The History of Lake Rzecin and Its Surroundings Drawn on Maps as a Background to Palaeoecological Reconstruction

The article presents the results of landscape analysis of the surroundings of Lake Rzecin in Noteć Forest depicted on cartographic materials. Morphometrical analysis and analysis of changes in the water conditions of Lake Rzecin were conducted. Thanks to many cartographic data, changes in lake geometry could be observed during almost the whole of the last two centuries. The results show that the major impact on the rate of lake level decrease in the last two hundred years was due to melioration works. Two periods of rapid decrease in the lake surface can be observed during this time. The first occurred as a result of the creation of Rzecin Ditch, which probably took place in the middle of the 19th century; the second, in all likelihood, with its cleaning out; the exact date of this operation is not known but the results of map analysis suggest that it could have happened between 1958 and 1966. Due to these two events the lake surface decreased by 73.6% during the analysed period. Apart from this phenomenon the lake surface area seems to be quite stable: there were some fluctuations; however, changes did not exceed more than 5%. That is why it can be assumed that the human factor has the biggest influence on succession rate of the lake ecosystem. Analysis of the map collection shows that during the last two centuries there were no huge changes in the local landscape; however, other historical sources do not confirm this. According to them, not only man but also fires and insect gradations had an enormous influence on the Noteć Forest ecosystem. Nonetheless, land use structure within the Rzecin Ditch catchment area did not change a great deal; the most significant modification was the increment of forested areas from 74.1 up to 85.1%.