In: Phyton 57 (2017): S. 91-106 DOI: 10.12905/0380.phyton57-2018-0091 Published online on 20th February 2018

Published online on 20th February 2018

Dynamics of alluvial grasslands: a 25-year study on the Morava river (Slovakia)

Ivan Jarolímek, Mária Šibíková, Marica Zaliberová, Jana Májeková, Tomáš Bacigál & Jana Medvecká

Key words: Alluvial grasslands, wetlands, Molinio-Arrhenatheretea, Phragmito-Magnocaricetea, Cnidion venosi, Potentillion anserinae, Bidention tripartitae, Oenanthion aquaticae, Deschampsion cespitosae, Phragmition australis. Vegetation succession, fluctuation, permanent plots, temporal species turnover. Water table dynamics. Morava river, Slo­vakia.

Summary
Jarolímek I., Šibíková M., Zaliberová M., Májeková J., Bacigál T. & Medvecká J. 2018. Dynamics of alluvial grasslands: a 25-year study on the Morava river (Slovakia). – Phyton (Horn, Austria) 57 (1–2): 91–106, with 8 figures and 6 tables.

We analyzed and interpreted the vegetation succession in alluvial grasslands in relation to the water regime during a 25-year period on permanent plots in four grassland types in the Morava river alluvium. We determined the cumulative species richness to show the rate of temporal species turnover. Sørensen’s similarity index between consecutive years and unconstrained ordination were used to determine changes in species composition. The influences of water regime and time on succession were analyzed using constrained ordination. For each species cover change, the trend was calculated using a regression model.

The species composition of plant communities and the rate and direction of vegetation succession in alluvial mead­ows depend mainly on water regime, which is directly connected with microtopography. Our results confirm that the number of flood weeks had a significant effect on the species composition. The most stable community during the 25-year period was the reed community. Cyclic fluctuations in species composition were found on the bottom of the relic oxbow, where plant communities of several classes alternated depending on the duration of the floods. Unidirectional succession was observed on two permanent plots. Species turnover led to changes in species composition and dominant species, and tall grasses (Phalaroides arundinacea or Glyceria maxima) prevailed.