Management of cats and rodents on inhabited islands: An overview and case study of Fernando de Noronha, Brazil

Abstract

In this paper, an overview of introduced cat and rodent impacts on islands, and methods for their control and eradication, are presented. Fernando de Noronha, an inhabited oceanic island of Brazil, is used as a case study to illustrate the challenges of cat and rodent management on inhabited islands. Cat impacts have been recorded for 175 vertebrate species, and rat impacts for 173 plant and animal species. Eradication of cats and rodents for species conservation has been successful on small to medium- sized uninhabited or sparsely inhabited islands. However, examples of successful cat and rodent management programmes for biodiversity on inhabited islands are limited. On inhabited islands localised control of cats and rodents occurs, but historically with a focus on agriculture, human livelihoods and animal welfare, and only more recently on native species conservation. Control of cats and rodents on inhabited islands for species conservation lags behind uninhabited islands and the reasons for this are social and complex. Conservation managers often perceive a lack of support from island residents or administrators, which may or may not actually be the case. Where support does not exist, it may relate to the provisioning of control versus eradication, the techniques proposed, or wider socioeconomic issues. This ultimately translates to conservation inaction, and the ongoing decline and extinction of island fauna. Abundance estimates for cats and density estimates for rats on Fernando de Noronha are presented, along with documented biodiversity impacts, to support recommendations for future management on Fernando de Noronha.

Keywords

• Conservation
• Control
• Eradication
• Invasive
• Mice
• Rats