We will probably never know the full impact of Aboriginal burning and firestick farming. On the one hand we have the view of people like historian Bill Gammage contending that fire had been pervasive across the continent for many thousands of years, used by Aboriginals as a highly sophisticated and finely honed system of land management. That “Most Australia was burnt about every 1-5 years depending on local conditions and purposes 
However, different factors are at play in different regions and as different fire regimes may be applied according to local conditions, so caution is needed in making generalisations about fire regimes of the past. Ecologically there seems a strong interdependence of fire, kangaroos, humans and grassland.
Many species are clearly adapted to fire and their numbers may have been increased by Aboriginal burning???. Possibly altered the balance of species through their hunting. Probably carried seeds, fruits and nuts around the country, digging and foraging being a form of cultivation. The winter clothing of Europeans was partly a product of pastures created by generations of Aboriginals.Blainey 83.
If Gammage is correct then the land was managed so well, and they trod on the land so lightly that western science has been unable to detect its presence, an incredibly subtle feat that nowadays grows annually in stature against the admired wonders of so-called civilisation from the pyramids, hanging gardens of Babylon, Roman roads and bridges to the modern megalopolis, space flights and nuclear fission.
Aboriginal influence on vegetation has been estimated through the presence of charcoal dated in sedimentary layers. The current superdominance of Eucalyptus in Australia may be a relatively recent phenomenon, the result of the extraordinary adaptation of the genus to fire.This was no doubt combined with the impact of Aboriginal burning.
There is a complex relationship between fire, vegetation types, fauna (extinctions and the effect of introduced carnivores and herbivores). Some animals probably multiplied through Aboriginal effect on predators or vegetation etc.
In recent times there has been a closer attention to climate modeling as a result of vegetation change as different vegetation types can influence evaporation and rainfall, alter surface reflectivity which, in turn, leads to changes in the weather and climate. Early studies are trying to assess the effect, on a global scale, of early agriculture involving land clearing and livestock, while in Australia there is the possible influence of Aboriginal burning. An “early anthropogenic hypothesis”, though slightly controversial, suggests that these practices had a definite influence on climate, agriculturalists producing an anomalous reversal in natural declines of atmospheric carbon dioxide 7,000 years ago and methane about 5,000 years ago.
Many of the food plants of the north seem to have remained the same as those of Indonesia, Malaysia and the Philippines rather than Australian natives, possibly hinting to times past