Low genetic diversity in captive populations of the critically endangered Blue-crowned Laughingthrush (Garrulax courtoisi) revealed by a panel of novel microsatellites

Background Captive populations permit research and conservation of endangered species in which these efforts are hardly implemented in wild populations. Thus, analysing genetic diversity and structure of captive populations offers unique opportunities. One example is the critically endangered Blue-crowned Laughingthrush, Garrulax courtoisi, which has only two known wild populations in Wuyuan, Jiangxi and Simao, Yunnan, China. We carried out the first conservation genetic study, in order to provide useful implications that allow for successful ex situ conservation and management of the Blue-crowned Laughingthrush. Methods Using the novel microsatellite markers developed by whole-genome sequencing, we genotyped two captive populations, from the Ocean Park Hong Kong, which are of unknown origin, and the Nanchang Zoo, which were introduced from the Wuyuan wild population since the year 2010–2011, respectively. The genetic diversity of captive Blue-crowned Laughingthrush populations was estimated based on genetic polymorphisms revealed by a new microsatellite data set and mitochondrial sequences. Then, we characterised the population structure using STRUCTURE, principal coordinates analysis, population assignment test using the microsatellite data, and haplotype analysis of mitochondrial data. Additionally, we quantified genetic relatedness based on the microsatellite data with ML-Relate. Results Our results showed equally low levels of genetic diversity of the two captive Blue-crowned Laughingthrush populations. The population structure analysis, population assignment test using the microsatellite data, and haplotype analysis of the mitochondrial data showed weak population structuring between these two populations. The average pairwise relatedness coefficient was not significant, and their genetic relatedness was quantified. Discussion This study offers a genetic tool and consequently reveals a low level of genetic diversity within populations of a critically endangered bird species. Furthermore, our results indicate that we cannot exclude the probability that the origin of the Hong Kong captive population was the wild population from Wuyuan. These results provide valuable knowledge that can help improve conservation management and planning for both captive and wild Blue-crowned Laughingthrush populations

Extent and potential impact of hunting on migratory shorebirds in the Asia-Pacific

Harvesting has driven population declines of migratory species. In the East Asian-Australasian Flyway (EAAF), declines of migratory shorebirds have been largely attributed to habitat loss. However, despite concerns about hunting, no study has considered this potential threat at a flyway scale. We synthesised and analysed the current state of knowledge of hunting of migratory shorebirds in the EAAF to determine: (i) whether there is flyway-wide coordination for monitoring hunting; (ii) the temporal, spatial, and taxonomic extent of hunting; and (iii) the potential population-level effects. We conducted an exhaustive literature search, aggregated data considering uncertainty in different dimensions, and appraised hunting levels against sustainable harvest thresholds. We identified 138 references (i.e., peer-reviewed journal articles, book chapters, books, conference proceedings, technical reports, theses, and newsletters) as potential sources of records of hunting of migratory shorebirds of which we were able to obtain 107. We discovered a lack of coordinated monitoring of hunting, despite harvest being temporally, spatially, and taxonomically pervasive, including species of conservation concern. Past harvest levels of migratory shorebirds may have reached at least half of the flyway-wide sustainable thresholds in the EAAF. Despite our inability to assess current hunting levels and unambiguous population-level effects, it is evident that hunting has the potential to be an additional stressor on migratory shorebird populations interplaying with habitat loss. We therefore highlight the need to develop a coordinated monitoring system of hunting at a flyway scale, as past levels of take are likely to have been unsustainable, hunting still occurs, and the current thresholds for sustainable harvest have become lower as a result of declines in shorebird populations