[4] Placostylus ambagiosus is highly valued by Te Aupōuri me Ngāti Kurī (the indigenous people of northern New Zealand) as a food source, musical instrument and in the past this snail provided alarm calls at night warning of approaching invaders.

It is restricted to a small fragmented area of Northland Region, including the Aupouri Peninsula and Motuopao Island.

[5] The species is endangered due to predation from rats[13] and birds,[14] habitat damage by pigs and horses and competition from introduced snails.

[13] Based on molecular phylogeny (mtDNA) and shell morphology research it was suggested in 2011 by Buckley et al.[15] that there are no subspecies of Placostylus ambagiosus.

[15] However, in the past, what were thought to be eight extant subspecies and a number of undescribed but distinct populations, were named;[7] six of these "subspecies" are now extinct[16] (marked with a †); conservation statuses were given according to the New Zealand Threat Classification System for the extant taxa: "nationally critical" and "nationally endangered":[17] At least five subspecies of Placostylus ambagiosus can be recognized using shell shape (not size or location) of individuals snails suggesting these represented distinct populations that require protection.