Print PageWe studied impacts of the introduced small Indian mongoose Herpestes auropunctatus on native reptiles and amphibians, native small mammals and the introduced ship rat Rattus rattus on six islands in the Adriatic Sea, Croatia, comparing abundances and activity times on three islands with the mongoose to those on three islands without it. We used four types of sampling surveys: distance-constrained surveys, visual encounter surveys, special searches and trapping.
Results/Conclusions
The horned viper Vipera ammodytes and Balkan green lizard Lacerta trilineata were absent from two mongoose-infested islands (Korčula and Mljet) and rare on the third (Hvar); they were common only on the mongoose-free island where they had historically been present (Brač). The European green toad was absent from one mongoose-infested island, where it had historically been present, and rare on the other two. It was common on two of the three mongoose-free islands. Most herpetofaunal species also occur on the mainland but are already scarce there; some are protected under Appendix II of the Berne Convention. Small mammal species were either scarce or completely absent on the three mongoose-infested islands but present on mongoose-free islands. Our findings support a large but mostly speculative literature that suggests the small Indian mongoose does not control introduced R. rattus populations. However, we found that R. rattus is solely nocturnal on islands infested with the mongoose, possibly to avoid predation. The recent spread of the mongoose to the European mainland suggests the need for urgent control to protect vulnerable native species.
