Lycaon Pictus Research Articles

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 and 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.

Genome sequences of two isolates of the yeast Candida zeylanoides: UCD849 from soil in Ireland, and AWD from an African wild dog.

We report genome sequences of two new isolates of the budding yeast Candida zeylanoides. Strain UCD849 from soil in Ireland was assembled into eight complete chromosomes. Strain AWD from an African Wild Dog in a US zoo was sequenced to draft level. The assemblies are 10.6 Mb and 99.57% identical.

An integrated population model reveals source-sink dynamics for competitively subordinate African wild dogs linked to anthropogenic prey depletion.

Many African large carnivore populations are declining due to decline of the herbivore populations on which they depend. The densities of apex carnivores like the lion and spotted hyena correlate strongly with prey density, but competitively subordinate carnivores like the African wild dog benefit from competitive release when the density of apex carnivores is low, so the expected effect of a simultaneous decrease in resources and dominant competitors is not obvious. Wild dogs in Zambia's South Luangwa Valley Ecosystem occupy four ecologically similar areas with well-described differences in the densities of prey and dominant competitors due to spatial variation in illegal offtake. We used long-term monitoring data to fit a Bayesian integrated population model (IPM) of the demography and dynamics of wild dogs in these four regions. The IPM used Leslie projection to link a Cormack-Jolly-Seber model of area-specific survival (allowing for individual heterogeneity in detection), a zero-inflated Poisson model of area-specific fecundity and a state-space model of population size that used estimates from a closed mark-capture model as the counts from which (latent) population size was estimated. The IPM showed that both survival and reproduction were lowest in the region with the lowest density of preferred prey (puku, Kobus vardonii and impala, Aepyceros melampus), despite little use of this area by lions. Survival and reproduction were highest in the region with the highest prey density and intermediate in the two regions with intermediate prey density. The population growth rate ( ) was positive for the population as a whole, strongly positive in the region with the highest prey density and strongly negative in the region with the lowest prey density. It has long been thought that the benefits of competitive release protect African wild dogs from the costs of low prey density. Our results show that the costs of prey depletion overwhelm the benefits of competitive release and cause local population decline where anthropogenic prey depletion is strong. Because competition is important in many guilds and humans are affecting resources of many types, it is likely that similarly fundamental shifts in population limitation are arising in many systems.

Automated identification of African carnivores: conservation applications

Photographic images taken by tourists and uploaded to the African Carnivore Wildbook have been used by Cozzi et al. to identify individual African wild dogs and study their dispersal behavior. Collaborations among citizen scientists, computer scientists, and researchers can expand the reach of conservation efforts spatially and temporally.

Coexisting with carnivores: insights into local attitudes toward African wild dogs (Lycaon pictus) in the Maasai Mara, Kenya

ABSTRACT Coexistence between humans and carnivores enables the persistence or recovery of wildlife populations. In 2018, we conducted a survey in Kenya’s Greater Mara Ecosystem to explore community attitudes toward the reestablishment of African wild dogs (Lycaon pictus) following their regional disappearance. Analyzing data from 60 households, we found that proximity to protected areas, land lease to conservancies, and risk perception significantly influenced people’s tolerance of African wild dogs, as revealed by Generalized Linear Models. Notably, there were no instances of human attacks and 78% of respondents had not experienced livestock predation, indicating positive coexistence. Among those perceiving a risk, 37 out of 46 recognized livestock predation only occurred when livestock were unguarded during the day. These findings highlight the potential for coexistence and species recovery in this mixed-use landscape, emphasizing the importance of effective conservation education, livestock management, and economic incentives.

Wire-snare bushmeat poaching and the large African carnivore guild: Impacts, knowledge gaps, and field-based mitigation

Wire-snare poaching for bushmeat is increasingly recognized as a serious threat to the species comprising the large African carnivore guild (African lion, African wild dog, spotted hyena, cheetah and leopard), with impacts described primarily through prey depletion and snaring by-catch mortality or injury. However, the species-specific impacts of snaring on this guild and on intraguild dynamics are not well-understood. These guilds evolved through competition and predation and have a diverse array of behaviors, space use, movements, diet, morphology, and densities; thus, it is logical to expect snaring impacts through prey depletion and by-catch will also be variable, subtle, and complex, yet significant. Utilizing the scientific literature and ongoing, long-term research we: 1) Summarize and describe the known and potential impacts of snaring by-catch and prey depletion on specific species in the guild and on intraguild dynamics, 2) Identify knowledge gaps and propose areas of future research to better understand and address snaring threats, and 3) Describe a successful strategy collaboratively merging conservation science work with resource protection, that has been implemented across carnivore strongholds in Zambia to combat the immediate threats from snaring on large carnivore populations. Collectively, this work can help mitigate snaring impacts while longer-term community-based solutions to the bushmeat crisis are developed and implemented.

