Dugno augalijos poveikis vaginių procesų vyksmui mažosiose Lietuvos upėse.

Benthic plants play an important role in sediment transport and settling in river channels. Investigations of the influence of plants on sediment transport were assumed in the first half of the 20th century, but comprehensive investigations were carried out only at the end of the 20th century. The ideas generated by Russian fluvioglacial geomorphology gave an impetus to these investigations. In the turn of the second millennium, the role of plants in the channel processes also became an object of research in the south Baltic countries. The link between bank and littoral plants and their influence on channel processes were investigated in the Verseka, Jiesia and Šušve rivers. Analysis of longitudinal channel profiles allowed distinguishing concave and convex river sectors, choosing reference areas and recording the distribution pattern of bank and littoral plants and channel relief forms. The bathymetric measuring of reference areas was complemented with channel cross-section data revealing the distribution pattern of plants and variations of bottom relief and sediments in the cross-sections of river channels. All the study rivers have their valleys formed in relief complexes of different genesis what predetermines the present hydrodynamic status of their channels. Moreover, all the mentioned rivers have been embanked. The embankments were responsible for deformations of longitudinal channel profiles. All profiles include concave and convex sectors with different slope angles. The inclinations of convex sectors as a rule are higher; somewhere they exceed the inclination of concave sectors a few times. The distribution of benthic plants in the river channels depends on channel morphology. Oxbow lakes and bights provide especially good conditions for thick vegetation. The depth of flows is an important decisive factor for the distribution of plant species. Some species of plants can grow only at a certain depth. It is known that channel bottom sediments largely influence the distribution pattern of plants. In gravel, pebble and drifting sand sediments, plants take root hard. The sectors of stable sand are overgrown with pondweeds. Some species of plants easily take root and flourish in clayey sediments of different degree of silting. Plants with floating leaves grow on loose organic silts of oxbow lakes and bights. In the last few decades, silt sediments have been accumulating on sandy and even gravel sediments. Similar processes are taking place in small and large rivers of Lithuania and neighbouring countries. Littoral vegetation of rivers directly predetermines benthic plants of channels. Shady bottom sectors of small rivers often have no plants. The bottom of these sectors is covered by gravel with pebbles and even boulders. Sand sediments are also widespread in shady river sectors. As a rule, they represent small (10-20 cm high, 0.3-0.5 m wide and 1-1.5 m long) beds of permanently moving sand. In the sunny river channel sectors, vegetation flourishes producing a direct influence on channel processes. Various species of pondweeds and elodea are widespread. They reinforce the sand beds with their roots. These sectors are characterized by sediment drift stabilization. Local aggradation of sediments takes place in the areas where sunny channel sectors of small rivers coincide with the sectors of reduced inclination values of longitudinal profiles. In these sectors, rivers become wider, their fairways are dissected and the stream channels are shallower. Shoals appear, emerging from the water during summer water sinking.… [ABSTRACT FROM AUTHOR]