Persistence and local extinction of lion prides in the Ngorongoro Crater, Tanzania
African lions (Panthera leo) live in social groups (prides) that exhibit group territorial behavior. Pride persistence is expected to depend on its ability to compete against neighboring prides as well as on average rates of reproduction and survival, thus providing a meaningful measure of intergenerational reproductive success. We used Akaike’s Information Criterion (AIC) to select the best approximating models explaining how demographic variables influenced pride persistence during a 30-year period in the Ngorongoro Crater, Tanzania, and identified landscape factors affecting those demographic variables. Pride persistence to 10 years depended on adult female density (pride size) and cub productivity (the ultimate source of new females). Average age of adult females had a weakly positive influence on pride persistence, while the effect of female mortality was weakly negative. Adult female mortality increased with disease epidemics and in territories with high human disturbance. Cub productivity was highest in territories closest to rivers and only slightly higher near swamps, and also high in areas of higher vegetative cover and high human use. No landscape variable significantly affected female density. The growth and population size of the Crater lions was closely linked to demographic performance of individual prides, while territorial behavior played a key role in mediating the interactive effects of landscape and demography.
KeywordsAnthropogenic factors Disease outbreak Landscape variables Pride territory Reproductive success Territorial behavior
We thank the Tanzania Wildlife Research Institute (TAWIRI) and the management of the Ngorongoro Conservation Area (NCA) for providing permission to conduct the field research work. We thank the many people who worked in the Crater over many years to assemble the long-term dataset for the Crater lion population. The long-term research in the Ngorongoro Crater was funded by NSF grants LTREB 9903416 and EF 022543.
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