Chapter 12. Golem grad: from a ghost island to a snake sanctuary
Résumé
Abstract Golem Grad is a small island situated in montane Prespa Lake, North Macedonia. Rock crevices, shrubs, and trees provide microhabitats favorable to reptiles. Ruins of old buildings from past centuries offer abundant shelters. Prespa Lake ecosystems have been spared from industrial agriculture and urbanization, and, for these reasons, Golem Grad hosts large populations of Hermann Tortoise (Testudo hermanni), Common Wall Lizard (Podarcis muralis), Nose-horned Viper (Vipera ammodytes), and amphibious Dice Snake (Natrix tessellata). These species also occur on the nearby mainland and in Eastern Europe. Compared with continental populations, the insular vipers are dwarf while insular Dice Snakes exhibit a trend to gigantism. Low-quality food resources (e.g., centipedes) may limit the growth and fecundity of vipers, whereas Dice Snakes benefit from high-quality prey (large schools of fish) that may promote large body size and sustain large populations. Hence, both dwarf and very large snake populations cohabit on Golem Grad.