Today's post is intended to give voice to the native tree snails of Oahu, genus Achatinella. I hope you become as enamored as I am with these "jewels of the forest." Once abundant throughout Oahu, this genus of forty-one species of endemic, nocturnal snails has suffered from a "perfect storm" of events that has caused the loss of at least half to extinction, with the rest endangered or critically endangered. Those that remain cling to life on isolated ridges in the Ko‘olau and Wai‘anae ranges. They are small wonders indeed; all species are just around two centimeters long, with beautiful coloration and patterning that varies from species to species. As their name suggests, they are arboreal, but do little damage to the native trees that they prefer. Instead, they dine on a fungus that grows on the leaves, which may actually help the trees to photosynthesize. Achatinella young develop in eggs inside the mother, then are born live. They live for as many as ten years, but their reproductive capacity is low. For example, Achatinella mustelinadoes only produces four to seven offspring a year, and this occurring only after sexual maturity is reached, between ages three to five.
As you can imagine, their slow growth rate and fecundity would make them a vulnerable species. Recovery would be extra tough after any event that would reduce their numbers. And there have been several. For years they were over-collected for their beautiful shells. Add to that the loss of much of their native habitat to farming and other human activities. If that isn't enough, we opened the door to one of their most dreaded predators: the carnivorous rosy wolf snail. Introduced in 1955 to combat the Giant African snail, the rosy wolf snail decided that the smaller, native snails tasted a lot better. Rats have also taken their toll on the population. But instead of throwing their hands up in the air, some have come to the snail's rescue, including The Hawaiian Tree Snail Conservation Lab, whose main goal is to care for rare Hawaiian tree snails and breed them in captivity. Nine species of Achatinella are under their loving care. Also fighting the good fight is the U.S. Fish and Wildlife Service and the Oahu Army Natural Resources Program (OANRP), who are involved with the effort to build snail refuges with elaborate "exclosure" systems to keep predators out. I, for one, am grateful for their efforts to save these jewels, and for the important lesson that sometimes, big things come in small packages.
welcomes you to visit with the all the wonderful flora and fauna that we share this lovely aina with.