trees also abound. The dominant understory is composed of thorny and aromatic woody species, such as rosemary (Rosmarinus officinalis), thyme (Thymus), and Cistus. In the wettest areas with acidic soils, the most abundant species are the oak and cork oak, and the cultivated Eucalyptus. In the woodlands, leafy hardwoods of genus Populus (poplars, aspens, cottonwoods) and Ulmus (elms) are also abundant; poplars are cultivated in the plains of Granada. The Andalusian woodlands have been much altered by human settlement, the use of nearly all of the best land for farming, and frequent wildfires. The degraded forests become shrubby and combustible garrigue. Extensive areas have been planted with non-climax trees such as pines. There is now a clear conservation policy for the remaining forests, which survive almost exclusively in the mountains. Fauna The biodiversity of Andalusia extends to its fauna as well. More than 400 of the 630 vertebrate species extant in Spain can be found in Andalusia. Spanning the Mediterranean and Atlantic basins, and adjacent to the Strait of Gibraltar, Andalusia is on the migratory route of many of the numerous flocks of birds that travel annually from Europe to Africa and back. The Andalusian wetlands host a rich variety of birds. Some are of African origin, such as the red-knobbed coot (Fulica cristata), the purple swamphen (Porphyrio porphyrio), and the greater flamingo (Phoenicopterus roseus). Others originate in Northern Europe, such as the greylag goose (Anser anser). Birds of prey (raptors) include the Spanish imperial eagle (Aquila adalberti), the griffon vulture (Gyps fulvus), and both the black and red kite (Milvus migrans and Milvus milvus). Among the herbivores, are several deer (Cervidae) species, notably the fallow deer (Dama dama) and roe deer (Capreolus capreolus); the European mouflon (Ovis aries musimon), a feral sheep; and the Spanish ibex (Capra pyrenaica, which despite its scientific name is no longer found in the Pyrenees). The Spanish ibex has recently been losing ground to the Barbary sheep (Ammotragus lervia), an invasive species from Africa, introduced for hunting in the 1970s. Among the small herbivores are rabbits—especially the European rabbit (Oryctolagus cuniculus)—which form the most important part of the diet of the carnivorous species of the Mediterranean woodlands. The large carnivores such as the Iberian wolf (Canis lupus signatus) and the Iberian lynx (Lynx pardinus) are quite threatened, and are limited to the Sierra de Andújar, inside of Sierra Morena, Doñana and Despeñaperros. Stocks of