Characteristic herbaceous vegetation types from wet habitats of the Váli-víz valley, Hungary

Abstract

The present paper discusses the geobotanical characterization of lowland swamp-meadows , reeds in „terrestrial“ situation and sedge (Magnocaricion) meadows that occur in the „Váli-víz“ valley. The codes in parentheses correspond to the Hungarian habitat classification system. Phytosociological samples were taken in the three vegetation types, then their characterization were made by using the species’ ecological indicator values. Similarities between the species pools of phytosociological releves were measured by the Sørensen -index.
Since the studied region suffers a medium to high level antropogenous effect all the three vegetation types proved to be more or less disturbed. In case of the lowland swamp-meadows the species number per quadrate varied between 22 and 36, and the majority of the species were members of the disturbance tolerant group with wide ecological amplitude. Some of them, like Festuca pratensis, Trifolium repens, T. pratense owe their abundance to over-sowing, an often applied grassland management practice in the region. Species with botanical value, like Lychnis flos-cucculi, Ranunculus spp., Sanguisorba officinalis, etc, were rather infrequent in these meadows with low abundance. In the Phragmites australis stands of „terresrial situation“ (without contact to the river side of the Váli-víz) altogether 52 species occourred in the releves. This number is cosiderably higher than that of the river side stands in which 33 species were listed. The inceased species number in the terrestrial reeds was resulted by immigration of opportunistic members of the dryer habitats (e.g. Agropyron repens, Calamagrostis epigeios, Galium mollugo, Urtica dioica, Vicia cracca, etc). However, these species did not become constant members of the terrestrial reeds, but instead they appeared occasionally and their constancy value always remained low. This vegetation pattern is reflected numerically by the low (0.19) value of average Sørensen -similarity between releve-pairs of the studied reeds. In the Magnocaricion stands altogether 30 species were registered and the species number per quadrate varied between 5 and 13. Considering these figures the tall sedge stands are the most species poor from the studied three vegetation types of the „Váli-víz“ valley. Their degraded status could probably be related to occasional trials of using these meadows for crop production. The only exception is the stand at village Kajászó, where the highest species number was detected and where the protected Eriophorum angustifolium was found.