Easter Island

In the fall of 1954 as a graduate student at the University of Oslo, Norway. I wanted to escape the cold, dark rain season in Norway so I asked to be sent to the Canary Islands to collect algae specimens while skin-diving into under-sea caves along the coast. I flew from Oslo to the City of Las Palmas on the island of Grand Canary. Outside the city I set up camp on the beach at a beautiful site. On the second day while I was in the sea diving, children stole my tent, money, stove and equipment. Fortunately, the clothes, sneakers and my skin diving equipment, items I was wearing, remained. Before I left Oslo, my professor, Dr. Braarud told me that Thor Heyerdahl was staying at the Hotel Santa Catalina in Las Palmas with his wife Yvonne and new baby girl Annette.

The most intriguing mysteries of human history are those posed by vanished civilizations. Anyone who has seen the abandoned structures of the Maya, Machu Pichu, or Angkor is moved to ask the questions: “Why did the societies that constructed these structures disappear? What lessons can we learn from their experiences, and, who can say that we on the planet Earth will not succumb to the same fate?”

The goal of this suggested eco-tourism plan for Rapa Nui National Park in Chile is to guide the development of an environmentally sensitive plan to carry the park, a World Heritage site, into the future. A plan developed from an expanded version of this plan will guide the use and development of this world heritage site while simultaneously preserving and protecting and, where possible, enhancing the park resources. It must also take into account the three thousand residents of Easter Island, especially the indigenous Rapa Nui who have taken care of these resources for centuries and depend on them for spiritual and economic well being.

Lost in the vastness of the south Pacific Ocean, Easter Island is the most isolated inhabited place on the face of the Earth. The first European to land on the island was the Dutch admiral, Jacob Roggeveen, who paid it a single day’s visit on Easter Sunday in 1722. An expedition dispatched by the Spanish viceroy of Peru rediscovered the island in 1770, calling it San Carlos. To the original Polynesian settlers, it was simply “the land,” the center of the world, Te Pito te Henua. The Spanish were the first to report that the aborigines had their own local form of writing and estimated the population to be some 3,000 persons. Civil war or plague seems to have raged on the island before the arrival of the British navigator, Captain James Cook, in 1774. He found a decimated, poverty-stricken, Polynesian population of only about 600 or 700 people, and observed that the large statues were no longer venerated, many having been overthrown.

Previous pollen investigations by Flenley et al. (1991) suggest that the Rano Aroi Crater, Easter Island (27 08’ S, 109 26’W) contained a record of vegetational history that is greater than 35,000 C-14 years old. The environmental setting and modern vegetation is fully discussed by Flenley et al (1991). Rano Aroi Crater was selected for further work for two reasons. The first is that we were interested in a sediment record that spanned the transition from glacial to interglacial conditions. The second is that the peat composition might prove ideal for macrofossil analysis. Large fluctuations in pollen percentages characterize the stratigraphy, suggesting that this small subtropical island showed a major vegetational response to climate change. In order to add insight into the vegetational and sediment changes that took place, we re-cored the Rano Aroi Crater and are in the process of analyzing the core at 2-cm intervals for pollen and macrofossils in addition to sediment characterization and AMS C-14 dating. Our preliminary results here focus on the most striking lithological change in the core, Drive 3, between 200 and 300 cm depth.

Among the most enduring enigmas of Easter Island surrounds the giant Moai statues found there. Much has been written about these unusual behemoths, yet why they were made and how they were carried—some distances of over ten miles—is still shrouded in mystery. Fragments of nearly nine hundred such statues were cataloged earlier this century by Father Sebastian Englert (Figure 1), who lived most of his life and wrote extensively on Easter Island ethnology and archaeology (Englert, 1948). Many of these statues were still standing when Europeans first arrived there in the early-18^th century, but nearly all were later thrown down and broken during the civil war and cast struggle that broke out around 1840 (Routledge, 1919). Clearly, superior engineering skills and stout materials were required in order to build and move these immense stones, many of which surpass 50 tons in weight and reaching heights of 10 meters. The presence of so many stone monoliths on one small island is indication of a robust and vigorous society. Yet, by the time the earliest European visitors arrived, Rapa Nui civilization was apparently already in significant decline, as no evidence of the engineering skills or materials necessary to move these statues were observed by European visitors. Roggeveen, the captain of the first European ship to visit Easter Island, wrote in his account of these statues:

