Related Experiment Videos
What limits the Serengeti zebra population?
Sophie Grange1, Patrick Duncan, Jean-Michel Gaillard
1Centre d'Etudes Biologiques de Chizé, CNRS UPR 1934, 79360 Beauvoir-sur-Niort, France. grange@cebc.cnrs.fr
Oecologia
|August 5, 2004
Summary
Low first-year survival limits Serengeti zebra populations, unlike wildebeest and buffalo. Predation on adult zebras is high, but foal mortality is the key factor impacting zebra population dynamics.
Area of Science:
- Ecology
- Wildlife Biology
- Population Dynamics
Background:
- Serengeti ungulate populations (zebra, wildebeest, buffalo) exhibit divergent trends since the 1960s.
- Wildebeest and buffalo populations surged post-rinderpest eradication, while zebra numbers remained stable.
- Ruminants are resource-limited, whereas zebra population stability suggests predation may be a limiting factor.
Purpose of the Study:
- To investigate the mechanisms driving Serengeti zebra population dynamics.
- To compare population dynamics of zebra, wildebeest, and buffalo using demographic models.
- To identify key factors influencing the contrasting population trends.
Main Methods:
- Demographic modeling based on age-class-specific survival and fecundity.
- Comparative analysis of population dynamics across three Serengeti ungulate species.
- Examination of reproductive potential and survival rates.
Main Results:
- Wildebeest exhibit higher reproductive potential than zebras (earlier breeding, shorter generation time).
- Differences in reproduction do not explain population trend disparities.
- Significantly lower first-year survival in zebras is sufficient to explain their stable population size.
Conclusions:
- Low first-year survival is the primary factor limiting Serengeti zebra populations.
- High predation rates on adult zebras contribute to population dynamics, but foal mortality is critical.
- Further research is needed to understand the high mortality rates in zebra foals.