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Introduction
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June 2010 - present
Publications
Publications (79)
Genetic resources for species monitoring are ideally relevant for the species’ full distribution range, feasible economically and logistically, and validated for the range of sample types collected from the field. This is particularly important for large carnivores that are elusive and wide-ranging, where individual and population processes often t...
Prey depletion threatens many carnivore species across the world and can especially threaten low‐density subordinate competitors, particularly if subordinates are limited to low densities by their dominant competitors. Understanding the mechanisms that drive responses of carnivore density to prey depletion is not only crucial for conservation but a...
The blue wildebeest (Connochaetes taurinus taurinus) is a keystone species in the savannahs of southern Africa, where it maintains shortgrass plains and serves as an important prey source for large carnivores. Despite being the second largest migratory wildebeest population, the wildebeest of the Greater Liuwa Ecosystem (GLE) of western Zambia have...
Within carnivore guilds, dominant competitors (e.g., lions, Panthera leo) are limited primarily by the density of prey, while subordinate competitors (e.g., African wild dogs, Lycaon pictus) have been limited by the density of dominant competitors. Historically, the fitness and population density of subordinate competitors have not been tightly lin...
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 c...
The Old World Vultures (OWV), constituting 16 species primarily in Africa, Europe and Asia, are currently being driven to extinction mostly by anthropogenic activities, especially poisoning. The vulture losses from poisoning caused by human-related activities are en masse at a single mortality event-level and occur in complex social-ecological syst...
Lions are one of the world’s most iconic species but are threatened with extinction. Developing effective range-wide conservation plans are crucial but hampered by the relative lack of knowledge on specific threats facing each population and the socio-political context for conservation. Here, we present a range-wide examination of the relative frag...
Introduction
Predators 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...
Interspecific competition has strong effects within carnivore guilds, and African wild dogs are strongly limited by intraguild predation by lions and food loss to spotted hyenas. The densities of these dominant competitors correlate tightly with prey density, and prey depletion due to snaring is contributing to declines of apex car-nivores across A...
Large herbivore migrations are imperiled globally; however the factors limiting a population across its migratory range are typically poorly understood. Zambia's Greater Liuwa Ecosystem (GLE) contains one of the largest remaining blue wildebeest (Connochaetes taurinus taurinus) migrations, yet the population structure, vital rates, and limiting fac...
My research work is on the evolutionary biology of African lions, with focus on behavioral ecology mechanisms for coexistance. Current projects include longterm ecological studies on Serengeti lions, Conflict mitigation through conservation translocation to foster coexistence at the interface and trophy harvest monitoring and evaluation of hunted p...
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 arr...
Background
Prey depletion is a threat to the world’s large carnivores, and is likely to affect subordinate competitors within the large carnivore guild disproportionately. African lions limit African wild dog populations through interference competition and intraguild predation. When lion density is reduced as a result of prey depletion, wild dogs...
Conservation translocations have become an important management tool, particularly for large wildlife species such as the lion (Panthera leo). When planning translocations, the genetic background of populations needs to be taken into account; failure to do so risks disrupting existing patterns of genetic variation, ultimately leading to genetic hom...
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....
Leopards (Panthera pardus) are 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 dominant competitors (lions) prey depletion could create both costs and benefits for su...
Leopards are the only big cats still widely distributed across the continents of Africa and Asia. They occur in a wide range of habitats and are often found in close proximity to humans. But despite their ubiquity, leopard phylogeography and population history have not yet been studied with genomic tools. Here, we present population-genomic data fr...
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...
Large carnivores have experienced considerable range contraction, increasing the importance of movement across human-altered landscapes between small, isolated populations. African wild dogs (Lycaon pictus) are exceptionally wide-ranging, and recolonization is an important element of their persistence at broad scales. The competition-movement-conne...
Apex carnivores are wide-ranging, low-density, hard to detect, and declining throughout most of their range, making population monitoring both critical and challenging. Rapid and inexpensive index calibration survey (ICS) methods have been developed to monitor large African carnivores. ICS methods assume constant detection probability and a predict...
Large herbivore communities around the world have declined steeply in recent decades. Although excessive bushmeat harvesting is thought to be the primary cause of herbivore declines in many ecosystems, the direct effects of anthropogenic pressures on large herbivore populations remain poorly described in most of the systems experiencing decline. To...
Current extinction rates are comparable to five prior mass extinctions in the earth’s history, and are strongly affected by human activities that have modified more than half of the earth’s terrestrial surface. Increasing human activity restricts animal movements and isolates formerly connected populations, a particular concern for the conservation...
Ungulate populations face declines across the globe, and populations are commonly conserved by using protected areas. However, assessing the effectiveness of protected areas in conserving ungulate populations has remained difficult. Using herd size data from four years of line transect surveys and distance sampling models, we modeled population den...
