Indigenous Protected Areas are a distinctly Australian invention: instead of a government drawing a line around a national park, First Nations groups voluntarily dedicate their own country to conservation, managing it through agreements that count toward the national reserve system. The Anindilyakwa IPA covers Groote Eylandt, Bickerton Island and the smaller islands of the archipelago, lying about fifty kilometres off the eastern Arnhem Land coast, opposite Blue Mud Bay and some 630 kilometres from Darwin. The Anindilyakwa Land Council has managed it since 10 June 2006 through its Land and Sea Rangers. The principle is simple and radical at once: the people who know the country best are the ones who care for it.

In 2016 the traditional owners did something unusual. They extended the protected area seaward, adding seven thousand square kilometres of surrounding Makarda, the sea country, and wrote a Plan of Management to guide it. Few protected areas anywhere are defined as deliberately by water as by land. For the Anindilyakwa, the boundary between earth and ocean was always artificial; the reefs, seagrass meadows and tidal flats carry songlines and resources just as the bush does. Mapping the Makarda has meant marrying marine science with traditional knowledge, ranger boats and survey gear working alongside the inherited understanding of currents, seasons and species that no instrument can supply.

The archipelago shelters creatures that are vanishing from mainland Australia. It is critical habitat for the northern quoll, a spotted, cat-sized marsupial carnivore in steep decline, and for the brush-tailed rabbit rat. Its beaches are nesting grounds for four threatened species of marine turtle. Tucked away here too is the only known population of the northern hopping mouse, a tiny desert-style jumper found nowhere else on the planet. In all, the protected area holds more than 900 plant species, over 330 land-living vertebrates and around 150 marine species, a tally remarkable for so compact a place, and many of them are threatened.

The people doing this work are the Anindilyakwa Land and Sea Rangers, and their authority runs deeper than any government permit. They track the quolls and the hopping mouse with motion cameras and field surveys, but they read the country the way their elders taught them, by season, current, fire and sign. When marine scientists arrived to help map the Makarda, the project only worked because it married instruments to inherited understanding, the data of survey gear laid over the knowledge of which reefs hold turtles and when the winds turn. That partnership is exactly why the Anindilyakwa IPA is studied far beyond the Gulf, a working answer to a question conservation keeps asking: who should care for country, and on whose terms?