Explore the vast range of titles available.

Overharvesting affects the size and growth of wildlife populations and can impact population trajectories. Overharvesting can also severely alter population structure and may result in changes in spatial organisation, social dynamics and recruitment. Understanding the relationship between overharvesting and population growth is therefore crucial for the recovery of exploited species. The black rhinoceros (Diceros bicornis; black rhino) is a long-lived megaherbivore native to sub-Saharan Africa, listed as Critically Endangered on the IUCN Red List of Threatened Species. Since 2009, the targeted illegal killing of rhino for their horns has escalated dramatically in South Africa. Given their slow life trajectories, spatial structure and social dynamics, black rhino may be susceptible to both direct and indirect impacts of overharvesting. Our study compared black rhino demography before and during extensive poaching to understand the impact of illegal killing. The population exhibited significant changes in age structure after four years of heavy poaching; these changes were primarily explained by a decrease in the proportion of calves over time. Population projections incorporating both direct poaching removals and decreased fecundity/recruitment were most similar to the observed demographic profile in 2018, suggesting that indirect impacts are also contributing to the observed population trajectory. These indirect impacts are likely a result of decreased density, through processes such as reduced mate-finding, population disturbance and/or increased calf predation. This study illustrates the combined effect of direct and indirect impacts on an endangered species, providing a more comprehensive approach by which to evaluate exploited populations.

Unrelenting poaching to feed the illegal trafficking of rhinoceros (rhino) horn remains the principle threat to the persistence of south-central black and southern white rhino that live in the Kruger National Park (Kruger), South Africa. Other global environmental change drivers, such as unpredictable climatic conditions, impose additional uncertainties on the management and persistence of these species. The drought experienced in Kruger over the 2015/2016 rainy season may have affected rhino population growth and thus added an additional population pressure to the poaching pressure already occurring. Under drought conditions, reduced grass biomass predicts increased natural deaths and a subsequent decrease in birth rate for the grazing white rhino. Such variance in natural death and birth rates for the browsing black rhino are not expected under these conditions. We evaluated these predictions using rhino population survey data from 2013 to 2017. Comparisons of natural deaths and birth rates between pre- (2013/2014 and 2014/15), during- (2015/2016) and post-drought (2016/2017) periods in Kruger showed increased natural mortality and decreased births for white rhino, but no significant changes for black rhino, supporting our predictions. As a result, despite reduced poaching rates, the total mortality rate of white rhino remains significantly higher than the birth rate. Decreased poaching, decreased natural deaths and no apparent drought effects in black rhino resulted in a lower total mortality rate than the estimated birth rate in 2017. Active biological management and traditional anti-poaching initiatives together therefore represent the most likely way to buffer the impacts of decreased population growth through climate change and wildlife crime on the persistence of rhinos.

The onslaught on the World's wildlife continues despite numerous initiatives aimed at curbing it. We build a model that integrates rhino horn trade with rhino population dynamics in order to evaluate the impact of various management policies on rhino sustainability. In our model, an agent-based sub-model of horn trade from the poaching event up through a purchase of rhino horn in Asia impacts rhino abundance. A data-validated, individual-based sub-model of the rhino population of South Africa provides these abundance values. We evaluate policies that consist of different combinations of legal trade initiatives, demand reduction marketing campaigns, increased anti-poaching measures within protected areas, and transnational policing initiatives aimed at disrupting those criminal syndicates engaged in horn trafficking. Simulation runs of our model over the next 35 years produces a sustainable rhino population under only one management policy. This policy includes both a transnational policing effort aimed at dismantling those criminal networks engaged in rhino horn trafficking-coupled with increases in legal economic opportunities for people living next to protected areas where rhinos live. This multi-faceted approach should be the focus of the international debate on strategies to combat the current slaughter of rhino rather than the binary debate about whether rhino horn trade should be legalized. This approach to the evaluation of wildlife management policies may be useful to apply to other species threatened by wildlife trafficking.

During 2020, South Africa reported 394 poached rhinoceros (rhino) carcasses – 34 at private properties and 360 at state properties.1 Poaching since 2008 has degraded South Africa’s rhino populations. By the start of 2020, South Africa had 14 410 southern white rhinos (Ceratotherium simum simum) and 1900 black rhinos, mostly south-central (Diceros bicornis bicornis) and south-western black rhino (D. b. minor) sub-species and a few nonnative eastern black rhinos (D. b. michaeli) (Table 1).

