The space utilization by the reptiles in Prespa National Park

Abstract

In the first part of this paper data are presented onthe habitat segregation of the reptile species of LakePrespa National Park. Twenty species of reptiles arepresent in the study area. Most of them are ofEast-Mediterranean origin, some are Balkan endemicsand a few are of northern origin. Systematic surveysand counts of reptiles were conducted in each of thefollowing habitats: marshes and reedbeds, wet meadows,rocky coastal areas and sandy beaches, cultivatedland, grazing lands, mixed deciduous, oak and beechforests, sub-alpine and alpine meadows. A list isprovided of the typical reptile species occurring ineach of these habitats, with notes on abundance andhabits. The highest reptilian diversity was found inman-made/modified habitats, namely the farmland zone,which structurally is the more diversified. There wasa dramatic fall of species richness with increasingaltitude. The second part of the paper describesqualitative differences in habitat utilization amongthe members of the two major reptilian groups, lizardsand snakes. The Sand Lizard Lacerta agilis isfound exclusively in the alpine and subalpinegrasslands above 1600 m. asl., the Common Wall LizardPodarcis muralis is the more euryecous while allother Lacertids show a clear specialization in habitatuse though retaining various degrees of overlap. Amongsnakes the Adder Vipera berus is restricted tohigh mountain grasslands, the two Natrix speciesare common and more or less confined to areas close tothe lakes while the Nose-horned Viper Viperaanmmodytes the third commonest species of the areaprefers rocky/stony slopes.The notes on habitatutilization by the remaining species of snakes areonly of indicative value because of small number ofobservations.