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article imageMeet the world's loneliest tree snail — Achatinella apexfulva

By Karen Graham     Sep 12, 2016 in Environment
The one and only member of a species of land snail that called the Hawaiian island of Oahu home now lives quietly in the conservation lab of the University of Hawaii. Nine years old, the snail has not reproduced and scientists don't know if it ever will.
The sole specimen of Achatinella apexfulva, a grayish-white tree snail once abundant on the island of Oahu is a sad symbol of just how ill-equipped we humans really are in the face of the loss of a species.
A. apexfulva lives in its own terrarium in what the University calls a "snail ark" in a single room on the University’s main Manoa campus on the outskirts of Honolulu. The ark is composed of six environmental chambers, looking like large refrigerators. It is in here that staff are able to control temperature, light and humidity around the clock.
Achatinella apexfulva apicata Newcomb  1855.
These specimens have been preserved.
Achatinella apexfulva apicata Newcomb, 1855. These specimens have been preserved.
Naturalis Biodiversity Center/Wikimedia Commons
Once every two weeks the slimy inhabitants are taken out of their individual homes and the terrariums are sterilized. The snails require local vegetation and their special diet of matt fungi that grows on the bark and leaves of the native trees. There is even a hose and sprinkler system to provide a little "rainfall" every eight hours.
Tree snails are hermaphrodites, having both male and female reproductive organs, and usually, produce one to four offspring a year after reaching maturity. The baby snails are born live with their tiny shells intact. Most Oahu tree snails will attach to the leaves of one tree and stay on that tree for the rest of their lives, which can a long time.
Hawaii is sometimes called the "extinction capital of the world," and with good reason. A recent study found that most of the forest birds native to the island of Kauai have reached that dangerous tipping point that means we will be seeing multiple extinctions in the next few decades.
Achatinella bulimoides. This snail was thought to be extinct for the past 20 years until the Army re...
Achatinella bulimoides. This snail was thought to be extinct for the past 20 years until the Army rediscovered it in Oahu's Ko'olau Mountains.
Army Environmental Update
At one time, about 750 species of terrestrial snails used to flourish in Hawaii, with most of them sporting colorful ringed shells about 2.0 centimeters (0.787 inches) long. Now, we may be lucky to find 45 to 50 species. “All are rapidly plunging to extinction. They will be gone in five to 10 years,” says Melissa Price at the University of Hawaii, according to New Scientist.
The U.S. Fish and Wildlife Service lists 1539 species of flora and fauna endemic to the United States that are endangered and threatened with extinction. Fully one-third of those species are found in Hawaii, including the monk seal, the hoary bat, many bird species and Oahu's tree snails.
O ahu tree snail shells collected ca. 1933 at an elevation of 1500 feet on Waialae Ridge in Honolulu...
O'ahu tree snail shells collected ca. 1933 at an elevation of 1500 feet on Waialae Ridge in Honolulu, Hawaii, Waialae Country Club.
William Pearl
Factors that have driven the extinction of Oahu's tree snails
Surprisingly, if you thought of climate change as being a major factor, you would be wrong, but it is man that has led to the demise of the terrestrial snails. One reason is the greed of collectors, with the best example being John Thomas Gulick, a 19th-century rival of Charles Darwin, who himself took over 44,000 snails for his personal collection.
The addition of invasive species is also on the list of reasons for the extinction of the snails. Polynesian settlers brought their rats along with them 1,000 years ago, and later, in the 1800s, the Europeans brought their rats, too. And rats love to eat snails.
And human blunder also played a role. In the 1950s, Euglandina rosea, a predatory snail from Florida was introduced to combat the giant African land snail, Achatina fulica that was a plant pest. But E. rosea, being carnivorous wasn't discriminating in what it ate and within one year of its introduction, many of the indigenous Oahu tree snails were hunted to extinction.
The land-snail  Euglandina rosea  at The Mounds Park  Tallahassee FL. These land snails were brought...
The land-snail, Euglandina rosea, at The Mounds Park, Tallahassee FL. These land snails were brought into Hawaii to combat the African land snail that was eating plants, but they ate the Oahu tree snails.
Tim Ross
“Hawaii is very underfunded for conservation,” says David Sischo, Hawaii’s snail extinction prevention program coordinator. “It gets a small proportion of funds and much of the money goes to large charismatic species like seabirds and monk seals, not slimy invertebrates.”
More about Hawaii, Oahu, less than 50 species, Achatinella apexfulva, tree snails
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