Australian Megafauna: Impacts on Soils

AlpinLuke

Forum Staff
Oct 2011
27,183
Italy, Lago Maggiore
Going back to Australia, it's licit to doubt about the real human impact considering the tiny human population who was active there in the last phase of Pleistocene and in early Holocene.


We should have the possibility to evaluate the timeline of the climate changes, the adaptability of the "megafauna" to this kind of changes and the extension of the human activities [geographical extension in the Australian continent].


Probably we could start considering what the European explorers noted, to begin to have an idea of which activities the Aboriginals run. This article can be a good introduction: http://nationalunitygovernment.org/pdf/2014/Evidence_for_Indigenous_Australian_Agriculture.pdf


If we go back to the most recent calculations of the prehistoric population of Australia [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3652441/], we can see that around 16,000 years ago [late Pleistocene - early Holocene], table 1, considering the most optimistic estimate, there were about 41,500 individuals [on the other side, the most pessimistic estimate says 8,235]. Going back to my prudential approach [on the base of my economical education] I would consider a range from 16,500 and 27,600 ... so I would keep the number of 22,000 as reference.


Now, thinking to the kind of activities they run ... which could have been the impact of a population of 22,000 individuals, 16,000 years ago on the Australian environment?
 

Ayrton

Ad Honorem
Jan 2017
4,268
Bendigo
So, it's a matter of fact that, despite the not irrelevant population, humans heven't been able to cause the exctinction of African megafauna. Partial extinction is not extinction.
Individual extinctions occur. How many due to First Person impacts? That might be the question better asked.
 
Last edited:
Mar 2015
870
Europe
So, it's a matter of fact that, despite the not irrelevant population, humans heven't been able to cause the exctinction of African megafauna. Partial extinction is not extinction.
In Eurasia, Americas, Australia, there was a modest remnant of smaller, more rapidly breeding and adapting animals left. Such as kangaroos of Australia. But the remnant was significantly less diverse, and mostly smaller, than what was before.
Africa kept more, but also lost a lot of what was.
 

AlpinLuke

Forum Staff
Oct 2011
27,183
Italy, Lago Maggiore
In Eurasia, Americas, Australia, there was a modest remnant of smaller, more rapidly breeding and adapting animals left. Such as kangaroos of Australia. But the remnant was significantly less diverse, and mostly smaller, than what was before.
Africa kept more, but also lost a lot of what was.

Africa during the glacial age had a well better climate, overall the deserts were absolutely less predominant, from a geographical viewpoint [Sahara wasn't, just to say]. It's a wide continent centered on the equator. I'm wondering about the effects of the climate changes during Pleistocene on it.


I have to check if also about Africa there are reliable researches regarding this aspect.


And now, overall, I have to find out which is the consensus about the definition of "megafauna".
 

AlpinLuke

Forum Staff
Oct 2011
27,183
Italy, Lago Maggiore
Individual extinctions occur. How many due to First Person impacts? That might be the question better asked.

That's what I'm wondering. Africa should have seen a total extinction and earlier than the other continents [humans colonized the world starting from Africa]. Was African megafauna so "mega" to resist, at least partially, to the impact of the human being?
 

AlpinLuke

Forum Staff
Oct 2011
27,183
Italy, Lago Maggiore
Problem: megafauna = animals over 97 lbs?

I'm noting that the so called "Pleistocene Megafauna" was composed by the first and the second category of it [category 1 = over 97 lbs - 44kg, category 2 = 2205 lbs - 1 ton]. https://en.wikipedia.org/wiki/Pleistocene_megafauna


Considering this definition, the African megafauna is substantially still all there [and it's not that "mega" a part some big species].


To have an idea of the animals which disappeared in Africa and Aisa during the Pleistocene: https://en.wikipedia.org/wiki/Quaternary_extinction_event#Megafauna_that_disappeared_in_Africa_and/or_Asia_during_the_Late_Pleistocene


And in Africa such an extinction seems to have been less than impressive ... in this article it's not listed among the regions more affected ... https://en.wikipedia.org/wiki/Pleistocene_megafauna#Regions_affected


This requires a further check.
 

AlpinLuke

Forum Staff
Oct 2011
27,183
Italy, Lago Maggiore
Something to ponder ...

Again from this WIKI page [https://en.wikipedia.org/wiki/Quaternary_extinction_event#Pleistocene_or_Ice_Age_extinction_event] I learn that ...


The Late Pleistocene extinction event saw the extinction of many mammals weighing more than 40 kg. The proportional rate of megafauna extinctions is consecutively larger the greater the migratory distance from Africa.
First question: the human population was more relevant in the continent of origin or not? Probably it was ...

So, why the extinctions happened in this way?


In Subsaharan Africa, 8 of 50 (16%) genera of mammalian megafauna were driven to extinction.

  • In Asia, 24 of 46 (52%)
  • In Europe, 23 of 39 (59%)
  • In Australasia, 19 of 27 (71%)
  • In North America, 45 of 61 (74%)
  • In South America, 58 of 71 (82%)
If the human factor was the main one it means that or humans left Africa in great numbers or that humans weren't able to dominate the African megafauna [or to cause so huge damages to the environment to determine a wider extinction].

Africa and Australia weren't reached by the ice cap during the last glacial age [South America saw a wide glacial cap made by the glaciers coming down from the mountains all along the continent], but the African continental mass is centered on the equator and so the climate was [and is] more constant. Comparing it with Australia, a well more little % of Africa knows fresh weather or cold weather [winter in South Africa].
 
Mar 2015
870
Europe
A common argument why Africa escaped with less harm is about coevolution.

In Africa, the extinctions started early and went on gradually, as people evolved to be better hunters over hundreds of thousands of years.
Over that period, the remaining megafauna adapted to resist hunting better.

Elsewhere, people invaded suddenly as evolved hunters, and caused rapid extinction of most megafauna before they had time to evolve.
 

AlpinLuke

Forum Staff
Oct 2011
27,183
Italy, Lago Maggiore
A common argument why Africa escaped with less harm is about coevolution.

In Africa, the extinctions started early and went on gradually, as people evolved to be better hunters over hundreds of thousands of years.
Over that period, the remaining megafauna adapted to resist hunting better.

Elsewhere, people invaded suddenly as evolved hunters, and caused rapid extinction of most megafauna before they had time to evolve.

It's a good argument, if we remain in the realm of the hunters-gatherers. So the extinction of the megafauna wasn't connected with farming activities but with hunting. It wasn't the human impact on the environment because of proto-agricultural activities to affect the megafauna, but the instinctive behavior of the human hunters.