L’ « opération éléphants » au Rwanda 1re partie. Structure de la population du Bugesera et transfert de jeunes au parc de l’Akagera

During an elephant eradication scheme in Rwanda, 134 indivi duals were shot or captured and data collected on their population structure. The overall sex-ratio was 65 males : 69 females, males being more numerous in the younger age group and females in the older. Pregnant and lactating females were always 15 years old at least. Mean calving interval was 5.1 years. The percentage of young of the year was 5.2 %. Population density ranged between 1.9. and 2.4/km2 and standing crop biomass between 3.2 and 4.6 metric tons per square kilometer. There were however significant differences between the two groups of 69 individuals living in the Karama and Rwinzoka areas respectively. The Karama population living in wooded grassland (34 km2), was younger (43.2 % of adult individuals) than the Rwin zoka population confined to 27 km2 of swamps (53.7 % of adult individuals). The mean calving interval was 3.5 years in the first population and 7.6 years in the second. Twenty six young elephants were successfully translocated to the Akagera National Park, where the species had become extinct in 1938