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Demography of Amboseli baboons, 1963-1983
Jeanne Altmann1, Glenn Hausfater2, Stuart A Altmann1
1Department of Biology, University of Chicago, Chicago, and Institute of Primate Research, National Museums of Kenya, Nairobi.
American Journal of Primatology
|January 29, 2020
Summary
Yellow baboon (Papio cynocephalus) populations in Amboseli declined dramatically from 1963-1979 due to environmental changes. Infant and juvenile mortality, sensitive to environmental shifts, drove this primate population decline.
Area of Science:
- Primatology
- Ecology
- Conservation Biology
Background:
- Yellow baboon (Papio cynocephalus) populations in Amboseli National Park, Kenya, experienced significant declines between 1963 and 1979.
- This decline coincided with environmental changes, including fever tree mortality and halophyte invasion, linked to rising groundwater and soil salinity.
Purpose of the Study:
- To analyze the demographic changes in the yellow baboon population over a 15-year period.
- To investigate the relationship between environmental shifts and primate population dynamics.
- To identify key demographic variables sensitive to environmental change.
Main Methods:
- Repeated censuses of the yellow baboon population in Amboseli National Park.
- Analysis of population density, group size, and age distribution.
- Examination of demographic parameters like age-specific mortality and natality for a social group.
Main Results:
- Population decreased from over 2,500 to 123 individuals (density from 73 to 1.8/km²).
- Median group size decreased from 43 to 27; largest and smallest groups declined most.
- Population stabilized by 1983 around 150 individuals, but decline began earlier, with greatest rate 1964-1969.
- Infant and juvenile mortality identified as the most sensitive demographic variable to environmental change.
Conclusions:
- Environmental changes, specifically rising groundwater and soil salinity, significantly impacted the yellow baboon population.
- The decline in baboon populations mirrored that of other savannah woodland mammals.
- Infant and juvenile mortality is a critical indicator of environmental stress in primate populations.
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