“At first these stone figures caused us to be filled with wonder, for we could not understand how it was possible that people who are destitute of heavy rope or thick timber, and also of stout cordage, out of which to construct gear, had been able to erect them; nevertheless some of these stature were a good 30 feet in height and broad in proportion.” (Roggenveen, 1722).

Easter Island (also known as Rapa Nui and Isla Pascua) lies within the southeastern Pacific high-pressure system, a feature that along with the Indonesian Low comprises the atmospheric dipole that defines the Southern Oscillation. Sea surface temperatures (SST) in the southeastern Pacific influence this limb of the basin-wide Walker circulation by modulating the stability and magnitude of convection within the regionally descending air. El Niño-Southern Oscillation (ENSO) research has most often focused on variability in the intensity and location of the Indonesian Low convective system or on teleconnections to various parts of the Northern Hemisphere. Long climate records from Easter Island will help elucidate the influence of oceanic variability on the overall ENSO system and its South Pacific teleconnections via the Walker Circulation. In addition, the Easter Island region of the South Pacific Gyre is a source for the shallow subsurface meridional flow that eventually upwells along the equator in the central and eastern Pacific [(Fig. 1); Levitus, 1982; Ji, et al., 1995; Gu and Philander, 1997]. In the northern Pacific, subsurface meridional flow has been suggested as a cause of decade-scale climate anomalies (Gu and Philander, 1997; Zhang et al, 1998). A similar mechanism may operate in the Southern Hemisphere; however, our current lack of a long time series of oceanic climate data from the eastern South Pacific Gyre, limits our ability to study this phenomenon.

Traditional knowledge and the earliest archaeological ¹⁴C date suggest that people arrived on Rapa Nui as early as A.D. 400 (Smith, 1961; Heyerdahl and Ferndon, 1961; Ayers, 1971; Bahn and Flenley, 1992). Prior to human arrival, much of the island was probably forested, with the largest trees a now-extinct species of palm (Flenley et al., 1991). Between A.D. 1000 and 1700, the Rapa Nui people erected megalithic sculpture, may have used a written language, and possibly numbered > 10,000 people (Bahn, 1993). However, when James Cook visited Rapa Nui in 1774, he found only several thousand people eking out a living amidst ruins on an island barren of trees. In a hypothesis originated by Mulloy (1970) and fully developed by Flenley and King (1984), Flenley et al (1991), and Bahn and Flenley (1992), uncontrolled population growth destroyed the natural vegetation, degraded the island’s ecosystems, and eventually led to the near extinction of the human population. This putative ecological history of Easter Island is cited as support for predictive models for the human use of natural resources (Brander and Taylor, 1998) and has passed into the modern folklore embodied by popular cinema. Accepting that Rapa Nui is a microcosm for the planet Earth, the “Lost Eden” interpretation of its history paints a grim picture of our collective future (Bahn and Flenley, 1992). On the other hand, the paleoecological data that describes the ecological history of Rupa Nui is far from complete (Orlic and Orliac, 1998; Nunn, 2000).

