The Sistema Central (Central Range)

Abstract

The Sistema Central or Central Range has an overall length of 600 km and is the most extensive mountain range on the Iberian Peninsula. It has an alpine orogeny and is located in the centre of the peninsula running northeast-southwest in its eastern part (Ayllón and Guadarrama ranges), and east-west in its western part (Guadarrama, Gredos and Estrêla ranges). The whole system comprises a continuous series of smaller mountain ranges, including valleys and various natural areas. It occupies a vast territory from the middle of Portugal (Serra da Estrêla) to the Sierra de Ayllón range in the east, and acts as a natural division of the Castilian central plateau, separating the northern plateau (Castile and León) from the southern plateau (Madrid, Castile-La Mancha and Extremadura). It generally represents the watershed between two of the most important Iberian rivers: the Duero and the Tagus. The highest point of the whole Iberian Central Range is the Almanzor Peak (2592 m) in the central massif of the Gredos mountains. Its characterisation and location on the Iberian Peninsula have interesting phytogeographical and geobotanical implications. These mountains are noteworthy for their bioclimatic, geomorphological and lithological features. Their remarkable bioclimatic complexity is a result of the dissymmetry between the northern and southern slopes (with average values of 1200 vs. 500 m), and their lithological homogeneity, dominated by plutonic igneous and –to a lesser extent– metamorphic rocks. All these factors condition the landscape in these territories. The natural vegetation in these mountains has a woodland character, except in the summit areas above the tree line, which are characterised by Mediterranean alpine grasslands. However other types of vegetation grow in these siliceous high-mountain areas, in the rocky places, peatland, meadows and shrubland that conform the landscape here. Natural Iberian Scots pine (Pinus sylvestris var. iberica) and Spanish black pine (Pinus nigra subsp. salzmannii) forests are distributed throughout the high- and mid-mountain territories respectively in spite of extensive deforestation –more pronounced in the westernmost mountain areas–, in addition to oak forests (Quercus pyrenaica and Quercus rotundifolia) in the rest of the mountain landscape, where natural forests have often been eliminated in order to cultivate several strains of pines, and to encourage the spread of meadows and grasslands which support an important livestock population. Some interesting small relict forests such as beech (Fagus sylvatica), birch (Betula celtiberica) and juniper woodlands (Juniperus thurifera and Juniperus oxycedrus subsp. lagunae) are scattered within the mountain areas. Also significant are the riparian and hygrophilous forests and other vegetation, and the seral vegetation complexes –both forest fringe vegetation and shrub communities– which often predominate throughout vast mountain areas in the landscape.