Paul Buzzard, Ph.D., is the Director of Conservation for the Detroit Zoological Society.
For nearly three decades, the Detroit Zoological Society (DZS) has been breeding a species of Tahitian land snails called Partula nodosa in an off-exhibit area as part of a collaborative effort credited with saving the species from extinction. Recently, 100 of these snails were carefully packaged and delivered to Detroit Metropolitan Airport to embark on a very special trip, returning the species to the tropical island of Tahiti in the south Pacific.
Beginning in 1989 as a project with 115 Tahitian land snails of five different species, the DZS focused its efforts on one species, P. nodosa. At one point all the P. nodosa in the world lived at the Detroit Zoo. Our efforts and successful breeding of the snails resulted in the rescue and recovery of the species – currently there are 6,000 individuals living in North American zoos, all descendants from the Detroit Zoo’s original small group.
P. nodosa snails are interesting because along with other Partulid snails, they were once found across Tahiti and other south Pacific islands in a dazzling array of more than 125 different species. These beautifully striped snails were important in the ceremonial jewelry and decorations of native islanders, and the snails served as an ideal study group to learn more about the evolution of diversity.
Much of the Partulid snail diversity was lost however, because of a botched attempt at what is known as “biological control”, or the control of a pest by the introduction of a natural enemy or predator. In 1967, giant African land snails were introduced to Tahiti and other south Pacific islands to serve as a source of protein for local people. However, some African snails escaped, bred very rapidly, and began eating farmers’ crops, threatening the local economy. To control the African snails, Florida rosy wolf snails were introduced a decade later, but the wolf snails preferred to eat the Partulid snails, which caused the extinction of many of the Partulid species.
Thankfully, before complete extinction, P. nodosa snails were placed at several zoos including the Detroit Zoo, where they’ve been maintained off-exhibit in a collaborative effort of the Bird, Reptile and Amphibian departments. Now that the captive population has grown sufficiently and a protected area has been established on Tahiti, we can officially say that this species has been saved.
– Paul Buzzard