Some aspects of aboriginal diets in southwestern Australia and southern Africa, with particular reference to tubers in mediterranean-type climates

@tonyrebelo @jeremygilmore @yvettevanwijk1941 @sedgesrock @nicky @robertarcher397

In August 1984, I discussed aboriginal diets with the late Sylvia Hallam (https://en.wikipedia.org/wiki/Sylvia_Hallam) and the late Hilary Deacon (https://en.wikipedia.org/wiki/Hilary_Deacon).

The following is a transcript of my notes at the time.

HALLAM:

The aboriginal population of Australia was remarkably sparse: possibly less than 0.5 million on the whole continent.

Dioscorea hastifolia (https://www.inaturalist.org/taxa/1003647-Dioscorea-hastifolia) is an indigenous liane. It occurs in a habitat-duality which I have found repeatedly for various spp. of plants: granite outcrops and alluvial banks.

In the relatively nutrient-poor landscapes of southern Australia and southern Africa, both situations - although at opposite ends of the catena - are somewhat enriched, the first by fresh weathering, and the second by concentration via the flow of water.

On alluvial banks, D. hastifolia grew in 'thickets' of Jacksonia sternbergiana (https://florabase.dpaw.wa.gov.au/browse/profile/4029 and https://www.inaturalist.org/taxa/525347-Jacksonia-sternbergiana), an extremely sclerophyllous, nitrogen-fixing tall shrub or low tree. The liane also climbed on the extremely sclerophyllous cycad Macrozamia riedlei (https://www.inaturalist.org/taxa/135854-Macrozamia-riedlei), another nitrogen-fixer.

In southwestern Western Australia, D. hastifolia occurred in local 'colonies', which were anthropogenically maintained free of the fires otherwise ubiquitous in the area. In these 'colonies', there were permanent 'rabbit-warren' holes dug by aboriginal people, to a depth of several metres in places. The repeated and intensive harvesting was tantamount to a kind of culturing of the food-plant, but did not qualify as domestication, because there was no selective breeding.

Some patches of Dioscorea were fairly extensive, viz. several hundred metres in diameter. Examples occurred at Upper Swan (https://en.wikipedia.org/wiki/Upper_Swan,_Western_Australia), where D. hastifolia formed fire-protected foci within woodland of Eucalyptus rudis (https://en.wikipedia.org/wiki/Eucalyptus_rudis), which was otherwise regularly burned by the aboriginal people.

Alluvial substrates were particularly supportive of the aboriginal people, partly because of the proximity of Typha domingensis (https://www.inaturalist.org/taxa/58392-Typha-domingensis) and Typha orientalis (https://www.inaturalist.org/taxa/341639-Typha-orientalis), with their edible rhizomes.

The tubers of D. hastifolia have diameter 1.3-4 cm and length up to 60 cm. This large size meant that they were economical to excavate, compared to the other tubers in this flora, all of which are small.

The aboriginal people also ate the unpalatable bulbs of Haemodorum (https://www.inaturalist.org/observations?place_id=6827&taxon_id=700230&view=species), an element of the kwongan flora, associated with extremely nutrient-poor sandplains.

DEACON:

Underground storage organs of plants are available for much of the year, and easily found by virtue of the dried above-ground traces. They tend to be unavailable only at that time of year when fleshy fruits are most available, namely autumn (March-May).

In the southwestern Cape of South Africa, the aboriginal hunter-gatherers depended mainly on geophytes.

Several of the 14 South African spp. of Diiscorea reach occur in the Fynbos Biome (https://www.inaturalist.org/observations?place_id=6986&taxon_id=82692&view=species), and one (https://www.inaturalist.org/taxa/430944-Dioscorea-elephantipes) occurs in the mediterranean-type climate. However, there seems to be no knowledge of any species of Dioscorea in the aboriginal diets. (@yvettevanwijk1941 ?)

Here, corms of Watsonia (https://www.inaturalist.org/observations?place_id=any&taxon_id=72425&view=species) were the main food, in places. This food is starchy, containing less protein than e.g. domestic potato (Solanum tuberosum).

This - the rapid spread of Watsonia as an invasive weed in southwestern Australia notwithstanding (https://www.bushlandperth.org.au/weeds/bugle-lily/#:~:text=About%20this%20weed&text=They%20were%20originally%20natives%20of,regrow%20from%20corms%20and%20seeds) - was a slowly-renewing resource, the harvested corms taking up to 4-5 years to be replaced.

Watsonia shoots foliage in late autumn, and grows by depleting the corm, while simultaneously dumping wastes in it, causing it to turn reddish, bad-tasting, and inedible. Then the new corm grows above it, pale and palatable, with minimal tannins, while the above-ground parts die down to leave a good, pale, edible corm in the ground over the summer.

For these reasons, autumn/early winter was really the only time when Watsonia corms were available to the aboriginal hunter-gatherers.

DISCUSSION

Please see https://www.inaturalist.org/journal/ludwig_muller/67812-dioscoreas-of-the-southern-cape#.

I find it remarkable that a genus poorly represented in Western Australia compared to South Africa, namely Dioscorea (Dioscoreaceae), was perhaps the most important of the stem-tuberous foods in the mediterranean-type climate in this state, while the category of cormous Iridaceae, so common and diverse in southwestern South Africa, was unavailable under similar climates and on similar soils in southwestern Australia.

There is only one geophytic member of the Iridaceae in southwestern Australia, namely Patersonia babianoides (https://en.wikipedia.org/wiki/Patersonia_babianoides). However, even this species only marginally/nominally/technically qualifies as a geophyte, because its above-ground parts hardly die down in summer, and the storage organ is merely a corm-like rhizome, hardly qualifying as food for humans, and scarce in the vegetation anyway.

Posted by milewski milewski, November 30, 2022 06:03 AM

Comments

Clarke P A (1988) Aboriginal use of subterranean tubers in southern South Australia. Records of the South Australian Museum 22(1): 63-76.

Posted by milewski about 2 months ago (Flag)

According to Dahlgren, Clifford, and Yeo (1985):

"Bulbils occur in the leaf axils of numerous species of Dioscorea; they...contribute greatly to vegetative propagation".

A velamen (https://en.wikipedia.org/wiki/Velamen) is present in Dioscoreaceae.

Posted by milewski about 2 months ago (Flag)

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