Stéphanie Périquet

Partage au sommet de la chaîne alimentaire : comment la hyène tachetée s'adapte à la présence de lions ? : coexistence des prédateurs apicaux dans une savane arborée: Étant au somment de la chaîne alimentaire, les grands prédateurs ont la capacité d'influencer le fonctionnement des écosystèmes, y compris au sein de leur guilde. En Afrique, les lions (Panthera leo) et les hyènes tachetées (Crocuta crocuta, hyènes ci-après) sont les plus gros et les plus nombreux prédateurs, et les hyènes sont souvent considérées comme subordonnées aux lions. Néanmoins, notre compréhension de leurs interactions est très limitée, d'autant plus dans les milieux boisés. Ce travail vise à identifier les mécanismes permettant la coexistence des hyènes et des lions. L'hypothèse principale est que les hyènes évitent les lions à la fois dans l'espace et dans le temps. Une revue de la littérature montre que malgré leur fort potentiel pour la compétition d'exploitation (régimes alimentaires similaires) et d'interférence (kleptoparasitisme et prédation), les lions partagent la quasi-totalité de leur distribution avec les hyènes et leurs densités sont positivement corrélées. J'ai collecté des données sur l'écologie des hyènes et des lions durant 2.5 ans à partir d'observations directes et de colliers GPS dans le Parc National de Hwange (PNH), au Zimbabwe. PNH est caractéristique d'une savane dystrophique arborée semi-aride dominée par l'éléphant (Loxodonta africana). L'écologie de la hyène y est largement influencée par la localisation des points d'eau artificiels, des carcasses d'éléphants et des lions. Les hyènes sélectionnent les habitats riches en proies et près des points d'eau, tout comme le font les lions qu'elles n'évitent que dans des conditions extrêmes de vulnérabilité et de risques. Les carcasses d'éléphants représentent une ressource alimentaire majeure pour les hyènes qui en ont augmenté leur utilisation en réponse à une augmentation de la compétition avec les lions. La disponibilité de ces carcasses facilite probablement la coexistence entre les deux carnivores. Les rencontres avec les lions autour de carcasses sont communes et les deux espèces peuvent rester à proximité pendant plusieurs nuits consécutives. En revanche, les rencontres non liées aux carcasses sont de très courte durée et les deux prédateurs s'éloignent rapidement l'un de l'autre. Contrairement à l'hypothèse classique, les hyènes n'évitent pas les lions de manière systématique. Les interactions entre les deux espèces sont complexes et les hyènes répondent aux lions de manière dynamique et réactive plutôt que prédictive. Bien que les lions soient leur plus grand compétiteur, les hyènes restent à proximité dans certaines circonstances, car ils représentent une source alimentaire grâce au charognage et au kleptoparasitisme. Ces résultats apportent de nouvelles connaissances sur les mécanismes de coexistence et d'interactions entre grands carnivores ainsi que sur l'impact potentiel des décisions de gestion sur leur écologie qui peuvent être utiles pour leur conservation

Non-invasive fecal sampling is essential for molecular wildlife studies such as gut microbiome (GMB) research, yet field conditions often limit preservation options. To test the effects of preservation methods on the results of GMB community composition, we compared gut bacterial communities in paired fecal samples preserved in stabilization tubes and air-dried in paper bags collected from anesthetized African lions ( Panthera leo ) and spotted hyenas ( Crocuta crocuta ) in Etosha National Park, Namibia. Additional opportunistic samples from the ground around carnivore feeding sites that varied in moisture content were also analyzed. No differences in alpha or beta diversity were detected between preserved and dried samples, although bacterial beta diversity differed between preserved and opportunistic samples, supported by NMDS ordinations and PERMANOVA results. Core bacterial communities remained consistent across opportunistic sample conditions, indicating that host-associated taxa persist despite environmental exposure supporting the use of opportunistic samples for GMB studies in remote arid settings. However, consistent sampling protocols and future field-based desiccation studies remain critical for comparative analyses. These findings highlight that rapid air-drying offers a reliable, low-cost preservation option that maintains core microbiome patterns, expanding the feasibility of GMB research in remote or resource-limited field contexts where refrigeration and preservatives may be unavailable.

