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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 predictable relationship between the index and the actual population of interest. The precision and utility of the resulting estimates from ICS methods have been questioned. We assessed the performance of one ICS method for large carnivores—track counts—with data from two long‐term studies of African lion populations. We conducted Monte Carlo simulation of intersections between transects (road segments) and lion movement paths (from GPS collar data) at varying survey intensities. Then, using the track count method we estimated population size and its confidence limits. We found that estimates either overstate precision or are too imprecise to be meaningful. Overstated precision stemmed from discarding the variance from population estimates when developing the method and from treating the conversion from tracks counts to population density as a back‐transformation, rather than applying the equation for the variance of a linear function. To effectively assess the status of species, the IUCN has set guidelines, and these should be integrated in survey designs. We propose reporting the half relative confidence interval width (HRCIW) as an easily calculable and interpretable measure of precision. We show that track counts do not adhere to IUCN criteria, and we argue that ICS methods for wide‐ranging low‐density species are unlikely to meet those criteria. Established, intensive methods lead to precise estimates, but some new approaches, like short, intensive, (spatial) capture–mark–recapture (CMR/SECR) studies, aided by camera trapping and/or genetic identification of individuals, hold promise. A handbook of best practices in monitoring populations of apex carnivores is strongly recommended. [ABSTRACT FROM AUTHOR]

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 costs and benefits, and to consider the effectiveness of alternative strategies to conserve exploited species. Age-restricted harvesting is widely recommended to mitigate negative effects of lion hunting, but this recommendation was based on a population model parameterized with data from a well-protected and growing lion population. Here, we used demographic data from lions subject to more typical conditions, including source-sink dynamics between a protected National Park and adjacent hunting areas in Zambia's Luangwa Valley, to develop a stochastic population projection model and evaluate alternative harvest scenarios. Hunting resulted in population declines over a 25-yr period for all continuous harvest strategies, with large declines for quotas >1 lion/concession (~0.5 lion/1,000 km2) and hunting of males younger than seven years. A strategy that combined periods of recovery, an age limit of ≥7 yr, and a maximum quota of ~0.5 lions shot/1,000 km2 yielded a risk of extirpation <10%. Our analysis incorporated the effects of human encroachment, poaching, and prey depletion on survival, but assumed that these problems will not increase, which is unlikely. These results suggest conservative management of lion trophy hunting with a combination of regulations. To implement sustainable trophy hunting while maintaining revenue for conservation of hunting areas, our results suggest that hunting fees must increase as a consequence of diminished supply. These findings are broadly applicable to hunted lion populations throughout Africa and to inform global efforts to conserve exploited carnivore populations. [ABSTRACT FROM AUTHOR]

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 projections under different strategies. We described population size, as well as age and sex structure of lions in 3 Zambian national park populations bordering hunting areas, and found them to be male-depleted relative to other systems. We then estimated rates of adult male loss leading to male depletion in these populations and the effect of different future hunting management options on population characteristics. Predictions from matrix population models constructed within a Bayesian framework confirmed that the observed population structure was likely due to high rates of adult male loss and that instituting age limits on male harvests with quota reductions would reduce male depletion, improve tourism by providing older and more abundant males, and slightly increase population size. Reducing male mortality from wire snare poaching would also result in similar demographic impacts, and in concert with changes in hunting regulations would substantially improve the quality and quantity of adult male lions. However, model results varied depending on whether we assumed historical population stability. Predictions assuming negative historical growth rate indicated that substantially more conservative lion harvest management is warranted. We discuss the relevance of these findings for maintaining viable lion populations in and around protected areas in Zambia. © 2012 The Wildlife Society. [ABSTRACT FROM AUTHOR]

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 found were Isospora spp., Spirometra sp., Taeniidae and Sarcosystis spp. Twenty-eight per cent of all samples were co-infected with Spirometra sp. and Taeniidae, with co-infection rates highest among lions (67%). Thirty-three per cent (3/9) of spotted hyaenas were infected with Isospora sp. Ninety-two per cent (12/13) of wild dog were infected with Sarcocystis, similar to results from studies in South Africa. One lion was infected with a parasite whose morphology suggested Strongyloides sp., not previously been reported in lions. Samples from one lion and two spotted hyaenas yielded no gastrointestinal parasites. Overall, parasite species were consistent with those found from studies in other regions of Africa and are likely a result of ingesting infected prey. To our knowledge this study provides the most comprehensive survey of gastrointestinal parasite infection in large carnivores from this region of Africa to date and provides baseline data for future studies. [ABSTRACT FROM AUTHOR]

Lions and other African large carnivores are in decline, due in part to effects of illegal hunting with snares, which can reduce prey availability and directly kill or injure carnivores. It is difficult to effectively remove snares from large ecosystems by patrolling, but an additional approach to reduce effects on large carnivores is to monitor the population closely and de-snare individuals who are found in a snare or have broken free but still carry the wire (often with serious injury). The effectiveness of de-snaring programs to reduce impacts on large carnivores has not been directly tested. Here, we used long-term demographic data from 386 individually identified lions in the Luangwa Valley Ecosystem to test the effects on population growth (λ) and population size (N) of a program to remove snares from injured lions and treat their wounds. Stochastic Leslie matrix projections for a period of five years showed that the population grew with the benefits of de-snaring, but was expected to decline without de-snaring. Mean annual growth (λ) with de-snaring was 1.037 (with growth in 70% of years), closely matching observed changes in population size. Mean annual growth was 0.99 (with growth in 47% of years) for a model that assumed snared animals would have died if not treated, and 0.95 (with growth in 37% of years) for models that also accounted for super-additive effects via the death of dependent cubs and increased infanticide with increased male mortality. De-snaring requires intensive effort, but it can appreciably reduce the effect of snaring on lion population dynamics. • Wire snares affect large carnivores by depleting their food supply and by directly injuring or killing the carnivores. • These effects may cause carnivore populations to decline, but are rarely measured. • We quantified the effectiveness of a program to remove snares from lions in Zambia's Luangwa Valley Ecosystem. • De-snaring lions allowed the population to grow, though it was expected to decline without this intervention. [ABSTRACT FROM AUTHOR]

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 cohort of offspring. We tested and expanded criteria for an age-based approach for sustainably regulating lion hunting. Using photos of 228 known-age males from ten sites across Africa, we measured change in ten phenotypic traits with age and found four age classes with distinct characteristics: 1–2.9 years, 3–4.9 years, 5–6.9 years, and ≥ 7 years. We tested the aging accuracy of professional hunters and inexperienced observers before and after training on aging. Before training, hunters accurately aged more lion photos (63%) than inexperienced observers (48%); after training, both groups improved (67–69%). Hunters overestimated 22% of lions < 5 years as 5–6.9 years (unsustainable) but only 4% of lions < 5 years as ≥ 7 years (sustainable). Due to the lower aging error for males ≥ 7 years, we recommend 7 years as a practical minimum age for hunting male lions. Results indicate that age-based hunting is feasible for sustainably managing threatened and economically significant species such as the lion, but must be guided by rigorous training, strict monitoring of compliance and error, and conservative quotas. Our study furthermore demonstrates methods for identifying traits to age individuals, information that is critical for estimating demographic parameters underlying management and conservation of age-structured species. [ABSTRACT FROM AUTHOR]