Invasive alien species are a major threat to native insular species. Eradicating invasive mammals from islands is a feasible and proven approach to prevent biodiversity loss. We developed a conceptual framework to identify globally important islands for invasive mammal eradications to prevent imminent extinctions of highly threatened species using biogeographic and technical factors, plus a novel approach to consider socio-political feasibility. We applied this framework using a comprehensive dataset describing the distribution of 1,184 highly threatened native vertebrate species (i.e. those listed as Critically Endangered or Endangered on the IUCN Red List) and 184 non-native mammals on 1,279 islands worldwide. Based on extinction risk, irreplaceability, severity of impact from invasive species, and technical feasibility of eradication, we identified and ranked 292 of the most important islands where eradicating invasive mammals would benefit highly threatened vertebrates. When socio-political feasibility was considered, we identified 169 of these islands where eradication planning or operation could be initiated by 2020 or 2030 and would improve the survival prospects of 9.4% of the Earth’s most highly threatened terrestrial insular vertebrates (111 of 1,184 species). Of these, 107 islands were in 34 countries and territories and could have eradication projects initiated by 2020. Concentrating efforts to eradicate invasive mammals on these 107 islands would benefit 151 populations of 80 highly threatened vertebrates and make a major contribution towards achieving global conservation targets adopted by the world’s nations.

Estimating population size of a nocturnal burrow-nesting seabird using acoustic monitoring and habitat mapping. Nature Conservation 7: 1-13. doi: 10.3897/natureconservation.7.6890 Abstract Population size assessments for nocturnal burrow-nesting seabirds are logistically challenging because these species are active in colonies only during darkness and often nest on remote islands where manual inspections of breeding burrows are not feasible. Many seabird species are highly vocal, and recent technological innovations now make it possible to record and quantify vocal activity in seabird colonies. Here we test the hypothesis that remotely recorded vocal activity in Cory's shearwater (Calonectris borealis) breeding colonies in the North Atlantic increases with nest density, and combined this relationship with cliff habitat mapping to estimate the population size of Cory's shearwaters on the island of Corvo (Azores). We deployed acoustic recording devices in 9 Cory's shearwater colonies of known size to establish a relationship between vocal activity and local nest density (slope = 1.07, R 2 = 0.86, p < 0.001). We used this relationship to predict the nest density in various cliff habitat types and produced a habitat map of breeding cliffs to extrapolate nest density around the island of Corvo. The mean predicted nest density on Corvo ranged from 6.6 (2.1-16.2) to 27.8 (19.5-36.4) nests/ha. Extrapolation of habitat-specific nest densities across the cliff area of Corvo resulted in an estimate of 6326 Cory's shearwater nests (95% confidence interval: 524). This population size estimate is similar to previous assessments, but is too imprecise to detect moderate changes in population size over time. While estimating absolute population size from acoustic recordings may not be sufficiently precise, the strong positive relationship that we found between local nest density and recorded calling rate indicates that passive acoustic monitoring may be useful to document relative changes in seabird populations over time. RESEARCH ARTICLE Launched to accelerate biodiversity conservation A peer-reviewed open-access journalSteffen Oppel et al. / Nature Conservation 7: 1-13 (2014) 2

The foraging plasticity in a pelagic seabird species, Cory's shearwater Calonectris diomedea, was compared during incubation and chick-rearing among 7 different breeding sites in the North Atlantic. These sites, with contrasting ecological conditions, were situated in the Azores (Corvo, Faial, Graciosa and Sta. Maria), Berlengas (Berlenga), Madeira (Desertas) and Selvagens (Selvagem Grande) archipelagos. Behavioural data were obtained by intensively deploying compasstemperature and temperature-depth data loggers, monitoring 302 and 22 foraging excursions, respectively. A principal component analysis revealed 2 main groups, one foraging along a neritic shelf (Berlengas population) and the other foraging in pelagic oceanic areas (populations from Azores, Madeira and Selvagens). There was a significant positive correlation (r S = 0.55) between the percentage of short foraging trips in the different breeding sites and the concentration of chlorophyll-a in the waters surrounding those sites. Birds exploiting neritic areas used shallower depths (4.9 ± 2.3 m) and shorter dives (17.0 ± 2.2 s) than birds feeding in oceanic waters (9.8 ± 2.4 m and 32.0 ± 5.8 s respectively). This indicates that birds adapted their modes of predation to cope with the diverse distribution of their prey items. Overall, the behavioural response of the different populations was mainly dictated by the heterogeneity of their habitat, which was driven by 2 productivity gradients present in the north Atlantic. (1) Productivity is expected to increase from the subtropical warmer waters close to Selvagens to northern colder waters north of the Azores archipelago. (2) Oceanic environments are expected to be less profitable than coastal areas (upwelling areas), such as the Portuguese and African coasts. KEY WORDS: Data loggers · Ecological plasticity · Environmental heterogeneity · Foraging behaviour · SeabirdResale or republication not permitted without written consent of the publisher

Abstract1. Effective prevention and control of invasive species generally relies on a comprehensive, coherent and representative list of species that enables resources to be used optimally. European Union (EU) Regulation 1143/2014 on invasive alien species (IAS) aims to control or eradicate priority species, and to manage pathways to prevent the introduction and establishment of new IAS; it applies to species considered of Union concern and subject to formal risk assessment. So far, 49 species have been listed but the criteria for selecting species for risk assessment have not been disclosed and were probably unsystematic.2. We developed a simple method to systematically rank IAS according to their maximum potential threat to biodiversity in the EU. We identified 1,323 species as potential candidates for listing, and evaluated them against their invasion stages and reported impacts, using information from databases and scientific literature. 4. Policy implications. We propose a systematic, proactive approach to selecting and prioritising IAS for risk assessment to assist European Union policy implementation.We assess an unprecedented number of species with potential to harm EU This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

No abstract