For an enlightening look at Australian flora and the damage that is been done in the name of conservation may I recommend Bill Gammage's book, "The Biggest Estate on Earth". Once read and understood you can begin to understand why the staff and students at the University of Tasmania Botany Department ganged together to stop Gammage from delivering a talk on Aboriginal fire management. The book questions one of the fundamental premises of Australian conservation; that natural features have natural causes.
Back on topic, I doubt that the carving of Marree Man did much to upset the flora and fauna when it was created and I doubt it would do much again if it was repeated. Having also driven down through that region it could certainly do with a lift and if the local Aboriginal people are supporting the idea then why not?