Drones search for impact of ancient civilizations on Amazon

Chuck Bednar for redOrbit.com – Your Universe Online

Researchers from the University of Exeter in the UK are turning to drones in order to search for evidence of ancient civilizations in the Amazon rainforests, with the hopes that they may be able to learn how large those communities were and how much they altered the landscape.

As the scientists explained recently at the annual meeting of the American Association for the Advancement of Science in San Jose, they are developing a remote sensing data device that will be attached to an unmanned aerial vehicle (UAV) in order to scan beneath the forest’s canopy.

According to BBC News, the project will be searching for earthworks that were constructed up to thousands of years ago, and the data they collect is expected to help guide modern-day policy on sustainable forest use. The project was just given a $1.9 million grant from the European Research Council, the British news outlet added.

The researchers hope to better understand the scale and activities of populations from the late pre-Columbian period (the last 3,000 years before the arrival of the first Europeans in the 1490s). It will focus on how these human societies caused changes to the environment, ranging from the minimal impact of hunters to the influence of more complex civilizations in the region.

By using the drones to look at the nature and scale of pre-Columbian land use and its impact on the modern Amazonian landscape, the scientists said they hope to resolve one of the most hotly- debated issues in New World archaeology, ethno-history, paleoecology, and conservation.

While it has long been assumed that the humans living in the region for the last 13,000 years did so without making a significant impact on the ancient forests, recent research has suggested that there were actually large, regionally-organized pre-Columbian societies that started to transform the landscape during the Late Holocene (1 A.D – present) at a previously unknown level.

“The data gathered through the project has the potential to estimate, for the first time, the spatial scale of past human disturbance across the entire Amazon basin,” Professor José Iriarte said in a statement. The research, he noted, will help to “resolve the previously overlooked role of humans as important agents of environmental change,” shaping the land “through agricultural practices.”

Iriarte added that, “it is critical that policy-makers have a sound understanding of the historical role of humans in shaping the Amazonian landscapes and to what extent forests were resilient to historical disturbances” so that they can “make informed decisions about a sustainable future.”

Searching for geoglyphs

Specifically, they will be looking to find geoglyphs, which are large geometric patterns left in the ground, according to BBC News. Currently, more than 450 of these have been identified in areas where the forest has been cleared, and while no one is certain what the structures are supposed to represent, they are undoubtedly evidence of collective behavior, Iriatre explained.

“It’s a hot debate right now in New World archaeology,” he said. “While some researchers think that Amazonia was inhabited by small bands of hunter-gatherers and shifting cultivators who had a minimal impact on the environment, and that the forest we see today is pristine and untouched for thousands of years – mounting evidence is showing this may not be the case.”

“This evidence suggests that Amazonia may have been inhabited by large, numerous, complex and hierarchical societies that had a major impact on the environment; what we call the ‘cultural parkland hypothesis’,” he added during an interview with the BBC.

Iriatre and his colleagues will use their UAV to fly across sample areas of forest, and its camera instruments will be used to reveal how many additional geoglyphs can be found beneath regions of the Amazon that are still covered by canopies. An algorithm will be used to separate signals that bounce off the leaves from those that manage to penetrate all the way to the ground.

If geoglyphs detected by the drone can be confirmed during follow-up inspections, researchers would then examine the site in search of specific changes left behind by the ancient civilization in the soil and vegetation there. Those areas could then be located in satellite imagery, allowing them to examine a far larger portion of the rain forest than is possible using the UAVs.

“Understanding the origin and dynamics of the pre-Colombian period’s agricultural practices has broader implications for the sustainable Amazonian futures,” said Iriatre. “We could learn valuable lessons from understanding what type of land management was used and what crops were planted and raised in the past.”

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