The Extinction of Endemic Species by a Program of Biological Control

Abstract

Land snails of the genus Partula, inhabiting the high islands of the
\nPacific Ocean, have provided exceptional opportunities for studies oil the origin
\nand differentiation of species: The endemic taxa of Moorea, in French Polynesia,
\nhave been particularly well studied.
\nIn an attempt to control the numbers of the giant African snail, Achatina
\nfulica, which is an agricultural pest, a carnivorous snail, Euglandina rosea; has
\nbeen introduced into Moorea. It is spreading across the island at the rate of about
\n1.2 km per year, eliminating the endemic Partula. One species is already extinct
\nin the wild ; and extrapolating the rate of spread of Ezigltmdina , it is expected that
\nall the remaining taxa (possibly excepting P. exigua) will be eliminated by
\n1986-1987.
\nEuglandina has been introduced into many other oceanic . islands, and it
\nappears that more than a hundred endemic species are at risk . These observations
\npoint to a serious danger in programs of " biological control. "