Although conservation of percolation mires is very important for the European biodiversity, our understanding of their functioning is still insufficient, as most of the studied sites are to some extent degraded. We present a study on the relationship between vegetation patterns, hydrochemical gradients and water level fluctuations carried out in the Rospuda valley (NE Poland), which was recently discovered for science as a uniquely preserved fully functioning percolation mire. Vegetation composition, mire water chemistry and water level dynamics were studied along five transects perpendicular to the valley. Eight major vegetation types were identified: brown moss-small and slender sedge fens, Sphagnum-small sedge fens, brown moss-tall sedge fens, tall sedge-reed fens, pinebirch fen woodlands and shrublands, spruce fen woodlands, inundated alder woodlands, alder spring fen woodlands. The seasonal dynamics of water table was revealed as the major factor explaining vegetation patterns. The studied chemical parameters were relatively homogeneous in the whole mire-there is a rather uniform type of mineral-rich nutrient-poor subsurface water all across the fen.
Outcrossed mating systems play a very important role in the persistence of endangered, selfincompatible plants such as shrub birch, Betula humilis Schrk. The goal of this study was to estimate, for the first time, the effectiveness of sexual reproduction in threatened edge and sub-central populations of shrub birch. The amplified fragment length polymorphism (AFLP) method revealed that all of the individuals at each locality had different genotypes. The matrix incompatibility count (MIC) suggested that the effectiveness of recombination was similar among all the populations of shrub birch under study. However, taking into account the greater germination ability of seeds in subcentral populations, we conclude that sexual reproduction in those populations can be more efficient. The germination capacity of seeds depends on their mass, which was significantly lower in dry or more shaded sites compared to wet or more exposed sites. Nonsignificant results of multiple regression models suggest that chemical parameters of the habitat (pH, EC, NH 4 + , PO 4 3− ) had no influence on the reproductive output of B. humilis. The discrepancy between the still quite substantial genetic diversity and the poor sexual reproduction in shrub birch populations can be explained by the production of a few phosphorus-rich seeds, insufficient time for a decrease in genetic variation in the disappearing part of the range or hybridization with close congeners.
Over the last 25 years, considerable changes have been observed in the littoral vegetation of 11 lakes within the Sejny Lake District. In eight lakes (Dowcien´, Jurkowo, Kunis, Miałkie, Pilwie, Płaskie, Wiłkokuk, Zelwa) where Chara species dominated, their communities declined or disappeared completely. In four of these lakes (Dowcien´, Jurkowo, Kunis and Miałkie), charophytes were replaced by communities of the class Potametea (mainly Nupharo-Nymphaeetum albae and Ceratophylletum demersi). In three other lakes (Pilwie, Płaskie and Wiłkokuk), the area covered by charophyte communities decreased. In Lake Zelwa, Charetum rudis and Charetum jubatae disappeared while Charetum tomentosae and Charetum fragilis expanded. A total area of charophyte communities remained approximately the same. A considerable increase in the water total hardness and PO 3À 4 concentration was noted in each of the eight lakes. In most of them increased levels of dissolved organic matter (measured as COD-KMnO 4 ) and pH were detected as well. However, the increase in the PO 3À 4 concentration was smaller in Lakes Wiłkokuk and Zelwa in which only slight changes in the vegetation were observed. In the above two lakes, the concentration of dissolved organic matter decreased and low water colour values are now noted. In three lakes (Długie, Dmitrowo and Gajlik), the charophyte communities tended to expand under the condition of moderate or high (Lake Długie) PO 3À 4 concentration, while dissolved organic matter concentrations were low. These lakes are also characterized by low values of colour. Charophyte communities may persist in lakes for a long period of time even when there is a moderate increase in PO 3À 4 concentration until the colour of water distinctly increases (420 mg Pt L À1 ).
The historical development of the hydroseral vegetation of three humic lakes was studied. We applied a combination of methods to reconstruct the past vegetation (plant macroscopic remains, peat decomposition, sediment chemistry and radiocarbon dating). The contemporary environment of these lakes was assessed by vegetation and water chemistry analyses. The oldest foreshore sediments were formed 13075-12700 cal BP (Lake Suchar VI), 10115-9670 cal BP (Lake Suchar III) and 8747-8479 cal BP (Lake Widne). The differences in contemporary vegetation are reflected in the subfossil plant assemblages. From the beginning, poor fens and bogs occurred beside Lake Suchar III, moderately rich and poor fens were developed at Lake Suchar VI, while reedswamps and moderately rich fens occurred at Lake Widne. The foreshore vegetation changed over time but only within a restricted range, specific for each lake corresponding to the hydrochemical differences between the lakes. Lakes are classified as humic if some features are combined, such as the specific vegetation and water parameters. However, over the past few decades escalating climatic and anthropogenic changes could transform the character of these water bodies. The application of multidisciplinary methods permitted comparison of the development of three apparently similar lakes and identification of significant ecological differences.
A comparative analysis of submerged Potametea communities in lakes of north-eastern Poland was conducted with respect to 16 water chemistry and 14 substrate parameters. The analysis of 187 releve´s based on TWINSPAN clustering showed the existence of 8 aquatic vegetation types. Each of them is characterized by a strong dominance of one of the following macrophytes: Potamogeton lucens, P. perfoliatus, Myriophyllum spicatum, M. verticillatum, Elodea canadensis, Ceratophyllum demersum, Ranunculus circinatus and Hydrilla verticillata. The above vegetation types correspond to the plant associations distinguished using the Braun-Blanquet method (Potametum lucentis, Potametum perfoliati, Myriophylletum spicati etc.) It was demonstrated that among properties of water analysed, COD-KMnO 4 , SO 4 2) , pH, Na + , K + , Ca 2+ , total hardness, total Fe, Cl ) and colour appear to be most important in differentiating the habitats of the communities studied. In the case of substrates the properties which best differentiated the habitats compared were hydration, organic matter content, total N, PO 43) , K + , dissolved SiO 2 , SO 4 2) , Cl ) and pH. Most of the aquatic plant communities investigated are distinct with respect to their phytocoenotic structure and ecology and could be good indicators of various types of habitats in lake ecosystems.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.