-1 Red Data List of Charophytes in the Balkans JELENA BLAZ ˇ ENC ˇ IC ´ 1,* , BRANKA STEVANOVIC ´ 1 ,Z ˇ IVOJIN BLA- Z ˇ ENC ˇ IC ´ 2 and VLADIMIR STEVANOVIC ´ 1 1 Institute of Botany and Botanical Garden ‘‘Jevremovac’’, Faculty of Biology, University of Belgrade, Takovska 43, Belgrade 11000, Yugoslavia; 2 Faculty of Veterinary Medicine, University of Belgrade, Belgrade, Yugoslavia; *Author for correspondence (e-mail: jblaz@eunet.yu; fax: +381-11-2769903) Received 17 August 2004; accepted in revised form 31 January 2005 Key words: Charophytes, Endemic species, Red list, Stoneworts, Threat categories Abstract. The occurrence of 47 species of all the six recent genera of charophytes recorded in the Balkans is demonstrated. Our aim was to assess their status of threat according to the 2001 IUCN threat categories and criteria, in order to establish the Red List of Charophytes distributed in the Balkan Peninsula. The List underlines the diversity of charophytes in this part of the world and provides guidelines for its conservation. Analysis of the charophytes in each category of threat has provided a general overview of their distribution, species richness, population features and possi- bility of survival throughout the various regions of the Balkan Peninsula. Introduction The Balkan Peninsula (SE Europe) is the richest and the most diverse region of the western Palaearctic regarding its general flora and vegetation (Stevanovic´ 1999). It is distinguished also by a rich algal flora, of which charophytes are particularly important. This botanical luxuriance has resulted from historical- evolutionary changes of the living world and conditions of the habitat in this part of Europe, from the Tertiary, through the Ice Age, up to present day. The Peninsula abounds in different terrestrial and aquatic habitats, ranging from low-land to high-land regions, as well as those in the littoral parts of the Adriatic Sea. Generally, the Peninsula is bordered by aquatic ecosystems: the Sava and the Danube rivers in the north, the Mediterranean Sea in the south, the Black, Marmara and Aegean Seas in the east and south-east, and the Adriatic and Ionian Seas in the west. The geomorphologic, pedologic and hydrologic variety of the Balkan Peninsula provides exceptional richness in both algae and other plant groups, including a large number of endemic spe- cies. The Balkan Peninsula is characterized by numerous ‘hot-spots’, or centres of diversity, and by the important plant area (IPA), which features, in particular, the specific group of charophytes. Charophytes or stoneworts are a group of complex, macroscopic, advanced algae, of great importance for both their evolutionary and ecological signifi- cance. They are commonly a very important component of the underwater Biodiversity and Conservation (2006) 15:3445–3457 Ó Springer 2006 DOI 10.1007/s10531-005-2008-5