Genetic analyses point to two conservation units that need protection.
The number of Bearded Vultures (Gypaetus barbatus) is drastically decreasing. In recent decades, several local extinctions occurred, such as the disappearance of populations on the Italian island Sardinia and in the Balkans. The main drivers of this decline include unintentional poisoning of birds, habitat loss, collisions with energy infrastructure and use of vulture body parts in traditional medicine (which is obviously based on pseudoscientific and misguided beliefs). There is, however, hope: in 1986, Bearded Vultures from a captive breeding program were reintroduced into the Alps. The current population is estimated to ca. 300 individuals. In order to extend this success story to other areas and protect this charismatic species, proper conservation measures will need to be implemented. In addition, a genetic perspective on the population structure of the Bearded Vulture can help conservationists to focus on genetically impoverished regions and take action quickly.
In a recent study in the journal BMC Ecology and Evolution, researchers used a set of 14 microsatellites to determine the genetic population structure of the Bearded Vulture. An impressive dataset of 236 individuals covered the entire range of the species, from Europe and Asia to the southern tip of Africa. The genetic analyses revealed little gene flow between four geographic populations: Europe, Asia, northern Africa and southern Africa. The highest level of genetic exchange occurred between Europe and Asia (28%), suggesting that there used to be a connection across the Balkans. There has been minimal gene flow with the population in southern Africa, which only received about 7% of genetic variation from northern Africa (and nearly nothing from Europe or Asia). In all analyses, the researchers noted that “the isolated southern African bearded vulture population is genetically distinct from all other bearded vulture populations.”
Hence, the Bearded Vulture populations can best be managed as two separate conservation units (similar to the Pink Cockatoo in Australia). The three northern populations – Europe, Asia and northern Africa – are connected by occasional gene flow, while the population in southern Africa is genetically isolated.
Apart from conservation, these findings might also have consequences for the taxonomy of the Bearded Vulture. Based on the current study, the authors advocate the recognition of G. b. barbatus in Eurasia and northern Africa and G. b. meridionalis in eastern and southern Africa. These subspecies probably became isolated by the expansion of the Sahara desert, followed by a stepping-stone connection between southern and eastern Africa (which explains the low level of gene flow uncovered in this study). Regardless of the taxonomic division, the researchers highlight “the need for conservation programmes to effectively manage populations of this species and maintain extant genetic diversity.”
Streicher, M., Krüger, S., Loercher, F., & Willows-Munro, S. (2021). Evidence of genetic structure in the wide-ranging bearded vulture (Gypaetus barbatus (Linnaeus, 1758)). BMC ecology and evolution, 21(1), 1-11.
Featured image: Bearded Vulture (Gypaetus barbatus) © Richard Bartz | Wikimedia Commons