"pittosporum mackeei" is an uncommon small tree, which occurs exclusively in the ponérihouen area of new caledonia at an altitude of 100 to 500 metres above sea level. its area of occupancy is equal to 20 km² and its extent of occurrence to 428 km². it occurs in just five subpopulations each of which is threatened by rusa deer ("rusa timorensis"). this deer is an invasive species thoroughly adapted to the ecosystems of new caledonia, and the cause of the continuous decline in habitat quality of "p. mackeei" and other endemic plant species of new caledonia's humid forests.