Pastoralist herds interact with their environment, and mediate human relations with the environment as a way of turning uncultivated plants (like wild grass) into food. In many places, grazing herds on savannas and in woodlands can help maintain the biodiversity of such landscapes and prevent them from evolving into dense shrublands or forests. Grazing and browsing at the appropriate levels often can increase biodiversity in Mediterranean climate regions. Pastoralists shape ecosystems in different ways: some communities use fire to make ecosystems more suitable for grazing and browsing animals.
