Detailed Instructions: In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.
Problem:A Rapa Nui Rock Garden, or agricultural field, with Poike volcano in the background. Credit: Christopher M. Stevenson (Phys.org)—A team of researchers with members from the U.S., Chile and New Zealand has uncovered evidence that contradicts the conventional view of the demographic collapse of the Rapa Nui people living on Easter Island, both before and after European contact. In their paper published in Proceedings of the National Academy of Sciences, the team describes how they conducted obsidian hydration dating of artifacts from the island to trace the history of human activity in the area and what they found in doing so. 
  
 For many years, Earth scientists and others have used Easter Island and its inhabitants, the Rapa Nui, as a lesson in what can happen when a parcel of land is overpopulated and thus overused—resources diminish and the people starve to death (or resort to cannibalism as some have suggested). But now, the researchers with this new effort suggest that thinking may be wrong. 
  
 Scientists believe Polynesians first settled on Easter Island sometime around 1200 AD—over the course of the next several hundred years the settlers became the Rapa Nui, famous for the massive maoi statues that were erected. Over that time period, the people cut down most of the trees on the northern part of the island and a lot of the other vegetation. That led to the loss of nutrient rich topsoil due to erosion and the idea that the people began to starve to death. 
  
 To better understand what actually occurred both before and after Europeans arrived in the 1700's, the researchers used a technique known as obsidian hydration dating on artifacts found at various sites on the northern part of the island where the Rapa Nui lived. That allowed them to gain insights into how the land in that area had been used during different time periods. From that they were able to construct a timeline that showed where the people were living over the course of hundreds of years. And that, the researchers report, showed that rather than a population crash due to starvation, there were population shifts that reflected changing weather patterns. Some areas did see population losses before European contact, and some actually saw initial gains afterwards. The population did see a dramatic decline, of course, sometime thereafter as the Rapa Nui people became exposed to European diseases such as smallpox and syphilis and as many were taken and sold into slavery. This means, the team concludes, that there is little evidence of population collapse prior to European contact. 
  
 Explore further: Genomic data support early contact between Easter Island and Americas 
  
 More information: Variation in Rapa Nui (Easter Island) land use indicates production and population peaks prior to European contact, Christopher M. Stevenson, PNAS, DOI: 10.1073/pnas.1420712112 
  
 Abstract 
  
 Many researchers believe that prehistoric Rapa Nui society collapsed because of centuries of unchecked population growth within a fragile environment. Recently, the notion of societal collapse has been questioned with the suggestion that extreme societal and demographic change occurred only after European contact in AD 1722. Establishing the veracity of demographic dynamics has been hindered by the lack of empirical evidence and the inability to establish a precise chronological framework. We use chronometric dates from hydrated obsidian artifacts recovered from habitation sites in regional study areas to evaluate regional land-use within Rapa Nui. The analysis suggests region-specific dynamics including precontact land use decline in some near-coastal and upland areas and postcontact increases and subsequent declines in other coastal locations. These temporal land-use patterns correlate with rainfall variation and soil quality, with poorer environmental locations declining earlier. This analysis confirms that the intensity of land use decreased substantially in some areas of the island before European contact. 
  
  ||||| The downfall of Easter Island may have had more to do with preexisting environmental conditions than degradation by humans, according to a new study of the remote speck of land made famous by its enormous stone-head statues. 
  
 Easter Island, also known as Rapa Nui, was first settled around A.D. 1200, and Europeans landed on its shores in 1722. The circumstances surrounding the collapse of the indigenous population of Rapa Nui are hotly debated both in academia and popular culture. Scientist and author Jared Diamond argued in his 2005 book "Collapse: How Societies Choose to Fail or Succeed" (Viking Press) that prior to European contact, the indigenous people of the island degraded the environment to the extent that they could no longer thrive. 
  
 The new study suggests that Easter Island's people were, indeed, suffering before Europeans came along. The story of their downfall, however, may be less about environmental degradation than the pre-existing environmental constraints of the 63-square-mile (163 square kilometers) isle. [Image Gallery: The Walking Statues of Easter Island] 
  
 "The results of our research were really quite surprising to me," said study co-author Thegn Ladefoged, an anthropologist at the University of Auckland in New Zealand. "Indeed, in the past, we've published articles about how there was little evidence for pre-European-contact societal collapse." 
  
