[1] It has been estimated there are about 100 species of land snail on Guam, the southernmost Mariana Island, but about 20 of these have been introduced by human activities.
[1] Nearly all of the native species of land snail are in decline throughout the Mariana Islands, and many have not been seen for decades.
The southern islands of the Mariana archipelago are now almost devoid of native land snails.
Since then, all three of these species are now reduced by another biocontrol, the New Guinea flatworm (Platydemas manokwari), which is also predating native snails.
[1] The tiny islet of Alupat off Guam has been identified as a potential site for a snail preserve, as it has not been invaded by New Guinea flatworms, rosy wolfsnails, or Gonaxis snails.