Extinct in the wild: The precarious state of Earth's most threatened group of species.

Extinct in the Wild (EW) species are placed at the highest risk of extinction under the International Union for Conservation of Nature Red List, but the extent and variation in this risk have never been evaluated. Harnessing global databases of ex situ animal and plant holdings, we report on the perilous state of EW species. Most EW animal species-already compromised by their small number of founders-are maintained at population sizes far below the thresholds necessary to ensure demographic security.

Genetic diversity in global populations of the critically endangered addax () and its implications for conservation.

Threatened species are frequently patchily distributed across small wild populations, ex situ populations managed with varying levels of intensity and reintroduced populations. Best practice advocates for integrated management across in situ and ex situ populations. Wild addax () now number fewer than 100 individuals, yet 1000 of addax remain in ex situ populations, which can provide addax for reintroductions, as has been the case in Tunisia since the mid-1980s.

Zoological institutions as hotspots of gastrointestinal parasites that may affect the success of ungulate reintroduction programmes.

Background: Ungulates from zoological institutions are frequently used as founders in reintroduction programmes. These animals are subject to specific parasite management as parasitic infections have previously been associated with failed Bovidae reintroductions.

Methods: Questionnaires to obtain data on how these institutions screen for seasonal parasite presence and the clinical signs they induced in threatened ungulates were sent to 65 institutions involved in European Ex situ Programmes (58.

Drivers of sex ratio bias in the eastern bongo: lower inbreeding increases the probability of being born male.

Parent sex ratio allocation has consequences for individual fitness, population dynamics, and conservation. Theory predicts that parents should adjust offspring sex ratio when the fitness returns of producing male or female offspring varies. Previous studies have assumed that only mothers are capable of biasing offspring sex ratios, but have neglected fathers, given the expectation of an equal proportion of X- and Y-chromosome-bearing (CBS) sperm in ejaculates due to sex chromosome segregation at meiosis.

Survey of husbandry practices for bovidae in zoos: the importance of parasite management for reintroduction programmes.

Animals from zoological institutions may be used for reintroductions. These individuals are considered healthy, but they are not necessarily free of parasites, despite the minimum husbandry standards required of zoological institutions as described in the European Association of Zoos and Aquaria guidelines. In this sense, parasitism has been identified as the cause of failure, or has added difficulties, in some reintroduction programmes.

Improving generation length estimates for the IUCN Red List.

The International Union for the Conservation of Nature (IUCN) Red List classifies species according to their risk of extinction, informing local to global conservation decisions. Here we look to advance the estimation of generation length, which is used as a time-scalar in the Red List as a way of accounting for differences in species' life-histories. We calculated or predicted generation length for 86 species of antelope following the Rspan approach.

Evaluating Conservation Breeding Success for an Extinct-in-the-Wild Antelope.

With the number of threatened species increasing globally, conservation breeding is vitally important now more than ever. However, no previous peer-reviewed study has attempted to determine how the varying conditions across zoos have influenced breeding by an extinct-in-the-wild species. We therefore use questionnaires and studbook data to evaluate the influence of husbandry practices and enclosure design on scimitar-horned oryx (Oryx dammah) breeding success, at the herd level.