Rocks on Rapa Nui tell the story of a small, resilient population – and contradict the thought of ​​a doomed, overpopulated island

The general belief is that the island of Rapa Nui, also referred to as Easter Island, once had a big population, but it surely collapsed after living beyond its means and depleting the island of its resources. A brand new Research study A study conducted by my colleagues and me has dealt this notion an additional blow through the use of artificial intelligence to research satellite data on rock piles on this small island in the midst of the Pacific Ocean.

Our study examined Rock gardensa type of subsistence agriculture, and concluded that the island – which is just 15.3 miles (24.6 km) long and seven.6 miles (12.3 km) wide at its widest point – was probably never home to many greater than the three,000 or so people encountered by European explorers in 1722.

The conventional wisdom arose from speculation about one other group of stone structures on the island: the long-lasting massive statues called Nicecarved by the ancestors of the Rapanui people. The statues are as tall as a three-story constructing and weigh as much as 70 tons. There are almost 1,000 of them across the island.

For an archaeologistThe mystery of what led people to take a position a lot time and energy in constructing these colossal figures cries out for a proof. My colleagues and I even have been trying to find a proof for twenty-four years.

Some of the primary European visitors assumed that the island will need to have housed a much larger population sooner or later in time to account for the number and extent of the NiceThis assumption has been repeated for generations and forms the idea of a Narrative collapse.

The collapse story goes that the island will need to have once had tens of hundreds of inhabitants, who were needed for the labor involved in carving and transporting the large statues. Such a big population was not sustainable, and eventually food shortages led to famine, wars, and even cannibalism. As a result, the population dropped to the low numbers observed by early European explorers.

large stone carved heads sit on a grassy treeless next to
Was it really essential to have an excessively large population centuries ago to carve and transport these huge stone statues?
AP Photo/Karen Schwartz

In our previous Studies of the island My colleagues and I wondered where the evidence was that so many individuals lived on the island sooner or later before the arrival of Europeans. We conducted a brand new study to research whether such a big population was possible, provided that the Rapanui people used rock gardens to grow much of their food. From our evaluation of the available data, we estimate that there was never greater than 3,000 to 4,000 peoplethey usually lived sustainably on the island.

What stones say about agriculture

In this study, we examined the archaeological record of how the Rapanui used rock gardens to grow their major crop, the sweet potato. Rock gardens are a type of cultivation through which broken rocks are mixed into the soil to counterpoint it. Extensive rock gardens are found throughout the island and provided a vital source of food, supplemented by marine resources.

Previous studies have determined the extent of those gardens and concluded that these efforts could have fed as much as 16,000 peopleHowever, our fieldwork revealed that most of the areas identified as rock gardens on this study were misidentified, so we wanted to conduct a more detailed evaluation to acquire a more accurate estimate of rock gardens, which would offer us with a more reliable source of knowledge on the utmost possible population size.

We combined fieldwork with latest evaluation of satellite imagery. During our fieldwork, we looked on the bottom for clear examples of rock gardens. We knew we were at sites with rock gardens once we found patches covered with stones in places that might not be explained simply as the results of erosion. Obsidian artifacts among the many stones confirmed that the areas were used for cutting and processing sweet potatoes. Another root crop, taro, often grows there even today. We also identified sites that may resemble rock mulch gardens but were just rock outcrops or randomly scattered pebbles and boulders.

We then acquired WorldView-3 satellite images for your complete island. The WorldView-3 satellite collects high-resolution visible light photos of the Earth’s surface and pictures that Information about shortwave infrared. Shortwave infrared includes wavelengths within the range between 900 nm and a pair of,500 nm, that are longer than the wavelengths visible to the human eye. Shortwave infrared is beneficial for distinguishing materials that look the identical to the naked eye. Shortwave infrared is especially sensitive to differences in moisture, a necessary feature of productive agricultural fields.

Using our field data, we trained machine learning models to tell apart areas with rock mulch gardens from those without. Machine learning generates an algorithm that may detect subtle differences – and does so repeatedly and systematically. This allowed us to quickly survey almost your complete island without spending years mapping fields.

A map of a triangular island
Red dots indicate rock gardens identified by satellite imagery.
Dylan Davis, From

Our analyses drastically reduced the entire area of ​​the island that could be related to rock gardens, from a spread of 4.3 to 21.1 square kilometers to 0.76 square kilometers. When we entered estimates for the productivity of those areas, our calculations showed that the utmost number of individuals this kind of cultivation can support is is about 3,000very much like the conclusions We have used other sources of knowledge.

Resilience as a substitute of hubris

Over the past 20 years, researchers have gained significant latest insights into the archaeological finds of Rapa Nui and have helped Reorientation of the island’s history away from the Idea of ​​collapse. Studies by my team show, for instance, that The statues were moved striding from the quarry to their final locations on platforms called ahu. We also checked out how the islanders built huge Multi-tone hats called Pukao on the tops of those statues.

However, the concept there have been many more people on the island stays entrenched in academic and popular literature. The persistence of this concept has consequences outside the sphere of Rapa Nui archaeology. Despite archaeological evidence on the contrary, for instance, it shouldn’t be unusual for ecologists to make use of Rapa Nui as a case study for so-called Malthusian demographywhere the population probably reached an unlimited peak that temporarily exceeded the island's resources and triggered an ecological disaster.

While my colleagues and I agree that we must urgently address the exploitation of natural resources, disasters should not the one option. Human history offers many examples of the way it is feasible to live sustainably despite all of the constraints.

On Rapa Nui we learned that the population didn’t experience a population decline before the arrival of the Europeans, but succeeded resulting from their ingenuity. The Rapanui people found clever ways to adapt to the island and sustain themselves through sustainable agriculture. This research project provides details concerning the ability of rock gardens to grow food and feed the island's population.

A pile of stones on a sunny, treeless hill
Rock gardens provide nutrients and preserve moisture in poor soils.
Carl Lipo

Our increasing understanding of the island has critical implications for the long run. As society learns to thrive in a limited environment, it could possibly adopt strategies that folks used previously. The archaeological evidence of Rapa Nui suggests that efforts that bring communities together in each cooperative and competitive ways, akin to within the production of moai carvings and transportation, result in greater resilience in times of adversity.

Finally, the story of Rapa Nui shouldn’t be a cautionary tale but a source of inspiration that could possibly be crucial for the long run of humanity.

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