Accurately estimating species population sizes and distributions is essential in wildlife conservation and management, particularly for keystone species such as large carnivores. These species play a pivotal role in ecosystems due to their position at the top of the food chain. Furthermore, it is often difficult to estimate the population size of carnivores by traditional census methods. This project aims to produce the first-ever population size estimates and spatial distributions for cheetahs and leopards in Etosha National Park, Namibia. Both species have unique coat patterns, allowing for individual identification from direct observation. Using photographs of cheetahs (Acinonyx jubatus) and leopards (Panthera pardus) submitted by visitors to Etosha National Park from 2024 to 2025, we use a specialized Artificial Intelligence (AI) platform (i.e. the African Carnivore Wildbook) to aid in identifying individuals. The data will be analysed within a spatially explicit capture–mark–recapture framework to generate population estimates and confidence intervals. The principal output of this project will be providing up-to-date population size estimates for cheetahs and leopards in Etosha National Park, a priority expressed by the Etosha Ecological Institute and the Ministry of Environment, Forestry and Tourism. This research will contribute to the management of Etosha National Park by providing essential data to inform conservation strategies, ensuring the long-term sustainability of these keystone species and their ecosystems.

There is growing evidence from around the globe about the crucial role of predators in ecosystem functioning at many trophic levels. Due to the expansion of anthropogenic activities, these species are becoming increasingly dependent on protected areas for their persistence. As carnivores move beyond protected area boundaries, they often interfere with human interests, frequently resulting in conflict and persecution. The Greater Etosha Landscape (GEL) in north-central Namibia exemplifies global conservation challenges. The GEL comprises one of the world's most renowned protected areas, the Etosha National Park, which is surrounded by a diverse matrix of land tenures and land uses, which translate into different management approaches and predator tolerances. While large carnivore research has a long history in the Etosha landscape, changing land use and climatic conditions require a new detailed understanding of the drivers of carnivore fitness and persistence. In close partnership, the Etosha Ecological Institute, as part of the Ministry of Environment, Forestry and Tourism, and the Ongava Research Centre have developed the long-term and large-scale Greater Etosha Carnivore Programme involving national and international collaborators. This collaborative programme aims to identify, understand and quantify the drivers of carnivore distribution and abundance in the GEL. Here, we provide general information about our programme's aim and partners, and this serves as an introduction to the more in-depth presentations on specific research and conservation projects falling under its umbrella.

Macrotermes termites play vital roles in nutrient, soil and water cycling in southern Africa. The geographic distribution of Macrotermes species was determined in large parts of this region during the National Survey of Isoptera of Southern Africa (1964–1967). Recently, DNA-based analyses of African Macrotermes lineages have highlighted taxonomic problems in the genus linked to the presence of cryptic diversity. Therefore, it is relevant to revisit the species diversity and distribution patterns of Macrotermes at the fine scale, using molecular tools that were unavailable to the researchers 60 years ago. For that purpose, we inferred the species diversity of Macrotermes termites in Namibia using new genetic data generated in our study along with historical taxonomic and occurrence records. Moreover, the influence of environmental variables and biomes on the occurrence and distribution of Macrotermes species was assessed using contemporary and historical sampling data. We identified four genetic groups of Macrotermes (G07, G18, G19, G21), in line with the number of taxa reported in the National Survey of Isoptera of Southern Africa, which comprised M. natalensis , M. michaelseni , M. vitrialatus and M. subhyalinus . However, phylogenetic analyses and DNA-based species delimitation within the wider context of available sequence data for African Macrotermes indicate that only G07 corresponds to M. natalensis as the correct nominal species, and that the three other groups represent novel lineages that have eluded historical taxonomic expertise until now. Our analyses of environmental variables agree with historical descriptions in that temperature influences the occurrence of species. Additionally, our findings suggest a potential decline in the abundance of M. vitrialatus and M. subhyalinus , the two rarest Macrotermes species in Namibia. Finally, this study confirms that the taxonomy of Macrotermes species is in dire need of revision under an integrated approach that should include genetic data collected over the geographic range of the genus in southern Africa.

