The effects of fire and mechanical habitat destruction on survival of the tortoise Testudo hermanni in northern Greece Original Research Article

The impact of fire and mechanical habitat destruction on a population of the tortoise Testudo hermanni in northern Greece varied with vegetation type and season. A major fire in summer 1980 caused low (<5%) mortality of sexable tortoises (>10 cm) in coastal heath, highest (about 50%) mortality in grassland, and intermediate levels in dry heath. Mechanical habitat destruction caused about 50% mortality in affected areas. Mortality of juveniles was greater than that of sexable animals. Overall, the 1980 catastrophe was more damaging than previously thought, causing a 64% decrease in the total size of the Alyki main heath population. A localized summer fire in 1986 caused a similar level and pattern of mortality to that of 1980, but a spring fire in 1988 had little effect on the tortoise population. A fire and mechanical habitat destruction in winter 1989/90 caused only a 14% decrease in population size; mortality was again concentrated in grassland areas, but affected juveniles and sexable animals equally. Variation of mortality with season suggests that any burning needed for habitat management at tortoise sites should occur in winter or early spring. Juveniles were undersampled by 3–4 times compared to sexable animals; their number increased greatly by 1990, reaching the same proportion as in the original population. There was, however, no recovery in the number of sexable tortoises in the decade after the 1980 catastrophe.