Scientists Reconstruct Pre-Columbian Human Effects on the Amazon Basin

Findings overturn idea that the Amazon had large populations of humans that transformed the landscape

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."

Other co-authors of the paper are D.R. Piperno of the Smithsonian National Museum of Natural History; M.R. Silman of Wake Forest University; A.R. Zimmerman of the University of Florida; M.F. Raczka of FIT; and L.C. Lobato of the Federal University of Rondônia in Brazil.

 -NSF-

New NASA Map Reveals Patterns Of Tropical Forest Carbon Storage

Steve Cole

Headquarters, Washington

 

Alan Buis

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- A NASA-led research team has used a variety of NASA satellite data to create the most precise map ever produced depicting the amount and location of carbon stored in Earth's tropical forests. The data are expected to provide a baseline for ongoing carbon monitoring and research and serve as a useful resource for managing the greenhouse gas carbon dioxide.

The new map, created from ground- and space-based data, shows for the first time the distribution of carbon stored in forests across more than 75 tropical countries. Most of that carbon is stored in the extensive forests of Latin America.

"This is a benchmark map that can be used as a basis for comparison in the future when the forest cover and its carbon stock change," said Sassan Saatchi of NASA's Jet Propulsion Laboratory in Pasadena, Calif., who led the research. "The map shows not only the amount of carbon stored in the forest, but also the accuracy of the estimate." The study was published May 30 in the Proceedings of the National Academy of Sciences.

Deforestation and forest degradation contribute 15 to 20 percent of global carbon emissions, and most of that contribution comes from tropical regions. Tropical forests store large amounts of carbon in the wood and roots of their trees. When the trees are cut and decompose or are burned, the carbon is released to the atmosphere.

Previous studies have estimated the carbon stored in forests on local and large scales within a single continent, but there existed no systematic way of looking at all tropical forests. To measure the size of the trees, scientists typically use a ground-based technique, which gives a good estimate of how much carbon they contain. But this technique is limited because the structure of the forest is extremely variable and the number of ground sites is very limited.

To arrive at a carbon map that spans three continents, the team used data from the Geoscience Laser Altimeter System lidar on NASA's ICESat satellite. The researchers looked at information on the height of treetops from more than 3 million measurements. With the help of corresponding ground data, they calculated the amount of above-ground biomass and thus the amount of carbon it contained.

The team then extrapolated these data over the varying landscape to produce a seamless map, using NASA imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA's Terra spacecraft, the QuikScat scatterometer satellite and the Shuttle Radar Topography Mission.

The map reveals that in the early 2000s, forests in the 75 tropical countries studied contained 247 billion tons of carbon. For perspective, about 10 billion tons of carbon is released annually to the atmosphere from combined fossil fuel burning and land use changes.

The researchers found that forests in Latin America hold 49 percent of the carbon in the world's tropical forests. For example, Brazil's carbon stock alone, at 61 billion tons, almost equals all of the carbon stock in sub-Saharan Africa, at 62 billion tons.

"These patterns of carbon storage, which we really didn't know before, depend on climate, soil, topography and the history of human or natural disturbance of the forests," Saatchi said. "Areas often impacted by disturbance, human or natural, have lower carbon storage."

The carbon numbers, along with information about the uncertainty of the measurements, are important for countries planning to participate in the Reducing Emissions from Deforestation and Degradation (REDD+) program. REDD+ is an international effort to create a financial value for the carbon stored in forests. It offers incentives for countries to preserve their forestland in the interest of reducing carbon emissions and investing in low-carbon paths of development.

The map also provides a better indication of the health and longevity of forests and how they contribute to the global carbon cycle and overall functioning of the Earth system. The next step in Saatchi's research is to compare the carbon map with satellite observations of deforestation to identify source locations of carbon dioxide released to the atmosphere.

For information about NASA and agency programs, visit http://www.nasa.gov.

- end -

Amazon: Kindle books outselling all print books

Some new data from Amazon.com this morning: it's now selling more Kindle e-books than print books.

This isn't exactly shocking as Amazon had previously announced that Kindle book sales had surpassed hardcover sales and more recently had overtaken paperback book sales. In fact, we're not sure why the announcement didn't come earlier because you'd figure that if Kindle e-book sales had passed both hardcover and paperback sales, they would be ahead overall. But apparently not. Until now, anyway.

