The diet of the introduced carnivorous snail Euglandina rosea in Mauritius and its implications for threatened island gastropod faunas

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Abstract

Euglandina was collected over a three-year period in four habitat types in Mauritius. Smaller collections were also made in Reunion and Rodrigues. The areas in which the Euglandina were collected were simultaneously sampled for potential prey species. Identification of the stomach contents and comparison with the available prey shows that most prey are eaten whole and that native species are eaten in greater numbers that would be expected form a consideration of their numbers in the habital. Achatina spp., which Euglandina was originally introduced to control, was not positively identified in the diet. Even if all unidentified prey fragments were form Achatina then this would form less than 5% of the total number of items in the stomachs.

Habital destruction, together with predation by Euglandina, appear to be major contributors to the extinctions of native Mauritian snails. The conservation of primary forests, into which Euglandina has not penetratd, is suggested as the most effective way to save the remaining endemic ground-dwelling snails form extinction. These results add further emphasis to the importance of preventing introductions of Euglandina to areas with native snail faunas, and show clearly that this predator is not a successful control agent for Achatina.

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