Seasonal density estimates of common large herbivores in Hwange National Park, Zimbabwe

The monitoring of ecosystem processes and states is a critical step in the management of protected areas. It allows for the assessment of the success or failure of practices ranging from ‘laissez-faire’ to strong hands-on policies. Much effort is for instance devoted to the monitoring of wildlife abundance, particularly when associated with large ecological influence or socio-economical values (Gordon, Hester & Festa-Bianchet, 2004). In Africa, the diversity of large herbivores represents both a major asset of protected areas and a global conservation target as a consequence of the dramatic decline of wildlife populations under other land uses. In addition to the local importance of such monitoring data, collation of data from multiple sites ultimately allows general patterns to be revealed (e.g. Fritz & Duncan, 1994). Here, we contribute to the general knowledge on large African herbivores by reporting on their seasonal abundance, using road transect counts, in Hwange National Park (thereafter HNP), north-western Zimbabwe

Climate effects on prey vulnerability modify expectations of predator responses to short- and long-term climate fluctuations

Climate changes affect the distribution and abundance of organisms, often via changes in species interactions. Most animals experience predation, and a number of models have investigated how climate fluctuations can influence predator–prey dynamics by affecting prey abundance through changes in resource availability. However, field studies have shown that prey vulnerability is a key feature determining the outcome of predator– prey interactions, which also varies with climatic conditions, via changes in prey body condition or in habitat characteristics (e.g. vegetation cover). In this theoretical work, we explore, with large mammals of African savannas in mind, how the interplay between climate-induced changes in prey abundance and climate-induced changes in prey vulnerability affects the immediate and long-term responses of predator populations. We account for prey body condition and habitat effects on prey vulnerability to predation. We show that predictions on how predator abundance responds to climate fluctuations differ depending on how climate influences prey vulnerability (habitat characteristics vs. prey body condition). We discuss how species traits influence the relative importance of the different sources of vulnerability. For example, our results suggest that populations of cursorial predators (such as spotted hyaenas) are expected to fare better than populations of ambush predators (such as African lions) in African ecosystems that will be characterised by an aridification. This study highlights the importance of understanding, and accounting for, the vulnerability factors associated to a given predator–prey pair, and improves our comprehension of predator–prey relationships in a changing climate.We thank C. Wilmers for providing the code of the published model that serves as the basis of ours. In addition, this work benefited from the computing cluster platform of the Centre d’Ecologie Fonctionnelle et Evolutive and from Biosphere, the IFB cloud for life sciences. We thank Bruno Spataro and Stéphane Delmotte from the LBBE computing services for their help in using computing facilities. Finally, we thank two reviewers for their fruitful comments on a previous draft of this manuscript.This work was partly funded by the Agence Nationale de la Recherche (project Landthirst ANR-16-CE02-0001- 01 and FUTURE-PRED ANR-18-CE02-0005-01) and was further supported by a grant from the “Ministère français de l’Enseignement supérieur, de la Recherche et de l’Innovation” through the “Ecole Doctorale E2M2” of “Université Claude Bernard Lyon 1”.The Agence Nationale de la Recherche and a grant from the “Ministère français de l’Enseignement supérieur, de la Recherche et de l’Innovation” through the “Ecole Doctorale E2M2” of “Université Claude Bernard Lyon 1”.https://www.frontiersin.org/journals/ecology-and-evolution#am2022Mammal Research InstituteZoology and Entomolog

Time-varying habitat selection analysis : a model and applications for studying diel, seasonal, and post-release changes

DATA AVAILABILITY STATEMENT : Data and code (Dejeante et al., 2023b) are archived in a Figshare collection at https://doi.org/10.6084/m9.figshare.c.6365415.v5.Resource selection functions are commonly used to evaluate animals' habitat selection, for example, the disproportionate use of habitats relative to their availability. While environmental conditions or animal motivations may vary over time, sometimes in an unknown manner, studying changes in habitat selection usually requires an a priori segmentation of time in distinct periods. This limits our ability to precisely answer the question “When is an animal's habitat selection changing?” Here, we present a straightforward and flexible alternative approach based on fitting dynamic logistic models to used/available data. First, using simulated datasets, we demonstrate that dynamic logistic models perform well in recovering temporal variations in habitat selection. We then show real-world applications for studying diel, seasonal, and post-release changes in the habitat selection of the blue wildebeest (Connochaetes taurinus). Dynamic logistic models allow the study of temporal changes in habitat selection in a framework consistent with resource selection functions but without the need to segment time in distinct periods, which can be a difficult task when little is known about the process studied or may obscure interindividual variability in timing of change. These models should undoubtedly find their place in the movement ecology toolbox. We provide R scripts to facilitate their adoption. We also encourage future research to focus on how to account for temporal autocorrelation in location data, as this would allow statistical inference from location data collected at a high frequency, an increasingly common situation.Project REPOS.https://onlinelibrary.wiley.com/r/ecyhj2024Mammal Research InstituteZoology and EntomologyNon

Heterogeneity of water physico-chemical characteristics in artificially pumped waterholes: do African herbivores drink at the same locations and does it lead to interference competition?

