Structure of Zoocenoses in the Ephemeral Pond Lilov Vir, Western Bulgaria

This study aimed to observe the development of zoocenoses in an ephemeral karst water body providing a dynamically changing habitat and unstable hydrological regime with an emphasis on assessing the main factors influencing the structure of the macrozoobenthos and zooplankton communities. The study was conducted in Pond Lilov Vir near Karlukovo Vil., Western Bulgaria. The main physicochemical parameters and the concentrations of nutrients were recorded. The macrozoobenthos (MZB) and zooplankton samples were taxonomically determined and statistical analyses of the obtained results were performed. The results have shown that the pond supports a variety of species and species typical to temporary waters. The variation in hydroperiod (HP) duration over the years leads to the formation of different communities. Longer HPs suggest greater biodiversity. In drying pools, especially those with a short HP, the leading factor for structuring communities is the abiotic environmental factors-HP and water volume (WVOL). Biotic factors, such as competition and predation, are not leading, due to the lack of fish and insufficient time for the development of invertebrate predators.