Australian Megafauna: Impacts on Soils

Ayrton

Ad Honorem
Jan 2017
4,267
Bendigo
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Don't underestimate human predation as an extinction factor

humans are the deadliest predator of all , in every continents save Africa humans appearance coincided with massive extinction event , sheer bad luck or those beasts didn't just fall of an ecological cliff ...they were pushed
I do not underestimate the possibility Aboriginals had a large hand in megafauna extinctions, but I wonder if it was just as big a factor that they ‘managed’ the environment to create ‘abundance’ which may have become less diverse; species becoming less various, numbers of certain species seeing increase, while others - beyond megafauna - diminishing.

I think of the OP on the Dark Emu thread (Ancient History) where much evidence is introduced regards how Aboriginals managed for abundance (I simplify the OP but hopefully catch the general thesis). But was this at a long term cost?

The Mesopotamian invention (?) of the city built on agriculture saw the long degradation of fertility in that region. Indeed, agricultural practices seem to be the main reason for the for the decline of fertility throughout much of the Fertile Crescent. This took a long time, thousands of years it seems. The city states, nonetheless, of Mesopotamia finally collapsed.

Aboriginal impacts on the Australian continent may not have followed exactly the same pattern, but the end point (if my speculating is at all correct) is that many landscapes became drier (dominated by fire requiring species all over the landscape) and the spread of deserts too. The Aboriginals managed ‘plantations’ for their existence, at the cost of having soils that were more fragile than they might have been, and deserts steadily encroaching.

Humans have altered landscapes all over the world, not all with exactly the same ‘agricultural’ practices, but altered for less diversity almost everywhere. There was short term human gains by ‘management’ but the cost in regard to species loss seems a high one, just about everywhere. Different timescales and different impacts, but all negative when considering human involvement in species loss.
 

sparky

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Jan 2017
5,012
Sydney
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" the main reason for the for the decline of fertility throughout much of the Fertile Crescent"
and the Indus valley , North Africa and probably other places as well



Aborigines were directly responsible for the extinction of the Giant short faced Kangaroo , it seems that being a large beast make one a choice target for hunters .
did the aborigines managed abundance ? I doubt it , they simply impacted their environment to suit themselves , if it had a beneficial effect on some specie that was largely incidental

nobody can claim our cities manage the abundance of pigeons or rats
 

Ayrton

Ad Honorem
Jan 2017
4,267
Bendigo
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" the main reason for the for the decline of fertility throughout much of the Fertile Crescent"
and the Indus valley , North Africa and probably other places as well



Aborigines were directly responsible for the extinction of the Giant short faced Kangaroo , it seems that being a large beast make one a choice target for hunters .
did the aborigines managed abundance ? I doubt it , they simply impacted their environment to suit themselves , if it had a beneficial effect on some specie that was largely incidental

nobody can claim our cities manage the abundance of pigeons or rats
You make some really interesting points.

Not sure how you know the Aboriginals were directly responsible for the extinction of the Giant Short Faced Kangaroo, but I certainly don’t discount the possibility. If you have more information on this, I would be really keen to see it.

I think Aboriginals managed for abundance. Just one example: they burned landscapes to encourage open areas with plenty of green pick to attract wildlife; kangaroos predominantly as is my understanding. Trees were not allowed to dominate, ash fertilised grasses (and forbs?) but perhaps soils declined slowly over time? I mean: a long period of time. The previous diversity before burning began- if land was prone to become a forest climax community through natural succession - may have been much more species ‘abundant’ than it was after the ’specialised’ abundance created by Aboriginals occurred. I guess a question for me, if I am speculating correctly here, is did the Aboriginals manage landscapes to a point of some kind of dynamic balance with their methods so that landscape was stable, like the prairies of America had formed to become in dynamic balance wth deep fertile soils under migrating herds, but which was an interrupted stage on the path toward becoming a forest community: this prior to the advent of European farming practices.

Pigeons and rats are abundant in cities. They are both edible. They have been ‘accidentally’ managed to almost plague proportions. If restaurants started a demand for city pigeons and rats, and the fashion took off, pigeons and rats would soon become extinct in my estimation. That’s what humans tend to do: exhaust (and contaminate) our resources. Sometimes swiftly, citing the degradation of prairies in America, sometimes slower, like in the Fertile Crescent, and sometimes (if I am guessing at all correctly) over slow Millenia, as in Australia (maybe?)
 
