About Me

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Canberra-based naturalist, conservationist, educator since 1980. I’m passionate about the natural world (especially the southern hemisphere), and trying to understand it and to share such understandings. To that aim I’ve written several books (most recently 'Birds in Their Habitats' and 'Australian Bird Names; origins and meanings'), and run tours all over Australia, and for 17 years to South and Central America. I've done a lot of ABC radio work, chaired a government environmental advisory committee and taught many adult education classes – and of course presented this blog, since 2012. I am a recipient of the Australian Natural History Medallion, the Australian Plants Award and most recently a Medal of the Order of Australia for ‘services to conservation and the environment’. I live happily in suburban Duffy with my partner Louise surrounded by a dense native garden and lots of birds.

Thursday 17 October 2024

The Magnificent Mallee; long despised, finally treasured. #1

 This is a topic close to my heart. I grew up in South Australia, and Adelaide is nearer to
remaining mallee than any other state capital (with the possible exception of Melbourne).
Dad loved it, and I spent time in the mallee long before I encountered any real forests,
let alone wet ones. It seems strange then that it has taken me this long to tackle it
here, but maybe I've never felt ready to do it justice. Such excuses however can lead to us
to never doing anything worthwhile so, prompted by a recent camping trip to
north-western Victoria, here's my tribute to a uniquely Australian habitat.

"No-one knows who made the mallee, but the devil is strongly suspected", at least according to an anonymous writer in The Bulletin in 1901. 

Mallee to the horizon from Warepil Lookout in Hattah-Kulkyne National Park,
north-western Victoria.

The Bulletin disparager came from a long line of whitefella mallee-bashers. Surveyor-General John Oxley (admittedly pretty much always a glass-three-quarters-empty character, judging by his journals), wrote of the mallee country along the Cocoparra Range in south-western NSW in 1817 as "country of the most miserable description... abandoned by every living creature capable of getting out of there". (The local people were understandably uninterested in making his acquaintance.) Others wrote similarly. Later reports however revealed the real reason for the general antipathy. Charles Sturt in 1833, the first to enter the vast South Australian-Victoria mallee lands, of which Hattah-Kulkyne above is but a remnant, described it as "barren and unproductive as the worst of the country we have passed through". An 1851 report to the Victorian Government Surveyor reported that "throughout the whole of the scrub there is neither stone nor timber fit for any useful purpose". The crime of this lovely, subtle and uniquely Australian landscape was that it wasn't apparently 'useful', so there was no point to it. 

Sandhill Wattle Acacia ligulata flowering in mallee in Wyperfeld NP, north-western Victoria.

Nor was this attitude limited to the 19th century by any means. The term 'desert' was applied to the spectacularly rich and highly floral mallee heath country of eastern South Australia and western Victoria - the Ninety Mile Desert in SA, Big and Little Deserts in Victoria. Now, I love the desert lands, but there was no affection in these labels. They couldn't grow wheat or wool, so were effectively sterile.

But there were mallee farmers, and they were tough. Low rainfall, low soil nutrients (ie by European farming standards) and the incredible resilience of the mallee eucalypts, which resprouted from massive underground lignotubers (of which more in a moment) immediately after clearing, made the farmers' lives hell. Moreover the lignotubers ('mallee roots') simply broke their ploughs. In time though ingenuity, technology and science proved too much for even the ancient mallee habitats. Mulleinising in the 1870s meant clearing the bush by dragging water tanks on chains between horses (later tractors), then burning, rough planting and again burning the stubble to knock the regrowth back again. Taller wheat strains just kept their heads above the regenerating scrub. About this time too a Mr Smith of Maitland on South Australia's Yorke Peninsula invented the 'stump jump plough' so that it wasn't necessary to grub out all of the stumps. The invention of superphosphate at Roseworthy College north of Adelaide in the 1880s allowed continuous cropping to assist in controlling regeneration. After this over a million hectares of mallee in the higher rainfall, sandy loam soils north of Adelaide, on the Yorke Peninsula (where almost no original vegetation now remains) and in Western Victoria, were rapidly cleared. 

Millions of hectares more followed in the periods after both world wars, in western NSW, the far north-west of Victoria, Eyre Peninsula and out towards the Nullarbor, and in the south-west of WA. The pace slowed though as erosion issues and soil degradation followed, though the discovery of the role played by missing trace elements (especially cobalt and copper) triggered another burst in the 1950s and 60s. Ironically the Ninety Mile Desert was now redubbed Coonalpyn Downs... It wasn't until the 1970s that mallee conservation became something to consider.

