Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract Full Text

Plans to eradicate invasive mammals on an island inhabited by humans and domestic animals (Corvo, Azores, Portugal).


Non-native invasive mammal species have been eradicated from many islands to conserve native species diversity. The Azores (Portugal) previously hosted very large seabird colonies, but since human colonization and the introduction of rodents (Rattus rattus and R. norvegicus) and cats (Felis catus) many seabird colonies have declined or disappeared as a result of predation. Because the Azores are also inhabited by humans and livestock, we reviewed the challenges associated with the eradication of invasive mammals from inhabited islands in order to plan for a seabird restoration project on the island of Corvo. Detailed analyses of the social, cultural, and economic costs and benefits of eradication are required to increase the probability of the local community supporting the eradication campaign. However, the ecological benefits of eradication are difficult to trade-off against social and economic costs due to the lack of a common currency. Local communities may oppose an eradication campaign because of perceived health hazards, inconvenience, financial burdens, religious beliefs, or other cultural reasons. Besides these social challenges, the presence of humans and domestic animals also complicates eradication and biosecurity procedures. For example, houses, garbage-disposal areas, and livestockfeeding areas can provide refuges for many synanthropic species and so decrease the probability of a successful eradication. Transport of humans and goods to an island increases the probability of inadvertent reintroduction of invasive mammals, and the establishment of permanent quarantine measures is required to minimize the probability of unwanted recolonization after eradication. Most of these challenges exist on Corvo, and continued work with the community is required before an eradication project can be initiated.