Livestock farming systems in Mediterranean mountain areas perform productive, economic and social functions and help to preserve the environment. The latter becomes very important in protected areas since livestock farming is a tool to maintain and manage them. This work describes range utilization in a protected area and types of sheep farms, based on some structural and surface-area variables. This series of 3 papers fits within the framework of a project whose aim is to establish practices of sustainable land use as well as to assess farms' technical management strategies in an attempt to reconcile economic objectives and preservation of natural resources.