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EN
Loss and degradation of wetlands is now one of the most important environmental issues on a global scale. Previous research based on analyses of cartographic materials allow for quantification of changes in wetland area in recent centuries. The results of lithological research of peat cores, reported in this publication, have established that the processes of anthropogenic loss of wetlands can be much older and in the Kłodnica valley were initiated in the first millennium BC. As a result of increased mineral sedimentation accompanying soil erosion some peatlands have been fossilized whilst the area of others has been reduced. In total, the surface area of peat-forming wetlands in the bottom of the Kłodnica valley decreased by over 60% between the time of the Lusatian Culture settlement and the Middle Ages. Post-peatland habitats are recently used for agricultural or colonized by non-peat forming vegetation. These processes have played a more important role in the degradation of peatland ecosystems than the direct human impact in historic times. Changes in hydrographic networks, land drainage and regulation of water levels in rivers and canals in the last century have contributed to further reducing the wetland areas by almost 50% compared to the 1880s. These processes, however, have mainly affected ephemeral non-peat forming wetlands.
PL
Artykuł prezentuje wyniki badań nad postglacjalną ewolucją roślinności siedlisk podmokłych w dolinach rzecznych Kotliny Raciborskiej. Scharakteryzowano w nim trzy, uznane za reprezentatywne, profile osadów niewielkich torfowisk starorzecznych w dolinach Osobłogi, Kłodnicy i Rudy. Wyniki analizy pyłkowej i makroszczątków wskazują na podobne uwarunkowania rozwoju siedlisk a w konsekwencji podobną historię roślinności mokradłowej w badanych dolinach i pozwalają wyróżnić następujące etapy ich rozwoju: (1) od późnego vistulianu po schyłek okresu borealnego – w zbiornikach wodnych rozwój zbiorowisk szuwaru właściwego (rzadziej wielkoturzycowego) przy współudziale roślin wodnych, zaś na siedliskach umiarkowanie wilgotnych – lasów łęgowych z udziałem wierzb i topoli; (2) okres atlantycki i subborealny – rozwój wielogatunkowych, klimaksowych lasów z dominacją olszy czarnej, w szczególności ols porzeczkowy na torfowi - skach; (3) okres subatlantycki – w warunkach antropopresji rozwój nieleśnych zbiorowisk turzycowo-mszystych, początkowo ze związku Magnocaricion, ewoluujących w kierunku zbiorowisk kwaśnych młak niskoturzycowych ze związku Caricion nigrae na torfowiskach oraz ponowny rozwój lasów łęgowych na glebach aluwialnych.
EN
The article presents the results of research on the post-glacial evolution of vegetation within wetland habitats in the river valleys of Racibórz Basin, southern Poland. Three sequences of deposits, representing small peatlands developed in the oxbow lakes of the Osobłoga, Kłodnica and Ruda Rivers, have been recognized. The results of pollen and macrofossil analyses indicate similar conditions for the development of habitats, and consequently a similar history of the wetland vegetation in the studied valleys. The following stages of vegetation changes can be distinguished: (1) from the Late Vistulian to the Late Boreal – the development of Phragmition (less frequently Magnocaricion) communities with the participation of aquatic plants in water bodies, whereas riparian forests with willows and poplars in moderately moist habitats; (2) the Atlantic and Sub-Boreal periods – multi-species, climax forests with the dominance of Alnus glutinosa, in particular communities of Ribeso nigri-Alnetum on swamps; (3) the Sub-Atlantic period – the expansion of non-forest, sedge-moss communities due to human impact, initially from the alliance Magnocaricion, evolving in acidophilic communities from the alliance Caricion nigrae on peatlands, whereas re-development of riparian forests on alluvial soils.
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