Past and estimated future impact of invasive alien mammals on insular threatened vertebrate populations

Abstract

Invasive mammals on islands pose severe, ongoing threats to global biodiversity. However, the severity of threats from different mammals, and the role of interacting biotic and abiotic factors in driving extinctions, remain poorly understood at a global scale. Here we model global extirpation patterns for island populations of threatened and extinct vertebrates. Extirpations are driven by interacting factors including invasive rats, cats, pigs, mustelids and mongooses, native species taxonomic class and volancy, island size, precipitation and human presence. We show that controlling or eradicating the relevant invasive mammals could prevent 41–75% of predicted future extirpations. The magnitude of benefits varies across species and environments; for example, managing invasive mammals on small, dry islands could halve the extirpation risk for highly threatened birds and mammals, while doing so on large, wet islands may have little benefit. Our results provide quantitative estimates of conservation benefits and, when combined with costs in a return-on-investment framework, can guide efficient conservation strategies.

Ecological effects of non‐native species in marine ecosystems relate to co‐occurring anthropogenic pressures

“…Our findings support an existing theory that anthropogenic stressors can exacerbate the effects of non-native species (Byers, 2002), as the overall effect of non-native species on native biodiversity became negative as human population density increased, which was most evident in areas with high cumulative human im- In this study, we performed a global assessment of concomitant effects of anthropogenic stressors and non-native species, which have been suggested to act synergistically (Byers, 2002). For instance, highly populated areas are associated with many impacts impact of non-native species on islands; Doherty et al, 2016;McCreless et al, 2016) and invasion meltdown (i.e., introduced species facilitate one another's establishment, spread, and impacts; (Simberloff, 2006 (Figure 4). Improvement of predictive models will occur as more quantitative data on the effects of non-native species can be included and as human footprint proxies measured at global scales become more accurate (i.e., global estimates of non-native richness exist only at marine providence scales) and…”

Global mapping of cost‐effective microalgal biofuel production areas with minimal environmental impact

“…For minimizing impacts on biodiversity, the selected attribute corresponded to the biodiversity value. Biodiversity value was based on the number of vertebrate species and the number of threatened vertebrate species (i.e., considering amphibians, birds, and mammals) (Jenkins, Pimm, & Joppa, ), the presence of islands (which harbor higher proportions of endemic and threatened species compared to the mainland) (McCreless et al, ; Tershy, Shen, Newton, Holmes, & Croll, ), and the presence of areas with low human pressures (which is related to the integrity of ecosystems) based on the Global Human Footprint (Venter et al, ). Water bodies (Lehner & Döll, ), protected areas (UNEP‐WCMC, ), Key Biodiversity Areas (BirdLife International, ), and urban areas (i.e., based on built areas) (Schneider, Friedl, & Potere, ) were assumed to be unsuitable for microalgal cultivation and excluded from final suitability maps (i.e., assigning No Data to water bodies and zero to the other layers).…”

Invasive alien species on islands: impacts, distribution, interactions and management

“…Courchamp et al 2003;Jones et al 2016;McCreless et al 2016). Reaser and colleagues (2007) comprehensively reviewed the ecological and socioeconomic impacts of IASs on islands.…”