His death highlights a larger concern: Scientists estimate that 90 percent of terrestrial snail diversity on the Hawaiian Islands has been lost
On New Year’s Day, a little land snail named George died in his terrarium at the University of Hawaii. He was 14 years old—a robust age for his species, Achatinella apexfulva. But George’s passing nevertheless came as a blow to the researchers who have nurtured him. George was, after all, likely the last snail of his kind.
Scientists greeted George’s death “[w]ithout surprise, but with sadness,” Michael Hadfield, founder of a captive breeding program for Hawaii’s faltering snail populations, tells the CBC’s Carol Off. George’s death, Hadfield adds, marks “[t]he end of another species. And another is an important word there, because we’ve been watching these tree snails vanish from the forest for a long, long time now.”
Hawaii was once crawling with land snails—more than 750 species, in fact. According to the New York Times’ Julia Jacobs, 19th century documents say the critters hung off plants like bunches of grapes. Achatinella apexfulva was the first species to be described in by Western explorers when, in 1787, the British captain George Dixon was given a lei adorned with a Achatinella apexfulva shell.
Some 90 percent of Hawaii’s land snail diversity has since been lost, however. A major contributor to their decline are invasive species, like rats and the rosy wolfsnail (Euglandina rosea), which eats other snails. The rosy wolfsnail was brought to Hawaii in the 1930s to combat yet another invasive species, the giant African snail, but it has instead wreaked havoc upon Hawaii’s native molluscs. Habitat destruction and drier conditions caused by climate change are also reducing the snails’ available habitat.
According to Hawaii’s Snail Extinction Program (SEP), which was founded to monitor and protect threatened species, snails increase nutrient cycling of forest litter, and feed on fungus and algae that grow on their host plants. The decline in snail populations thus has dire implications for Hawaii’s ecosystems. And the situation has only gotten worse in recent years.
“We’ve had populations that have been monitored for over a decade, and they seemed stable… then, within the past two years they’ve completely disappeared,” David Sischo, a wildlife biologist with the Hawaii Department of Land and Natural Resources and coordinator of SEP, tells Christie Wilcox of National Geographic. “We’ve all broken down and cried in the field.”
In the hope of rescuing threatened snails from the brink of extinction, scientists began breeding rare species in captivity in the 1980s. The last known Achatinella apexfulva snails were collected on the island of Oahu in the 1990s, and George was one of several offspring they produced. All of the other snails eventually died, however, leaving hardy George as the lone survivor.
“He” is actually a hermaphrodite. Some hermaphroditic snails do not need a partner to reproduce, but Achatinella apexfulva isn’t one of them, so George spent years in his enclosure on his own. He is, in fact, named after Lonesome George, the last remaining Pinta Island tortoise who died in the Galapagos in 2012.
But George’s death may not spell the end of his species. His body is being preserved in alcohol, and according to Hawaii’s Department of Land and Natural Resources, scientists collected a snippet of tissue from his foot (the tapered end of the snail opposite his head) in 2017 to preserve for research. The hope is that with technological advances, and if steps are taken to preserve land snails’ habitat, George’s clones may one day re-populate the Hawaiian Islands.
Reprinted from Smithsonian.com
By Brigit Katz, smithsonian.com, January 14, 2019