This was because they saw that a short time after they arrived the population dropped almost half the size. They then gest that the population started out around the size of 30,000. This though is thought not to be the reason for people's death, but instead from the Europeans bringing diseases that the Polynesians were not immune to. But as more research is being done at Easter Island it is found that the Polynesians were getting along with scearce resources using what they had left.
Easter Island is often used as an example of the Tragedy of the Commons. The Tragedy of the Commons is when an area or thing is open to all without limits. Then the Commons, or people, take advantage of it without thinking about the consequences. The people end up using the source faster than it can replenish itself causing downsize in the product. In the end the people end up taking consequences of it by not having the needed resources to