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Accueil du site → Doctorat → Royaume-Uni → 2017 → The effect of resource abundance and dispersion on the ecology of African lions (Panthera leo) in a semi-arid landscape

University of Oxford (2017)

The effect of resource abundance and dispersion on the ecology of African lions (Panthera leo) in a semi-arid landscape

Moreangels Muchaneta Mbizah

Titre : The effect of resource abundance and dispersion on the ecology of African lions (Panthera leo) in a semi-arid landscape

Auteur : Moreangels Muchaneta Mbizah

Université de soutenance : University of Oxford

Grade : Doctor of Philosophy (PhD) 2017

Résumé
In natural ecosystems, resources are often heterogeneously distributed and one of the key challenges in ecology is to understand how environmental heterogeneity influences population dynamics, species distributions, community composition, social structure and individual behaviour. In this study, the spatial and temporal heterogeneity of the Hwange National Park landscape and the ability to measure and quantify the abundance, dispersion and the richness (characterised by herd size and prey size) of prey at the lion home range scale provided us with a unique opportunity to examine the effects of resources on the ecology of a social large carnivore. The abundance, dispersion and richness of prey patches is expected to influence various aspects of the ecology of African lions, including patterns of sociality, ranging behaviour and foraging behaviour. In this study I first assessed the applicability of the spoor count method in estimating relative abundance of herbivores and found it to be a useful index (Chapter 2). I then tested the effect of prey availability on the ranging behaviour (home range size) and the broad-scale social structure (group size) of lions by applying the four main prediction of the Resource Dispersion Hypothesis (RDH) (Chapter 3). Results revealed that all four predictions of the RDH were supported. Indeed home range size increased with increase in the dispersion of prey while lion group size increased with increase in patches richness. I then went on to test the effect of prey availability on the fine-scale social structure (community structure) of lion prides using the social network toolbox and advanced analytical methods (Chapter 4). Results showed that all prides demonstrated strong patterns of within-pride sub-grouping, or ‘communities’, and that the intensity of sub-grouping behaviour is linked to resource availability. More specifically, communities were more strongly defined as prey dispersion increased and when the body size of available prey decreased. Finally, I applied the optimal foraging and social foraging theories to understand the drivers of lion foraging behaviour (prey preference) (Chapter 5). Results revealed that the richness of prey patches both in terms of prey body size and herd sizes as well as lion hunting group size were important factors in influencing prey preference of lions. The foraging behaviour of this lion population suggested that they seek to maximise energy gain and optimise foraging success. Together the results of this thesis reveal that the dispersion and richness of resource patches are important factors in influencing lion ecology.

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