Résumé
This study investigates the evolution of a population of Hermann's tortoises, located on the edge of the massif des Maurcs, over a period of 30 years through capture recapture monitoring. It shows a considerable decline of 73% in the number of adult tortoises between the early 1980s and 1999; then from 1999, the population stabilized at around 100 adult tortoises. The fall in numbers during the first period seems to be linked to several factors. The 22% increase in forest cover between 1983 and 1995 increased the concentrations of eggs laid in some open areas, making it easier for the species' natural predators to find them. Mechanized clearance of undergrowth carried out in 1989 and 1994 has undoubtedly reduced the size of the population. The presence of dogs has posed an additional threat (97% of the adult tortoises have bite marks and 7% are missing limbs). In addition, the impact of dog bites on the tortoises' shells has, over time, removed individual markings, thereby distorting survival estimates. The stabilization of numbers over the last decade seems to be due to the discontinuation of certain practices (notably mechanized undergrowth clearance). However, the demographic structure (with almost no juveniles) could soon lead to another decrease in population. This situation seems to be specific to this particular population and cannot be applied generally to all the populations in Provence.