DISTRIBUTION OF AQUATIC MACROPHYTES IN PIT LAKES IN RELATION TO THE ENVIRONMENT (BORSKÁ NÍZINA LOWLAND, SLOVAKIA)

The numerous pit lakes in the Borska nizina lowland, are the results of gravel and sand extraction that took place in the later half of the 20th century. After the retreat of natural wetlands from the farming lowland landscape, pit lakes contributed to its diversification. Hydrophytes and environmental parameters (morphometry, age of water bodies, land use and human impact) of eleven pit lakes were surveyed and mapped in 2001-2003. Among the 17 species identified in the set of lakes submerged plants prevailed. The find of critically endangered species Hydrocotyle vulgaris in sand pits is especially important. The dominant Myriophyllum spicatum and subdominant Ceratophyllum demersum showed continual distribution. Patches of floating leaf plant Potamogenton nodusus were found in almost all lakes. The mass of Myriophyllum spicatum positively correlated with segmentation of lakes (r = 0.52) and the age of a reservoir (r = 0.76), while Ceratophyllum demersum correlated with the muddy sediment (r = 0.95). The study emphasises the significance of location, morphometry and use of pit lakes in environmental planning. [PUBLICATION ABSTRACT]