engleski

Towards a Revised Classification of Pontic- Pannonian Steppe Grasslands

We studied the main phytosociological subdivision of Pontic-Pannonian steppe grasslands using a large dataset of vegetation plots covering the whole Carpathian Basin (Eastern Austria, Moravia, Slovakia, Hungary, Romania, N Croatia, N Serbia) as well as Ukraine and adjacent regions in southern Poland and south-western Russia (Bryansk region). Altogether 43 706 relevés from 11 countries were gathered. Species taxonomy and nomenclature was unified according to the Euro Med Checklist. Critical species were merged to aggregates. From this initial data set, we selected all relevés with the presence of at least one (of 143 pre-defined) diagnostic species of the target vegetation types (steppe meadows, meadow steppes and grass steppes), of rocky steppes or of Pannonian sand steppes. Thus, we included all units traditionally included or closely related to the class Festuco–Brometea. Relevés with a plot size <9 m² or >100 m², and relevés with a shrub or tree layer covering >10% were excluded. To avoid biases due to oversampling of some areas, we applied a heterogeneity-constrained random resampling. The resampled data set was classified using TWINSPAN. Higher syntaxa (classes, orders, alliances) were identified and diagnostic species for the different syntaxonomic levels were calculated using various fidelity measures (phi coefficient, constancy ratio, total cover ratio). Finally, we re-assigned the plots using the summarised cover of diagnostic species. As next step, a detailed classification on the association level of the units corresponding to steppe meadows, meadow steppes and grass steppes will follow.

dry grasslands; Europe

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