The whole primitive tribal people living in harmony with nature thing is general bull. They don't have as much effect on the ecology only because they don't have the technology and scale to do so. History shows that they are just as happy to hunt a species into extinction as anybody else.
This is one of those things that gets under my skin. It's probably a reaction to watching a lot of Anime for several years. The whole ecological-primitive good / technological-sophisticated bad thing really began to rub me the wrong way with some of them.
Jay