 Collapse of civilization? 
  
 The new study challenged Ladefoged and his colleagues' view. Changes on Easter Island have been well documented, archaeologically. Over time, elite dwellings were destroyed, inland agricultural fields were abandoned, and people took refuge in caves and began manufacturing more and more spear points made out of volcanic glass called obsidian, perhaps suggesting a period of war and upheaval. 
  
 The problem with pinning down the island's history, according to the researchers, is that the dates of all these events and abandonments remain murky. Going into the study, the researchers expected to find that most of the disaster occurred after Europeans arrived, Ladefoged told Live Science. 
  
 To clarify the timeline, the researchers analyzed more than 400 obsidian tools and chipped-off obsidian flakes from six sites scattered around the island, focusing in particular on three with good information on climate and soil chemistry. 
  
 Obsidian absorbs water when exposed to air. By measuring the amount of water absorption in the surfaces of the obsidian tools and flakes, the research team was able to gauge how long those surfaces have been exposed, thus revealing when the tools were made. A greater number of tools from a certain time period indicates heavier human use of that area during that time. [History's 10 Most Overlooked Mysteries] 
  
 Natural challenges 
  
 The obsidian dates varied widely across the sites. Site 1, on the northwestern coast of the island, saw a steady increase in use between about 1220 and 1650, with a fast decline starting after 1650 — long before Europeans arrived on the island. 
  
 Site 2, an interior mountainside site, saw a rapid increase in land use between about 1200 and 1300, a slower increase until about 1480, and then constant use until a decline that started between 1705 and 1710, also before European contact. By the time Europeans came along, coastal Site 1 was at about 54 percent of its peak land use, and mountainous Site 2 was at only about 60 percent. 
  
 Site 3 told a different story. This near-coastal area saw a slow increase in human activity between 1250 and 1500, and then a faster increase until about 1690, after which settlement remained fairly constant until after European contact. In fact, the decline in use of this site didn't begin until 1850 or later, the researchers found. 
  
 The differing climates of the sites may explain the uneven decline, the researchers said. Site 1 is in the rain shadow of the volcano Ma'unga Terevaka, making it prone to droughts. Site 2 is wetter, but its soil fertility is low. Site 3, the longest-lasting spot, is both rainy and fertile. 
  
 What this means is that the people of Easter Island may have been struggling against natural environmental barriers to success, rather than degrading the environment themselves, the researchers reported Monday (Jan. 5) in the journal Proceedings of the National Academy of Sciences. 
  
 "It is clear that people were reacting to regional environmental variation on the island before they were devastated by the introduction of European diseases and other historic processes," Ladefoged said. The next step, he said, would be to take a detailed look at the archaeological remnants of dwellings on the island over time to better understand how humans and the environment interacted. 
  
 Follow Stephanie Pappas on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science. |||||  
  
 Stone statues of the Rapa Nui culture on Easter Island in 2013. (Gregory Boissy/AFP/Getty Images) 
  
 In 1722, Dutch explorer Jacob Roggeveen was in the middle of a bad career move. 
  
 The year before, at 62, the successful notary and Dutch East India Company employee had ditched it all to follow his father’s dream of discovering Terra Australis, a mythical continent in the Southern Hemisphere thought to be as large as the vast land masses that crowded the Northern Hemisphere. 
  
 The problem: Terra Australis didn’t exist. Sure, Australia and Antarctica are down under somewhere, but these measly continents are nowhere near large enough to balance out the great expanses of terra firma north of the Equator, an equilibrium thought necessary by Age of Exploration theorists. 
  
 So Roggeveen — a bit of a Don Quixote on a fool’s errand — wandered about the seas. He rounded Cape Horn. He battled ice and bad weather up the coast of Chile. Then he turned left into the great, largely empty unknown. And on Easter Sunday, he made his most significant discovery: a land mass of about 60 square miles notable for its giant statues and lack of large trees that he named Easter Island, now called Rapa Nui. 
  
 He stayed for a week. His crew killed some Rapa Nui locals. And then he split, sailing northwest into obscurity. 
  
