formally named to date, and there are good grounds for believing that several million more species exist but remain undiscovered and undescribed’.
While it's true that most unknown species are insects or deep-sea marine organisms, many people will be surprised to learn that a lot of terrestrial plants remain undiscovered (estimated at over 10% or 30 000 species).
A scrambling pigface with broad, flat leaves (Gunniopsis spp.). Photo Paul Foreman.
And even though botanists have been poring over the continent since the era of Joseph Banks and Charles Darwin, it's still possible to find completely new things today – usually in remote places with unique or highly restricted environments.
The spectacular 1994 discovery of the Wollemi pine (Wollemia nobilis), a large prehistoric tree, only 150km from Sydney is a memorable example. And, excitingly, Bush Heritage’s newest reserve in central Queensland, Edgbaston, is also revealing new treasures.
What might be perceived by most as ‘just another cow paddock’ or even a ‘terrible place’ (as described by a local grazier in our Spring 2008 newsletter) is in fact a biological hot spot. By now many readers would be aware of Edgbaston’s unique, critically endangered fish, the redfin blue-eye, which was only discovered in 1990.
However, the story of Edgbaston’s endemic plants is less well known and understood.
Paul Foreman assessing the Mitchell grass plains on Edgbaston. Photo Jen Grindrod.
In June this year, a team from Bush Heritage collected no less than three new plants from the reserve – all saltbushes that are endemic to the saline scalds that fringe the property’s natural springs. One notable example is a delicate saltbush with distinctive and bizarre ‘antler-like’ fruits (opposite).
This plant grows only a few hundred metres from a spring on a low, saline white-sand ridge covered in porcupine spinifex (Triodia longiceps).
These new discoveries at Edgbaston mean there are now no less than 15 plants that have been described only very recently or still wait for a name to be assigned. Some interesting examples include a scrambling pigface with broad, flat leaves, an apparently long-lived ‘woody’ species of ‘beautyheads’ and a giant pipewort (up to 50cm tall) growing in springs shaded under tea-tree thickets.
The distinctive ‘antlerlike’ fruits of Atriplex spp. first collected in June 2009 along with two other new copper burrs (Sclerolaena spp.) Photo Paul Foreman.
All of these species are either endemic solely to Edgbaston or found in just one or two other nearby locations with similar ecosystems. Amazingly, it's likely there are still more species to be found.
So why is Edgbaston so biologically rich? The answer lies squarely with the permanent artesian springs scattered across the Pelican Creek/ Lake Mueller complex in the reserve’s east. These springs discharge from thin sandstone aquifers that recharge in the surrounding desert uplands to the north and east.
These discharge points are often in the lowest parts of the landscape and can be separated by tens to hundreds of kilometres of unwatered land.
It's thought that the resulting isolation for very long periods drives the evolution of new species that have adapted to specific springs environments. The surprisingly high numbers of unique organisms at Edgbaston suggests this spring complex has been relatively stable and effectively isolated for longer than most, but no one really knows for sure.
In a recent seminal paper on the redfin blue-eye, Edgbaston was called ‘the most significant springs for biodiversity conservation in the entire [Great Artesian Basin]’. The more we get to know this reserve, the more we can see why!