Modificaciones climáticas y evolución de la cubierta vegetal en las áreas culminantes de la Sierra de Guadarrama (Sistema Central español) durante la segunda mitad del siglo XX : las altas cuencas del Ventisquero de La Condesa y de Valdemartín

Abstract

The purpose of this study was to determine the relationship between recent climate changes and observed changes in the plant cover in the supraforest areas of the Central Mountain Range in Spain. Two small adjacent basins (La Condesa and Valdemartin) were selected as research sites at high altitude near a long-established national weather station at Puerto de Navacerrada in Sierra de Guadarrama. Aerial photograph interpretation was used to detect changes in vegetation at the sites in 1957, 1972, 1984, 1991 and 1998, and the results showed a correlation among the 18 climate-related parameters for the period 1951-2000. High index values and a basic similarity in tendencies confirmed that the extension of the plant facies had changed in accordance with variations in temperature and snow cover. As are result, it was determined that plant cover was sensitive to climate changes that had occurred during the study period and had responded by reducing the extent of the snowfields, hydrophytic meadows and open scrublands while expanding the pychroxerophytic meadows and dense scrublands.