RESUMO
The wild yak Bos mutus was believed to be regionally extinct in Nepal for decades until our team documented two individuals from Upper Humla, north-western Nepal, in 2014. The International Union for Conservation of Nature (IUCN) seeks further evidence for the conclusive confirmation of that sighting. We conducted line transects and opportunistic sign surveys in the potential wild yak habitats of Humla, Dolpa, and Mustang districts between 2015 and 2017 and collected genetic samples (present and historic) of wild and domestic yaks Bos grunniens. We also sighted another wild yak in Upper Humla in 2015. Phylogenetic and haplotype network analyses based on mitochondrial D-loop sequences (~450 bp) revealed that wild yaks in Humla share the haplotype with wild yaks from the north-western region of the Qinghai-Tibetan Plateau in China. While hybridization with domestic yaks is a major long-term threat, illegal hunting for meat and trophy put the very small populations of wild yaks in Nepal at risk. Our study indicates that the unprotected habitat of Upper Humla is the last refuge for wild yaks in Nepal. We recommend wild yak conservation efforts in the country to focus on Upper Humla by (i) assigning a formal status of protected area to the region, (ii) raising awareness in the local communities for wild yak conservation, and (iii) providing support for adaptation of herding practice and pastureland use to ensure the viability of the population.
RESUMO
Wolves in the Himalayan region form a monophyletic lineage distinct from the present-day Holarctic grey wolf Canis lupus spp. (Linnaeus 1758) found across Eurasia and North America. Here, we analyse phylogenetic relationships and the geographic distribution of mitochondrial DNA haplotypes of the contemporary Himalayan wolf (proposed in previous studies as Canis himalayensis) found in Central Asia. We combine genetic data from a living Himalayan wolf population collected in northwestern Nepal in this study with already published genetic data, and confirm the Himalayan wolf lineage based on mitochondrial genomic data (508 bp cytochrome b and 242 bp D-loop), and X- and Y-linked zinc-finger protein gene (ZFX and ZFY) sequences. We then compare the genetic profile of the Himalayan wolf lineage found in northwestern Nepal with canid reference sequences from around the globe with maximum likelihood and Bayesian phylogeny building methods to demonstrate that the Himalayan wolf forms a distinct monophyletic clade supported by posterior probabilities/bootstrap for D-loop of greater than 0.92/85 and cytochrome b greater than 0.99/93. The Himalayan wolf shows a unique Y-chromosome (ZFY) haplotype, and shares an X-chromosome haplotype (ZFX) with the newly postulated African wolf. Our results imply that the Himalayan wolf distribution range extends from the Himalayan range north across the Tibetan Plateau up to the Qinghai Lakes region in Qinghai Province in the People's Republic of China. Based on its phylogenetic distinction and its older age of divergence relative to the Holarctic grey wolf, the Himalayan wolf merits formal classification as a distinct taxon of special conservation concern.