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Pasmaditta jungermanniae

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA MOLLUSCA GASTROPODA STYLOMMATOPHORA PUNCTIDAE

Scientific Name: Pasmaditta jungermanniae
Species Authority: (Petterd, 1879)
Common Name(s):
English Cataract Gorge Snail

Assessment Information [top]

Red List Category & Criteria: Vulnerable D2 ver 3.1
Year Published: 2006
Date Assessed: 2006-01-31
Assessor(s): Bonham, K.
Reviewer(s): Seddon, M.B. & Ponder, W.F. (Mollusc Red List Authority)
Justification:
Pasmaditta jungermanniae is known only from a single confirmed location. It is apparently very hardy within that locality and occurs in some quite compromised environments. Currently, there are no known threats to the species, however its highly restricted range makes it vulnerable to potential unforseen threats, such as the introduction of a new predator. For this reason, it is assessed as Vulnerable.
History:
1996 Data Deficient
1994 Vulnerable (Groombridge 1994)

Geographic Range [top]

Range Description: Only one known location within a gorge in Tasmania. Known range (extent of occurrence) is about 2 km². Area of occupancy is very small, possibly as little as 50 hectares. It is unknown whether there are any other locations despite considerable searching. Unconfirmed records have been reported from elsewhere, however searches at that locality have failed to find the species present there and the record for that locality is not considered reliable (K. Bonham, pers. comm).
Countries:
Native:
Australia (Tasmania)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: At least three subpopulations are known within the only known locality, divided by a river and an area of exotic vegetation (K. Bonham, pers. comm). The main subpopulation has densities of dozens of specimens per metre. It is likely that the population is at least several thousand individuals. There probably have been some losses over the past 100 years but this has largely stopped, and the extent of this decline is unclear
Population Trend: Stable

Habitat and Ecology [top]

Habitat and Ecology: Currently known from rocky wet forest, scrub and mossy cliff faces. Nothing is known of life history parameters (age at maturity, life span, etc).
Systems: Terrestrial

Threats [top]

Major Threat(s): Reason for past population decline is mainly clearing (which has now halted) but possibly also environmental degradation and exotic species invasion. Specifically, habitat alteration resulted from a dam being built upstream which resulted in more irregular water flows through the gorge, high floods stripped the rocks directly by the waterside of vegetation. There was also some clearing of parts of habitat: most of what remains is not clearable because it is just bare steep rock covered with shrubs and mosses (K. Bonham, pers. comm). However, any humidity changes resulting from this (and I believe there have been some because there are documented minor vegetation changes) have had no discernable impact on the snail in about 70 years since the dam was built.

The gorge is a major recreational reserve, the single most significant "park" for a large city. It is unlikely that its reserve status will be revoked. Currently there are no known threats to the species.

Citation: Bonham, K. 2006. Pasmaditta jungermanniae. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 20 December 2014.
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