Final answer:
Transhumance or nomadic herding is the movement across areas in search of grazing lands, common in pastoral societies to maintain sustainable livestock production.
Step-by-step explanation:
Movement across an area in search of grazing lands is called transhumance or nomadic herding. This pattern of movement is especially common in pastoral societies where the primary subsistence is based on herding groups of animals across various landscapes to find suitable grazing grounds. These practices allow for the sustainability of the livestock and the people that depend on them by preventing overgrazing and ensuring a reliable source of food and resources. Transhumance often involves moving herds between fixed points seasonally, while nomadic herding may involve more unpredictable movements as herders search for new pastures.