Anthropogenic disturbance induces opposing population trends in spotted hyenas and African lions
Large carnivore populations are declining worldwide due to direct and indirect conflicts with humans. Protected areas are critical for conserving large carnivores, but increasing human-wildlife conflict, tourism, and human population growth near these sanctuaries may have negative effects on the carnivores within sanctuary borders. Our goals were to investigate how anthropogenic disturbance along the edge of the Masai Mara National Reserve, Kenya, influences the demography and space-use of two large carnivore species that engage in intense interspecific competition. Here we document, in one disturbed region of the Reserve, a rapid increase in the population size of one large predator, the spotted hyena (Crocuta crocuta), but a striking concurrent decline in numbers of another, the African lion (Panthera leo). Anthropogenic disturbances negatively affected lion populations, and decreasing lion numbers appear to have a positive effect on hyena populations, indicated here by an increase in juvenile survivorship. We also saw an increase in the number of livestock consumed by hyenas. Our results suggest human population growth and indirect effects of human activity along Reserve boundaries may be effecting a trophic cascade inside the Reserve itself. These results indicate both top-down and bottom-up processes are causing a shift in the carnivore community, and a major disruption of guild structure, inside the boundaries of one of the most spectacular protected areas in Africa.
KeywordsAnthropogenic disturbance Crocuta crocuta East Africa Mara-Serengeti ecosystem Panthera leo Protected areas
We thank the Kenyan National Commission for Science, Technology and Innovation, the Narok County Government, The Mara Conservancy, and the Kenya Wildlife Service for permission to conduct this work. We also thank all those who assisted with data collection in the field. We thank Brian Heath for allowing us to study in the Mara Triangle, and for maintaining the Mara Triangle in such pristine condition. Project infrastructure was supported by National Science Foundation Grants OISE 1556407 and DEB 1353110 to KEH. DSG and LJU were supported by National Science Foundation Graduate Research Fellowships. Much of this work was made possible by funding from the Lakeside Foundation and the Kenya Wildlife Trust.
- Craft ME, Hampson K, Ogutu JO, Durant SM (2015) Carnivore communities in the greater Serengeti ecosystem. In: Sinclair ARE, Metzger KL, Mduma SAR, Fryxell JM (eds) Serengeti IV: sustaining biodiversity in a coupled human-natural system. The University of Chicago Press, Chicago, pp 419–450Google Scholar
- Dloniak SM (2006) Masai Mara Predator Research Project; Masai Mara National Reserve, Kenya. 1–18Google Scholar
- Gelman A, Meng XL, Stern H (1996) Posterior predictive assessment of model fitness via realized discrepancies. Stat Sin 6:733–760Google Scholar
- Gelman A, Carlin JB, Stern HS et al (2013) Bayesian data analysis, 3rd edn. CRC Press, Boca RatonGoogle Scholar
- Green DS (2015) Anthropogenic disturbance, ecological change, and wildlife conservation at the edge of the Mara-Serengeti ecosystem. PhD Dissertation. Michigan State UniversityGoogle Scholar
- Kellner K (2016). jagsUI: A wrapper around ‘rjags’ to streamline ‘JAGS’ analyses. R package version 1.4.4. https://CRAN.R-project.org/package=jagsUI
- Kruuk H (1972) The spotted hyena: a study of predation and social behavior. University of Chicago Press, ChicagoGoogle Scholar
- Plummer M (2003) JAGS: a program for analysis of Bayesian graphical models using Gibbs sampling in Proceedings of the 3rd International Workshop on Distributed Statistical Computing (DSC) (Vienna). pp 1–10Google Scholar
- R Core Team (2016) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. http://www.R-project.org/
- Sinclair ARE, Norton-Griffiths M (1979) Serengeti: dynamics of an ecosystem. The University of Chicago Press, ChicagoGoogle Scholar
- Woodroffe R (2001) Strategies for carnivore conservation: lessons from contemporary extinctions. In: Gittleman J, Wayne RK, Macdonald DW, Funk SM (eds) Carnivore conservation. Cambridge University Press, Cambridge, pp 61–92Google Scholar
- Yirga G, De Iongh HH, Leirs H et al (2012) Adaptability of large carnivores to changing anthropogenic food sources: diet change of spotted hyena (Crocuta crocuta) during Christian fasting period in northern Ethiopia. J Anim Ecol 81:1052–1055. https://doi.org/10.1111/j.1365-2656.2012.01977.x CrossRefPubMedGoogle Scholar