In his book Human Natures: Genes, Culture and the Human Prospect , Paul Ehrlich argues that the cultural practices of a given society develop largely as a result of the large-scale environmental factors of the area in which the society lives. He gives the striking example that all religions that developed in deserts are monotheistic, whereas those that began in rainforests are polytheistic (Ehrlich, pp 9 of handout, 2000). Ehrlich argues that the size and geography of a region, its climate, the availability of resources - the "macroevolutionary" forces - will have an enormous effects on the cultures that develop there.
Ehrlich continues by pointing out that cultures do not only develop as simple, predictable reflections of their environments. The influences do not only run in one direction; cultural beliefs and practices may lead to large-scale environmental changes made by a society. The culture of a given society may influence how and to what extent that society interacts with its environment. The rate at which cultures acquire new technologies has historically been highly variable; on the one hand, a culture may deliberately restrict the use of a given technology or simply may not have the cultural demand for an available technology (1) . On the other hand, many cultures seem to have desires and appetites that far exceed a sustainable method of utilizing their environment. All too often, the practices of a society over-strain its existing resources in ways that leave those resources irretrievably damaged.
A telling example of the complex interactions between a culture and its surroundings is the relative fates of two Pacific islands: Easter Island and Tikopia. Although it would be impossible to pin-point a simple cause-and-effect relationship between the people of each island and their respective environments, there are several interesting features of the ecosystems and cultures on the two islands that seem to have largely affected how their histories played out up to the point of their initial contact with Europeans in the 18th century.
Clive Ponting (1991) gives the history of Easter Island roughly as follows: In the fifth century CE, the 150 sq. mile island (2) was reached by no more than twenty or thirty Polynesians. The population slowly grew as agriculture developed on the island. Many native Polynesian food sources could not be propagated on the island, but sweet potatoes and chickens were successfully imported. The islanders were also heavily dependent on fishing, which they did in wooden canoes. By the sixteenth century, the population peaked at around 7,000 people. Initially, the agriculture was successful enough so as to only require a relatively small amount of labor, leaving the inhabitants with large amounts of free time that enabled them to develop complex religious ceremonies and rituals.
The most striking aspect of the religion on Easter Island was the carving of up to a thousand massive stone busts located throughout the island, some weighing nearly eighty tons. Although their function is not completely understood, these statues are generally believed to have been used in religious ceremonies and also as signs of prestige among the different clans on the island. These statues were transported over the island on enormous systems of wooden tracks. Ponting suggests that the building of these giant wooden transport structures was ultimately responsible for the almost complete deforestation of the island.
By 1600, this deforestation had dried out and practically ruined the soil, making agriculture much less productive. In addition, the islanders could no longer make boats for fishing, and more importantly, were essentially trapped on the island. In 1722, when Easter Island was first discovered by Dutch explorers, the 3,000 islanders were "engaged in almost perpetual warfare and resorting to cannibalism in a desperate attempt to supplement the meager food supplies available on the island." (Ponting, pp 1, 1991)(3) .
Although many of the details regarding Easter Island are unknown, it is interesting to think about the way in which the environment of the island contributed to the development of certain cultural practices, and the subsequent ways that the culture had a massive effect on the environment. The ease of farming gave the people sufficient time to develop their culture, the availability of stone allowed for the massive quarrying, and the lack of draught animals and the seeming abundance of trees most likely prompted the people to transport these statues the way that they did. Because the trees native to Easter Island are extremely slow growing (Ehrlich, 2000), what may have been a standard deforesting process for the early islanders in their previous homes could have been too much for Easter Island to support. Although the culture that developed on Easter Island seems to have been largely influenced by the ecosystem of the island, certain aspects of the society became increasingly incompatible with that ecosystem. It was the cultural practices of the islanders and their inability to change their ways that destroyed the resources (namely forests) that the society depended on, ultimately destroying the society of Easter Island.
The society that developed on Tikopia turned out quite differently. First settled in 900 BCE, Tikopia is the western-most Polynesian island. Though it is much smaller than Easter Island (Ehrlich reports the size as 1.8 sq. mi), the maximum population density of Tikopia was much greater than that of Easter Island (4).
According to Ehrlich, the first thousand years of resource depletion on the island were similar to those of Easter Island. Indeed, by 500 BCE, megapode and other wild birds were extinct on Tikopia (Kirch & Yen, pp 361, 1982). However, between 100 CE and 1200 CE, a sustainable orchard-system unlike anything on Easter Island was implemented that has allowed for a relatively stable population to this day.
In many ways, the physical environment of Tikopia may have made it more capable of sustaining human life than Easter Island. As Ehrlich points out, Easter Island was large enough for several groups to develop independently and relatively isolated from each other while Tikopia was small enough that "everyone in the relatively small population must have been on rather close terms with everyone else, and this encouraged collective decision making." (Ehrlich, pp 246, 2000). In addition, the soil of Tikopia was highly fertile and supported much more diversity of crops (Ehrlich, 2000)
The anthropologist Raymond Firth has done extensive cultural studies of Tikopia from the 1920s through the 1960s, and his book History and Traditions of Tikopia explains some aspects of the culture that may have contributed to the people's survival. His findings both support Ehrlich's assertions that the geography of Tikopia had an incredible effect on the culture that developed there, and also include other fascinating aspects of Tikopian society that may have played important roles in its survival.
