Population status and migration trends of Marco Polo argali (Ovis ammon polii) in Pakistan

Marco Polo sheep (Ovis ammon polii) occurring in the rugged mountainous landscapes of Central and South Asia, are difficult to survey and conserve due to their straggling habits in remote and inhospitable habitats. The paper presents population estimates and migration trends of Marco Polo sheep in Khunjerab, Pakistan, over 20 years (1992–2012), determined through direct count method. During this period a total of 1069 sheep visited Pakistan, with mean annual herd size of 76.35 (SD=±40.87). Sex ratio in the population skewed towards females, having male:female ratio of 0.69:1 with 43 lambs to 100 ewes. Annual population density of the immigrant populations oscillated between 0.42 and 2.13 animals/km2 (SD=±0.53). The visitation showed drastic decline over 20 years, possibly due to fencing at the Sino-Pakistan border and dietary competition with wild herbivores. Fewer lambs in summer populations is another point of concern, probably as result of predation of young cohort by avian and mammalian predators. Removing obstructions on migratory routes and reducing dietary competition with sympatric herbivores are suggested for viability of argali populations in Pakistan.