Across the Barkly Tableland: a great drive

One of the great drives in Australia, in my opinion only of course, is across the great wild extent of the Barkly Tableland in the north-east of the Northern Territory. It's sealed all the way, so a bit disappointing if you're looking for four-wheel drive adventure, but in the 460 kilometres from Tennant Creek on the Stuart Highway to Camooweal just inside Queensland there is only one 'settlement', the Barkly Homestead Roadhouse which also incorporates a nice camping area and rooms.

Approximate position of the Barkly Tableland - its boundaries are not precisely defined, and some
would have it stretching further east into Queensland or south in the Northern Territory.

Sealed roads notwithstanding, this is not country to take lightly; this is the start of the Tablelands Highway
which runs north from Barkly Homestead to the Carpentaria Highway near Borroloola.
And it's single lane all the way, which means pulling partly off the bitumen when someone's coming towards you.
If that someone is a huge roadtrain, then my strong advice is to get completely off and let them have the tar!
A rock thrown up by one of those could end your trip.

The Barkly is essentially a vast grassland on the cracking black soil plains which don't support tree growth; the heavy clays swell when wet and break up with deep wide cracks when dry, which pulls tree seedling roots apart. The east-west Barkly Highway however skirts the major Mitchell Grass grasslands to the north. The Tablelands Highway, running north from the Barkly Homestead (about halfway across the Barkly Highway) is a better option for viewing the pure treeless grasslands, but the eastern end of the Barkly Highway gives access to them.

Starting from the west the highway runs through lovely low shrubland with scattered eucalypts.

Acacia hilliana and Grevillea wickhamii east of Tennant Creek.

Acacia hilliana is a lovely flat-topped wattle which grows on poor soils from the Western Australian Pilbara to the Queensland border.We were there in late May, when it was in full bloom.

It was named for a remarkable character called Gerald Freer Hill, born 1880, who went from orchardist to
shorthand instructor to self-taught naturalist, to the first entomologist to be employed by the precursor of
Commonwealth Scientific and Industrial Research Organisation (the peak national science body, at least until
the current anti-science federal government began slashing its funding)
and eventually the country's foremost termite expert.
Hill collected the type specimen on one of his collecting trips to northern Australia.

 

This is not the only acacia to feature prominently. Turpentine Wattle Acacia lysiphloia also has a wide range across northern Australia.

Turpentine Wattle is notorious for burning away completely in a bushfire, leaving a sharp up-pointing
stake at ground level. The eucalypt is Silver Box E. pruinosa which is here at its southern-most limit,
but further north can dominate landscapes, and most attractively.

I hope you're now getting the sense of a rich - perhaps surprisingly rich if you've not experienced this country - and diverse landscape of flowering plants. Here on the fringes of the grassy plains there are certainly trees, perhaps most notably the beautiful but somewhat ominously titled Snappy Gum E. leucophloia.

Snappy Gum, which grows on gravelly soils across the tropics.

Other trees might be less familiar, though in some cases we know the genus well from shrubs in other places.

Beefwood Grevillea striata. This one is pretty straggly, but it can grow as a straight furrow-barked tree
to 15 metres tall. A few unrelated Australian trees were called beefwood by our carnivorously Freudian ancestors.
(I think we can assume they were referring to the timber's appearance rather than its culinary qualities!)

And in each of these photos grasses are prominent in the understorey. This predominance increases with the prevalence of the cracking clay soils.

Mitchell Grasses Astrebla spp. coming to the fore in ground coverage.
These support significant stock grazing on the tableland - along with native herbivores and numerous
seed-eaters - but the pressures seem not to have caused the catastrophic changes
suffered by grasslands elsewhere in Australia.

And where there are grasses - especially the spiky hummocks of Porcupine Grass, or Spinifex Triodia spp. - there will be termites in vast numbers.

Termite mounds in spinifex, Barkly Highway.
Termites in Australia have been likened in biomass to large grazing mammals in grasslands
elsewhere, with lizards playing the role of carnivores.

The point where the cracking clays suddenly take over is marked by a line so sudden as to be startling - nature is usually more nuanced than that.

Abruptly the trees are no more - the line can be seen continuing into the background.

After that, only a very occasional tree - usually growing in a sandy ephemeral stream bed - breaks
the vistas that stretch to the horizons.

Eventually, as we approach the Queensland border, we come to another unexpected sight - a river!

The James River flows south, into the Georgina River in south-west Queensland and
ultimately, in a a rare very wet La Niña year, into Lake Eyre in the deserts of South Australia.

White-faced Heron Egretta novaehollandiae and Giant Waterlilies Nymphaea gigantea;unexpected sights after hours in semi-arid shrubland and grassland!

 

It was quite cool when we crossed, so no reptiles to see, though there were certainly birds around, especially where water had been provided by bores for stock or at scattered rest stops, such as Sowden Bore where the following were taken.

Zebra Finches Taeniopygia guttata (one of my favourite Australians) will always find water. Their dry seed
diet compels them to drink daily, though they live in the driest parts of the continent.
These seemed entirely blasé about the warning sign!

Deep pits - I suspect from road fill quarries - provide sporadic dams (when the summer monsoons drift south) which support stands of the Broadleaf Paperbark Melaleuca viridiflora whose flowers are nearly as attractive to us as they are to visiting honeyeaters.

Brown Honeyeater Lichmera indistincta, found across most of the country except for the south-east.
Nor was its interest in the paperbark flowers purely aesthetic!

As for the grasslands, one of the birds I always look forward to on the Barkly is the elegant Australian Pratincole Stiltia isabella; its folk-name of Swallow-plover sums up its elegance very nicely. This time we found it during a late afternoon detour up the Tablelands Highway (actually looking for Letter-winged Kites, a perennial birding bête noir of mine - ironic really, given that they're white!).

Australian Pratincole on the Tablelands Highway - literally! This beautiful bird breeds in arid inland southern Australia
and in winter migrates north; some stay in tropical Australia, others continue as far as south-east Asia.
It is the only pratincole (family Glareolidae) not a member of the genus Glareola.

There is much more to the Barkly than this sketchy introduction but I do hope this has been enough to encourage you to plan your next northern Australian trip so that you can experience it for yourself. You won't regret it, and it will be more than Victorian Governor Henry Barkly, for whom it was named, ever did.

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