Partulids on Tahiti: Differential persistence of a minority of endemic taxa among relict populations

The extinction of many species of endemic land snails in French Polynesia because of the introduction of the carnivorous snail Euglandina rosea is a salutary lesson in hasty biological control undertaken without adequate scientific field trials. Fewer than 20 of the original 70+ nominal species of the family Partulidae in French Polynesia survive. lu 2004 surveys were carried out in nearly 70 of the valleys of Tahiti. All of the populations found were of Partula hyalina, the closely related Partula clara, or Samoana attenuata. No individuals of the Partula otaheitana/Partula affinis complex were found, yet P. otaheitana, together with Samoana burchi, still survive in many montane forest areas (over 1000 m altitude), while P. affinis persists on the Peninsula of Tahiti. Partula nodosa, with a previous distribution of just 7 valleys, has most likely been extirpated in the wild but persists well in captive populations. The species Partula filosa, Partula producta, and Partula cytherea (each previously inhabiting a single valley) are almost certainly extinct, as is Samoana jackieburchi.