Distribución de la vegetación en una ladera sometida a riego temporal

A quantitative analysis of the vegetation on a slope of a "dehesa" of Salamanca pro- vince has been made for the purposes of observing the effects of temporal irrigation. The 17 samples takings that were made included the presence of a total of 102 species whose abundance was studied by means of the analysis of correspondances. The first 3 components, which cover 47,21 % of the variance, are deduced and are interpreted from the analysis; the first as reflecting the access to water, the second as representative of the retention of water. The third seems to be related to the similarity between samplings. In the plañe defined by the first and second components, three zones became apparent; these were identified as swamping, aridity and an intermediate zone between these two. This intermediate zone is formed in the vértex of the directions of the other two which may be schematically represented as two linear trajectories which have the form of lines regres- sion and of which the coefficient of correlation are significantly different of zero. PASTOS