Class One Protected Species under China’s national legislation, CITES Appendix I. The wild yak has an important role in Tibetan culture. Currently, there are no precise statistics for the wild yak population globally, but scientists estimate the population to be about 15,000 to 20,000, mostly inhabiting the Northern Tibet Grassland.
The Wild Yak (Bos mutus) lives at elevations of 4,000 to 6,100 meters in the alpine tundra, grasslands and cold desert regions of the Tibetan plateau. The worldwide population has probably declined more than 30% in the last 3 decades, and in 1995, was estimated to number a mere 15,000 individuals. Within China, wild yaks occur in a number of large nature reserves, including the Changtang, Arjin Shan, Kekexili, Sanjiangyuan, and Yanchiwan Nature Reserves. Of these remaining individuals, about 7,000–7,500 wild yaks, almost half of the global population, reside within the Changtang National Nature Reserve in Tibet. Although the wild yak remains one of the most threatened species of the Tibetan Plateau, protection from illegal hunting might be permitting wild yak to increase in number and recolonize former habitat in some areas. However, increasing pressure on yak habitat from livestock grazing coupled with climate-change mediated habitat alteration, threatens to undo recent population gains.
Where wild yak have held on or increased in numbers, interactions and conflicts with domestic pastoralists have increased, and habitat loss and increasing interactions between wild and domestic yak have become major conservation challenges. Steppe meadow is a favored habitat of wild yaks and the best pasture for domestic livestock, and the expansion of livestock grazing is displacing wild yaks and reducing the habitat available to them. Interbreeding with domestic yak presents the major threat to remaining wild yak populations, not only by threatening the genetic purity of wild yak, but also by creating conflict between wild yaks and pastoralists (who do not want to lose their domestic yak cows when they join wild bulls). Due to these pressures, the population trend remains one of decline in many areas; wild yaks in the southern 24% of Changtang have been almost completely exterminated since the arrival of pastoralists in the 1960s. Consequently, while yak range has expanded in some pockets, the overall range of the wild yak has shrunk, and only fragmented, isolated populations remain in the core area in northern Tibet and northwestern Qinghai Province.
Potentially amplifying the effect of expanded grazing by domestic livestock on wild yak-human conflict are the unknown consequences of climate change, which may also impact the availability and distribution of wild yak habitat. Owing to its dual characteristics of aridity and extremely high elevation, the Tibetan Plateau is warming at nearly twice the rate as other parts of Earth. As a direct consequence, seasonal-melting is intensifying, thereby accelerating glacial recession, escalating river flows, and increasing lake levels. Associated alteration of hydrological regimes and vegetation biomass may open areas for additional colonization by semi-nomadic Tibetan pastoralists, and consequent increases in yak-human conflict for grazing habitat are likely to occur. Warming temperatures from climate change are also likely to impact wild yaks and other high elevation or high latitude wildlife because of their intolerance to heat, a reduction in habitat brought about by decreased food access (e.g., changing plant communities) and associated declines in yak survival and/or reproduction. Alternatively, glacial recession might create suitable habitat for yak where previously it was under ice.
To combat the entwined threats of human-wildlife conflict and climate change, the Wildlife Conservation Society is undertaking complementary research and conservation programs in Changtang National Nature Reserve. In collaboration with the Changtang National Nature Reserve Management Bureau of the Tibetan Autonomous Region, Tibetan Academy of Agriculture and Animal Husbandry Sciences, Tibetan Forestry Bureau, and Nyma County Forestry Bureau, WCS will be undertaking a project to create buffer zones around existing wild yak habitat, where livestock grazing will be effectively eliminated. This will 1) separate the domestic and wild population, 2) provide more habitat for wild yak, and 3) help reduce interactions between wild and domestic yak. Thus by controlling human-livestock expansion, wild yak should have more suitable habitat south of their current distribution and populations will be able to increase.
To inform wild yak conservation and better predict the effect of climate change on the availability and distribution of habitat for wild yaks, WCS scientists are also partnering with Tibetan agencies and the University of Montana to address two key questions: 1) to what extent are wild yak reliant on peri-glacial zones?, and 2) what are the most ecologically important areas for enhancing long-term protection? This information is vital to ongoing conservation projects and the future of wild yak in China.