New Caledonia is a fragment of the ancestral Gondwana, once united with Antarctica and Australia. It is thought that one of its endemic plant species, Amorella trichopoda, is a sister of the original parents of all flowering plants. Rainforest which once covered 70% of Grand Terre, the largest of the islands, is now reduced to isolated pockets on the east side of its mountain chain. Its profusion of Araucariaceae (13 species of Araucaria, 5 of Agathis) and 5 Nothofagus species is probably typical of the primordial Gondwanan forest. Current thinking is that because New Caledonia suffered neither the drying out that affected Australia nor the glaciation that occurred in New Zealand, it retains a higher proportion of typical Gondwanan species.
What is in question now is how much longer the ancient rainforests of New Caledonia can survive. Plant species hanging on in isolated pockets soon begin to suffer from inbreeding; dieback is already affecting New Caledonian tree species that can live a thousand years. The several Araucaria species endemic to the maquis minier are almost certainly doomed.
Since 1875 New Caledonia has been mined for nickel and other metals, with scant regard for the environmental consequences. Whole landscapes have been changed by dumping of rocks and spoil, waterways polluted, mangroves suffocated and vegetation reduced to scrub. The mining industry is now subject to controls, but the impact of extensive strip mining and the construction and operation of smelters is still severe. A further serious threat to the survival of New Caledonia’s endemic vegetation is frequent wild fire, some of which is started by hunters to flush out (introduced) deer, and some apparently as protest against perceived social injustice. The area of 4,192 square kilometers that is now protected has no defense against fire.