Or you could reestablish pre-human conditions in the large uninhabited areas of Australia. Killing of the kangaroos is a lazy and temporary solution. Preservation and reestablishment of original environment is the most important thing to do here, especially for the rare wildlife. You don't honestly think this rare wildlife is save from human meddling with the environment in the long run, do you ? Cities are going to expand and non one will care for the demise of the rare wildlife when living space for humans is the issue. We either preserve and reestablishment original environment on huge scales or kiss goodbye most of the earths ecosystems. Lots and lots of species are going to die out if we don't do something. Only species that can take a real blow are going to survive. I'm not sure what the eventual impact of that will be but I'm afraid this scenario spells doom for human kind as well in the long run. Which is maybe a small consolation. Having said all this, I am skeptic about the future. Man will keep putting himself above the environment and life will suffer the consequences, humans included. I think it's too late.