來源： Lee et al. 2008
Following the deliberate introduction of the alien carnivorous snail E. rosea on Raiatea in 1986 for misguided biological control purposes (of another alien mollusc, the giant African land snail Achatina fulica), native tree snail populations collapsed, prompting the emergency 1991 establishment of off-island captive populations for five (Partula dentifera, P. faba, Partula hebe, Partula tristis and Partula turgid) of the 33 single-island endemic taxa, in addition to follow-up surveys of the island by the International Partulid Conservation Programme in 1992, 1994 and 2000 (Coote & Loeve 2003, in Lee et al. 2008). However, the Raiatean endemic P. turgid experienced sequential culture failure in captivity, culminating in its extinction in 1996 (Cunningham & Dasak 1998). No living snails were encountered in the 2000 survey, leading to the conclusion that only the four surviving captive taxa remained extant (Coote & Loeve 2003, in Lee et al. 2008). However, in early February 2006 a botanical and entomological field expedition to Raiatea led by J-YM encountered two relict populations of partulid land snails on Mount Tefatua (also called Mount Toomaru), the highest peak on the island. The 2006 two surviving Raiatean partulid lineages (Samoana attenuata and Partula
Meyeri) were discovered on the upper slopes of Mount Tefatua.
The unexpected discovery of these two surviving montane populations raises the possibility of preserving some fraction of Raiatea’s endemic tree snail diversity in the wild (Lee et al. 2008).
Despite its relatively advanced age (2.5 to 3.2 MYA) within the archipelago, Raiatea has retained a high island profile (maximum altitude 1 017 m), and its size (171 km2) is second only to the much younger Tahiti. These geological characteristics may have promoted the evolution of Raiatea’s exceptionally rich partulid tree snail fauna comprising 34 species, all but one being single-island endemics (Kondo 1968, in Lee et al. 2008). This endemic malacofauna represents c. 25% of partulid nominal species diversity, a remarkable fraction for one oceanic island considering that the family Partulidae ranges over 10 000 km of Oceania from Belau and the Marianas in the north-west to the Marquesas, Austral and Society Islands in the south-east (Cowie 1992, in Lee et al. 2008).
降低本地生物多樣性: The greatest single loss of Society Island tree snail diversity occurred on Raiatea, French Polynesia (Coote & Loeve 2003).
最後修改 ： 9/03/2010 3:06:15 p.m.