14 DAY TRIAL // It's "a microcosm of the world's situation" says Douglas Kennett, a University of Oregon archaeologist. In the middle of South Pacific is Rapa, a horseshoe-shaped, 13.5 square-mile island of volcanic origin.
Little was known about this island, with a current population of less than 500, until recent studies. Archaeological, linguistic and genetic data proved that the island, like much of East Polynesia, was inhabited in a last wave of colonization by seafaring travelers who originated from Southeast Asia.
New research - led by Kennett - has shed fresh new light on Rapa, especially on what life may have been like for as many as 1,500 to 2,000 people who lived there before the arrival of European explorers.
Kennett's team reported that Polynesians arrived on the island around A.D. 1200, much later than thought.
The settlers spread across the island, splintering from a shoreline-based society into competing groups that built and likely defended a growing number of heavy fortifications carved from mountaintops in the years before English explorer George Vancouver sailed by, in 1791, ushering in European contact.
Rapa's earliest occupants lived in coastal rock shelters. One such cave, Tangarutu, is being mined for sand to construct roads. However, Kennett's team delineated some 400 years of occupation in the cave. Among items found were fragments of sleeping mats, cordage and fish hooks made from shell.
When the Polynesians arrived in Rapa, "there was massive erosion, clearing of the land?that had an impact," he said. "People also brought things with them, like different crops and rats, as well as their main staple of taro." Environmental degradation and competition for resources led the people of Rapa to split into warring factions, Kennett argues.
Radiocarbon dating indicated that people relocated their residences to fortified interior locations 300 years after the island had been colonized. "These were all related people who arrived in Rapa," Kennett said.
"They generally get along and collaborate when they arrive, but with time and growing populations there was division, then competition between different family lineages, resulting in significant amounts of aggression. This division led to the establishment of fortifications in not very desirable locations, such as mountaintop ridges, where it's cold, windy, inhospitable for crops, and far away from water."
In the course of expansion, the islanders developed pond agriculture, similar to rice paddies, for growing taro (foto), a root-crop. The expansion of pond-field agriculture on the island parallels evidence from sediment cores for deforestation and erosion. Taro remains the island's food staple. Extending into the sea, from the various drainage systems flowing from the upland fortifications, are linear walls that likely served as tidal fish traps.
"The archaeological landscape is phenomenal," Kennett said. "There are domestic and agricultural terraces all around the island. Many of the ridge tops are flattened and there are staircases carved into the mountainsides. Arable land and access to fishing grounds were limited, and the farming areas and fish traps would have been well defended."[more than 300 miles] from its closest neighbor; those fortifications weren't for outside invaders."
The conclusions of Kennett's team are based on 48 radiocarbon dates drawn from samples taken from a variety of sites, including archaeological excavations at five of 16 known coastal rock shelters and four of 15 upland fortifications, each with a central tower surrounded by a series of large domestic terraces.
The settlement date for Rapa fits with the data from Easter Island (Rapa Nui meaning "Big Rapa").
"Our research confirms that approximate settlement date and supports the idea of a late pulse of colonization into East Polynesia," Kennett said. "However, we believe that the archaeological record of Rapa's later history is more compelling than Easter Island's in terms of what it teaches us about the social and political mechanisms for population dispersal."
Kennett argues that Polynesians moved to Rapa and several other parts of the remote Pacific after a 1,500-year rest in their major migrations. Around 3,000 years ago, he said, Polynesians had moved into West Polynesia (Fiji, Tonga and Samoa), far to the northwest of Rapa, where they lived until population densities and dwindling food resources spawned fragmentation and aggression.
"We see the same thing happen on those islands, but to a lesser degree," Kennett said. "There were enough small outposts concentrated in the immediate area that people could move on," rather than duke it out for resources. They finally traveled to Rapa-which they may have known about from reconnaissance or trade journeys-only when the other islands were exhausted, he believes.
The resource-depletion had a greater effect on the people of Rapa, which numbered about 2,000 at the time, because they were all forced to stay put, he said. "There was just nowhere else to go-this was the end of the line."
The findings and satellite maps taken by Kennett's team are being shared with the people of Rapa, with whom the team is continuing to work as part of Kennett's Rapa Heritage Project.
"Rapa is a compelling story," Kennett said. "To me, this is an example of what's happening on the planet today in terms of expanding populations, environmental degradation and increasing warfare. Rapa is a little microcosm of our planet.
There are lessons about the consequences of population growth to be learned there". Its first settlers turned to violence when faced with the same pressures of environment and competition happening right now across the globe.
"Rapa is a very remote place, like another planet. When settlers arrived there, there was an immediate impact on the environment," said study leader Douglas Kennett. "With populations expanding, you can see the same thing on a larger scale today. It leads to social strife."
"With the world's population exceeding six billion, human-induced environmental change is an acute problem confronting our increasing inter-dependent global community," Kennett writes in his research paper. "Remote islands provide well-bounded microcosms for studying the ecosystem effects of human colonization."
There are more and more modern examples of population expansion causing environmental problems - experts say - and not just in the Third World.
Parts of California, Arizona and the northeastern United States are experiencing severe water shortages that can only get worse, said popular UCLA geographer Jared Diamond, writing in a 2003 issue of Harper's. And we can't rely on technology to prevent an eventual social collapse, according to Diamond.
"These particular environmental problems, and many others, are enormously expensive in terms of resources lost, cleanup and restoration costs, and the cost of finding substitutes for lost resources: a billion dollars here, 10 billion there, in dozens and dozens of cases," he said.
"Even the mildest of bad scenarios for our future include a gradual economic decline, as happened to the Roman and British empires."