Genetic surfing during the range expansion of an endangered large carnivore

In an effort to halt the global decline of large carnivores, reintroductions have become increasingly popular to establish satellite populations and reduce the risk of stochastic events. These artificial range expansions are typically formed by a small number of founders, which can lead to changes in population genetic structure. For instance, serial founder events can lead to neutral and even deleterious alleles reaching higher than expected frequencies along the front end of an expansion, referred to as gene surfing. One of the world’s most extensive range expansion programmes has been for endangered African wild dogs (Lycaon pictus). In this study, we examine the effect of continent-wide translocations on spatial genetic diversity, by determining what effect genetic surfing has on population structure in wild dogs, and measuring how long it will take for population structure to homogenize in the face of ongoing dispersal. We used a set of microsatellite loci to look at surfing alleles in five populations across southern Africa, and simulated the movement of these alleles forward in time under the current demographic scenario. We found that it would take about 150 generations for the expanding population to be 50% introgressed with genes from the free-roaming population. With the current rate of translocations, genetic differentiation in southern Africa will disappear, overturning the effects of genetic drift or surfing alleles. Understanding genetic patterns in expanding populations is of great interest to conservation, and we demonstrate that reintroduction programmes can help restore genetic diversity, and consequently adaptive potential, in recovering wildlife populations.

Patterns of scent marking by African wild dogs, Lycaon pictus, at shared marking sites

Patterns of scent marking by African wild dogs, Lycaon pictus, at shared marking sites

Increasing ambient temperatures trigger shifts in activity patterns and temporal partitioning in a large carnivore guild

Shifts in species’ interactions are implicated as an important proximate cause underpinning climate-change-related extinction. However, there is little empirical evidence on the pathways through which climate conditions, such as ambient temperature, impact community dynamics. The timing of activities is a widespread behavioural adaptation to environmental variability, and temporal partitioning is a key mechanism that facilitates coexistence, especially within large carnivore communities. We investigated temperature impacts on community dynamics through its influence on the diel activity of, and temporal partitioning amongst, four sympatric species of African large carnivores: lions ( Panthera leo ), leopards ( Panthera pardus ), cheetahs ( Acinonyx jubatus ) and African wild dogs ( Lycaon pictus ). Activity of all species was shaped by a combination of light availability and temperature, with most species becoming more nocturnal and decreasing activity levels with increasing temperatures. A nocturnal shift was most pronounced in cheetahs, the most diurnal species during median temperatures. This shift increased temporal overlap between cheetahs and other carnivore species by up to 15.92%, highlighting the importance of considering the responses of interacting sympatric species when inferring climate impacts on ecosystems. Our study provides evidence that temperature can significantly affect temporal partitioning within a carnivore guild by generating asymmetrical behavioural responses amongst functionally similar species.

An AI‐based platform to investigate African large carnivore dispersal and demography across broad landscapes: A case study and future directions using African wild dogs

AbstractUnderstanding dispersal patterns and demographic processes is crucial for the development of evidence‐based conservation practices. Obtaining such information relies on the ability to identify and track individuals across spatial and temporal scales relevant to the life‐history events under investigation. This knowledge can be achieved by combining photographic and sighting data collected by various sources with a high accuracy automated individual identification platform. Here, we present the African Carnivore Wildbook (ACW), an AI‐based graphical user interface tool capable of identifying individuals of several African carnivore species and specifically developed to accommodate the above outlined needs. We showcase the ACW functionality using the endangered African wild dog as an example. Pictures collected over an area >56,000 km2 and submitted to ACW allowed inferences on movement patterns and dispersal at regional and international scales; for instance, transboundary dispersal events >200 km were documented. ACW furthermore enabled monitoring some individuals for >4 years; such information is invaluable for reliable survival analyses. We discuss how the ACW can contribute to data collection at appropriate spatial and temporal scales to support population monitoring, scientific research and management of African wild dogs and other apex carnivores and to the conservation of these charismatic species.

