Education AN ATTEMPT AT EVALUATING THE INFLUENCE OF WATER QUALITY ON THE QUALITATIVE AND QUANTITATIVE STRUCTURE OF EPIPHYTIC FAUNA DWELLING ON STRATIOTES ALOIDES L., A CASE STUDY ON AN OXBOW LAKE OF THE £YNA RIVER*

The paper contains the results of a study on the dependence of the qualitative and quantitative structure of the phytophilous macrofauna dwelling on Stratiotes aloides L. (water soldier) on the quality of waters in a lentic oxbow lake of the £yna River. The observations were carried out during the vegetative season (April – June) 2006 at high and moderate water levels. During the study, a total of 18 taxa of invertebrates dwelling on the above plant species were identified, with the exact number of taxa varying in time: 11 taxa were noticed in April and May, and in June their number went up to 13. The examination of hydrochemical parameters of the oxbow lake waters revealed that the den-sity of macrofauna was lower at higher values of proper conductivity and macronutrients, ammonia nitrogen and COD, increasing at high levels of sulphates. High concentrations of ammonia nitrogen and non-organic components coincided with decreased biomass of epi-phytic animals on water soldier. Additionally, it has been observed that elevated concentra-tions of potassium ions have a negative influence on the biomass of most epiphytic ani-mals (except Erpobdella sp.)