Cantabria has vegetation typical of the Atlantic side of the Iberian Peninsula. It is characterized by forests of leafy deciduous trees such as oak and European beech. Nevertheless, human intervention dating back to ancient times has favored the creation of pastures, allowing the existence of large areas of grassland and prairies suitable for grazing cattle. These grasslands are mingled with plantations of eucalyptus and native oak. The southern part of Cantabria, including the "comarca" of Campoo the fringes of the Castilian plateau, is characterized by the transition to drier vegetation. Another diversifying factor which contributes to local variation within the region is the Mediterranean ecotone, giving rise to species unique to the region, such as the holm oak and arbutus trees, which are found in poor limestone soils with little moisture.