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EN
Our research was conducted in two different mire habitats . in the minerotrophic and ombrotrophic mires adjoining the lakes (LM) of the Łęczna-Włodawa Lakeland and in the eutrophic and calcium-rich mires of the river valleys (RM) of the Roztocze Highlands region (both study regions in Eastern Poland). The study aimed to evaluate (1) the position of mire phytocoenoses in the environmental gradient - from minerotrophic to ombrotrophic ones, (2) the influence of the species and life-form composition of plant communities on the density of bryophytes, and (3) the quantitative and sociological relations between the density of vascular plants and bryophytes. Phytosociological releves (180) were made in six lakeland mires and in four river valleys. The area of each phytosociological releves (16-25 m2) represented species composition and vertical structure of communities. In the study of the relation vascular plants-bryophytes we took into consideration the following parameters: species abundance, cover of particular plant layers (trees, shrubs, herbs, bryophytes), and the number of species in particular life-form groups. In the LM the cover of particular layers was correlated negatively with the abundance of Sphagnum mosses. Betula pendula, B. pubescens and Frangula alnus overgrowing the LM affect negatively the abundance of some peat mosses. Less distinct relations were found between the tree density and bryophyte cover in the RM, but there is a positive correlation between the shrub cover and its predominant species - F. alnus - and the abundance of Polytrichum commune. Taking into account the relations between the herbaceous cover and the abundance of bryophytes, the dependencies are also less pronounced in the RM phytocoenoses. A negative effect of the herbaceous cover and its species richness on the abundance of P. commune was observed, as well as positive relation between the number of herbaceous species and the abundance of Calliergonella cuspidata. In the LM phytocoenoses, a negative correlation was found in the case of S. palustre, while in the case of Aulacomnium palustre and S. cuspidatum the relations were positive. Among herbaceous plants of LM habitats the biggest number of statistically significant correlations were observed for abundance of Carex lasiocarpa and different bryophytes, while in the RM habitats the correlations between the abundance of bryophyte and vascular plant layers are less distinct.
EN
The aim of this study is to present short-term changes in the spatial structure of water vegetation in Lake Rotcze. Field studies were carried out during the growing seasons of 2000 and 2005. The obtained results allowed to estimate the following parameters that characterize the spatial structure of macrophytes: species frequency in particular ecological groups, the average vegetation cover in these groups, the average cover of particular species, both in the whole reservoir and in different depth ranges, as well as the PVI (Percent Volume Infested) coefficient for ecological groups. The frequency and cover of some species and ecological groups of macrophytes changed during the study period.
EN
Ecotone zones are very interesting objects for the investigations of the ecological succession of plant communities. The main aim of the present study was to analyse the rate and direction of changes in ecotone vegetation caused by changes in a level of groundwater table. In the studies carried out during years 1993-1998 a generally accepted method of a belt transect was applied. Transed 5 m wide ran across all aquatic, litoral and land phytocenoses. Most visible changes took place in the aquatic and littoral phytocenoses. Some of them disappeared and then reconstructed themselves within a new range, in others the species composition was changed.
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