The rat species introduced to the Hawaiian Islands are among the most noxious species on islands worldwide.
So it stands to reason that rat eradication would be a good thing…or does it?
A study of Rattus rattus, the most abundant species in Hawaiian conservation areas, indicates they dine not only on native plants and snails, but on destructive non-native snails as well.
University of Hawaiʻi at Mānoa PhD candidates Wallace Meyer (zoology) and Aaron Shiels (botany) captured rats in Oʻahu’s Waiʻanae mountains and collected both voracious giant African snails and the smaller Euglandina rosea snails introduced to control them.
In laboratory feeding trials, the rats showed a definite taste for the mollusks. Moreover, resulting damage to the snail shells was consistent with damaged non-native snail shells observed in the wild.
Conservation managers should proceed cautiously lest rat control efforts result in a surge in non-native snail populations that prey on native plant and snail species, they write in the July 2009 issue of Pacific Science.