Why an apparently prosperous subspecies needs strict protection: The case of testudo hermanni boettgeri from the central balkans

Abstract

© 2018. Sonja Nikolić All rights reserved. According to the International Union for Conservation of Nature (IUCN), more than half of all chelonian species are seriously threatened. Habitat loss and illegal trade contribute substantially to this trend. Rare and vulnerable taxa often enjoy formal protection while taxa with large populations are usually neglected, despite worrying trends. The two subspecies of the Hermann’s Tortoise (Testudo hermanni) present a good example of this contrast: the western subspecies (T. h. hermanni) is rare, while the eastern conspecific (T. h. boettgeri) is still relatively common in appropriate habitats. The IUCN lists the entire species as Near Threatened. In practice, the western subspecies is treated as endangered, while the assessment of the conservation status of the eastern counterpart is still lacking. Using field data collected from five populations of T. h. boettgeri in th re e Ba lk an countries, we aim at filling this gap. Population Viability Analyses (PVAs) suggest that even large and dense populations inhabiting favorable environments could face extinction by over-harvesting in a matter of years. Natural causes (e.g., higher female mortality) or stochastic events (e.g., wildfires) could be detrimental to peculiar isolated populations. The uncertain viability of the studied populations casts considerable doubt over the apparent stability of T. h. boettgeri. For this subspecies to avoid the fate of its western cousin, we propose the upgrade of its IUCN category to Vulnerable throughout its distribution range.