The Herpetological Journal

pp.294-301

Authors: A. Hailey,  J. Wright And E. Steer

Abstract: Population characteristics of sympatric Testudo hermanni and T graeca were compared at four sites in northern Greece; Alyki, Epanomi, Keramoti and Lagos. These had different habitats and levels of human disturbance. The density of tortoises larger than 10cm was similar at all sites, in the range 7-2 1 ha- 1 • Population size structures were more variable. The ratio of juveniles to adult females ranged from about 0.1 at the most disturbed site ( Lagos) to about 4 in a protected area (Epanomi). This ratio was similar for the two species at any site, even though they occupied different habitats. The main feature of disturbance was thought to be predation of eggs and juveniles by human commensals (rats and domestic animals) rather than habitat degradation .
The sample sex ratio of T hermanni was male-biased at all four sites, with an average of 3. 1 males per female. Males had more tick parasites than females, higher body temperatures, and were recaptured twice as frequently. There was an even sex ratio in T graeca, the sexes had similar numbers of ticks and body temperatures, and females were recaptured more frequently. The population sex ratio of T. hermanni is known to be male-biased at Alyki. The data on ticks, body temperatures, and recapture frequencies show that sample sex ratios are complicated by sexual differences of activity or microhabitat use. It is suggested that male T hermanni used more open areas than females, within the wood, scrub or heath occupied by this species. T graeca occupied coastal heath at all sites, an open habitat with little spatial variation of cover.