Invasive Species, Humans and Easter Island

Through the ages, Man has developed into a highly analytic and inventive being. Modern human beings represent millions of years of incredible evolutionary changes. Since their primate ancestors, humans have developed larger brains, used not only to develop technology but also to manipulate their environment in order to adapt. Communication has allowed even early humans to develop communication, society and even spirituality. The ability to walk on two feet leaves the hands free to make tools, gesture, and even create art.

Despite all of their useful tools and abilities, humans seem to neglect—or simply lack—a crucial component to development: foresight. Today, global warming, natural resource exhaustion and environmental destruction threaten humanity’s comfortable way of life. However, overextension of resources is not a modern concept. It seems that for much of human existence man has acted as a parasite, concerned only with immediate self-fulfillment. Perhaps one of the most interesting and dramatic examples of nonexistent foresight and resource depletion exists in the story of Easter Island. Though much of its history remains ambiguous, Easter Island, or Rapa Nui, represents a delicate ecosystem that was objectified after the arrival of humans.

The Rapanui, the native inhabitants of the island of Polynesian descent, supposedly arrived between 800 and 1200 CE (Current Era). Terry Hunt disagrees with previous evidence of a landing around 800 CE. In his article “Rethinking the Fall of Easter Island,” he summarizes his recent findings from the beach where the Rapanui landed, which lead him to believe that occupation did not begin until 1200 CE. The later date has great significance to the history of Easter Island. If the Rapanui did arrive in 1200 CE, this means that it took a mere 500 years for their society to collapse.

Historians agree that Europeans arrived at Rapa Nui in 1722. They described the islanders as a once-technically advanced society that had since resorted to warfare and cannibalism to survive their nearly treeless environment. Some of the only remains of order were the hundreds large stone statues, or moai, scattered about the small island. The statues show the Rapanui’s ability to not only sculpt but also to transport the enormous rocks without wheels. Clive Ponting, in A Green History of the World, compares moai to Polynesian statues called ahu, which were used as a form of ancestor worship. Polynesian societies, including the Rapanui, were well developed, generally revolving around small groups of extended families and a group leader. The Rapanui were definitely a developed and organized society with leaders and even spiritual guidelines.

Then what was it that created the decline on Rapa Nui? When the Europeans came to the island for the first time, they were shocked by the lack of trees on the island. Ponting argues that trees were used as rollers because of the lack of “draught animals” to help pull the loads. Thus, due to the sculpting of so many moai, the tree population dropped rapidly. Peak population estimates range from 3,000 to 15,000 (although recent evidence leans toward a lower maximum population), and with seemingly little else to do on the island, it is relatively easy to imagine that an obsession with building moai developed among the natives. Perhaps erecting the huge heads became a competition between families to prove their prowess. When resources began to diminish, factions may have become violent, causing social disintegration. Ponting emphasizes this argument in A Green History of the World to expose the striking similarities between the environmental exploitation of the Rapanui and modern societies.

A chapter from Historical Aspects of Environmental Destruction by Charles Southwick supports the theory that humans very well could have destroyed Easter Island. He does not write about the island specifically, but instead about the changing relationship between nature and man. He claims that at one time, hunter and gatherer societies were aware of nature’s limits. Rather than pushing an environment to its limits, groups lived symbiotically with nature. After using resources, they would leave for a period of time to allow the environment to recover and stabilize. As societies became more advanced technologically, they became more negligent of their footprint on the environment. The Rapanui are an excellent example of a people who, to supply their rituals, ignored the limits of their resources.

Although Ponting’s point is convincing and quite plausible, it is important to incorporate another reason for decline that is equally threatening today: invasive species. The Rapanui brought chickens and rats, both non-native species, to an island completely void of large animals. In the article previously mentioned, Terry Hunt explains that both chickens and rats were sources of food on the island. In addition to this, he speculates without any predators that the rat population would have exploded in a very short time. He states that in about three years, “a single mating pair could… reach a population of almost 17 million” (Hunt, Terry L. “Rethinking the Fall of Easter Island.” American Scientist Online [Sept.-Oct. 2006]). The main source of food for the rodents happened to be the seedpods of the now-extinct palm tree that was abundant on the island before the arrival of the Rapanui. Hunt expects that the rat population exploded, staved off, and then finally died out completely when the European rat arrived. The combination of humans cutting down the existing trees and rats preventing new ones from growing by eating their seeds created a cycle that quickly snuffed any chance of replenishing the island’s natural habitat. Finally, with trees all but gone, the Rapanui had no way to escape the force of the Europeans’ superior weapons and desire for slaves. Considering the colonization fetish of the era, it seems rather odd that Europeans would simply leave Easter Island alone. It is likely, instead of internal conflict, that the Europeans finally ended the brief civilization of Rapa Nui.

Clive Ponting presented the story of Easter Island as a warning to modern societies. If humans continue at the current pace and scale of destruction, we will eventually hit a wall and collapse much like the Rapanui. However, this metaphor of destruction needs to be expanded. As Hunt explained, invasive species can be incredibly destructive to ecosystems. Similar evidence in other areas, such as Hawaii, shows that even small creatures can wreak havoc on the environment. Modern technology and transportation have made possible the exchange of species from region to region. Humans continue to fail to recognize the danger of introducing and displacing species.

Like the rats that spread over Rapa Nui, humans act as an invasive species in most all ecosystems on the planet. The rat, whose only objective was to survive, probably had no idea that it was destroying the population of trees. Perhaps ancient peoples can’t be held responsible for such knowledge either, but it seems that modern society has no excuses. Southwick finishes his chapter by warning against repeating history. With the technology available today, it seems that it is just a matter of time before we gather the courage to change, or exhaust our resources and collapse like the Rapanui.


Hunt, Terry L. "Rethinking the Fall of Easter Island." American Scientist Online (Sept.-Oct. 2006). 30 Jan. 2008. <>. [Link to article]

Ponting, Clive. A Green History of the World: The Environment and the Collapse of Great Civilizations. St. Martin's Press, New York, 1991. pp. 1-7 [Link to article]

Ponting, Clive. A Green History of the World: The Environment and the Collapse of Great Civilizations. St. Martin's Press, New York, 1991. pp. 18-67 [Link to article]

Southwick, Charles H."Historical Aspects of Environmental Destruction." Oxford Univ. Press, 1996. pp. 127-141 [Link to article]