Distribución de leguminosas pratenses en relación con la altitud y el fitoclima en la cuenca del Narcea (Asturias)

Abstract

The distribution of the leguminosae species of the Narcea River. Basin (Asturias, SPAIN) in relation to the altitude and phytoclima has been studied. Techniques of elaboration and ordination of altitude frequeney histograms —C.E.P.E. (Montpellier, FRANCE) Methodology— has been applied. Many of the species show preferences for different altitudes. The number of species decreases with the altitude. Three altitudinal zones have been established. It may be pointed out that some of the more frequent species, Vicia sativa, Vicia hirsuta and Trifolium campestre show high affinity for altitudes lower than 1.000 m. The rest of the most important and frequent species, Trifolium pratense, T. repens, Lotus corniculatus, T. dubium and Lotus uliginosus have a range of total variation, although all of them decrease their frequencies in high altitudes. Following Allue's methodology, two Mediterranean phytoclimatic subregions —IV (V) and IV (VI)— have been determined. It is remarkable that Trifolium patens is found in a number of low grasslands with atlantic climate V (VI), and Hippocrepis comosa is preferently found in grasslands with Mediterranean characteristics.