Scientists have debunked a popular myth surrounding Easter Island.
An analysis of the island's famed rock gardens, undertaken by a team of researchers including faculty from Binghamton University, revealed that the island never experienced a dramatic population crash as previously believed.
A widely accepted narrative suggested that the inhabitants of Easter Island, also known as Rapa Nui, overexploited their resources, leading to environmental degradation and a drastic decline in population by the time Europeans arrived in 1722. However, recent findings indicate that the island's population was never as large as previously thought.
Binghamton researchers employed advanced technology to more precisely estimate the number of rock gardens on the island and assess Rapa Nui's pre-contact agricultural output. The study was co-authored by Professor Carl Lipo of Anthropology and Environmental Science, Environmental Studies Research Development Specialist Robert J. DiNapoli, and anthropology alumnus Dylan S. Davis, now a post-doctoral fellow at Columbia University's Climate School.
The volcanic origins of Easter Island, dating back a million years, resulted in soils depleted of essential nutrients like potassium, phosphorus, and nitrogen, explained Lipo. Additionally, oceanic salt spray further diminished soil fertility.
"Rapa Nui's soils were never highly fertile," Lipo said in a statement. "The island's first settlers had to adapt to these limitations."
Initial agricultural practices involved slash-and-burn techniques, which temporarily enriched the soil but led to deforestation. When trees became scarce, the islanders shifted to composting plant waste and using rock mulch.
While composting alone was insufficient to sustain agriculture, rock mulch proved effective, albeit labor-intensive. Islanders broke off pieces of bedrock and mixed them with soil, enhancing nutrient levels and preventing further erosion.
Rock mulching is a method used by other cultures, including the Maori in New Zealand, indigenous peoples in the American Southwest, and farmers in the Netherlands, Lipo mentioned.
"Modern agriculture uses machines to crush rocks into small particles, which exposes more surface area," Lipo said. "Rapa Nui inhabitants did this manually, breaking rocks and incorporating them into the soil."
The primary crops grown in these gardens included dry-land taro and yams, but sweet potatoes, with numerous varieties, were the mainstay, according to DiNapoli.
Not all rock formations on the island are remnants of ancient gardens, which raises the question of their true extent.
Early European visitors estimated that gardens covered 10 percent of the island. Previous studies using satellite imagery misidentified various features, such as roads, as gardens.
Davis used shortwave infrared (SWIR) satellite imagery and machine learning to produce a more accurate estimate, revealing about 180 acres of mulched land, significantly less than previously thought.
SWIR imagery, typically used for geological mapping, can distinguish between different mineral compositions and moisture levels, Davis explained. These characteristics help rock gardens stand out more distinctly from the surrounding terrain.
Based on the revised garden area, researchers estimated that around 3,000 people lived on Rapa Nui at the time of European contact. Early European accounts suggesting a population of 3,000 to 4,000 align with archaeological findings, Lipo said.
"The island's ecological constraints meant it could never support a large population," Davis stated. "The inhabitants adapted their environment to maximize agricultural yield, but the population remained relatively small. This case illustrates sustainable adaptation rather than ecological collapse."
Misconceptions about the island's population size stem from the impressive moai statues, Lipo noted, and the assumption that large workforces were needed to build them. Ecologists often use Easter Island as an example of how population pressures can lead to environmental disaster.
"We should not simplify Easter Island's history to fit convenient narratives," Lipo said. "Understanding the island within its own ecological context reveals a different story than what has been popularly believed."
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Uncommon Knowledge
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Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
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Robyn White is a Newsweek Nature Reporter based in London, UK. Her focus is reporting on wildlife, science and the ... Read more
