Tanada wrote:Easter Island, as was pointed out up thread, was raided by Europeans after which time disease and ecological invasive species were introduced and the society collapsed under all of the massive new stress.
My understand is that they'd already collapsed before contact with Europeans:
The first-recorded European contact with the island was on 5 April (Easter Sunday) 1722 when Dutch navigator Jacob Roggeveen visited for a week and estimated there were 2,000 to 3,000 inhabitants on the island. This was an estimate, not a census, and archaeologists estimate the population may have been as high as 10,000 to 15,000 a few decades earlier. His party reported "remarkable, tall, stone figures, a good 30 feet in height", the island had rich soil and a good climate and "all the country was under cultivation".
Fossil pollen analysis shows that the main trees on the island had gone 72 years earlier in 1650. The civilization of Easter Island was long believed to have degenerated drastically during the century before the arrival of the Dutch, as a result of overpopulation, deforestation and exploitation of an extremely isolated island with limited natural resources. The Dutch reported that a fight broke out in which they killed ten or twelve islanders.
http://en.wikipedia.org/wiki/History_of_Easter_Island
I saw a documentary recently that mentioned rats may have been the problem on Easter Island. Something along the lines of a couple breeding pairs stowing away on the first settlers' boats. The rats ate the palm tree seeds, and with no natural predators on the island over time the rat population exploded and pretty much ate the trees into extinction.
Add to that the societal pressure for each generation to build more and bigger moai statues, and it's no surprise they used up all their trees.
My problem with the Easter Island example is that it's a CLOSED SYSTEM. The collapse went down during a period of time where the islanders had no contact with the rest of the world off-island. Closed, small scale systems are vulnerable by nature. So I don't think Easter Island is comparable to other civilizations that have give and take with the larger world around them -- when there's famine in one area, there's surplus in another etc.
I think this open-system equilibrium effect is why you can't really find many examples of resource collapse. History shows that when populations outgrow available resources, *something* will happen to reduce the population before the whole civilization collapses. That could be population reduction through warfare, or natural diseases caused by overcrowding (plague, etc.). After the Black Death in Europe, civilization didn't collapse -- life actually got a lot better for those left standing, and the improved living conditions sparked the Renaissance.
So I think that's the natural norm in these situations, simple population reduction vs. outright collapse and extinction. Let's not forget that our species was once reduced to a mere thousand breeding pairs planetwide.. in opnion, if we recovered from that we can bounce back from anything. (talking about survival of the species here, not necessarily firstworld living standards)