Once plentiful on a tiny coral atoll in the Indian Ocean, the Aldabra banded snail (Rachistia aldabrae) was declared extinct in 1997 as one of the world’s first recorded direct casualties of climate change. But last month, a monitoring team found a population on one of the atoll’s islands, surprising the team and giving hope that other species whose habitats are being degraded by climate change may still be able to cling to existence.

 

The snail was named after the Aldabra atoll, a UNESCO World Heritage Site that is part of the island nation of Seychelles. It was declared extinct in a paper published in Biology Letters in 1997 after extensive searches turned up no evidence of the species’ existence. But on August 23, a staff member with Seychelles Islands Foundation (SIF) – the organization tasked with management and protection of Aldabra – chanced upon a peculiar snail on a native tree on the island Malabar.

 

The staff member showed the snail to Senior Ranger Catherina Onezia, and its identity was confirmed by mollusk expert Vincent Florens and prominent Seychelles naturalist Pat Matyot.

 

Scientists have linked human-caused climate change to shifting rain patterns in the Seychelles. In particular, the Aldabra Atoll has dried out significantly in the past few decades, wiping out suitable habitat for the moisture-loving snails.

 

The find gives hope for other island species on the precipice of extinction, according to SIF Chief Executive Officer Frauke Fleischer-Dogley.

 

 

PHOTO: The Aldabra banded snail (Rachistia aldabrae) is distinctive, with a dark purple shell encircled by pink rings. Photo by Catherina Onezia, SIF.