What is the key lesson learned from Easter Island?

The key lesson learned from what has happened on the Easter Island is that the humans should live in balance with the nature and to use the natural resources responsibly. The Easter Island was inhabited by people until relatively recently, and they lived on the island for some time, but there's nothing left from them apart from numerous large heads made out of stone. The people that lived on the island died, and that happened because of their irresponsible way of using the natural resources and destroying the environment. The people that lived on the Easter Island managed to use and destroy all natural resources that were enabling their survival there, putting themselves in a situation where they didn't had anything to eat, nor having material to build boats and move on another place. They were tuck there, isolated, started to kill and eat each other until the last one of them was left and died. This is a very nice example and lesson for the humans in the present that they should be very careful with the nature and the natural resources because there's always a line that after it is crossed there's no coming back.