Firth's description of Tikopian folklore reinforces the notion that the size of the island led to the development of a singular culture on the island. At the time that he was writing, there were 23 lineages on the island, each "with major ritual privileges and an office-holder as head." (Firth, pp 85,1961). Eight of these lineages claim to have descended from immigrants to Tikopia, and the remaining are fifteen are said to be "earth-sprung," meaning that they originated on the island. Clan loyalties are important in social affairs, but Firth says that all Tikopians recognize one culture-hero, The Supreme Deity of Kafika. "He was regarded as having been responsible for many of the major items of Tikopia culture." (Firth, pp 95,1961). The people of Tikopia therefore have a notion that all people on the island (aside from the immigrant lineages) descended from the same stock, all partake in the same governmental structure, and have at least some sense of unity of all inhabitants on the island. Firth also mentions that although tensions between lineages do exist, marriages between clans and other cross-lineage relationships prevent deep rivalries from forming.
Certainly, recognition of common ancestry or a singular culture-hero do not necessarily lead to a healthy and cohesive society (Christianity seems like a good counter-example), but the ability to make society-wide decisions as a group has definitely made a contribution to the relative peace on Tikopia. The island is described by Marc Howard Ross as a "low-conflict society." Ross claims that although verbal abuse occurs on the island, physical violence is rare. Ross, citing Firth, attributes this to cultural beliefs of Tikopians, which do "not promote peaceful conflict management through the threat of force. Rather…the leader's legitimacy is well established and connected to strong identification with the community." (Ross, pp 53, 1993).
There are several other ways in which Tikopian culture has allowed for sustainability. As Firth describes, one of the defining characteristics of life on the island is the practice of frequent oversea voyages. Firth estimates that over the four generations preceding his arrival, 100 over-sea voyages were made. Of the men on these 100 voyages, more than half died at sea and more were said to have died in foreign lands. In all, only one-third of the voyagers were thought to have returned.
According to Firth, these voyages are undertaken for excitement and adventure and as a matter of prestige among men. They were also often the result of shame on the island, when a man lost face. As Firth notes, this has proved to be powerful population control mechanism: "the institution of overseas voyaging served as an overflow mechanism for population pressure." (Firth, pp 151, 1961). In his writing about Tikopia, Ehrlich claims that infanticide, celibacy, and birth-control also contributed to population-controls (Ehrlich, pp 245, 2000). (5)
One of the most interesting aspects of cultural history on Tikopia is the deliberate removal of pigs from the island sometime around 1600. Patrick Kirch and D. E. Yen describe this decision as largely the response to environmental pressure (pigs were continually eating or destroying a large amount of crops), but at a recognized social cost. Because pigs were detrimental to the orchard system on the island, their removal led to increased stability. However, pigs were used in religious rituals, so "the positive effects were thus environmental, the negative, cultural." (Kirch & Yen, pp 358,1982). While exact evidence is scarce, it seems that the islanders were aware that pigs were becoming too great a strain on the agriculture of the island, and were able to sacrifice a part of their culture for the benefit of the society.
Kirch and Yen also note other instances of deliberate avoidances of certain edible animals. From about 100 BCE until 1200 CE, sharks, turtles and rays were not hunted. Kirch and Yen speculate that his may have had to do with their religious importance rather than an environmental precaution. At 1200 CE, the prohibition was lifted and these animals have been eaten since. However, the authors do say that currently eel and puffer fish are not eaten on Tikopia, and that the islanders find "the eating of eel flesh disgusting." (358). While this avoidance is clearly not a deliberate attempt to further sustainability, it may help do so anyway.
All of these cultural practices and more must have contributed to the survival of the Tikopians. They are also a beautiful example of the complex interactions between a culture and it's surroundings - it is nearly impossible to identify which are the causes and which are the effects of these practices. As Firth wrote, "in this island the works of nature and of man merge easily." (Firth, as quoted by Kirch & Yen,1936).
I do not think there is any reason to believe that the inhabitants of Easter Island were irresponsible and short-sighted, while those of Tikopia were patient and considerate. Rather, it seems that the geography and resources of each island contributed differently to the cultures that developed there. With a hundreds years of hindsight, it may be easy to realize the beneficial decisions and the mistakes made by each culture, but it seems much more realistic to imagine that each of these decisions was made slowly, not always deliberately, and certainly without accurate knowledge of the consequences. For example, it seems ridiculous to assume that the Tikopians developed a cultural habit of sending their young men to die at sea as a conscious effort to reduce the population. It appears more likely to me that whatever the origins of this practice, it was most likely one of the causes of their success, not a deliberate reaction to the threat of doom. In other words, I would argue that this practice was not developed as a conscious fix-it for an environmental stress, but rather sprung from much more complex and mysterious ideas and appears to have been an integral part of the societies survival.
The fates of Easter Island and Tikopia both illustrate the ways that an environment influence the development of a culture and that culture may in turn affects its environment. In the case of Easter Island, the society that developed had such a drastic effect on their environment as to make it virtually uninhabitable. The Tikopian society, on the other hand, was able to accommodate for the precarious ecosystem on their island and developed cultural and technological practices that allowed for their survival. On both islands, the cultures developed not as simple mirrors of their surroundings, but rather as complex interactions between humans and their environments. As in any society, it is impossible to imagine what may have happened had any small part of each island's history been different. Every interaction between the islanders and their environment must have built on the past but also taken their society in an unforeseeable direction, affecting their future.

