Easter Island – ecocide?

Easter Island is widely referred to as a classic case of ecocide “where the ancient Polynesians recklessly destroyed their environment and, as a consequence, suffered collapse” (Hunt & Lipo 2009:601). In this post, as Jo rightly mentions (who, by the way has a great blog about societal collapse of the Norse in Greenland – here), I will be examining how accurate this is – to what extent was the collapse of the Easter Island society a result of ecocide?

As I established in previous posts, Easter supported a subtropical tall forest and a range of food resources from shellfish to land birds (Diamond2005, Hunt 2007). However, the island was also a relatively fragile and vulnerable environment, with quite poor soil subject to strong winds and highly variable rainfall (Hunt & Lipo 2009). It is therefore no surprise that the arrival and growth of human populations on such a small and isolated island led to the depletion of these resources and the degradation of the environment as a whole.

On the surface the widely known image of collapse on Easter as a case of ecocide seems likely. Early research puts the blame largely on the shoulders of the Polynesians, the French explorer La Perouse commented in 1786 that the islanders “were indebted to the imprudence of their ancestors for their present unfortunate situation” (1789:318-319 in Hunt and Lipo 2009:602). The common explanation being that as population grew, more forest was cut down for agriculture, fuel and statue building and at a rate faster than it could regenerate (Diamond 2005).

Although this seems plausible, recent research casts doubt on this version of events. Although to summarise all the research against this case would be beyond the scope of this meagre blog, I will discuss a couple of issues raised in recent papers.

Hunt (2007:485) argues that “prehistoric deforestation did not cause population collapse,” using numerous observations to illustrate his argument. One major issue is that all palaeo-environmental evidence used in papers discussing the conventional story has questionable reliability and validity, with error margins often between 100 to 200 years (Hunt 2007). In this paper Hunt stresses that humans were not the sole driver of deforestation and points to the huge impact rats would have had. As a small, closed ecosystem Easter would have had little biodiversity and few, if any predators, making invasive species hugely threatening (Hunt 2007).

Documented rat population growth rates on other Pacific islands suggest rats could have grown into huge numbers in a very short space of time on Easter. Many other Pacific and Hawaiian islands have seen severe deforestation resulting solely from rats, as they use tree nuts as a primary food resource, thus preventing tree populations from regenerating (Hunt 2007). Hunt argues the relative contribution of rats to deforestation remains poorly understood and that is highly likely that both a combination of humans and rats, and indeed other factors, would have driven deforestation.

Doesn't seem so bad does he?

Hunt and Lipo (2009) make a number of points, but one argument that struck me was that the period of greatest deforestation occurs between AD 1200 and 1650, a period where population actually rose, with the only sustained decline of population occurring between AD1750 and 1800, after the arrival of European visitors (Hunt & Lipo 2009).

Source: Hunt T.L. and Lipo C.P. (2009:609)
Obsidian hydration dates used to infer population - obsidian used to make tools, weapons etc.
Population rises between 1200-1650, only sustained drop post European contact (downward arrow)

In both papers (Hunt 2007, Hunt & Lipo 2009) the sharp population decline on the island is framed as resulting largely from contact with Europeans, due to disease and slavery, with conventional arguments being based on speculation about prehistoric population size and unreliable palaeo-environmental records. Even in Diamond’s book Collapse (2005) this issue is clear, as many conclusions are drawn from evidence on the Poike Peninsula which are then extrapolated to the entire island (Diamond 2005). This is an important issue as Poike is in fact relatively peculiar in that is one of the few places on the island not covered in bedrock outcrops (Hunt & Lipo 2009) and therefore an unreliable analogue for the rest of Easter.

I therefore think that the collapse on Easter is not a clear cut case of ecocide, as records show that there was not a solid trend of deforestation matching population decline and that the largest periods of population decline occur after contact with Europeans. Furthermore, humans were likely not the only cause of the environmental degradation, as mentioned earlier the soil on the island was poor to begin with and as Hunt (2007) shows, other factors such as rats would have had a huge impact. I will go into alternatives in more detail in later posts, but it is clear that the conventional story is not completely sound.