Island restoration: Exploring the past, anticipating the future

Abstract

Predator control and eradication of introduced mammals affecting seabird populations has greatly accelerated since pioneering efforts by New Zealand biologists in the 1970s. The resulting dramatic recovery of seabirds inspired further research and more eradications on larger islands and helped set the Conservation Agenda for the 1990's: Removal of Alien Predators from Seabird Colonies by the Pacific Seabird Group, which in turn helped identify islands of the highest priority from which introduced organisms should be removed. That effort facilitated a number of eradication successes from smaller seabird islands in Mexico, Hawaii and the tropical Pacific, and the removal of Arctic foxes from the Aleutian Island Archipelago. Complete eradication was successful for large herbivores, rabbits, foxes and feral cats, but the eradication of rodents presented the greatest challenge. The development of a second-generation anticoagulant, brodifacoum. enhanced the rate of successful eradications and allowed larger areas to be cleared. By 2002, technical confidence developed to the point where sub-Antarctic Campbell Island (11 300 ha) was successfully treated with bait dispersed from helicopters. Many remaining potential eradication programs are challenged by remote locations, extreme weather, complex ecosystems, non-target species, proximity to human habitation, toxicant resistance, compliance with environmental regulations, opposition by animal rights advocates, and inadequate funding sources for large-scale programs. Once eradications are complete, monitoring and quarantines need to be guaranteed. Future techniques to exploit are fencing for large mainland areas and control or eradication of the enclosed pests, with exclusion of reinvasions. Finally, the use of biocontrol through genetic engineering and disease holds promise.