Posted on 07/10/2014 12:35:30 PM PDT by BenLurkin
Carson and his colleagues wanted to explore the question of whether early Amazonians had a major impact on the forest. They focused on the Amazon of northeastern Bolivia, where they had sediment cores from two lakes nearby major earthworks sites. These sediment cores hold ancient pollen grains and charcoal from long-ago fires, and can hint at the climate and ecosystem that existed when the sediment was laid down as far back as 6,000 years ago.
An examination of the two cores — one from the large lake, Laguna Oricore, and one from the smaller lake, Laguna Granja — revealed a surprise: The very oldest sediments didn't come from a rainforest ecosystem at all. In fact, the Bolivian Amazon before about 2,000 to 3,000 years ago looked more like the savannas of Africa than today's jungle environment.
The question had been whether the early Amazon was highly deforested or barely touched, Carson said.
"The surprising thing we found was that it was neither," he told Live Science. "It was this third scenario where, when people first arrived on the landscape, the climate was drier."
The pollen in this time period came mostly from grasses and a few drought-resistant species of trees. After about 2,000 years ago, more and more tree pollen appears in the samples, including fewer drought-resistant species and more evergreens, the researchers report today (July 7) in the journal Proceedings of the National Academy of Sciences. Charcoal levels also went down, indicating a less-fire-prone landscape. These changes were largely driven by an increase in precipitation, Carson said.
The earthworks predate this shift, which reveals that the diggers of these ditches created them before the forest moved in around them
(Excerpt) Read more at livescience.com ...
They predate the rain forest. Maybe they were just building elevated positions for better fields of fire.
FMCDH(BITS)
Cataclysmic astrobleme ping.
Are these scientists now telling us that all that bio diversity came into being in a mere 6,000 years?
So if the jungle went away again, it’s normal and we won’t all die?
It has been my opinion for many years that we know very little about mans past, let alone the world in detail.
Most of what I have seen as revealed science and predictions of the future and past are uneducated guesses based on fragmentary evidence.
>Are these scientists now telling us that all that bio diversity came into being in a mere 6,000 years?
And they are telling you that if one thing changes in the next 6000, we’re all gonna die.
Gee, really honey child?
You mean that when you have fruit producing trees in a percentage that is several hundred percent over any other "wild forest" in the world that might be a sign that people planted them?
And soil does not naturally have pot shards and charcoal pounded into it? Well, who knew!
Bush’s Fault
The key point is that man has been radically altering the “natural” landscape for as long as he has been Man. Famously, aboriginal Australians had the whole place on fire at various times of the year - it increased the productivity, “naturally”.
Fire was the chief tool of landscape management; that’s why we should celebrate Earth Day with fire - lots of fires - it’s a good time of year to burn the ditches and such. ;^)
Glowbull Warming! It's retroactive now.
That sounds like a fortification, and a pretty substantial one. I wonder if they have found destruction layers, mass graves, etc., and whether we should expect to find much of that nature given the present climate.
Now let me get this straight. It is said that the Amazonian rainforest contains plant and animal species found nowhere else in the world (save the rainforest). If the rainforest is only 2,000-3,000 years old is that enough time to evolve these unique species?
Does this mean to imply... that the climate might have changed?
No.
Ice ages remove most evidence or make it unrecognizable. Imagine hail the size of cantaloupes traveling toward the ground at 100 mph. It is starting to happen again.
These sediment cores hold ancient pollen grains and charcoal from long-ago fires, and can hint at the climate and ecosystem that existed when the sediment was laid down as far back as 6,000 years ago. An examination of the two cores — one from the large lake, Laguna Oricore, and one from the smaller lake, Laguna Granja — revealed a surprise: The very oldest sediments didn't come from a rainforest ecosystem at all. In fact, the Bolivian Amazon before about 2,000 to 3,000 years ago looked more like the savannas of Africa than today's jungle environment.
I would imagine that the 2000 to 3000 years ago (I wonder if they meant 3000 years BC, since the cores go back 6000 years), the rainforests were just in a different place. Say SW North America which is now desert. As the climate changes in various places, the species (plants, animals, birds, etc.) just follow.
I recall reading some National Geographic article years ago. One article was about some animal that is being more and more rare in the U.S. due to Global Warming, and something needs to be done, etc. (The article did bury the fact that they are just heading north into Canada).
In the same mag, another article was shouting with joy the sighting of some rare bird, the first time it has been seen in the states for 200 years, and people from all over were coming to see it. (It’s usual range was a few hundred miles south of the border in Mexico. No mention of global warming).
I was watching on PBS within the last month, the reason the rainforests in the Amazon exist is due to the dust kicked up in the Sahara desert in Africa that travels around the world, creates rainclouds and drops.
We know that several thousand years ago the Sahara was no desert. And now we see that the Amazon was no rainforest around the same time.
Climate changes all on it’s own. Apparently alot.
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