Aaadonta constricta ssp. constricta

The sub-species is listed as Critically Endangered. It is a single island endemic, and the very small area where it is currently found, relative to where it was found in 1936, is of particular concern, especially given the fragility of endodontid populations elsewhere in the Pacific. It is now known from a single location and its forest habitat is experiencing declines in quality and extent. Site protection is required, and surveys to determine the current distribution of this species and its population size, status and trends are also recommended.

The historical geographic range of A. constricta constricta was 12km². The area of occupancy for this subspecies is now estimated at 1.5km², reflecting the single locality in native forest where very few specimens were found in recent surveys.

This sub-species is threatened by destruction and modification of native lowland forest. Therefore it is not surprising that the area of occupancy of the species has been greatly reduced since World War II, when much of the island’s forest was decimated by flamethrowers (Hinz 1995, Crombie and Pregill 1999). Disruption of the ground, rocks and leaf litter may be of particular significance to this and other endodontid species. Endodontoid land snails are among the most threatened land snails on Pacific Islands in the few places where they still exist (Solem 1983).

Field work to define the current distribution of this species, as well as research on its population status and trends, is required. Identification of priority sites for species conservation (e.g. key biodiversity areas that include threatened land snails) and reducing the impacts of human activities, is also urgently needed. The Palau Conservation Society has been supportive of recent land snail survey work in Palau.