Though grazing within protected areas is banned, it is still pervasive and prevalent in the Himalayan region. The effects of grazing on herbivore competition, disease spread, vegetation structure and the attendant herder impacts are hotly debated with limited action on the ground. The Khangchendzonga National Park (KNP) is a part of the eastern Himalaya global biodiversity hotspot and is located in the Sikkim state of India. Increasing livestock populations coupled with the government policy to ban grazing and its selective implementation resulted in conflict. A multi-disciplinary sustainability assessment involving consultations with traditional resource users, field surveys and remote sensing was carried out to analyze the economic, ecology and equity aspects. The assessment found that in the greater Himalayan part, over the past six decades, sheep have been increasingly replaced by yaks (and their crossbreeds), who descend only up to the multi-layered temperate and sub-alpine forests during winter. These forests have been extensively manipulated by the yak herders to increase the fodder availability.