WPŁYW WEZBRAŃ NA FAUNĘ ZAMIESZKUJĄCĄ ALUWIA NA PRZYKŁADZIE DOLNEGO BIEGU DUNAJCA

Abstract

THE EFFECT OF WATER-LEVEL FLUCTUATIONS ON RIVER BANK FAUNA IN THE DUNAJEC RIVERAbstract. Water-level fluctuations are the main factor disturbing channel-bank burrowing biota and controlling their diversity and abundance. The most frequently observed burrow ers in recent alluvial sediments of the Dunajec River include European mole (Talpa europaea Linnaeus), common earthworm (Lumbricus terrestris Linnaeus), a few species of ground beetles (Carabidae Latreille) and solitary bees (Ammophila Kirby). A large majority of the small organisms inhabiting the alluvial deposits have not developed the appropriate features to survive floods that can completely modify river banks, making them unsuitable to quick re-colonisation for a several months. Best adapted are European mole and bank swallow (Riparia riparia Linnaeus) building their terminal chambers beyond the range of large or medium flood and the progressive erosion of the banks. Changes in the river bank ecosystem of the Dunajec River, caused by floods, were examined in 2010 and 2011. It resulted in an impact of environmental factors on the distribution of fauna in the alluvial sediments of meandering rivers. Their effect varies according to the depth in the alluvial profile and the distance from the recent river channel. Based on comparison of the two Early-Holocene alluvial profiles with the recent deposits of the Dunajec floodplain, an attempt to assess the usefulness of recent bioturbation structures for paiaeoenvironmental analysis was made.