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22 April 2017 Lions influence the decline and habitat shift of hartebeest in a semiarid savanna
Caroline C. Ng'weno, Nelly J. Maiyo, Abdullahi H. Ali, Alfred K. Kibungei, Jacob R. Goheen
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Abstract

Efforts to restore large carnivores often are conducted with an assumption of reciprocity, in which prey populations are expected to return to levels approximating those prior to carnivore extirpation. The extent to which this assumption is met depends on the intensity of predation, which in turn can be influenced by the magnitude of environmental change over the period of large-carnivore extirpation. Recent declines of hartebeest (Alcelaphus buselaphus) populations in Laikipia, Kenya have coincided with recolonization by large carnivores, particularly lions (Panthera leo), over the past 20 years. To understand whether and the extent to which predation by lions underlies hartebeest declines, we monitored vital rates of hartebeest that were variably exposed to or protected from lions. Lion exclusion shifted rates of population growth from negative to positive (λ = 0.89 ± 0.04 versus 1.11 ± 0.11 for control and lion exclusion zones, respectively) and, consistent with other studies on ungulate demography, adult survival was the most sensitive and elastic vital rate. Analysis of life table response experiments revealed that 32% of the variation in population growth was due to fecundity, which had the greatest proportional effects on λ. In addition, hartebeest selected open (grassland) areas more strongly where lions occurred, and avoided areas with dense tree cover. Our work provides experimental evidence to support the hypothesis that hartebeest declines have been driven primarily by lion restoration, although we cannot eliminate the possibility that predation by spotted hyenas (Crocuta crocuta) additionally suppressed populations of hartebeest. Given that tree cover has increased across Laikipia over the past 50 years, we suggest that lion-driven declines of hartebeest have been exacerbated by landscape change.

© 2017 American Society of Mammalogists, www.mammalogy.org
Caroline C. Ng'weno, Nelly J. Maiyo, Abdullahi H. Ali, Alfred K. Kibungei, and Jacob R. Goheen "Lions influence the decline and habitat shift of hartebeest in a semiarid savanna," Journal of Mammalogy 98(4), 1078-1087, (22 April 2017). https://doi.org/10.1093/jmammal/gyx040
Received: 10 November 2016; Accepted: 22 March 2017; Published: 22 April 2017
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KEYWORDS
Alcelaphus
antelope
carnivore restoration
demography
habitat selection
savanna
sensitivity
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