Species richness and above-ground biomass of poor and calcareous spring fens in the flysch West Carpathians, and their relationships to water and soil chemistry.

Species richness and above-ground biomass of vascular plants and bryophytes of poor acidic fens (the Sphagno recurvi-Caricion canescentis alliance), rich Sphagnum fens (the Caricion fuscae and Sphagno warnstorfii-Tomenthypnion alliances) and calcareous spring fens (the Caricion davallianae alliance including tufa-forming spring fens) were studied. The study area was in the western parts of the Outer Carpathians in the border region of the Czech and Slovak Republics. The numbers of species were recorded in plots ranging from 0.00196 to 16m2 and correlated with chemical factors and above-ground biomass. The chemical properties of springwater (mainly pH, conductivity, Ca2+, Mg2+) were the main factors influencing the species richness of vascular plants. Tufa-forming calcareous fen communities (Carici flavae-Cratoneuretum) had the highest species richness of vascular plants. In contrast, the highest species richness of bryophytes occurred at pHneutral sites, in peat forming calcareous fen communities (Valeriano-Caricetum flavae) and in those with Sphagnum warnstorfii and S. teres. Bryophyte species richness of small plots was correlated with the iron concentration in the springwater. The differences in species richness of calcareous fens were related to the mowing regime. Litter mass had a negative effect on the species richness of vascular plants. Mosses responded to high amounts of litter or vascular plant biomass by a significant decrease in biomass. Two types of Sphagnum fens: (a) strongly dominated by Sphagnum flexuosum or S. palustre (rich in phosphates) and (b) polydominant (poor in phosphates), were also compared. In the former, the slope of the regression for the dependence of bryophyte species richness on plot size was less steep.