(1): Ehrlich gives the example of China. China had, for instance, gunpowder, the "Bessemer" steel process, and an incredibly advanced fleet of large sea-ships well before Europe did. Yet, due largely to cultural views of these technologies, they did not have such an explosive effect on the planet until they spread to Europe. (Ehrlich, 2000)

(2) This is the size given by Ponting. The Encarta Encyclopedia says that Easter Island is closer to 45 sq. mi.

(3) In 1877, 110 inhabitants remained, the rest having been taken into slavery by European explorers.

(4) My own calculation. The peak population of Easter Island is given by Ponting as 7,000, so the population density would have been 46.7 people/sq. mi. The earliest population estimates for Tikopia (1828), as given by Kirch & Yen, was 400-500 people, which would yield approximately 222.2 - 277.8 people/sq. mi. In addition, the highest recorded population for Tikopia (in 1952) is reported as 1,753, which would give a density of 973.9 people/sq. mi, about 20 times more than that of Easter Island.

(5) Tikopia is also highly prone to massive storms. For example, in January of 2003, Cyclone Zoe hit Tikopia. No islanders were killed because they had received early notice and were able to protect themselves in caves. However, their water supply was affected, threatening their fruit supply. These storms have historically hit the island with terrible frequency. In one instance in the 1950s, 200 islanders were killed by a famine in the aftermath by a storm. (ABC News Online, January 4, 2003)

Literature Cited:
Ehrlich, Paul. Human Natures: Genes, Culture, and the Human Prospect. Island Press, 2000.

Firth, Raymond. History and Traditions of Tikopia. New Zealand: Avery Press Limited. 1961.

Kirch, Patrick Vinton and Yen, D.E. Tikopia: The Prehistory and Ecology of a Polynesian Outlier. Hawaii: Bishop Museum Press. 1982

Ponting, Clive. A Green History of the World. New York: St. Martin's Press. 1991.

Ross, Marc Howard. The Management of Conflict. New Haven: Yale University Press. 1993.