In other cases, such as New Zealand and Canada, treaties allowed native peoples to maintain a minimum amount of autonomy. In the case of indigenous Australians, unlike with the Māori of New Zealand, no treaty was ever entered into with the indigenous peoples entitling the Europeans to land ownership, under the doctrine of terra nullius (later overturned by Mabo v Queensland, establishing the concept of native title well after colonization was already a fait accompli). Such treaties between colonizers and indigenous peoples are an important part of political discourse in the late 20th and early 21st century, the treaties being discussed have international standing as has been stated in a treaty study by the UN.

Answer this question, if possible (if impossible, reply "unanswerable"): What doctrine was overturned by Mabo v Queensland establishing the concept of native title?
terra nullius