Evaluation of the applicability of different age determination methods for estimating age of the endangered African wild dog (Lycaon Pictus)

African wild dogs (Lycaon pictus) are endangered and their population continues to decline throughout their range. Given their conservation status, more research focused on their population dynamics, population growth and age specific mortality is needed and this requires reliable estimates of age and age of mortality. Various age determination methods from teeth and skull measurements have been applied in numerous studies and it is fundamental to test the validity of these methods and their applicability to different species. In this study we assessed the accuracy of estimating chronological age and age class of African wild dogs, from dental age measured by (i) counting cementum annuli (ii) pulp cavity/tooth width ratio, (iii) tooth wear (measured by tooth crown height) (iv) tooth wear (measured by tooth crown width/crown height ratio) (v) tooth weight and (vi) skull measurements (length, width and height). A sample of 29 African wild dog skulls, from opportunistically located carcasses was analysed. Linear and ordinal regression analysis was done to investigate the performance of each of the six age determination methods in predicting wild dog chronological age and age class. Counting cementum annuli was the most accurate method for estimating chronological age of wild dogs with a 79% predictive capacity, while pulp cavity/ tooth width ratio was also a reliable method with a 68% predictive capacity. Counting cementum annuli and pulp cavity/tooth width ratio were again the most accurate methods for separating wild dogs into three age classes (6±24 months; 25±60 months and > 60 months), with a McFadden's Pseudo-R2 of 0.705 and 0.412 respectively. The use of the cementum annuli method is recommended when estimating age of wild dogs since it is the most reliable method. However, its use is limited as it requires tooth extraction and shipping, is time consuming and expensive, and is not applicable to living individuals. Pulp cavity/tooth width ratio is a moderately reliable method for estimating both chronological age and age class. This method gives a balance between accuracy, cost and practicability, therefore it is recommended when precise age estimations are not paramount.S1 Fig. Raw data for themanuscript. This is the raw data used in all the analysis in this manuscript.This work was funded by grants awarded to RJG from National Geographic Conservation Trust, Columbus Zoo and Aquarium, Disney Worldwide Conservation Fund and The Rufford Foundation.http://www.plosone.orgam2016Companion Animal Clinical Studie

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

Can an herbivore affect where a top predator kills its prey by modifying woody vegetation structure?

International audienceIn large mammal communities, little is known about modification of interspecific interactions through habitat structure changes. We assessed the effects of African elephants (Loxodonta africana) on features of woody habitat structure that can affect predator–prey interactions. We then explored how this can influence where African lions (Panthera leo) kill their prey. Indeed, lions are stalk-and-ambush predators and habitat structure and concealment opportunities are assumed to influence their hunting success. During 2 years, in Hwange National Park, Zimbabwe, kill sites (n = 167) of GPS-collared lions were characterized (visibility distance for large mammals, distance to a potential ambush site and presence of elephant impacts). We compared characteristics of lion kill sites with characteristics of random sites (1) at a large scale (i.e. in areas intensively used by lions, n = 418) and (2) at the microhabitat scale (i.e. in the direct surrounding available habitat, < 150 m, n = 167). Elephant-impacted sites had a slightly higher visibility and a longer distance to a potential ambush site than non-impacted sites, but these relationships were characterized by a high variability. At large scale, kill sites were characterized by higher levels of elephant impacts compared to random sites. At microhabitat scale, compared to the direct nearby available habitat, kill sites were characterized by a reduced distance to a potential ambush site. We suggest a conceptual framework whereby the relative importance of habitat features and prey abundance could change upon the scale considered

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

Is there an elephant in the room? A Response to Batavia et al

Non peer reviewe

Overcoming racism in the twin spheres of conservation science and practice.

It is time to acknowledge and overcome conservation's deep-seated systemic racism, which has historically marginalized Black, Indigenous and people of colour (BIPOC) communities and continues to do so. We describe how the mutually reinforcing 'twin spheres' of conservation science and conservation practice perpetuate this systemic racism. We trace how institutional structures in conservation science (e.g. degree programmes, support and advancement opportunities, course syllabuses) can systematically produce conservation graduates with partial and problematic conceptions of conservation's history and contemporary purposes. Many of these graduates go on to work in conservation practice, reproducing conservation's colonial history by contributing to programmes based on outmoded conservation models that disproportionately harm rural BIPOC communities and further restrict access and inclusion for BIPOC conservationists. We provide practical, actionable proposals for breaking vicious cycles of racism in the system of conservation we have with virtuous cycles of inclusion, equality, equity and participation in the system of conservation we want

Guidelines for evaluating the conservation value of African lion (Panthera leo) translocations

As the top predator in African ecosystems, lions have lost more than 90% of their historical range, and few countries possess strong evidence for stable populations. Translocations (broadly defined here as the capture and movement of lions for various management purposes) have become an increasingly popular action for this species, but the wide array of lion translocation rationales and subsequent conservation challenges stemming from poorly conceived or unsuitable translocations warrants additional standardized evaluation and guidance. At their best, translocations fill a key role in comprehensive strategies aimed at addressing the threats facing lions and fostering the recovery of wild populations in their historic range. At their worst, translocations can distract from addressing the major threats to wild populations and habitats, divert scarce funding from more valuable conservation actions, exacerbate conflict with humans in recipient sites, disrupt local lion demography, and undermine the genetic integrity of wild lion populations in both source and recipient sites. In the interest of developing best practice guidelines for deciding when and how to conduct lion translocations, we discuss factors to consider when determining whether a translocation is of conservation value, introduce a value assessment for translocations, and provide a decision matrix to assist practitioners in improving the positive and reducing the negative outcomes of lion translocation.Grant from the European Union through IUCN Save Our Species, and the United States Fish and Wildlife Service.https://www.frontiersin.org/journals/conservation-scienceam2023Zoology and Entomolog

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

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.</p

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

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 âcommunitiesâ, 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.</p

Diet of four sympatric carnivores in Savé Valley Conservancy, Zimbabwe: implications for conservation of the African wild dog (Lycaon pictus)

Most populations of wild dogs (Lycaon pictus) are declining across southern and southeastern Africa, and in the Savé Valley Conservancy (SVC) the decline appears to be associated with declining populations of prey and increasing numbers of competitors. Identifying the threats to this wild dog population is currently needed to determine the most appropriate conservation actions. We studied the diet composition, breadth and overlap among four sympatric carnivores in SVC: African wild dog, spotted hyaena (Crocuta crocuta), lion (Panthera leo) and leopard (Panthera pardus), using faecal analysis. We found remains of 16 mammalian prey species, ranging fromsmall to large mammals (2–525 kg).The four carnivores had many prey species in common (>70% diet overlap), with impala (Aepyceros melampus) consistently the most frequent. The frequency of occurrence of impala, however, was highest in the diets of wild dogs (74%), and wild dogs were found to have the narrowest standardized dietary niche breadth (0.087). The diets also varied significantly in the contribution of different prey-size categories, with large prey (>100 kg) contributing most to the diets of lions and hyaenas, and small prey (<5 kg) to the diet of leopards. With impala populations in decline, competition for prey can explain the observed decline in the less competitive and more specialized wild dog, whose main food resource is shared with a rapidly increasing population of spotted hyaenas and lions in the SVC