Charophytes of Gornje Podunavlje ponds: Revitalization process aspect

Unique marshland area in the Danube floodplain - Special Nature Re?serve Gornje Podunavlje is considered to be one of the last aquatic flora and fauna refuges in the region. The revitalization projects in SNP Gornje Podunavlje started in 2011. They were conducted in order to protect biodiversity and to provide the natural ecosystem. The aim of this study was to investigate and compare the present diversity and distribution of the charophytes in five ponds of SNR Gornje Podunavlje, depending on phases of the revitalization process within the ponds. The researched area includes the following ponds: Semenjaca, Sarkanj, Siroki rit, Sakajtas and Ribolov. The Siroki rit pond was under the process of revitalization during the field surveys, Semenjaca and Sarkanj have already been revitalized, and Ribolov and Sakajtas were not exposed to the revitalization processes at all. The field surveys were conducted monthly, from May to September 2016. Water quality parameters were measured in situ and in laboratory. Ponds differed considerably when it comes to water chemistry; Semenjaca and Sarkanj were associated with highest nutrient concentrations, while Siroki rit was characterized by highest conductivity and water hardness. The highest diversity was found in Siroki rit pond, which was still in process of revitalization when the field survey was conducted. Charophytes were not detected within previously revitalized ponds (Semenjaca and Sarkanj). Eight species of charophytes were detected: Chara contraria, Chara globularis, Chara tenuispina, Chara vulgaris, Nitella confervacea, Nitella gracilis, Nitella syncarpa and Tolypella prolifera.