LONGITUDINAL GRADIENT OF RIPARIAN VEGETATION ASSOCIATED TO THE MOUNTAIN STRETCH OF THE BERNESGA RIVER (LEÓN, SPAIN)

Abstract

The distribution of macrophytic vegetation associated to the mountain stretch of the Bernesga river (León, Spain) is anaiysed on the basis of the data coliected in 36 transects distributed on both banks and perpendicular to the river bed. The similarity among the sarnples placed along the river is on the whole low, except in those having an outstanding presence of Carex acuta subsp. broteriana; nevertheless, the strongest affinity among close transects allows to taik o€ a continous change in the vegetation. The best delimited areas embrace, on the one hand, the first kilometers where there are no real banks and both sides o€ the river are covered mainly by swampy meadows and harvest grassland with a high degree of dampness; and, on the other, the lower part where the riparian community gets its own physiognomy and Agrostis stolonifera, Mentha longifolia and mostly Carex acuta subsp. broteriana constitute the most important species.