endemic to a single state or province
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (<100-250 square km (less than about 40-100 square miles)) ENDEMIC TO kOOLAU MOUNTAINS. SINGLE POST-1945 SIGHTING ON HELEMANO RDG. HISTORICAL RANGE FROM WAHIAWA (SCHOFIELD- WAIKANE) TO KAWAILOA, A RANGE OF 5 TO 6 MILES (PILSBRY & COOKE).
Habitat and Ecology
Habitat Type: Terrestrial
Comments: ARBOREAL; MOSTLY ON GLABROUS NATIVE PLANTS.
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 0 (zero)
Comments: ONE POST-1945 RECORD (1949) on Helemano Ridge. Likely extinct (Hawaii Biological Survey web site http:/hbs.bishopmuseum.org/endangered/ext-snails.html, updated 9 February 1997).
1 - 1000 individuals
Comments: ONE SNAIL OBSERVED IN 1949. NO POPULATION ESTIMATE.
IUCN Red List Assessment
Red List Category
Red List Criteria
- Needs updating
- 1994Extinct?(Groombridge 1994)
National NatureServe Conservation Status
Rounded National Status Rank: NX - Presumed Extirpated
NatureServe Conservation Status
Rounded Global Status Rank: TX - Presumed Extinct
Reasons: GX. SINGLE POST-1945 SIGHTING IS OF A SINGLE SNAIL IN 1949. CONSIDERED EXTINCT BY KONDO. PRESUMED EXTINCT WHEN GENUS WAS LISTED AS ENDANGERED ON FEDERAL REGISTER. Likely extinct (Hawaii Biological Survey web site http:/hbs.bishopmuseum.org/endangered/ext-snails.html, updated 9 February 1997).
Other Considerations: MALACOLOGISTS BELIEVE THAT VIRTUALLY ALL NATIVE TERRESTRIAL SNAILS OF HAWAII ARE RARE AND IN DANGER OF EXTINCTION.
Degree of Threat: Very high - high
Comments: From the recovery plan of the Oahu tree snails of the genus Achatinella (USFWS, 1993):
Decline is the result of many factors acting over an extended period of time coupled by low reproductive rates and limited dispersal abilities. Habitat destruction was caused by removal of forests and introduction of invasive vegetation for pasture, agriculture, or housing. Forests not cleared for agriculture were invaded by feral cattle, horses, goats and pigs and their grazing reduced the forest understory and aided the invasion of exotic plants. Human activities such as hunting, hiking, military maneuvers, clearing for illegal marijuana patches, construction of helicopter landing sites, and building of roads and trails contribute to exotic vegetation spread. Logging has significantly altered native forests including reforestation with non-native species. Forest fires have had a catastrophic effect on small populations (kill snails, allow for spread of non-native plants, alteration of understory leading to moisture and humidity changes unsuitable for tree snails).
The carnivorous snail, Euglandina rosea, and European rat, Rattus rattus, are predators of native tree snails. Other predators are the predatory flatworm, Geoplana septemlineata, terrestrial snail, Oxychilus alliarus, Norway rat, Rattus norvegicus, and Polynesian rat Rattus exulans. Parasitism and disease have not been documented in Achatinella but may contribute to future decline.
Collecting historically was probably responsible for decline in ranges and abundance of some species and even today (despite listing on the U.S. Endangered Species List), removal of even two or three adults can remove a large percentage of the reproductive population in a bush or tree.
Names and Taxonomy
Comments: Considered by Welch and Cowie et al. (1995) as a subspecies of A. bulimoides. Considered a separate species by Pilsbry and Cooke.