The onslaught on the World's rhinoceroses continues despite numerous initiatives aimed at curbing it. When losses due to poaching exceed birth rates, declining rhino populations result. We used previously published estimates and growth rates for black rhinos (2008) and white rhinos (2010) together with known poaching trends at the time to predict population sizes and poaching rates in Kruger National Park, South Africa for 2013. Kruger is a stronghold for the south-eastern black rhino and southern white rhino. Counting rhinos on 878 blocks 3x3 km in size using helicopters, estimating availability bias and collating observer and detectability biases allowed estimates using the Jolly's estimator. The exponential escalation in number of rhinos poached per day appears to have slowed. The black rhino estimate of 414 individuals (95% confidence interval: 343-487) was lower than the predicted 835 individuals (95% CI: 754-956). The white rhino estimate of 8,968 individuals (95% CI: 8,394-9,564) overlapped with the predicted 9,417 individuals (95% CI: 7,698-11,183). Density- and rainfall-dependent responses in birth- and death rates of white rhinos provide opportunities to offset anticipated poaching effects through removals of rhinos from high density areas to increase birth and survival rates. Biological management of rhinos, however, need complimentary management of the poaching threat as present poaching trends predict detectable declines in white rhino abundances by 2018. Strategic responses such as anti-poaching that protect supply from illegal harvesting, reducing demand, and increasing supply commonly require crime network disruption as a first step complimented by providing options for alternative economies in areas abutting protected areas.

Species typically occupy fewer sites, and average population densities decline from the centre to the edge of a species’ range when the range contracts. The poaching of rhinoceroses (rhinos) for their horn has degraded the black and white rhino populations in Kruger National Park (Kruger). Rhino populations have declined, and their distributions have contracted since 2010. We surveyed the black and white rhino populations in the Kruger during 2021 and 2022. We also identified core areas where rhino densities are greater and defined these as priority conservation zones. We then tested the prediction that population growth within priority conservation zones will exceed population growth beyond these zones for both black and white rhino. The results highlighted the continued decline of the white rhino population, while the black rhino population has stabilised since 2020. Growth rates were negative for white rhinos within priority conservation zones, but higher than those beyond these zones. For black rhinos, growth in priority conservation zones was positive and higher than those beyond zones. Priority conservation zones offer an opportunity to combat rhino poaching in a more tactical manner, concentrating resources on key areas for rhino survival.Conservation implicationsWe highlight complementary approaches to the existing anti-poaching tactics that focus on exploiting easier access control, situational awareness, integrity and individual-based rhino monitoring when targeting priority conservation zones within Kruger.

South African National Parks (SANParks) manage landscapes rather than numbers of elephants (Loxodonta africana) to mitigate the effects that elephants may have on biodiversity, tourism and stakeholder conservation values associated with protected areas. This management philosophy imposes spatial variability of critical resources on elephants. Restoration of such ecological processes through less intensive management predicts a reduction in population growth rates from the eras of intensive management. We collated aerial survey data since 1995 and conducted an aerial total count using a helicopter observation platform during 2015. A minimum of 17 086 elephants were resident in the Kruger National Park (KNP) in 2015, growing at 4.2% per annum over the last generation of elephants (i.e. 12 years), compared to 6.5% annual population growth noted during the intensive management era ending in 1994. This may come from responses of elephants to density and environmental factors manifested through reduced birth rates and increased mortality rates. Authorities should continue to evaluate the demographic responses of elephants to landscape scale interventions directed at restoring the limitation of spatial variance in resource distribution on elephant spatiotemporal dynamics and the consequences that may have for other conservation values. Conservation implications: Conservation managers should continue with surveying elephants in a way that allows the extraction of key variables. Such variables should focus on measures that reflect on how theory predicts elephants should respond to management interventions.

