Diversity of hay meadows in the Czech Republic: major types and environmental gradients
Havlová, Marcela; Chytrý, Milan; Tichý, Lubomír
A stratified data set of 3102 relevés of meadows and mesic pastures of the Czech Republic was analysed by detrended correspondence analysis and cluster analysis. Major gradients and clusters were interpreted using Ellenberg indicator values. The major gradient in species composition was associated with soil moisture and the second most important gradient with available nutrients. Clusters proposed by numerical classification reproduced some of the traditional phytosociological alliances, namely Arrhenatherion, Molinion and Polygono-Trisetion, while some other alliances were less clearly differentiated (e.g. Alopecurion, Cnidion and Cynosurion). Wet meadows of the Calthion alliance were divided among several clusters, which corresponded to the main associations recognized in traditional phytosociological literature. This patterns suggests that wet meadows have a higher beta-diversity than mesic meadows. We tested this hypothesis by calculating mean pair-wise Sörensen dissimilarity for bootstrap subsamples of meadow relevés for partitions of the moisture gradient, and confirmed that beta-diversity of meadows increases with increasing soil moisture. In traditional phytosociological literature, this fact is reflected by higher numbers of associations distinguished within wet meadows than in mesic meadows.