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Funkce allochtonní organické hmoty v tůni aluvia horní Lužnice
Dvořák, Jan ; Pechar, Libor
Pro aluviální tůně a říční ramena je charakteristický přísun značného množství organické hmoty ve formě listů a dalšího opadu z pobřežních dřevin. Tento materiál je zdrojem živin (C, N, P), současně funguje jako substrát pro jejich akumulaci a transformaci. V příspěvku jsou popsány procesy, spojené s dekompozicí opadu listů na základě sledování jejich rozkladu metodou "litter mesh-bags", které byly exponovány in situ po období listopad 1989 - listopad 1990. Opad představuje značný rezistentní materiál, který spíše než zdroj živin funguje jako substrát pro akumukaci dusíku a fosforu.
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Stabilization of the natural landscape in Bohemian Forest frontier area (Czech Republic/Germany) abandoned for 40 years
Kučera, Tomáš ; Guth, J.
Land cover and its development is an object of study in applied landscape ecology and landscape conservation. Historical aerial photos are the basic data source for studies of long-term landscape development. All of the data can be analysed by the use of geographical information systems, GIS. GIS IDRISI is recommended for academic and nature conservation purposes, because of its powerful tools for spatial pattern (landscape structure) evaluation, user-friendliness and low price.Own case study is located in the borderland along the former "Iron Curtain". After the landscape was abandoned, the processes of "desynanthropisation" started. In the Bohemian Forest Mts. in SW Bohemia, (i) patch size and shape were evaluated and (ii) spatial pattern was characterised by various indices: diversity, fragmentation, contagion, etc. Land cover development is presented in a special triangular "landcovergram". The changes of indices are closely, but not simply, related to the intensity of human influence (management). Two types of local differences are important: the original situation ("the starting point") and both the quality and quantity of postsynanthropic management. Two main developments of landscape structure have occured in the upper floodplains near the Bohemian/Bavarian borderline: (i) the managed parcels were homogenised, and at the same time, (ii) wetlands were abondoned within their natural borders.
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