Here are the numbers Amazon is highlighting in its press release:

• Since April 1, for every 100 print books Amazon.com has sold, it has sold 105 Kindle books. This includes sales of hardcover and paperback books by Amazon where there is no Kindle edition. Free Kindle books are excluded and if included would make the number even higher.

• So far in 2011, the tremendous growth of Kindle book sales, combined with the continued growth in Amazon's print book sales, [has] resulted in the fastest year-over-year growth rate for Amazon's U.S. books business, in both units and dollars, in over 10 years. This includes books in all formats, print and digital. Free books are excluded in the calculation of growth rates.

• In the five weeks since its introduction, Kindle with Special Offers for only $114 is already the bestselling member of the Kindle family in the U.S.

• Amazon sold more than 3x as many Kindle books so far in 2011 as it did during the same period in 2010

• Less than one year after introducing the UK Kindle Store, Amazon.co.uk is now selling more Kindle books than hardcover books, even as hardcover sales continue to grow. Since April 1, Amazon.co.uk customers are purchasing Kindle books over hardcover books at a rate of more than 2 to 1.

Needless to say, Amazon CEO Jeff Bezos was rather proud of the latest metrics.

"We had high hopes that this would happen eventually, but we never imagined it would happen this quickly--we've been selling print books for 15 years and Kindle books for less than 4 years," Bezos said.

The one statement worth examining a bit further is about Amazon's growth in print book sales. As print sales continue to decline significantly overall, Amazon's gain is clearly an indication that it is taking market share away from traditional and independent booksellers. Borders, of course, filed for bankruptcy earlier this year and has closed about 30 percent of its stores (around 200) as Barnes & Noble also shutters select stores around the country.

Contributed by Bob Johnson's Computer Stuff

NASA Satellites Detect Extensive Drought Impact On Amazon Forests

Steve Cole

Headquarters, Washington                              

 

Ruth Dasso Marlaire

Ames Research Center, Moffett Field, Calif.

 

WASHINGTON -- A new NASA-funded study has revealed widespread reductions in the greenness of Amazon forests caused by last year's record-breaking drought.

"The greenness levels of Amazonian vegetation -- a measure of its health -- decreased dramatically over an area more than three and one-half times the size of Texas," said Liang Xu, the study's lead author from Boston University. "It did not recover to normal levels, even after the drought ended in late October 2010."

The drought sensitivity of Amazon rainforests is a subject of intense study. Computer models predict a changing climate with warmer temperatures and altered rainfall patterns could cause moisture stress leading to rainforests being replaced by grasslands or woody savannas. This would release the carbon stored in rotting wood into the atmosphere, which could accelerate global warming. The United Nations' Intergovernmental Panel on Climate Change has warned similar droughts could be more frequent in the Amazon region in the future.

The comprehensive study was prepared by an international team of scientists using more than a decade's worth of satellite data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) and Tropical Rainfall Measuring Mission (TRMM). Analysis of these data produced detailed maps of vegetation greenness declines from the 2010 drought. The study has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

The authors first developed maps of drought-affected areas using thresholds of below-average rainfall as a guide. Next, they identified affected vegetation using two different greenness indexes as surrogates for green leaf area and physiological functioning.

The maps show the 2010 drought reduced the greenness of approximately 965,000 square miles of vegetation in the Amazon -- more than four times the area affected by the last severe drought in 2005.

"The MODIS vegetation greenness data suggest a more widespread, severe and long-lasting impact to Amazonian vegetation than what can be inferred based solely on rainfall data," said Arindam Samanta, a co-lead author from Atmospheric and Environmental Research Inc. in Lexington, Mass.

The severity of the 2010 drought also was seen in records of water levels in rivers across the Amazon basin, including the Rio Negro which represents rainfall levels over the entire western Amazon. Water levels started to fall in August 2010, reaching record low levels in late October. Water levels only began to rise with the arrival of rains later that winter.

"Last year was the driest year on record based on 109 years of Rio Negro water level data at the Manaus harbor," said Marcos Costa, co-author from the Federal University in Vicosa, Brazil. "For comparison, the lowest level during the so-called once-in-a-century drought in 2005 was only eighth lowest."

As anecdotal reports of a severe drought began to appear in the news media last summer, the authors started near-real time processing of massive amounts of satellite data. They used a new capability, the NASA Earth Exchange (NEX), built for the NASA Advanced Supercomputer facility at the agency's Ames Research Center in Moffett Field, Calif. NEX is a collaborative supercomputing environment that brings together data, models and computing resources.