So, perhaps belatedly on my part, what is 'the mallee'?

This map (courtesy of the Australian National Botanic Gardens) gives an indication of
the current (green) and estimated former (pink) distribution of mallee woodlands,
mostly in the semi-arid 200 - 550mm rainfall zone. However we should note that the
current range by no means implies continuous or undamaged mallee.
Most is fragmentary, and what remains doesn't reflect the
original diversity of the different mallee habitats.
The word apparently echoes one used by people in western Victoria to describe the multi-stemmed habit of eucalypts that grow in these low rainfall, low nutrient regions.
Mallee form, Mungo National Park, western NSW.
This form comprises a massive underground lignotuber (ie literally a woody tuber), a 'mallee root' up to a metre in diameter from which grow several equal-sized 'stems' which are actually branches. The foliage grows only at the tips of these branches. The key trigger appears to be low phosphate levels; it seems that low soil phosphate levels inhibit the cell growth which would otherwise lead to stem or leaf formation, and diverts it to carbohydrate production which is converted to wall material in the lignotuber. The lignotuber thus holds considerable nutrient reserves (but not water, despite a much-repeated myth). Roots grow from the lignotuber and these may hold water, a fact which was of course well known to Indigenous people. The lignotuber confers a remarkable resiliency, as the mallee farmers discovered. In a 1920s experiment scientists defoliated one-year-old seedlings 26 times in succession before they, not the eucalypt, gave up the battle.
The top of a large lignotuber protruding from the ground, with the branches growing
up from it. Hattah-Kulkyne National Park.
Some 130 species of eucalypts grow as mallees. However, only about 20 of these always grow thus; the other 130 surprisingly adopt the form only if the conditions - especially the low-phosphate soils - require it. Lignotubers are known in other plant groups elsewhere in the world, but what is unique to Australia is the ability of these species to adopt a mallee form only if the conditions are right. I have stood on dunes in the south-east of South Australia among mallee Pink Gums E. fasciculosa, and looked out at tall single-stemmed trees of the same species growing in the deep soil of the paddocks. This was before digital camera days I'm afraid, but here's another example.
Gum-barked Coolabah (though it has several names across its broad inland distribution)
E. intertexta, near Cobar, western NSW.
The same species growing as a mallee at Redbank Gorge,
western Tjoritja (MacDonnell Ranges) National Park.
This raises another point too; that mallee eucalypts can be found well outside of the area designated on the map above, provided of course that the soil conditions are right.
Port Jackson Mallee E. obstans, Currarong, north end of Jervis Bay, south coast NSW.
This mallee grows in sand and sandstone along the coast from here to Sydney.

Blue Mountains Mallee Ash E. stricta, Blackheath, Blue Mountains, NSW.
This one too, well out of the mallee zone, grows on shallow sandy soils on ridges.
And this in turn leads us the secondary use of the term 'mallee', which I have more than hinted at already. Almost inevitably the habitat that produced the mallee tree's unique form became in time known as simply 'the mallee'. But in this sense too there is not just one uniform 'mallee'. The model may have been updated since, but in Victoria back in the 1990s there were 31 major communities and some 100 vegetation sub-communities recognised. However for our purposes I'm going to look at just three basic mallee habitat 'types', defined by their dominant understorey (though course nature is never interested in being put in our boxes, so it's not always so clear cut).

Mallee-Heath, as the name suggests, has an understorey of heathy shrubs (banksias, hakeas, grevilleas, casuarinas and callitris for example) and grows in deep sand in higher rainfall areas of the zone. For this reason it was one of the first regions of the mallee zone to be cleared for agriculture. Here are a couple of surviving examples.

Sand Stringybark E. arenacea, Little Desert NP, north-western Victoria.
(This species was, until 1988, included with the more widespread Brown Stringybark, E. baxteri.)

