Small, shifting human populations existed in the Amazon before the arrival of Europeans, with little long-term effect on the forest.
That's the result of research led by Crystal McMichael and Mark Bush of the Florida Institute of Technology (FIT). The finding overturns the idea the Amazon was a cultural parkland in pre-Columbian times with large human populations that transformed vast tracts of the landscape.
The Amazon Basin is one of the highest biodiversity areas on Earth. Understanding how it was modified by humans in the past is important for conservation and for understanding the ecological processes in tropical rainforests.
McMichael, Bush and a team of researchers looked at how widespread human effects were in Amazonia before Europeans arrived. They published their results in this week's issue of the journal Science.
"The findings have major implications for how we understand the effect of the land-use change now occurring in Amazonia," said Alan Tessier, program director in the National Science Foundation's Division of Environmental Biology, which funded the research.
"Making the assumption that this system is resilient to deforestation, it turns out, isn't a position supported by historical evidence," Tessier said.
If the pre-Columbian Amazon was a highly altered landscape, then most of the Amazon's current biodiversity could have come from human effects.
The team retrieved 247 soil cores from 55 locations throughout the central and western Amazon, sampling sites that were likely disturbed by humans, such as river banks and other areas known from archaeological evidence to have been occupied by people.
They used markers in the cores to track the histories of fire, vegetation and human alterations of the soil.
The scientists conclude that people lived in small groups, with larger populations in the eastern Amazon--and most people lived near rivers.
They did not live in large settlements throughout the basin as was previously thought. Even sites of supposedly large settlements did not show evidence of high population densities and large-scale agriculture.
All the signs point to smaller, mobile populations before Europeans arrived. These small populations did not alter the forests substantially.
"The amazing biodiversity of the Amazon is not a by-product of past human disturbance," said McMichael. "We can't assume that these forests will be resilient to disturbance, because most of them have, at most, been lightly disturbed in the past."There is no parallel in western Amazonia for the scale of modern disturbance that accompanies industrial agriculture, road construction and the synergies of those disturbances with climate change."
Cheryl Dybas | EurekAlert!
New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Life Sciences
18.07.2018 | Materials Sciences
18.07.2018 | Health and Medicine