Cutaneous apocrine gland neoplasia in 16 captive African wild dogs (Lycaon pictus)

This retrospective study documents the occurrence of single and multiple cutaneous apocrine gland tumours (CATs) on the dorsal midline of 16 captive African wild dogs (AWDs, Lycaon pictus) derived from 161 submissions to diagnostic laboratories in South Africa, France and Germany between 1997 and 2022. Animals included in the study came from zoological institutions in South Africa (n = 2), France (n = 5) and Germany (n = 1) and ranged from 5 to 14 years of age. Fifteen affected animals were female (94%) and one was male. CATs presented as raised, hairless, multilobular, grey firm masses, consistently located along the dorsal midline. Apart from a single cutaneous apocrine adenoma and a cystadenoma occurring concurrently with two non-cystic adenocarcinomas, neoplasms were consistent with malignant cutaneous apocrine adenocarcinomas with lymphatic spread and visceral metastases. Advanced age and female sex were identified as risk factors. A genetic component or association with the increasing use of GnRH agonist contraceptives was suspected but could not be established. This study highlights the need for close clinical monitoring of AWDs over the age of 5 years for the development of CATs along the dorsal midline and supports early surgical intervention. More research is needed to determine the role of inbreeding, endocrine changes and husbandry factors that may play a role in the development of CATs on the dorsal midline of AWDs.

A novel record of African wild dogs (Lycaon pictus) in Vwaza Marsh Wildlife Reserve, Malawi.

Most African wild dog (Lycaon pictus) populations are in decline and, due to habitat fragmentation and conflict rates in areas of higher anthropogenic land-use, are primarily restricted to protected areas. As a species that occurs at low densities, with a strict reproductive social structure, wild dogs rely on long-range dispersal to facilitate colonization, reproduction, and pack formation. In Malawi, large carnivores have been subject to widespread population decline and several protected areas have a reduced large carnivore guild, including the loss of resident wild dog populations. Here, during a biodiversity monitoring camera trap survey, we captured a novel record of wild dogs in Vwaza Marsh Wildlife Reserve (Vwaza), Malawi. The 11 photographic captures of potentially three individual wild dogs represent the first documented evidence of the species in Vwaza and the first record since an unconfirmed report in 2011. We hypothesize that this group of wild dogs moved into Vwaza through the Malawi-Zambia Transfrontier Conservation Area (MZTFCA), with the MZTFCA linking protected areas in Malawi with the Luangwa Valley, Zambia. The evidence provided here, and similar documentation in Kasungu National Park, Malawi, show that large carnivores can potentially move through the MZTFCA into protected areas in Malawi. We argue that the MZTFCA provides an important dispersal corridor that could help facilitate the recolonization of wild dogs, and other large carnivores, in Malawian protected areas. However, further research is needed to assess the permeability and status of the MZTFCA corridor into Malawi. We show that camera traps can be useful to document novel records of rare species and can be used to inform conservation management planning.

Evaluating patterns and drivers of mammal space use and richness in the Angolan savannah woodlands of the Kavango‐Zambezi Transfrontier Conservation Area

AbstractLarge transboundary protected areas such as the Kavango‐Zambezi Transfrontier Conservation Area (KAZA‐TFCA), improve mammal conservation by addressing biodiversity threats on regional and international levels, but an adequate understanding of mammal space use and richness within protected areas is critical for effective management planning. This information has however been missing from the Angolan component of the KAZA‐TFCA, such as areas of Luengue‐Luiana National Park (LLNP), especially compared with neighbouring countries. We used camera trap data from 2021 to 2023 to investigate species richness of medium‐ and large‐sized mammals in two hotspot areas of LLNP, as well as assess the space use patterns of 9 carnivore and 16 herbivore species. A total of 48 species were recorded over 10,781 camera trapping nights, with African elephant (Loxodonta africana) and small antelope (e.g. common duiker Sylvicapra grimmia and steenbok Raphicerus campestris) being the most common. Species composition differed significantly between sites, with 21 species more relatively abundant at Ndunjuru, including cheetah (Acinonyx jubatus) and African wild dog (Lycaon pictus), and eight species more relatively abundant at Bico, including lion (Panthera leo) and hippopotamus (Hippopotamus amphibius). The detection probability of 22 species were affected by one or more ecological (e.g. proximity to rivers) or anthropogenic (e.g. human settlement) covariate. These results are intended to act as a baseline to monitor conservation effort and aid habitat management in LLNP, as well as similar protected areas within the KAZA‐TFCA and elsewhere.

