Ngarkat — the great mallee reserve

Drive east over the top of the Mount Lofty Ranges and the country does something abrupt. The tall wet forest thins, the air dries, the horizon opens out, and within a few kilometres you are in a low, grey-green scrub that seems to run on forever toward the Murray. You have crossed into the rain shadow, the dry lee where the ranges have already wrung the rain out of the westerlies before they arrive, and at its far edge sits the biggest single block of it left anywhere in the state: Ngarkat, more than a quarter of a million hectares of near-unbroken mallee (DEH 2004). Early surveyors, unimpressed, called this the Ninety Mile Desert. It is not a desert — it is mallee, hardier and more particular — but the old name is a fair measure of how little anyone once thought it was worth.

That low opinion is exactly what saved it. Country this dry could be cleared and cropped, but not farmed with any confidence, and much of it was abandoned in the bust years rather than fought for. So while the fertile plains around Adelaide were cleared to a few scattered percent of their original cover, Ngarkat survived close to whole, and today it stands as the largest remnant of native vegetation in the entire settled agricultural belt of South Australia (DEH 2004).

What is out there was established the unglamorous way: two ecologists, Foulkes and Gillen, walked 678 vegetation plots across the Murray Mallee and ran vertebrate surveys on 173 of them, tallying nearly 21,000 plants, over 5,000 birds, 1,500 reptiles and close to 800 mammals plot by plot rather than glimpsed from a car window (Foulkes 2000). Underneath it all runs fire, on its own patient schedule: the spinifex hummocks that carpet the sandier dunes need something like fifteen years unburnt before they are dense enough to support the animals that depend on them (Haslem 2011), and the mallee eucalypts above them are built to burn to the ground and resprout from an underground lignotuber, over and over, indefinitely.

That schedule is not optional, as Ngarkat itself proved in 2014, when a single vast wildfire tore through the reserve’s oldest spinifex and wiped the mallee emu-wren out of South Australia in one afternoon — a four-gram bird too small and weak-flying to outrun a fire front (DEWHA 2010). From 2018 conservationists began carrying the same species west from Victoria, releasing founders into spinifex that had finally grown back thick enough to hide them. It keeps company with nineteen other mallee-dependent birds now reckoned together, since 2021, as a single Commonwealth-listed endangered community — because you cannot save one mallee bird without saving the reserve underneath it (TSSC 2021).