Rhinoceros (rhino) poaching has become a dominant topic in wildlife management in southern Africa since the poacher onslaught started in 2008. As social concerns about rhino poaching have grown, so have various forms of persuasive communication in attempts to curb, discourage, stigmatise and stop rhino poaching as well as discourage end users. Governmental and conservation agencies, non-governmental organisations (NGOs) dedicated to stopping rhino poaching, international organisations, documentary film-makers, television producers, and international figures like Prince William and celebrities like Jackie Chan, DJ Fresh and South African football star Maps Maponyane have tried many different methods to persuade end users, local communities or intermediaries that killing rhinos for their horns is wrong. How effective are such initiatives, particularly given that the demand for rhino horn shows little sign of abating and poached carcasses increased to over 1000 in South Africa by 2014? A reasonable response would be that such campaigns are usually ineffective particularly given that campaigns seldom consider outcomes such as changing or maintaining changed attitudes, or, even more difficult, changed behaviours. The inducements driving rhino poaching are so strong that it may be that no appeals are likely to deter offenders. Traditions of trade, inelasticity of demand and high profit potential may provide large enough incentives to override any persuasive appeals or threats, particularly when past social injustices may give an added sense of justification to poachers.

White rhinoceros (rhinos) is a keystone conservation species and also provides revenue for protection agencies. Restoring or mimicking the outcomes of impeded ecological processes allows reconciliation of biodiversity and financial objectives. We evaluate the consequences of white rhino management removal, and in recent times, poaching, on population persistence, regional conservation outcomes and opportunities for revenue generation. In Kruger National Park, white rhinos increased from 1998 to 2008. Since then the population may vary non-directionally. In 2010, we estimated 10,621 (95% CI: 8,767-12,682) white rhinos using three different population estimation methods. The desired management effect of a varying population was detectable after 2008. Age and sex structures in sink areas (focal rhino capture areas) were different from elsewhere. This comes from relatively more sub-adults being removed by managers than what the standing age distribution defined. Poachers in turn focused on more adults in 2011. Although the effect of poaching was not detectable at the population level given the confidence intervals of estimates, managers accommodated expected poaching annually and adapted management removals. The present poaching trend predicts that 432 white rhinos may be poached in Kruger during 2012. The white rhino management model mimicking outcomes of impeded ecological processes predicts 397 rhino management removals are required. At present poachers may be doing \"management removals,\" but conservationists have no opportunity left to contribute to regional rhino conservation strategies or generate revenue through white rhino sales. In addition, continued trends in poaching predict detectable white rhino declines in Kruger National Park by 2016. Our results suggest that conservationists need innovative approaches that reduce financial incentives to curb the threats that poaching poses to several conservation values of natural resources such as white rhinos.

Understanding the dietary composition of large carnivores and how these relate to the availability of suitable habitat and prey is crucial to population management, especially in fenced reserves. This study aimed to determine the current diet of the lion (Panthera leo) in the Karoo National Park and to establish whether prey preference has changed over the 12 years post-introduction. Global positioning system-collar-based kill-site cluster investigations and scat analyses were used to determine contemporary lion diet, while multinomial logistic regressions were used to investigate longitudinal changes in prey preference by comparing a decade of historical kill and aerial census records. Lion (n = 8) collar fixes identified 358 (12%) 'potential' kill-site clusters across 2945 discernible clusters over 15 months (i.e. 2021/2022). The subsequent in-field investigation of 227 (63%) 'potential' kill sites yielded 144 (63%) and 103 (45%) independent lion kill and scat samples, respectively. While these two methods offered different sampling advantages, both provided sufficient data to show lion preference for greater kudu (Tragelaphus strepsiceros), common eland (Tragelaphus oryx) and red hartebeest (Alcelaphus buselaphus caama). Other prey species included gemsbok (Oryx gazella), springbuck (Antidorcas marsupialis), common duiker (Sylvicapra grimmia) and mountain zebra (Equus zebra). Historical carcass records (n = 1035, x¯ = 89.6 ± 13.8 Standard Error [SE] per annum), since the reintroduction of lions in 2010, indicate no significant change in dietary composition over time (Χ[sup.2] = 1.98, df = 5, p = 0.85), when controlling for lion population size, despite post-introduction acclimation with substantial inter-annual variability in rainfall and prey availability. Conservation implications Understanding dietary changes in response to systemic disturbances is crucial to ensuring that lions are ethically and sustainably managed for their ecological efficacy in fenced metapopulations. With no significant change in hunting behaviour, management concerns are unlikely to be driven by reduced prey suitability or availability.