Habitat affinities of the red-listed and EU Habitat Directive moss species Hamatocaulis vernicosus and the more widely distributed allied species Scorpidium cossonii and Warnstorfia exannulata were analysed. Ecological preferences of these fen mosses, with respect to water pH, water conductivity, Ellenberg’s moisture and nutrient indicator values, were compared in three different European locations (Bohemian Massif, the West Carpathians and Bulgaria) using logistic regressions fitted by means of Huisman-Olff-Fresco models. Inter-specific co-occurrences of the species were also investigated. Warnstorfia exannulata preferred slightly acid conditions, about pH 5.6 at all the locations studied. Ecological behaviour of S. cossonii was very similar at all the locations, where it occupied base-rich habitats (pH > 7). The pH optimum of H. vernicosus, occupying habitats in the middle part of the base richness gradient, varied between locations from 6.0 in Bulgaria to 6.7–7.0 in the West Carpathians and Bohemian Massif. Niche diversification followed the gradient in Ellenberg nutrient indicator values and was similar at all the locations. In the Bohemian Massif and Bulgaria, the occurrence of W. exannulata was further associated with a relatively high moisture indicated by the Ellenberg indicator value. The results obtained from the Huisman-Olff-Fresco models accord with the results of inter-specific co-occurrences. Moreover, the latter method revealed a link between H. vernicosus and the occurrence of disjunctly occurring boreal sedges, suggesting the relic nature of H. vernicosus habitats at these locations.
Vegetation with species of Utricularia and that dominated by Eleocharis quinqueflora, which occupy the same habitats. was studied in minerotrophic mires and oligotrophic wetlands associated with ponds. Relative towater and soil chemistry, the communities of Utricularia ochroleuca s.l. and U. intermedia occurred in mineral-poor and those of U. minor and U. australis in mineral-rich conditions. Rare stands with U. vulgaris occurred in conditions that were intermediate in mineral richness. Four communities belonging to the class Isoëto-Littorelletea were distinguished. Vegetation without bladderworts and dominated by E. quinqueflora occurs in calcareous fens and belongs to the class Scheuchzerio-Caricetea fuscae (the Caricion davallianae alliance). Vegetation with U. intermedia is characterized by high vascular plant cover and belongs to the class Scheuchzerio-Caricetea fuscae. Utricularia ochroleuca s.l. prefers open, acidic and waterlogged depressions in peat, whereas U. intermedia grows mostly in the shade under vegetation canopy. In this study, U. minor and U. australis have been found mainly in the more alkaline and mineral-rich habitats, and both species also tolerated extremely high mineral richness.
In summer 1992 through spring 1994, amphibian abundance and breeding was studied in the pristine temperate forests, typical of central European lowlands. The years 1991, 1992, and 1993 were among the driest in the recent decades, with the spring-summer precipitation 35% lower than the long-term average. In the primeval forests of Białowieża National Park, common frogs Rana temporaria spawned in small (on average, 0.2 ha) ponds (postglacial melt-out hollows) devoid of wood cover and characterised by water pH 5.1-6.0 (as measured in April). Breeding success of frogs, monitored qualitatively in 1993, was rather poor due to pond desiccation. The capture of amphibians on forest grids revealed that densities and seasonal dynamics differed between wet and drier deciduous forests. No amphibians were captured in the mixed coniferous forests during the study. In the wet ash-alder forests, on average, 39 amphibians ha-1 were recorded in late April, 12 ind ha-1 in summer, and 195–222 ind hasup-1 in autumn (September). In those forests, 90% of captured amphibians were common frogs, 6% common toads Bufo bufo, and 4% moor frogs R. arvalis. In the drier oak-lime-hornbeam forests, amphibians appeared in May, and increased in numbers towards summer (19–24 ind ha-1) and autumn (45–71 ind ha-1). Of all amphibians caught in those forests, 43% were common frogs, 38% common toads, and 19% were moor frogs. A majority of amphibians captured in autumn were young of the year. By mid-October, all amphibians had left the forest for their hibernation sites. Comparison of our data collected in very dry years with other available data from Bia∏owie ̋a Primeval Forest (various years between 1955 and 1998) revealed that summer indices of amphibian abundance were strongly positively correlated with rainfall in April-June of the census year and the previous year.
The composition of the vegetation of fishpond mires in the Třeboň Basin (Czech Republic) was studied in relation to temporal fluctuations in certain environmental factors. The water-table depth, water pH and electrical conductivity at 49 permanent plots were measured at approximately threeweek intervals from March to October 2003. Minimum, maximum, mean, median and variation in the above-mentioned environmental factors were correlated with vegetation composition. The most important environmental factors explaining the variation in vegetation were mean pH and maximum water-table level. Median conductivity increased with increase in waterlogging and eutrophication. Some seasonal trends in the dynamics of these parameters were observed. The lowest conductivity was in spring, increased continuously throughout summer and peaked in autumn. In contrast, water level decreased in summer, when evapotranspiration was greatest, and rose in autumn after heavy rainfall. The pH increased from March to June, then was stable and decreased at the end of summer. Seasonal trends were generally identical in all vegetation types. The fluctuations in the environmental factors were so considerable that they may influence the reliability of vegetation environmental analyses.