Giraffe populations have declined in abundance by almost 40% over the last three decades, and the geographic ranges of the species (previously believed to be one, now defined as four species) have been significantly reduced or altered. With substantial changes in land uses, loss of habitat, declining abundance, translocations, and data gaps, the ex...
Many studies have shown that behavioral responses to the risk posed by predators can carry costs for prey by reducing fecundity or survival, with consequent effects on population dynamics. Responses to risk include increased vigilance and reduced foraging, movement to safe habitats, increases or decreases in group size, and changes in patterns of m...
Allocating resources to growth and reproduction requires grazers to invest time in foraging, but foraging promotes dental senescence and constrains expression of proactive antipredator behaviors such as vigilance. We explored the relationship between carnivore prey selection and prey foraging effort using incisors collected from the kills of coursi...
Protected area managers need reliable information to detect spatial and temporal trends of the species they intend to protect. This information is crucial for population monitoring, understanding ecological processes, and evaluating the effectiveness of management and conservation policies. In under-funded protected areas, managers often prioritize...
Globally, large carnivores are declining due to direct persecution, habitat loss, and prey depletion. The effects of prey depletion could be amplified by changes in the composition of the herbivore (prey) community that provoke changes in carnivore diets, but this possibility has received little attention.
We tested for changes over the past half‐c...
Factors that limit African lion populations are manifold and well-recognized, but their relative demographic effects remain poorly understood, particularly trophy hunting near protected areas. We identified and monitored 386 individual lions within and around South Luangwa National Park, Zambia, for five years (2008–2012) with trophy hunting and fo...
Models fit to describe age and sex-specific survival in the study lion population from 2008–2015.
Along with a base model derived from Rosenblatt et al. (2014) that identified cubs (0.00–1.99 years), subadults (2.00–3.99 years), and 3 adult age categories: young adults (4.00–5.99 years), prime adults (6.00–7.99 years), and old adults (≥8.00 years),...
Input data file.
Final data file containing encounter histories for the period between 2008–2015.
(CSV)
Best supported CJS model coefficient estimates.
Coefficient estimates from the best supported Cormack-Jolly-Seber model of age, gender, and trophy hunting effects on lion survival and individual heterogeneity, season, and year effects on detection {Phi(age[0,1,2,4+) & ♀[2,4,10+) & hunting:♂[2+)), p(mixture*season*year), pi(.)}.
(DOCX)
Estimated detection probability.
Estimated detection probability from eight closed mark-recapture model of annual abundance assuming detection varied as a function of individual heterogeneity (plow and phigh) and season (cool dry, Apr–Sept and hot dry, Oct-Nov), {p(h2 × season),c(),pi(.)}. The mixing parameter (π) and its complement (1 –π) describi...
Both short-term and long-term variation in predation risk can affect the behaviour of prey, thus affecting growth, reproduction, survival and population dynamics. Inferences about the strength of such ‘risk effects’ in the wild have been limited by a lack of studies that relate antipredator responses to the magnitude of direct predation, measure re...
Understanding the influence of environmental conditions and people on ungulate density and distribution is of key importance for conservation. We evaluated the effects of ecological and anthropogenic factors on the density of migratory wildebeest and zebra and resident oribi in Zambia's Liuwa Plain National Park where human settlements were present...
Most species adjust their behavior to reduce the likelihood of predation. Many experiments have shown that antipredator responses carry energetic costs that can affect growth, survival and reproduction, so that the total cost of predation depends on a trade-off between direct predation and risk effects. Despite these patterns, few field studies hav...
Rapid global large carnivore declines make evaluations of remaining populations critical. Yet landscape-scale evaluations of presence, abundance and distribution are difficult, as many species are wide-ranging, occur only at low densities and are elusive. Insufficient information-gathering tools for many large carnivore species compounds these chal...
Significance
Here, we compile and present the most comprehensive data available on cheetah distribution and status. Our analysis shows dramatic declines of cheetah across its distributional range. Most cheetah occur outside protected areas, where they are exposed to multiple threats, but there is little information on population status. Simulation...
Within a large carnivore guild, subordinate competitors (African wild dog, Lycaon pictus, and cheetah, Acinonyx jubatus) might reduce the limiting effects of dominant competitors (lion, Panthera leo, and spotted hyena, Crocuta crocuta) by avoiding them in space, in time, or through patterns of prey selection. Understanding how these competitors cop...
Trophy hunting plays a significant role in wildlife conservation in some contexts in various parts of the world. Yet excessive hunting is contributing to species declines, especially for large carnivores. Simulation models suggest that sustainable hunting of African lions may be achieved by restricting offtakes to males old enough to have reared a...