With NEX, the study's authors quickly obtained a large-scale view of the impact of the drought on the Amazon forests and were able to complete the analysis by January 2011. Similar reports about the impact of the 2005 drought were published about two years after the fact.

"Timely monitoring of our planet's vegetation with satellites is critical, and with NEX it can be done efficiently to deliver near-real time information, as this study demonstrates," said study co-author Ramakrishna Nemani, a research scientist at Ames. An article about the NEX project appears in this week's issue of Eos, the weekly newspaper of the American Geophysical Union.

For more information about this study and the NEX project, visit https://c3.ndc.nasa.gov/nex/projects/1209/.

For more information about the MODIS sensor and data products, visit http://modis.gsfc.nasa.gov.

For information about the Tropical Rainfall Measuring Mission, visit http://trmm.gsfc.nasa.gov.

- end -

NASA Satellites Detect Extensive Drought Impact on Amazon Forests

A new NASA-funded study has revealed widespread reductions in the greenness of the forests in the vast Amazon basin in South America caused by the record-breaking drought of 2010.

"The greenness levels of Amazonian vegetation -- a measure of its health -- decreased dramatically over an area more than three and one-half times the size of Texas and did not recover to normal levels, even after the drought ended in late October 2010," said Liang Xu, the study's lead author from Boston University.

The drought sensitivity of Amazon rainforests is a subject of intense study. Scientists are concerned because computer models predict that in a changing climate with warmer temperatures and altered rainfall patterns the ensuing moisture stress could cause some of the rainforests to be replaced by grasslands or woody savannas. This would cause the carbon stored in the rotting wood to be released into the atmosphere, which could accelerate global warming. The United Nations' Intergovernmental Panel on Climate Change (IPCC) has warned that similar droughts could be more frequent in the Amazon region in the future.

The comprehensive study was prepared by an international team of scientists using more than a decade's worth of satellite data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) and Tropical Rainfall Measuring Mission (TRMM).

Analysis of these data produced detailed maps showing vegetation greenness declines from the 2010 drought. The study has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

The authors first developed maps of drought-affected areas using thresholds of below-average rainfall as a guide. Next they identified affected vegetation using two different greenness indices as surrogates for green leaf area and physiological functioning. The maps show the 2010 drought reduced the greenness of approximately 965,000 square miles of vegetation in the Amazon -- more than four times the area affected by the last severe drought in 2005.

"The MODIS vegetation greenness data suggest a more widespread, severe and long-lasting impact to Amazonian vegetation than what can be inferred based solely on rainfall data," said Arindam Samanta, a co-lead author from Atmospheric and Environmental Research Inc. in Lexington, Mass.

The severity of the 2010 drought was also seen in records of water levels in rivers across the Amazon basin. Water levels started to fall in August 2010, reaching record low levels in late October. Water levels only began to rise with the arrival of rains later that winter.

"Last year was the driest year on record based on 109 years of Rio Negro water level data at the Manaus harbor. For comparison, the lowest level during the so-called once-in-a-century drought in 2005, was only eighth lowest," said Marcos Costa, coauthor from the Federal University in Vicosa, Brazil.

As anecdotal reports of a severe drought began to appear in the news media during the summer of 2010, the authors started near real-time processing of massive amounts of satellite data. They used a new capability, the NASA Earth Exchange (NEX), built for the NASA Advanced Supercomputer facility at the agency's Ames Research Center in Moffett Field, Calif. NEX is a collaborative supercomputing environment that brings together data, models and computing resources.

With NEX, the study's authors quickly obtained a large-scale view of the impact of the drought on the Amazon forests and were able to complete the analysis by January 2011. Similar reports about the impact of the 2005 drought were published about two years after the fact.

"Timely monitoring of our planet's vegetation with satellites is critical, and with NEX it can be done efficiently to deliver near-real time information, as this study demonstrates," said study coauthor Ramakrishna Nemani, a research scientist at Ames. An article about the NEX project appears in this week's issue of Eos, the weekly newspaper of the American Geophysical Union.

For more information about this study and the NEX project, visit https://c3.ndc.nasa.gov/nex/projects/1209/.

For more information about the MODIS sensor and data products, visit http://modis.gsfc.nasa.gov.

For information about the Tropical Rainfall Measuring Mission, visit http://trmm.gsfc.nasa.gov.

Ruth Dasso Marlaire

Ames Research Center, Moffett Field, Calif.