Abstract

Hydrological, chemical and biological methods were applied to investigate the ecological status of the Gemenc floodplain area. The examined wetland was generally poor in planktonic organisms, however benthonic eutrophication was evident. 81 plant species and 17 associations were proved to appear during the examined years. Formation of vegetation was influenced by water-level. The hydrological regime changed extremely. Multiple floods and the almost dried-out bed were both unfavourable for the macro-vegetation. The ecological status was mostly good as indicated by the periphyton community. During floods, the chemical parameters depended on the quality of water flowing from the Danube river and during floodless times, it determined the composition of the macrophytes. The concentrations of inorganic nutrient parameters were generally not too high. The floodless times were more critical, considering the pH-value, concentration of free ammonia and deficit of dissolved oxygen. There were connections between water-balance, the chemical and biological quality of water, and the nesting and feeding conditions for waterfowls. The results showed that it is necessary to carry out further intervention in order to keep the nature of the habitat. Habitat management should mean flexible conservation and preservation practice through revitalization by ensuring the predominance of natural processes and better water supply by technical interventions.

Key words: Natural wetland, ecological status, nature conservation treatment.