Naree and Yantabulla stations have many iconic symbols of the Australian bush, and one of the most noticeable as you drive around the two properties is 'the mulga' – silvery grey acacia shrubs and trees growing on brilliant red sandy soils.
Almost 40% of the two properties supports mulga – which are unusual in being long-lived acacias where most species are known for having short lives. It can take 100 years for a mulga tree to reach maturity, and the trees may live for up to 300 years in undisturbed habitats.
One of our key targets in managing Naree and Yantabulla is to see old growth mulga returned to the landscape. Mulga is nutritious drought food for sheep and cattle (as well as for wild goats and kangaroos!), so much of the 'Mulga Lands' (extending from just south of Longreach in Queensland to Broken Hill in NSW) has been periodically lopped or pushed to feed livestock over the past 150 years, and mature mulga can be hard to find.
Mulga is a common plant of arid and semi-arid Australia, but has many fascinating attributes. It has adapted in ingenious ways to survive and thrive in the difficult conditions in which it grows – low and very unpredictable rainfall, very hot summers and cold winters.
The trees are extremely well drought-proofed both top and bottom, with very long tap roots as well as extensive shallow roots, and long, thin, leathery, silver grey phyllodes (thickened leaf stems) instead of leaves, to reflect heat and minimise evaporation. The phyllodes point directly upwards on branches arranged like an upside down umbrella, to minimise the effects of the midday sun and maximise the collection of rainwater. If you stand under a mulga tree when it’s raining you can see the water cascading down the trunk directly to the roots below.
Mulga doesn’t reproduce every year – it’s thought that a major germination event only happens perhaps once a decade, but even that's not for certain. Bright yellow flowers followed by conspicuous bunches of green seed pods only occur after good rains, and when things get particularly tough mulga drops its leaves – the leaf litter becoming an important part of the whole ecosystem.
Mulga habitats are very diverse despite the harsh conditions, and more than 130 other plant species have been noted in the mulga shrublands and woodlands of Naree and Yantabulla by our staff and volunteers since its purchase in 2012. Discovering some of the species is an interesting challenge, as many of them only appear in very specific climatic conditions, which don't occur every year.
At the moment we're enjoying the results of good winter rainfall (155mm since May) and winter annuals of all kinds are bursting through the red sandy soils. The mulga understorey is glowing with carpets of flowers, many of them daisies – yellow, blue, purple, white and pink.
Amongst the most unusual to appear this year, for the first time in the four winters we’ve been here, are ground-heads (Chthonocephalus pseudevax), a dwarf, stemless plant in the daisy family with flowers produced directly on the ground. We also have wires-and-wool (Angianthus burkittii), named for its very characteristic appearance of tiny, wiry leaves and small cotton-puff looking flowers.
The landscapes here still have many secrets to reveal to those, like us, who are fortunate enough to watch and wait through the erratic seasons. It really is a land where you never know quite what might happen next!