While trophy hunting provides revenue for conservation, it must be carefully managed to avoid negative population impacts, particularly for long-lived species with low natural mortality rates. Trophy hunting has had negative effects on lion populations throughout Africa, and the species serves as an important case study to consider the balance of c...
Human activities on the periphery of protected areas can limit carnivore populations, but measurements of the strength of such effects are limited, largely due to difficulties of obtaining precise data on population density and survival. We measured how density and survival rates of a previously unstudied leopard population varied across a gradient...
Terrestrial large carnivores have great ecological, economic and cultural importance, but are in global decline due to habitat loss, prey depletion, poaching, retributive killing and regulated hunting. While regulated carnivore hunting potentially reduces conflict with humans and livestock, increases social tolerance and provides revenue for conser...
1. In dryland ecosystems, mobility is essential for both wildlife and people to access unpredictable and spatially heterogeneous resources, particularly in the face of climate change. Fences can prevent connectivity vital for this mobility.
2. There are recent calls for large-scale barrier fencing interventions to address human–wildlife conflict an...
Digital photography enables researchers to rapidly compile large quantities of data from individually identifiable animals, and computer software improves the management of such large datasets while aiding the identification process. Wild‐ID software has performed well with uniform datasets controlling for angle and portion of the animal photograph...
Many African protected areas (PAs) are not functioning effectively. We reviewed the performance of Zambia's PA network and provide insights into how their effectiveness might be improved. Zambia's PAs are under-performing in ecological, economic and social terms. Reasons include: a) rapidly expanding human populations, poverty and open-access syste...
Large carnivores are declining globally, with strong direct and indirect ecological impacts on protected area networks (PANs). Human encroachment on ecosystems is a global threat for large carnivores, particularly in savanna Africa, where increasing human resource demands continue to degrade the connectivity and viability PANs. Zambia has a regiona...
A molecular survey was conducted for several hemoparasites of domestic dogs and three species of wild carnivores from two sites in Zambia. Three Babesia spp. were detected including Babesia felis and Babesia leo in lions (Panthera leo) and a Babesia sp. (similar to Babesia lengau) in spotted hyenas (Crocuta crocuta) and a single lion. All wild dogs...
Wire-snare poaching is fueling the rapidly growing illegal bushmeat trade in Africa’s savanna ecosystems
given the region’s relatively abundant wildlife, increasing commercial bushmeat demand, and burgeoning
human populations; thus understanding snaring dynamics is critical to addressing this crisis. Community
conservation areas often border Nation...
Packer et al. reported that fenced lion populations attain densities closer to carrying capacity than unfenced populations. However, fenced populations are often maintained above carrying capacity, and most are small. Many more lions are conserved per dollar invested in unfenced ecosystems, which avoid the ecological and economic costs of fencing.
Abstract Disease transmission within and among wild and domestic carnivores can have significant impacts on populations, particularly for threatened and endangered species. We used serology to evaluate potential exposure to rabies virus, canine distemper virus (CDV), and canine parvovirus (CPV) for populations of African lions (Panthera leo), Afric...
The bushmeat trade, or the illegal acquisition and exchange of wild meat, has long been recognised as a severe problem in forest biomes, but receives little attention in savannas, perhaps due to a misconception that bushmeat hunting is a low-impact subsistence activity. Though data on impacts are scarce, indications are that bushmeat hunting is a w...
We define African savannahs as being those areas that receive between 300 and
1,500 mm of rain annually. This broad definition encompasses a variety of habitats. Thus
defined, savannahs comprise 13.5 million km2 and encompass most of the present range of the African lion (Panthera leo). Dense human populations and extensive conversion of
land to hu...
Little is known about gastrointestinal parasite infections in large carnivores in Africa and what is available is largely from East Africa. We collected faecal samples from nine spotted hyaenas (Crocuta crocuta), 15 lions (Panthera leo) and 13 African wild dog (Lycaon pictus) from Luangwa Valley, Zambia. The most common gastrointestinal parasites f...
African lions (Panthera leo) are declining continent-wide, with protected area populations subject to a variety of anthropogenic effects. Zambia contains viable lion populations of considerable importance for photographic and hunting tourism, but long-term lion demographic data do not exist to guide recent management directives and population proje...
In the absence of an effective predator, spatial patterns of large herbivores in northern temperate regions are largely influenced by food acquisition and energy conservation during winter, when resources are limited and the energetic cost of movement is high. In these circumstances animals would be expected to minimize movement to avoid unnecessar...
The nonmigratory elk population in the Madison headwaters area of Yellowstone National Park appeared to be regulated near ecological carrying capacity by food limitation for at least three decades prior to the reestablishment of wolves. Eight years of post-wolf data indicated a substantial proportion of wolf predation was additive and overwhelmed a...