Island Conservation Society

About: Island Conservation Society is a nonprofit organization based out in Victoria, Seychelles. It is known for research contribution in the topics: Population & Critically endangered. The organization has 27 authors who have published 37 publications receiving 1257 citations.

Global Conservation Priorities for Marine Turtles

Abstract: Where conservation resources are limited and conservation targets are diverse, robust yet flexible priority-setting frameworks are vital. Priority-setting is especially important for geographically widespread species with distinct populations subject to multiple threats that operate on different spatial and temporal scales. Marine turtles are widely distributed and exhibit intra-specific variations in population sizes and trends, as well as reproduction and morphology. However, current global extinction risk assessment frameworks do not assess conservation status of spatially and biologically distinct marine turtle Regional Management Units (RMUs), and thus do not capture variations in population trends, impacts of threats, or necessary conservation actions across individual populations. To address this issue, we developed a new assessment framework that allowed us to evaluate, compare and organize marine turtle RMUs according to status and threats criteria. Because conservation priorities can vary widely (i.e. from avoiding imminent extinction to maintaining long-term monitoring efforts) we developed a ‘‘conservation priorities portfolio’’ system using categories of paired risk and threats scores for all RMUs (n = 58). We performed these assessments and rankings globally, by species, by ocean basin, and by recognized geopolitical bodies to identify patterns in risk, threats, and data gaps at different scales. This process resulted in characterization of risk and threats to all marine turtle RMUs, including identification of the world’s 11 most endangered marine turtle RMUs based on highest risk and threats scores. This system also highlighted important gaps in available information that is crucial for accurate conservation assessments. Overall, this priority-setting framework can provide guidance for research and conservation priorities at multiple relevant scales, and should serve as a model for conservation status assessments and prioritysetting for widespread, long-lived taxa.

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.

Global status and conservation potential of reef sharks

Abstract: Decades of overexploitation have devastated shark populations, leaving considerable doubt as to their ecological status1,2. Yet much of what is known about sharks has been inferred from catch records in industrial fisheries, whereas far less information is available about sharks that live in coastal habitats3. Here we address this knowledge gap using data from more than 15,000 standardized baited remote underwater video stations that were deployed on 371 reefs in 58 nations to estimate the conservation status of reef sharks globally. Our results reveal the profound impact that fishing has had on reef shark populations: we observed no sharks on almost 20% of the surveyed reefs. Reef sharks were almost completely absent from reefs in several nations, and shark depletion was strongly related to socio-economic conditions such as the size and proximity of the nearest market, poor governance and the density of the human population. However, opportunities for the conservation of reef sharks remain: shark sanctuaries, closed areas, catch limits and an absence of gillnets and longlines were associated with a substantially higher relative abundance of reef sharks. These results reveal several policy pathways for the restoration and management of reef shark populations, from direct top-down management of fishing to indirect improvement of governance conditions. Reef shark populations will only have a high chance of recovery by engaging key socio-economic aspects of tropical fisheries. Fishing has had a profound impact on global reef shark populations, and the absence or presence of sharks is strongly correlated with national socio-economic conditions and reef governance.

Seabird population changes following mammal eradications on islands

Abstract: Seabirds are among the most threatened groups of birds, and predation by invasive mammals is one of the most acute threats at their island breeding stations. Island restoration projects increasingly involve the eradication of invasive non-native mammals, with benefits for seabirds and other island fauna. To date, demonstrated benefits of invasive mammal eradication include increased seabird nesting success and enhanced adult survival. However, the recovery dynamics of seabird populations have not been documented. Drawing on data from across the world, we assemble population growth rates (λ) of 181 seabird populations of 69 species following successful eradication projects. After successful eradication, the median growth rate was 1.119 and populations with positive growth (λ > 1; n = 151) greatly outnumbered those in decline (λ < 1; n = 23, and seven showed no population change). Population growth was faster (1) at newly established colonies compared to those already established, (2) in the first few years after eradication, (3) among gulls and terns compared to other seabird groups, and (4) when several invasive mammals were eradicated together in the course of the restoration project. The first two points suggest immigration is important for colony growth, the third point reflects the relative lack of philopatry among gulls and terns while the fourth reinforces current best practise, the removal of all invasive mammals where feasible.