 Not long after this first encounter between the Old World and the New, Easter Island’s population began to decline. Some scholars blamed a dwindling food supply resulting from Rapa Nui residents’ abuse of the environment. Others blamed Europeans. Did the meandering Dutch notary discover a remote civilization later undone by invaders, or was it already on the brink of collapse? 
  
 A new paper provides evidence that, for the Rapa Nui, depleted resources were not a problem — leaving Europeans as a possible culprit. 
  
 “Our paper evaluates a long-standing debate and examines whether the prehistoric population of Rapa Nui experienced a significant demographic collapse prior to European contact,” researchers led by Christopher M. Stevenson of Virginia Commonwealth University wrote. “… This analysis demonstrates that the concept of ‘collapse’ is a misleading characterization of prehistoric human population dynamics.” 
  
 The so-called collapse of Rapa Nui’s food supply, which resulted in starvation and cannibalism, is a long-held theory and, on occasion, a parable for the dangers of abusing the environment. After coming to the island in about 1200 A.D., the story goes, Polynesian settlers stripped it bare of trees, eroding nutrient-rich topsoil. Jared Diamond presented this case in his book “Collapse: How Societies Choose to Fail or Succeed.” 
  
 “They had the misfortune to be living in one of the most fragile environments, at the highest risk of deforestation, of any specific people,” he wrote. “… Easter’s isolation makes it the clearest example of a society that destroyed itself by overexploiting its own resources.” 
  
 Investigating this thesis for the study, which appeared in the Proceedings of the National Academy of Sciences, researchers tried to figure out how people on Rapa Nui used their land — and whether they had enough to eat. Their technique: good old obsidian hydration dating, which allowed them to figure out when artifacts discovered in different parts of the island were used. 
  
 Their conclusion: Yes, food production probably declined on Rapa Nui before Roggeveen’s arrival. But that wasn’t a disaster. 
  
 “We propose that precontact declines in the intensity of land use (and presumably population) in dry and infertile regions of Rapa Nui better reflect a framework of environmental constraint than of environmental degradation,” they wrote. 
  
 As Phys.org translated: “Rather than a population crash due to starvation, there were population shifts that reflected changing weather patterns.” 
  
 There’s no doubt that Rapa Nui was devastated not long after Roggeveen‘s visit. Its population was in the thousands when the Dutchman made landfall in 1722. By the time British navigator Captain James Cook arrived in 1774, it was about 700. 
  
 The reason for the decline? The new paper in the Proceedings of the National Academy of Sciences did not speculate. But other writers pointed to sexually-transmitted disease — and slavery — brought to Rapa Nui by Europe. 
  
 “Some areas did see population losses before European contact, and some actually saw initial gains afterwards,” Phys.org noted. “The population did see a dramatic decline, of course, sometime thereafter as the Rapa Nui people became exposed to European diseases such as smallpox and syphilis and as many were taken and sold into slavery.” |||||
Solution:
A new study is wading into the hot debate over exactly why Easter Island's indigenous people declined—and already news sources are interpreting it differently. The international team of researchers come to one clear conclusion: Environmental conditions made life hard for the Rapa Nui people before Europeans ever arrived at Easter Island in 1722, LiveScience reports. According to the study, the Rapa Nui used two of three areas on the island far less in the late 1650s and very early 1700s, possibly because one site was susceptible to droughts and another suffered from poor soil fertility. Researchers pegged those years by analyzing water absorption in obsidian flakes from Rapa Nui tools scattered around the island. "The results of our research were really quite surprising to me," says co-author Thegn Ladefoged. "Indeed, in the past, we've published articles about how there was little evidence for pre-European-contact societal collapse." That's the old hot point: whether Europeans devastated the Rapa Nui with disease and slavery, or the locals had already ruined the land with over-use and possibly resorted to cannibalism, phys.org reports. Now other sources, like Science News and the Washington Post, are saying, hey, environmental conditions worsened life for the Rapa Nui but didn't ruin their civilization—so Europeans did that. And Ladefoged doesn't disagree, saying that the Rapa Nui reacted "to regional environmental variation ... before they were devastated" by European disease and other changes. (Read about teeth that solve an Easter Island mystery.)