International audienc

Effect of ecological factors on fine‐scale patterns of social structure in African lions

International audienceEnvironmental variations can influence the extent to which individuals interact with other individuals by changing the value of grouping. It is well known that many species can form and disband groups, often in response to the distribution and abundance of resources.While previous studies showed that resources influence the broad‐scale structure of animal groups, knowledge gaps remain on whether they affect fine‐scale patterns of association among individuals within groups.We quantify association patterns in African lions while simultaneously monitoring the abundance and distribution of prey. We test how social and ecological factors, including individual trait (age, sex, reproductive state) similarity and prey availability (prey abundance, dispersion, herd size and body size) affect within‐pride social structure in African lions.We found that individual decisions about associates depended on resource availability with individuals associating equally across all members of the pride when prey herds were scarce, aggregated or large bodied, and associating more exclusively (in subgroups of preferred associates) when prey herds were abundant, dispersed or small bodied. Individuals within lion prides seemed to be buffering against changes in prey availability by modulating their strength and density of connections with conspecifics when prides split into subgroups. The strength and density of connections among individuals within subgroups was greater when prey herds were large and lower when prey herds were dispersed or are large bodied.Our findings suggest that individual lions are making social decisions at both the subgroup level and the pride level, with decisions representing putatively fitness‐enhancing strategies. Individuals were typically shifting between having few strong connections and having many weaker connections depending on prevailing ecological conditions, with prey abundance, dispersion and body size having the greatest impact on decisions about splitting into subgroups. The maintenance of connections within prides and subgroups in the face of ecological change suggests that the fission–fusion nature of lion prides might be essential for the long‐term maintenance of social connections even when short‐term conditions do not allow them. More broadly, our study reveals how fission–fusion dynamics and ecological factors can simultaneously have an effect on animals across multiple levels of sociality

Behavioural adjustments of a large carnivore to access secondary prey in a human-dominated landscape

1. Conflict between people and large carnivores is an urgent conservation issue world-wide. Understanding the underlying ecological drivers of livestock depredation by large carnivores is greatly needed. 2. We studied the spatial, foraging and behavioural ecology of African lions Panthera leo in the Botswana Makgadikgadi ecosystem. This ecosystem comprises a protected area, characterized by high seasonal fluctuation in wild prey abundance, and adjacent lands, which are used for livestock grazing and characterized by stable livestock abundance, but also a risk of anthropogenic mortality. 3. Makgadikgadi lions preferentially preyed upon migratory wild herbivores when they were present; however, data from GPS (Global Positioning System) radiocollared lions revealed that the majority of the study lions did not follow the migratory herds but remained resident at one or other border of the park and switched to livestock (abundant and readily available), and to a lesser extent resident wild herbivores (relatively scarce), in periods of migratory wild herbivore scarcity. 4. Resident lions’ use of space differed between periods of wild prey abundance and scarcity. These changes were likely to increase the frequency of encounter with their primary prey in periods of primary prey abundance and with livestock in periods of primary prey scarcity. 5. The risk of conflict with humans was a major driver of lion ecology in the human-dominated landscape surrounding the protected area. Resident lions generally avoided the close vicinity of cattle- posts.When they used such areas, they avoided temporal overlap with periods that humans were most active and travelled at high speed reducing the time spent in these areas. 6. Synthesis and applications. This study suggests that lions balance the benefits of accessing livestock with the costs associated with livestock raiding. Hence, reduction in livestock availability through effective livestock husbandry in periods of wild prey scarcity should lead to reduced conflict.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-2664ab201

Food resource competition between African wild dogs and larger carnivores in an ecosystem with artificial water provision

Predators of similar size often compete over prey. In semi-arid ecosystems where water is a limiting resource, prey availability can be affected by water distribution, which further increases resource competition and exacerbate conflict among predators. This can have implications for carnivore dietary competition. Hence, we evaluated the dynamics of food resource competition between African wild dogs and four competing predators (cheetahs, leopards, lions and spotted hyaenas) in different seasons and across areas with different waterhole densities in Hwange National Park, Zimbabwe. We used the frequency of occurrence of prey items found in predators’ scats to analyse diet composition, overlap and prey preference. For most predators, kudu was most frequently consumed and preferred. Low and medium water-dependent prey (medium and small-sized) were mostly consumed by wild dogs, leopards and cheetahs. Wild dog diet overlap was high with all predators, particularly with hyaenas and lions. There were no seasonal differences in the predators diet. The diet overlap of wild dogs with lions was highest in the low waterhole density area, and wild dog diet composition did not differ significantly from the diet of lions and hyaenas. In the low waterhole density area, wild dogs and hyaenas broadened their niche breadth, and predators diet had a higher proportion of low water-dependent prey. A low density of waterholes increased food resource competition. However, high density of waterholes, where there is more prey availability, can increase the aggregation and density of predators, and hence, increase the risks involved in interspecific competition on wild dogs. To reduce food resource competition on wild dogs, we propose to conserve larger-bodied prey that are less dependent on water (e.g. kudu, reedbuck, eland, gemsbok). As the use of water pumping is common practice, we propose maintaining water management heterogeneity where prey which is less dependent on water can also thrive

Temporal dynamics of dry-season water-hole use by large African herbivores in two years of contrasting rainfall in Hwange National Park, Zimbabwe

International audienc