Yalata Mallee E. yalatensis, Nullarbor Plain, South Australia.
This very attractive mallee is found around the fringes of the Nullarbor
and, curiously, in an isolated population far to the east near Mannum,
on the Murray River in South Australia.
Mallee with a sparse heathy understorey (with also some saltbush I think),
Gawler Rangers NP, north of the Eyre Peninsula, South Australia.
Fire in Mallee-Heath (as well as the following Mallee-Spinifex) is especially ferocious. All above ground vegetation is burnt and the volatile oils burn in great gas flares above the vegetation. Regeneration though is probably the most rapid of any tree formation in the world. A new stem cluster appears immediately, growing far faster than in other situations because of added potash in the soil, the resources in the lignotuber and reduced root competition for nutrients.
Regenerating burnt mallee, Gluepot Reserve, north of the River Murray in South Australia.
(Actually this was not at all the fiercest mallee fire, as the dead stems are still standing,
though most other plants have gone.)
Mallee-Spinifex also grows on deep sands but in lower rainfall areas. Spinifex refers to various species of the very prickly hummock grass Triodia spp., also known as Porcupine Grass, which forms very important animal habitat, especially for reptiles and invertebrates, but also small birds and mammals. Beyond the mallee, spinifex dominates some 25% of the Australian land area. Here are examples of Mallee-Spinifex from five different states and territories!
Sharp-capped Mallee Eucalyptus oxymitra in harsh gravel on exposed hillsides at the
start of the Ormiston Pound walk, western Tjoritja (MacDonnell Ranges) NP,
central Australia in the Northern Territory.
Normanton Box Eucalyptus normantonensis growing as a mallee form over
spinifex by the excellent dinosaur museum at Lark Quarry, central Queensland.
Mallee with a dense spinifex ground cover, Mungo National Park, south-western NSW.
Thick-leaved Mallee E. pachyphylla growing in a sandy spinifex plain,
Great Sandy Desert, central eastern Western Australia.
Huge (ie long unburnt) spinifex hummock in mallee, Wyperfeld NP, north-western Victoria.
The third broad mallee type is Mallee-Chenopod, ie various species of saltbushes, bluebushes, samphires etc. This is in low rainfall situations where the soil is sandy-clay. For some reason I find this habitat especially aesthetic.
Mallee with a bluebush (Maireana spp.) understorey, Red Banks Conservation Park,
mid-north South Australia.

Late afternoon over mallee-bluebush at Caiguna, west of the Nullarbor Plain
in south-eastern Western Australia.

Samphire (probably Tecticornia spp.) growing on a clay pan in mallee-bluebush
near Normantion, central southern Western Australia.
And I'm going to end this first instalment of a short series with some portraits of mallee species which I (totally subjectively) find particularly pleasing and/or interesting.
Blue-leaved Mallee E. gamophylla, Plenty Highway, central eastern
Northern Territory. The striking blueish rounded leaves are
juvenile leaves which remain in that form. It is found in sandy
country mostly dominated by spinifex.
Curly Mallee E. gillii has similar foliage. It grows in just two areas of
inland ranges; in the Barrier Range near Broken Hill,
in far western NSW (above) and in the Northern Flinders Ranges
of South Australia (at Weetootla Gorge below).

 Port Lincoln Mallee E. albopurpurea, Coffins Bay, South Australia.
This lovely mallee is found only here at the tip of Eyre Peninsula and on
Kangaroo Island. It was formerly regarded as a subspecies of E. landsdowneana
from the Gawler Ranges to the north.
Bushy Yate E. lehmanii, Cape Le Grande NP, in the east of south-western WA.
A spectacular mallee from Albany eastwards as far as Israelite Bay in hill country and dunes.
Mottlecah E. macrocarpa (above and below), Yandin Hill Lookout,
north of Perth, WA. Its flowers are possibly the most dramatic of all eucalypt flowers,
and can be up to 10cm across.

Red, Oil or Acorn Mallee E. oleosa has one of the most extensive distributions of
any mallee species, found from the south-west of WA to eastern Victoria. It flowers
profusely and its leaves were formerly harvested for their high oil content.
Here it is growing on the eastern fringe of the Nullarbor Plain.
Thick-leaved Mallee E. pachyphylla, here deep in the Great Sandy Desert of
central eastern WA though it is found widely in central Australia.
Moort E. platypus, Ravensthorpe, south-west WA. The name means 'flat or broad foot',
for the oddly shaped buds. It grows only along this section of coastline.
Bell-fruit Mallee E. preissiana, Stirling Ranges, south-west WA.
So, the first part of my ode to the marvellous mallee. I hope you've stuck with me through it, and that it has either aroused some good memories of your own, or perhaps sparked some curiosity in a habitat that you may not be familiar with. I'll be looking at some other plants and some animals of the mallee in forthcoming posts - not sure yet if it will two or three parts in all. Hope to join you then, and thanks for coming this far into the mallee with me.

NEXT POSTING THURSDAY 7 NOVEMBER
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