2000 years of pastoralism and fire shaping high-altitude vegetation of Sierra de Gredos in central Spain

The palynological record of Puerto de Serranillos provides insights into the late Holocene vegetation history of Sierra de Gredos in the Central Mountain System of the Iberian Peninsula. Overgrazing around the timberline has occurred at least throughout the past two millennia, related to the human management of the landscape. Before the 12th century AD, Pinus sylvestris forests were dominant with a diversity of accompanying trees and understorey. The current landscape of the Gredos Range is clearly anthropogenic, and includes a combination of forest patches, pastures, dense shrubby formations and prostrate junipers, overall generated during the transition between the 17th and 18th centuries AD, when continued human activity in the mountain pine forests, using fire and intensifying grazing practices, caused a progressive deforestation, and the expansion of the current fire-prone scrub.