Sunday, November 14, 2010

Will climb mountains for land snails

Our intrepid terrestrial malacologist, Collections Manager John Slapcinsky, recently returned from climbing the highest peak on Moorea- the mountain Tohiea.  

Much of the climb is near-vertical, but pays off in the form of an isolated patch of forest, largely protected from the invasive species that dominate the lowlands of this and most other tropical islands.  This area is high enough to be in the path of many clouds, so the vegetation is moist and can be considered "cloud forest".  

The view is spectacular, but so are the relict populations of snails that are now gone from much of the island below.  One family of land snails, the Partulidae, was believed to be extinct until small relict populations were located at locations similar to this one.  

In the late sixties an African landsnail Achatina fulica was introduced to the island.  This species was perceived as a threat to agribusiness, and a biological control entity was sought.  In order to control this species, as second snail, the predator Euglandina rosea, was imported from Florida.  Euglandina had a rapid and terrible impact on the snails of Moorea- and bypassed the Achatina.  The genus of native tree-snail, Partula, which was common, diverse, culturally important, and the subject of decades of population research was chased across the mountain side in a loosing battle.  The genus was declared extinct in the wild in 1988.

Our lab is happy to confirm reports that small populations of these snails still exist in the wild.  Though they may never be as common as they were, at least they are still around.


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