By whatever name it is called, Easter Island, Isla de Pascua, or Rapa Nui, this small (ca. 106 km²) spot of land in the central Pacific Ocean (27° 08’S, 109°20’W) has the distinction of being perhaps the most isolated spot on earth. It is approximately 3800 km from the South American mainland to the east, and over 2200 km from it’s nearest neighbor to the west, Pitcairn Island. The closest landmass is tiny Sala y Gómez 415 km to the east, a bleak uninhabited rock. Easter Island is, of course, most famous for its anthropological history, and the numerous stone statues (moai) that dot the landscape. Not surprisingly, most of the preservation effort directed at Easter Island in this century has been towards these archaeological and cultural artifacts. That the biological component of the island has received less attention is also not surprising, given the relatively depauperate fauna and flora reported on and around the island. What animals lived on the island in historical times is unknown and the few terrestrial species living there today, from the common isopods to the ubiquitous hawks, were introduced either on purpose (hawks from Chile for rodent control; see Klemmer and Zizka, 1993) or by accident (cosmopolitan isopod species brought in on plants). Of the terrestrial invertebrate fauna, only the insects have been studied in any detail (Compos & Peña, 1973); there are no comprehensive published accounts of the sparse isopod, mollusk, or flatwork freshwater faunas to date (see Kuschel, 1963; Klemmer and Zizka, 1993).

The Rano Kau Caldera is the largest inactive volcano on Easter Island. This Chilean island, a triangle of volcanic rock located 2,600 miles west of Santiago, is the most remote of all populated islands on our planet. Rano Kau is located on the southwestern tip of the island. Its crater is the basin of a large freshwater lake. As part of the cooperative expedition undertaken by the National Park Service of the United States and CONAF of Chile, fish specimens were collected from the Rano Kau Caldera and brought back to the United States for identification and study.

Easter Island is one of the most isolated and fascinating locales on Earth. Its mysteries have spawned volumes of speculation and dozens of expeditions over two and a half centuries since its discovery by European Explorers in the early 18^th century. Located more than 2000 miles west of South America and about the same distance from Tahiti to the west, the island rises abruptly from the sea and is pounded by the ocean on all sides. On only sixty-four square miles can be found the remains of a culture which produced many unique features including gigantic statues weighing scores of tons, large stone burial platforms, a profusion of pedographs, and a written language yet to be deciphered. Within a thousand years the people of Easter Island deforested the island, crowded many plants and animals to extinction, and saw their society descend into social and political chaos and even cannibalism. Easter Island’s culture, much like that of the Mayans but existing on a far more limited and fragile land mass, may have fallen for many of the same reasons: overpopulation (with no other place to go), environmental degradation, warfare among the clans for diminishing resources and perhaps adverse weather conditions such as a prolonged El Nino which could have created excessive rains or drought.

Mysterious Easter Island? How the people will embrace the 21^st Century is the real mystery. Electricity arrived in the 70’s, taxis and the Concord in the 90’s. And the Internet arrives in a few weeks. The beauty of the flowering African Tulip tree and the serenity of a lone horseman crossing the ceremonial field at Tahai at sunset remain as first impressions. One image represents the impact of introduced culture to the island; the other, the communion of man with his land. Both are key to an understanding of Easter Island today.

Rapa Nui (Easter Island) is known world wide for its huge stone statues, the moai, which grace the covers of numerous books and lure travellers to the island. These monuments are but one of many kinds of archaeological features of the island. Others, such as the ahu platforms upon which the ancient moai rested, the beautifully restored stone house complexes at Orongo, and a wealth of petroglyphs are well familiar to visitors to the island. These remains, and many others, reflect a remarkable record of more than 1,500 years of human history on this remote dot of land in the southeast Pacific.

A summary of the work completed by scientists/specialists involved in the 1997–98 and ’99 Interdisciplinary expeditions follows:

Dr. Daniel Mann, ’97 and ’98 — Paleobotanist Soil Geologist, University of Alaska: Obtained cores from the craters of Rano Raraku and Rano Roi (a record 55 feet, containing sediments dating back 80,999 years). Post analysis, working with Dr. Dorothy Peteet Lamont-Doherty Laboratories, Columbia University should determine: 1) resettlement climate fluctuations; 2) timing of forest clearance; 3) chronology of crop introductions; and 4) climate change over the last 1,000 years through the analysis of pollen, plant seeds and microfossils.