Previous work has focused on how prey availability and fear of people affect apex predators' habitat selection, but few have studied the effects of intraguild interactions. Patterns of co‐occupancy between sympatric carnivores have started to be well described, but understanding the underlying habitat selection processes is lacking. We evaluated whether the risk of encountering African lions (Panthera leo) influences habitat selection by spotted hyaenas (Crocuta crocuta, hyaena hereafter) using GPS‐collar data and two approaches: (1) resource selection functions considering the static long‐term risk of encountering lions, and (2) step selection functions considering the dynamic, immediate risk of encountering lions. We explored the interplay between the risk of encountering lions, vegetation type and moonlight illumination, and examined individual variation in habitat selection. As expected, hyaenas did not avoid areas intensively used by lions, and there was even a positive effect of the long‐term risk of encountering lions on habitat selection by hyaenas. As in other study sites, this likely arises because hyaenas select the same areas as lions. At the finer scale, unexpectedly, hyaenas did not generally move away from lions. We believe this occurs because hyaenas can sometimes be attracted to lions because of scavenging opportunities or because they outnumber lions and are likely to win an aggressive encounter. These two circumstances can lead to highly contrasting outcomes and highlight the high dynamics of intraguild interactions. This also illustrates the limits of GPS‐based studies that lack crucial information about the context of interactions. While at the population level, we detected a selection for open vegetation areas, which are rich in prey in the study ecosystem and potentially good hunting grounds for cursorial predators, such as hyaenas; our results show a very high inter‐individual heterogeneity underlying this population level result. Our work therefore illustrates the importance of investigating individual habitat selection.

Human impacts on the environment and wildlife populations are increasing globally, threatening thousands of species with extinction. While wildlife‐based tourism is beneficial for educating tourists, generating income for conservation efforts, and providing local employment, more information is needed to understand how this industry may impact wildlife. In this study, we used motion‐activated cameras at 12 waterholes on a private game reserve in northern Namibia to determine if the presence of humans and permanent infrastructure affected mammal visits by examining their (1) number of visits, (2) time spent, and (3) diel activity patterns. Our results revealed no differences in the number of visits based on human presence for any of the 17 mammal species studied. However, giraffes (Giraffe camelopardalis) spent more time at waterholes before observer presence compared to during. Additionally, several species changed diel activity patterns when human observers were present. Notably, several carnivore and ungulate species increased overlap in their activity patterns during periods while humans were present relative to when humans were absent. These modifications of mammal temporal activity patterns due to human presence could eventually lead to changes in community structure and trophic dynamics because of altered predator–prey interactions. As humans continue to expand into wildlife habitats, and wildlife‐based tourism increases globally, it is imperative that we fully understand the effects of anthropogenic pressures on mammal behavior. Monitoring of wildlife behavioral changes in response to human activity is crucial to further develop wildlife tourism opportunities in a way that optimizes the impact of conservation goals.

Current theory predicts that plains zebra (Equus quagga) populations should be resource‐limited. Long‐term, detailed work in the Hwange ecosystem (Zimbabwe) on zebras and all their major predators provides empirical data to test this on a population that has been at a low density for at least 2 decades and is largely naturally regulated. Information on body condition is used as an indicator of resource use, and offtakes by the three major predators are estimated from a synthesis of data on densities and diets. This information leads to rejection of the expectations for resource limitation. Zebras provide a significant part of the diets of all the main predators and are important (11%) for the most abundant of these, spotted hyaenas (Crocuta crocuta). Using conservative values, we calculate that the three main predators, hyaenas, lions (Panthera leo), and leopards (Panthera pardus), kill some 17.5% of the zebra population. Given that this estimated offtake is of the same order of magnitude as maximum population growth (22.3% per year), we conclude that this population is likely to be limited by predation. Further work is needed to better understand the mechanisms by which the greater susceptibility of juveniles to predation in ungulates contributes to population limitation.