Invasive mammal eradication on islands results in substantial conservation gains

Abstract

More than US$21 billion is spent annually on biodiversity conservation. Despite their importance for preventing or slowing extinctions and preserving biodiversity, conservation interventions are rarely assessed systematically for their global impact. Islands house a disproportionately higher amount of biodiversity compared with mainlands, much of which is highly threatened with extinction. Indeed, island species make up nearly two-thirds of recent extinctions. Islands therefore are critical targets of conservation. We used an extensive literature and database review paired with expert interviews to estimate the global benefits of an increasingly used conservation action to stem biodiversity loss: eradication of invasive mammals on islands. We found 236 native terrestrial insular faunal species (596 populations) that benefitted through positive demographic and/or distributional responses from 251 eradications of invasive mammals on 181 islands. Seven native species (eight populations) were negatively impacted by invasive mammal eradication. Four threatened species had their International Union for the Conservation of Nature (IUCN) Red List extinction-risk categories reduced as a direct result of invasive mammal eradication, and no species moved to a higher extinction-risk category. We predict that 107 highly threatened birds, mammals, and reptiles on the IUCN Red List-6% of all these highly threatened species-likely have benefitted from invasive mammal eradications on islands. Because monitoring of eradication outcomes is sporadic and limited, the impacts of global eradications are likely greater than we report here. Our results highlight the importance of invasive mammal eradication on islands for protecting the world's most imperiled fauna.conservation | restoration | invasive species | island | eradication T he rate of global species decline and extinction is rapid and likely to increase (1-4), although at least US$21.5 billion is spent annually worldwide on conservation of biodiversity (5). Improving conservation outcomes has focused largely on highlevel increases in efficiency, including the distribution of funding across countries (5), or on identifying the ecoregions, habitats, and species most in need (6). Although great strides have been made in promoting evidence-based conservation (7), systematic evaluations of the effectiveness of different actions taken to protect biodiversity at the global scale are rare, with the exception of protected areas (8).Islands occupy ∼5.5% of the terrestrial surface area but contain more than 15% of terrestrial species (9), 61% of all recently extinct species, and 37% of all critically endangered species on the International Union of the Conservation of Nature (IUCN) Red List (10). Invasive nonnative mammals (hereafter, "invasive mammals") are the main cause of animal extinctions on islands and are one of the most important threats to remaining insular biodiversity (10-12). Eradicating invasive mammals from islands is an increasingly common conservation tool and has been ...

Estimating Burdens of Neglected Tropical Zoonotic Diseases on Islands with Introduced Mammals

“…64,65 There has been substantial recent attention investigating the relationship between biodiversity and human health, 26,66 but there are few concrete examples of the potential for synergistic interventions that benefit both. 67,68 However, the biodiversity benefits of eradicating introduced mammals from islands has been well documented, 55,69 and our study enables a way to connect these biodiversity benefits to improve public health. …”

“…Specifically eradications are currently feasible on islands with population sizes less than approximately 1,000 people. 55 A substantial fraction of the islands that are therefore suitable for management were less populous than the range of islands in the dataset we used to fit the models. As a result, these extrapolated predictions should be used in planning with extreme caution and, as with all our predicted estimates, should be verified by on-the-ground measurement before any rigorous cost-benefit analyses are undertaken.…”

Invasive predators and global biodiversity loss

“…Given the many islands on which invasive predators occur and the high costs involved in controlling or eradicating them, prioritization of islands for eradications is an important exercise (30)(31)(32)(33). Facilitation between multiple invasive species (e.g., rodents providing abundant food for cats, thus maintaining high densities of the latter) can exacerbate their respective impacts on native species (1,9).…”

Staat van de natuur van Caribisch Nederland 2017 : een eerste beoordeling van de staat (van instandhouding), bedreigingen en managementimplicaties van habitats en soorten in Caribisch Nederland

“…Sindsdien hebben vele anderen de zeer kwalijke gevolgen van exotische grazers op eilandelijke ecosystemen aangetoond (Gould en Swingland, 1980;Debrot en De Freitas, 1993;Fernández-Lugo et al, 2009;Carrion et al, 2011). In een recente wereldwijde evaluatie van 251 campagnes voor de ruiming van invasieve zoogdieren op eilanden, wordt geconcludeerd dat verwijdering daarvan bijna altijd tot snel en effectief natuurherstel heeft geleid (Jones et al, 2016).…”