Genetic diversity and differentiation of Egyptian vulture (Neophron percnopterus) populations in oceanic islands: implications for conservation

Genetic monitoring is central to the conservation of threatened species, particularly those with small and isolated populations, as reduced diversity can limit long-term survival and adaptive potential. Islands are ideal for examining these processes due to restricted gene flow and the enhanced effects of genetic drift and inbreeding. The Egyptian vulture ( Neophron percnopterus ), a long-lived species in global decline, serves as a model for examining how insularity shapes genetic diversity and structure. The main goals of this study are: (i) to assess patterns of genetic diversity, inbreeding and differentiation in four island populations (Cabo Verde, Canary Islands, Balearic Islands, and Socotra) and compare them with their continental counterparts (Maghreb, Iberian Peninsula and Oman), and (ii) to evaluate temporal genetic changes using museum and contemporary samples from the formerly abundant population of Cabo Verde. Island populations generally exhibited reduced genetic diversity. In particular, Cabo Verde showed a pronounced decline in genetic diversity and increased inbreeding over only a few decades, a striking pattern given the species’ long generation time. The four island populations formed distinct genetic clusters, whereas mainland populations showed higher levels of admixture. Contemporary patterns reflect both long-term isolation and rapid recent genetic erosion associated with population decline, particularly in Cabo Verde. These findings highlight that insularity can increase genetic vulnerability. Although Egyptian vulture island populations are genetically unique, they are vulnerable and require targeted conservation to prevent introgression and preserve evolutionary distinctiveness, particularly in programs involving translocations or exchanges with continental populations.