Higher Mortality Is Not a Universal Cost of Dispersal: A Case Study in African Wild Dogs.

AbstractMortality is considered one of the main costs of dispersal. A reliable evaluation of mortality, however, is often hindered by a lack of information about the fate of individuals that disappear under unexplained circumstances (i.e., missing individuals). Here, we addressed this uncertainty by applying a Bayesian mortality analysis that inferred the fate of missing individuals according to information from individuals with known fate. Specifically, we tested the hypothesis that mortality during dispersal is higher than mortality among nondispersers using 32 years of mark-resighting data from a free-ranging population of the endangered African wild dog (Lycaon pictus) in northern Botswana. Contrary to expectations, we found that mortality during dispersal was lower than mortality among nondispersers, indicating that higher mortality is not a universal cost of dispersal. Our findings suggest that group living can incur costs for certain age classes, such as limited access to resources as group density increases, that exceed the mortality costs associated with dispersal. By challenging the accepted expectation of higher mortality during dispersal, we urge for further investigations of this key life history trait and propose a robust statistical approach to reduce bias in mortality estimates.

RETROSPECTIVE STUDY OF MORBIDITY AND MORTALITY OF CAPTIVE AFRICAN WILD DOGS (LYCAON PICTUS) HELD WITHIN UNITED KINGDOM ZOOLOGICAL INSTITUTIONS BETWEEN 2000 AND 2020.

The African wild dog (Lycaon pictus) is listed as Endangered by the International Union for Conservation of Nature and is part of captive breeding programs designed to support free-living populations and genetic diversity. This study's aim was to identify common causes of morbidity and mortality objectively in United Kingdom captive African wild dogs to inform management recommendations that will improve health and welfare and reduce disease prevalence. Data were gathered from 140 individual dogs housed in 10 institutions, with morbidity records for 122 individuals and 70 postmortem reports. Descriptive statistics including the Mann-Whitney U test and odds ratios were used to analyze morbidity and mortality across age and sex. The most common cause of death for African wild dogs, excluding those,< 7 d old, was trauma (23%), followed by geriatric (18%), degenerative (15%), and neoplastic (14%) conditions. The most common morbidity was also trauma (62%), of which 76% was caused by intraspecific aggression. Integumentary disease secondary to trauma was the most common morbidity by body system. Eight independent incidents of barbiturate toxicosis from consumption of contaminated carcasses, affecting 18 animals, were identified. Records for neonatal deaths were incomplete and conclusions limited; neonatal loss was estimated at 20.5%. Recommendations include research into factors affecting intraspecific aggression in captivity, operant conditioning for hand injection, provision of dietary carcasses from reputable sources, and improved record-keeping.

ANESTHESIA OF ZOO-MANAGED AFRICAN PAINTED DOGS (LYCAON PICTUS) USING A DEXMEDETOMIDINE-KETAMINEBUTORPHANOL-MIDAZOLAM COMBINATION.

Zoo-managed adult African painted dogs (Lycaon pictus; n = 17) were anesthetized with mean dosages of dexmedetomidine 5 µg/kg, ketamine 1.93 mg/kg, butorphanol 0.2 mg/kg, and midazolam 0.15 mg/kg IM. Times to induction milestones (mean ± SD or median [range]) were initial effects at 2 min (1-4 min), recumbency at 3.2 ± 1.1 min, and intubation at 11.6 ± 1.3 min. Two dogs required isoflurane supplementation for intubation. Anesthesia was antagonized with mean dosages of atipamezole 0.05 mg/kg IM, naltrexone 0.2 mg/kg IM, and flumazenil 0.01 mg/kg IV. Times from antagonist administration to recovery milestones were extubation at 3.9 ± 1.5 min, control of head at 7.6 ± 2.5 min, sternal positioning at 8.8 ± 2.3 min, and standing at 12.1 ± 3.5 min. Animals were judged ready for reunification with conspecifics at 41.5 min (28-127 min), and reunification occurred at 62.1 ± 35.2 min. Paired arterial blood gas samples were obtained (n = 13). There was a significant decrease in temperature and blood pressure and increase in pO2, BEecf, and HCO3- (P < 0.05). Decreased respiratory rate with hypercapnia was occasionally observed. This protocol provided consistent anesthesia using a low dose α-2 agonist and permitted quick pack reunification.

