|
|
Funkce allochtonní organické hmoty v tůni aluvia horní Lužnice
Dvořák, Jan ; Pechar, Libor
Large amounts of leaf litter enter into the pool ecosystem from the canopy of riparian woody plants every year. If the leaf litter is spread out over bottom in a dense layer it becomes a medium for nutrient exchange between the benthic and pelagic zones of the water body. Leaf litter processing was studied in material closed in nylon mesh-bags laid out on the bottom surface from the time of leaf abscission in November 1989 until the next autumn when the bottom was covered by a new leaf layer (exposure time was 372 days). The residual matter becomes deposited in bottom sediments storing the rest of the original nutrient content in an enriched form as immobilization products in the bottom deposits.
|
|
| |
|
|
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.
|
|
| |
|
| |
|
| |
guest ::
