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Accueil du site → Doctorat → Royaume-Uni → 2012 → Niche segregation by cheetah (Acinonyx jubatus) as a mechanism for co-existence with lion (Panthera leo) and spotted hyaena (Crocuta crocuta)

University of Oxford (2012)

Niche segregation by cheetah (Acinonyx jubatus) as a mechanism for co-existence with lion (Panthera leo) and spotted hyaena (Crocuta crocuta)

Broekhuis, Femke

Titre : Niche segregation by cheetah (Acinonyx jubatus) as a mechanism for co-existence with lion (Panthera leo) and spotted hyaena (Crocuta crocuta)

Auteur : Broekhuis, Femke

Etablissement de soutenance : University of Oxford

Grade : Doctor of Philosophy (PhD) 2012

Résumé
Intraguild competition and predation have been recognised as important ecological factors influencing the population dynamics of carnivores. The effects of these interactions are often asymmetrical due to a size-related dominancy hierarchy. However, it has been suggested that competitively subordinate carnivores can minimise the costs of predation and competition through spatial and temporal avoidance. Here I investigate the ecological and behavioural mechanisms by which cheetahs (Acinonyx jubatus) coexist with competitively stronger lions (Panthera leo) and spotted hyaenas (Crocuta crocuta). Fieldwork was carried out in the Okavango Delta, northern Botswana, between October 2008 and August 2011. A total of 20 Global Positioning System (GPS) radio-collars were fitted on all known cheetahs (n=6), lion prides (n=5) and spotted hyaena clans (n=6) in the study area (approx. 3 000 km2). Pre-programmed radio-collars recorded locations and activity continuously for each individual and these data were complemented with direct behavioural observations. Cheetah data were analysed with respect to the temporal and spatial likelihood of encountering lions and spotted hyaenas. Results suggest that the response to the risks posed by other predators is species-specific, habitat-specific and dependent on the immediacy of the risk. Resource partitioning was not the main mechanism for coexistence as cheetahs overlapped extensively with lions and spotted hyaenas in time, space and habitat use. Instead, cheetahs adjusted their spatial distribution in response to immediate risks or adapted their habitat use depending on their vulnerability (e.g. behaviours such as feeding or with differing levels of moonlight at night). In general, cheetah temporal and spatial distribution is a hierarchal process, firstly driven by resource acquisition and thereafter fine-tuned by predator avoidance. In addition, habitat heterogeneity seemed to be key in facilitating coexistence. Understanding the behavioural mechanisms that interacting apex predators adopt to regulate these negative interactions could be crucial to carnivore conservation, especially as human-related habitat loss is forcing species into ever smaller areas.

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