Distribution and population status of the African wild dog in Bicuar National Park, Angola: Insights from interview-based surveys and camera trapping

Distribution and population status of the African wild dog in Bicuar National Park, Angola: Insights from interview-based surveys and camera trapping

Periodic measure of a stochastic single-species model in periodic environments

In this letter, we consider a widely used stochastic single-species model in periodic environments. Under some conditions, we show that the model admits a unique non-boundary periodic measure which could be utilized to dissect the periodic variations of the species in the real world. We also take advantage of the theoretical results to explore the growth law of African painted dogs with the help of real data.

Climate change is predicted to cause population collapse in a cooperative breeder.

It has been suggested that animals may have evolved cooperative breeding strategies in response to extreme climatic conditions. Climate change, however, may push species beyond their ability to cope with extreme climates, and reduce the group sizes in cooperatively breeding species to a point where populations are no longer viable. Predicting the impact of future climates on these species is challenging as modelling the impact of climate change on their population dynamics requires information on both group- and individual-level responses to climatic conditions. Using a single-sex individual-based model incorporating demographic responses to ambient temperature in an endangered species, the African wild dog Lycaon pictus, we show that there is a threshold temperature above which populations of the species are predicted to collapse. For simulated populations with carrying capacities equivalent to the median size of real-world populations (nine packs), extinction risk increases once temperatures exceed those predicted in the best-case climate warming scenario (Representative Concentration Pathway [RCP] 2.6). The threshold is higher (between RCP 4.5 and RCP 6.0) for larger simulated populations (30 packs), but 84% of real-world populations number <30 packs. Simulated populations collapsed because, at high ambient temperatures, juvenile survival was so low that packs were no longer recruiting enough individuals to persist, leading them to die out. This work highlights the importance of social dynamics in determining impacts of climatic variables on social species, and the critical role that recruitment can play in driving population-level impacts of climate change. Population models parameterised on long-term data are essential for predicting future population viability under climate change.

Habitat shifts in response to predation risk are constrained by competition within a grazing guild

IntroductionPredators can affect prey not only by killing them, but also by causing them to alter their behavior, including patterns of habitat selection. Prey can reduce the risk of predation by moving to habitats where predators are less likely to detect them, less likely to attack, or less likely to succeed. The interaction of such responses to risk with other ecological processes remains relatively unstudied, but in some cases, changes in habitat use to avoid predation may be constrained by competition: larger, dominant competitors should respond freely to predation risk, but the responses of smaller, subordinate competitors may be constrained by the responses of dominant competitors. For large grazing herbivores, an alternative hypothesis proposes that smaller prey species are vulnerable to more predators, and thus should respond more strongly to predation risk.MethodsHere, we tested these two hypotheses with 775 observations of habitat selection by four species of obligate grazers (zebra, wildebeest, puku and oribi) in the immediate presence or absence of four large carnivores (lion, spotted hyena, African wild dog and cheetah) in three ecosystems (Greater Liuwa, Greater Kafue and Luangwa Valley). Patterns of predation within this set were described by observation of 1,105 kills.ResultsOur results support the hypothesis that responses to predation risk are strongest for larger, dominant competitors. Even though zebras were killed least often, they showed the strongest shift into cover when carnivores were present. Wildebeest, puku and oribi showed weaker habitat shifts, even though they were more frequently killed. These patterns remained consistent in models that controlled for differences in the hunting mode of the predator (stalking, coursing, or intermediate) and for differences among ecosystems. There was no evidence that smaller species were subject to predation by a broader set of predators. Instead, smaller prey were killed often by smaller predators, and larger prey were killed often by larger predators.DiscussionBroadly, our results show that responses to predation risk interact with interspecific competition. Accounting for such interactions should help to explain the considerable variation in the strength of responses to predation risk that has been observed.