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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 (λ) 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. [ABSTRACT FROM AUTHOR]

The leopard Panthera pardus is in range-wide decline, and many populations are highly threatened. Prey depletion is a major cause of global carnivore declines, but the response of leopard survival and density to this threat is unclear: by reducing the density of a dominant competitor (the lion Panthera leo) prey depletion could create both costs and benefits for subordinate competitors. We used capture–recapture models fitted to data from a 7-year camera-trap study in Kafue National Park, Zambia, to obtain baseline estimates of leopard population density and sex-specific apparent survival rates. Kafue is affected by prey depletion, and densities of large herbivores preferred by lions have declined more than the densities of smaller herbivores preferred by leopards. Lion density is consequently low. Estimates of leopard density were comparable to ecosystems with more intensive protection and favourable prey densities. However, our study site is located in an area with good ecological conditions and high levels of protection relative to other portions of the ecosystem, so extrapolating our estimates across the Park or into adjacent Game Management Areas would not be valid. Our results show that leopard density and survival within north-central Kafue remain good despite prey depletion, perhaps because (1) prey depletion has had weaker effects on preferred leopard prey compared to larger prey preferred by lions, and (2) the density of dominant competitors is consequently low. Our results show that the effects of prey depletion can be more complex than uniform decline of all large carnivore species, and warrant further investigation. [ABSTRACT FROM AUTHOR]

Large carnivores are experiencing range contraction and population declines globally. Prey depletion due to illegal offtake is considered a major contributor, but the effects of prey depletion on large carnivore demography are rarely tested. We measured African lion density and tested the factors that affect survival using mark–recapture models fit to six years of data from known individuals in Kafue National Park (KNP), Zambia. KNP is affected by prey depletion, particularly for large herbivores that were preferred prey for KNP lions a half‐century ago. This provides a unique opportunity to test whether variables that explain local prey density also affect lion survival. Average lion density within our study area was 3.43 individuals/100 km2 (95% CI, 2.79–4.23), which was much lower than lion density reported for another miombo ecosystem with similar vegetation structure and rainfall that was less affected by prey depletion. Despite this, comparison to other lion populations showed that age‐ and sex‐specific survival rates for KNP lions were generally good, and factors known to correlate with local prey density had small effects on lion survival. In contrast, recruitment of cubs was poor and average pride size was small. In particular, the proportion of the population comprised of second‐year cubs was low, indicating that few cubs are recruited into the subadult age class. Our findings suggest that low recruitment might be a better signal of low prey density than survival. Thus, describing a lion population's age structure in addition to average pride size may be a simple and effective method of initially evaluating whether a lion population is affected by prey depletion. These dynamics should be evaluated for other lion populations and other large carnivore species. Increased resource protection and reducing the underlying drivers of prey depletion are urgent conservation needs for lions and other large carnivores as their conservation is increasingly threatened by range contraction and population declines. [ABSTRACT FROM AUTHOR]

Conservation of competitively subordinate carnivores presents a difficult challenge because they are limited by dominant competitors. Prey depletion is one of the leading causes of large carnivore decline worldwide, but little is known about the net effect of prey depletion on subordinate carnivores when their dominant competitors are also reduced. African wild dogs are often limited by high densities of dominant competitors, particularly lions. We measured African wild dog density and survival, using mark-recapture models fit to 8 years of data from 425 known individuals in the Greater Kafue Ecosystem, Zambia. The GKE is affected by prey depletion, particularly of large herbivores, and thus the density of lions is significantly lower than ecologically comparable ecosystems. Counter to expectations from mesopredator release theory, wild dog density in GKE was far lower than comparable ecosystems with higher lion and prey density, though annual survival rates were comparable to large and stable populations. Average pack size was small and home range size was among the largest recorded. Our results show that low lion density did not competitively release the GKE wild dog population and we infer that the low density of wild dogs was a product of low prey density. Our results suggest that there is an optimal ratio of prey and competitors at which wild dogs achieve their highest densities. This finding has immediate implications for the conservation of the endangered African wild dog, and broad implications for the conservation of subordinate species affected by resource depletion and intraguild competition. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]