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sparky

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Jan 2017
5,012
Sydney
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on the short faced extinction

Giant kangaroo extinction theory disputed › News in Science (ABC Science)


there is a racist narrative to paint aborigines as some "nice "people ,that's Rouseau's "good savage" narative

this reduce them to the status of some societal teddy bear , it diminish them as an object of interested curiosity
Abbos drink beer , love cars and country music

they are people with just as much vicious stupidity as all of us , they are us
 

Ayrton

Ad Honorem
Jan 2017
4,267
Bendigo
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on the short faced extinction

Giant kangaroo extinction theory disputed › News in Science (ABC Science)


there is a racist narrative to paint aborigines as some "nice "people ,that's Rouseau's "good savage" narative

this reduce them to the status of some societal teddy bear , it diminish them as an object of interested curiosity
Abbos drink beer , love cars and country music

they are people with just as much vicious stupidity as all of us , they are us
Not to tell the truth about Aboriginals - to romanticise them and overlook anything that might seem distasteful to our modern perspectives sent back in time - is as bad a form of paternalism as it is to unfairly judge them. To look at history with with an open mind, to find cause and effect and side step good and bad (modern judgments misapplied) should be what we do. It is also the respectful way to look at history quite some distance from us IMO.

What little I know of Aboriginal history, pre-colonialism, is fascinating. There is much to learn. But to pretend them to a status in technology or culture or whatever that is politely false, is an insult to them. To recognise their achievements, when proven in the record, is the correct historical thing to do. So, like all humans, we can look back with a ‘mixed bag’ assessment of what was handled well and what may not have been: here I mean the long-look of history, and if the Aboriginals had a hand in megafauna extinctions, then so be it. If they - over Millenia - aided desertification in the continent, so be it.

As I mention above, all humans seem to have had what we might see as negative impacts on the biosphere in their regions during the passing of the ages. So be it. Learning about these things may benefit us, if we are wise enough to learn from history.
 
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Ayrton

Ad Honorem
Jan 2017
4,267
Bendigo
I am beginning to wonder a lot about Aboriginal impact on their environment. Their modification of the flora around them, predominantly by burning, and their impact on the megafauna by flora change and hunting may have been more than just marginal.

I wonder, were Aboriginals, say twenty thousand years ago, far more populace? And were they more sedentary? As resources diminished gradually over Millenia, did their own numbers decrease, and did they need to hunter-gather more than when they first reached this continent?

Humans can deplete and degrade their environment either very swiftly (American prairies, Australian settlers etc.) or more slowly (Mesopotamian city states), or very slowly (?) over Millenia (Aboriginals of the Australian continent???)
 

sparky

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Jan 2017
5,012
Sydney
While I have no proof of this , I would suppose than an abundant megafauna would allow larger hunting bands while smaller preys would imply smaller ones
at one extreme with very small preys one could conceive of family groups limited to a few individuals
 

Ayrton

Ad Honorem
Jan 2017
4,267
Bendigo
Interesting thoughts. Diminishing food reserves would suggest diminishing human numbers. I guess in basic evolutionary ecology, species re-jig their populations in relation to the pressures of the niche they are in; that’s if they even survive major changes to their biome, whether human made or via cataclysms or climate change etc. Why not humans? Especially ones who were not as dominant in their environment in a management sense as we modern humans with our technology and major power to alter environments.

In regard to the megafauna: were they forest species, and, if so, was the ice age of circa 20,000(?) ago one that saw forests totally diminished? When the ice age ended, did forests not regrow to climax states, but was much of the continent just desert and dry land?
 

sparky

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Jan 2017
5,012
Sydney
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There is no particular obstacle to have mega-fauna in forests , however this environment doesn't seems to be favorable to large herds
it seems that The Ice ages are rather dry , but that's debatable in the case of Australia , the lack of nutrient seems to be the one limiting factor
something to keep in mind is that while the Genus "Eucalyptus" are 60 millions years old it never prospered much until quite recently
it is a very poor feed for grazers and tend to kill off others species ,
so the gum tree took over most of the subcontinent to the detriment of pretty much everything else