ABSTRACT
Apart from benthic algae and lichens, the plant life of running water is made up of macrophytes: Bryophytes, Pteridophytes, and Spermatophytes. Macrophytes in turn constitute a substrate for algae and fauna and help to protect them from the current. Colonization of a rocky substrate by Bryophytes begins in the water or close to water, in shaded zones that are kept moist by trickles of water or the spray from waterfalls, or even under an overhanging rock, sheltered from the current. Although the Bryophytes are confined to stable, hard substrates, Pteridophytes and Phanerogams are associated with a substrate consisting of small pebbles, gravel, sand, and silt. The colonization of an environment by vegetation follows a dynamic process resulting from the current and also from the plant-substrate interaction. There are consequently three factors involved in the distribution of vascular plants in the Estibere stream: current, nature of the substrate, and depth.
