Pacific rats

Think of a challengeing conservation problem you have encounteres - protecting a rare species, winning support for legislation, cleaning up a river, or sustainably managing a forest.

The study of dispersal processes of small mammals, and especially of rodents, has a wide range of applications and until recent years there were few publications discussing the

The three most invasive rat species, black or ship rat Rattus rattus, brown or Norway rats, R. norvegicus and Pacific rat, R. exulans have been incrementally introduced to islands as humans have explored the world’s oceans. They have caused serious deleterious effects through predation and competition, and extinction of many species on tropical islands, many of which are biodiversity hotspots. All three rat species are found in virtually all habitat types, including mangrove and arid shrub land.

The restoration of the small offshore islands of Nu’utele (108ha) and Nu’ulua (25ha) has long been identified as a priority for biodiversity conservation in Samoa. The first step towards restoration was the aerial spreading of brodifacoum to eradicate Pacific rats (Rattus exulans) in August 2009. Procedures for the eradication followed those used in New Zealand and involved technical experts from that country.

Several aspects of the ecology of Rattus exulans are reviewed in an effort to collate a large proportion of the widely scattered literature relating to the species. Subspecific relationships are discussed to illustrate the early confusion regarding taxonomic position. Literature convening R. exulans geographic distribution, habitat, nutrition, reproduction, movements, and competition with other species of Rattus, is reviewed and discussed.