The Fauna

Native Pacific island biotas are disappearing rapidly. A major and relatively well-known component of the island faunas are the land snails, which are recognized especially for their high diversity and high levels of endemism. But they are also recognized for being under severe threat from human activities including habitat destruction and introduction of alien predators. The tree snails in the family Partulidae, for example, have been termed the "flagships of terrestrial invertebrate conservation in the Pacific" (Cowie & Cook, in press) because of the recent drastic decline and extinction of many species. Many nonindigenous snail species are being introduced, replacing the native species, and leading to a homogenization of land snail faunas across the Pacific and more widely.

The land snail fauna of the Samoan archipelago is no exception. As recognized in a comprehensive nomenclatural catalog of the Samoan snails and slugs (see the list of publications of the Samoan Snail Project), developed as the first step in the present assessment of the fauna, there are (or were) 94 recognized native land snail species. Of these 94 species, 59 are endemic to the archipelago, with 34 of these 59 recorded from only single islands. The catalog also listed 18 species of nonindigenous snails and slugs, most of them widespread synanthropic species.

Threats to the Fauna

  1. Habitat destruction for traditional and modern agriculture.
  2. Deforestation.
  3. Shell collecting for ornamental use.
  4. Introduced predators (rats, predatory snails, predatory flatworms).
  5. Urban encroachment on habitat.
  6. Habitat modification by alien plants.

Funding Sources

The Samoan Snail Project is supported by the National Science Foundation under Grant No. DEB 9705494. Additional funding has come from the U.S. Department of the Interior National Parks Service, the U.S. Geological Survey Biological Resources Division, and the Bishop Museum. Any opinions, findings and conclusions or recomendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF) or any other funding source.