2017 Partula expedition
Partula tree snails and the Euglandina threat
Partula snails Partula conservation Euglandina

Planned Partula 2017 research expedition by Justin Gerlach

For many years Partula snail conservation seemed like a hopeless task, with no prosect of eliminating their Euglandina predators and little hope of re-establishing the tree-snails in the wild. This has now changed, with experimental reintroductions of several species. Current data suggest that some of these may be successful, as long as predator populations remain low. We don't know what determines the occasional reappearance of the predators, and this is a point that needs urgent investigation.

I am intending to answer this question by re-examining the status of the predators in Polynesia. My planned 2017 Partula expedition will investigate the ecology of the predators (the Euglandina snail and the Platydemus flatworm) and survey the surviving wild Partula populations. Excellent work has been done by Trevor Coote in monitoring populations for many years, especially on Tahiti and Moorea. In addition to the monitored populations there are isolated records of survivors of a few other species. I intend to search for as many of these as possible, in the hope that some continue to survive and could be protected from the predators. Islands to be visited and species to be searched for are:

  • Tahiti - four species have been reported from high-altitude sites in the past 20 years: Partula compressa (overlooked since 1884 but a population was found in 1997), Partula cytherea (recent shells of a misidentified population were found in the 1990s), Partula jackieburchi (high-altitude populations may have been misidentified), Partula laevigata (overlooked since the 1840s, until a population was found in 1997 but misidentified until now), in addition to the monitored populations of Partula affinis, Partula clara, Partula hyalina, Partula otaheitana, Samoana attenuata, Samoana burchi, Samoana diaphana
  • Moorea - monitored populations of Partula taeniata, Samoana attenuata
  • Huahine - Samoana annectens was photographed from the top of the island in 1995
  • Raiatea - Partula meyeri was discovered on the highest peak of the island in 1997, Samoana attenuata has been photographed twice
  • Tahaa - no reported survivors but Partula sagitta was a canopy species and could have survived
  • Bora-Bora - no reported survivors
  • Maupiti - only reports are shells of an unidentified species

    Many of the important sites are high forest areas, rarely visited as it is difficult to climb up to them. Some can only sensibly be reached by helicopter. If you wish to support this project please contact Justin Gerlach