Human impact on native flora and fauna is real. There seems to be no way the detrimental affects can be ameliorated. Aboriginals have been in Australia for 40,000 years. apart from the unanswered question about extinction of mega fauna Aboriginals did not alter the external environment at all.
Sedentary agriculture is the major contributing factor to habitat damage. Planting mono-crops seriously changes land features. In Western Australia, for example, water points are located at 50 sq km on average. In its pre-European natural state water holes could be found 2.5 sq km apart. This is serious change with species of native birds declining.
Unless we set areas aside as pristine, protected sectors only introduced pest species will remain. Even without the pest birds, the proportion of native birds is altered. Some die out while others increase in number. The ecosystem is no longer in balance.