The present book is aimed at summarizing the most of the studies have been carried out during the last two decades on the ecosystems of the lake Srebarna – the most prominent Bulgarian Nature Reserve on the Lower Danube bank. The studies have been performed mostly by scientists and researchers of the newly established Institute of Biodiversity & Ecosystem Research, with close collaboration with colleagues from the Biological Faculty of the Sofia University and other institutes of the Bulgarian Academy of Sciences and/or high schools/universities of that country.