Hanlie Winterbach

The Evolutionary Dynamics of the Lion Panthera leo Revealed by Host and Viral Population Genomics

The lion Panthera leo is one of the worlds most charismatic carnivores and is one of Africas key predators. Here, we used a large dataset from 357 lions comprehending 1.13 megabases of sequence data and genotypes from 22 microsatellite loci to characterize its recent evolutionary history. Patterns of molecular genetic variation in multiple maternal (mtDNA), paternal (Y-chromosome), and biparental nuclear (nDNA) genetic markers were compared with patterns of sequence and subtype variation of the lion feline immunodeficiency virus (FIVPle), a lentivirus analogous to human immunodeficiency virus (HIV). In spite of the ability of lions to disperse long distances, patterns of lion genetic diversity suggest substantial population subdivision (mtDNA ΦST = 0.92; nDNA F ST = 0.18), and reduced gene flow, which, along with large differences in sero-prevalence of six distinct FIVPle subtypes among lion populations, refute the hypothesis that African lions consist of a single panmictic population. Our results suggest that extant lion populations derive from several Pleistocene refugia in East and Southern Africa (∼324,000–169,000 years ago), which expanded during the Late Pleistocene (∼100,000 years ago) into Central and North Africa and into Asia. During the Pleistocene/Holocene transition (∼14,000–7,000 years), another expansion occurred from southern refugia northwards towards East Africa, causing population interbreeding. In particular, lion and FIVPle variation affirms that the large, well-studied lion population occupying the greater Serengeti Ecosystem is derived from three distinct populations that admixed recently.

Pathological manifestations of feline immunodeficiency virus (FIV) infection in wild African lions

Abstract Feline immunodeficiency virus (FIV) causes AIDS in the domestic cat (Felis catus) but has not been explicitly associated with AIDS pathology in any of the eight free-ranging species of Felidae that are endemic with circulating FIV strains. African lion (Panthera leo) populations are infected with lion-specific FIV strains (FIVple), yet there remains uncertainty about the degree to which FIV infection impacts their health. Reported CD4+ T-lymphocyte depletion in FIVple-infected lions and anecdotal reports of lion morbidity associated with FIV seroprevalence emphasize the concern as to whether FIVple is innocuous or pathogenic. Here we monitored clinical, biochemical, histological and serological parameters among FIVple-positive (N =47) as compared to FIVple-negative (N =17) lions anesthetized and sampled on multiple occasions between 1999 and 2006 in Botswana. Relative to uninfected lions, FIVple-infected lions displayed a significant elevation in the prevalence of AIDS-defining conditions: lymphadenopathy, gingivitis, tongue papillomas, dehydration, and poor coat condition, as well as displaying abnormal red blood cell parameters, depressed serum albumin, and elevated liver enzymes and gamma globulin. Spleen and lymph node biopsies from free-ranging FIVple-infected lions (N =9) revealed evidence of lymphoid depletion, the hallmark pathology documented in immunodeficiency virus infections of humans (HIV-1), macaques, and domestic cats. We conclude that over time FIVple infections in free-ranging lions can lead to adverse clinical, immunological, and pathological outcomes in some individuals that parallel sequelae caused by lentivirus infection in humans (HIV), Asian macaques (SIV) and domestic cats (FIVfca).

Landscape suitability in Botswana for the conservation of its six large African carnivores.

Wide-ranging large carnivores often range beyond the boundaries of protected areas into human-dominated areas. Mapping out potentially suitable habitats on a country-wide scale and identifying areas with potentially high levels of threats to large carnivore survival is necessary to develop national conservation action plans. We used a novel approach to map and identify these areas in Botswana for its large carnivore guild consisting of lion (Panthera leo), leopard (Panthera pardus), spotted hyaena (Crocuta crocuta), brown hyaena (Hyaena brunnea), cheetah (Acinonyx jubatus) and African wild dog (Lycaon pictus). The habitat suitability for large carnivores depends primarily on prey availability, interspecific competition, and conflict with humans. Prey availability is most likely the strongest natural determinant. We used the distribution of biomass of typical wild ungulate species occurring in Botswana which is preyed upon by the six large carnivores to evaluate the potential suitability of the different management zones in the country to sustain large carnivore populations. In areas where a high biomass of large prey species occurred, we assumed interspecific competition between dominant and subordinated competitors to be high. This reduced the suitability of these areas for conservation of subordinate competitors, and vice versa. We used the percentage of prey biomass of the total prey and livestock biomass to identify areas with potentially high levels of conflict in agricultural areas. High to medium biomass of large prey was mostly confined to conservation zones, while small prey biomass was more evenly spread across large parts of the country. This necessitates different conservation strategies for carnivores with a preference for large prey, and those that can persist in the agricultural areas. To ensure connectivity between populations inside Botswana and also with its neighbours, a number of critical areas for priority management actions exist in the agricultural zones.

Relative availability of natural prey versus livestock predicts landscape suitability for cheetahs Acinonyx jubatus in Botswana

Prey availability and human-carnivore conflict are strong determinants that govern the spatial distribution and abundance of large carnivore species and determine the suitability of areas for their conservation. For wide-ranging large carnivores such as cheetahs (Acinonyx jubatus), additional conservation areas beyond protected area boundaries are crucial to effectively conserve them both inside and outside protected areas. Although cheetahs prefer preying on wild prey, they also cause conflict with people by predating on especially small livestock. We investigated whether the distribution of cheetahs’ preferred prey and small livestock biomass could be used to explore the potential suitability of agricultural areas in Botswana for the long-term persistence of its cheetah population. We found it gave a good point of departure for identifying priority areas for land management, the threat to connectivity between cheetah populations, and areas where the reduction and mitigation of human-cheetah conflict is critical. Our analysis showed the existence of a wide prey base for cheetahs across large parts of Botswana’s agricultural areas, which provide additional large areas with high conservation potential. Twenty percent of wild prey biomass appears to be the critical point to distinguish between high and low probable levels of human-cheetah conflict. We identified focal areas in the agricultural zones where restoring wild prey numbers in concurrence with effective human-cheetah conflict mitigation efforts are the most immediate conservation strategies needed to maintain Botswana’s still large and contiguous cheetah population.

The influence of social and environmental factors on organization of African lion (Panthera leo) prides in the Okavango Delta

Carnivores that exhibit fission–fusion social organization can adapt group sizes to prevailing social and ecological conditions. This study focuses on social organization of African lions (Panthera leo) in the Okavango Delta, a seasonally flooded wetland. We used generalized estimating equations and generalized linear mixed models to estimate the effects of flooding, as well as prey availability and intraspecific competition on group sizes of lions. During years of high flood, total lion pride sizes as well as reproductive rates declined. Prides showed extensive overlap in annual home ranges, likely as a result of habitat saturation at high densities, and pride sizes were not limited by prey availability. At the subgroup level, the number of attending cubs was the most consistent predictor of subgroup size of adult females. For subgroups without cubs, higher numbers of neighbors in adjacent, competing prides resulted in larger subgroups in focal prides, likely to maintain numerical advantage in inter-pride encounters. Larger subgroups were also formed in response to greater availability of large prey, as successfully hunting large prey requires a greater degree of cooperation. In the southwestern Okavango Delta, competition for space resulting from changing flooding regimes is a greater limiting factor for total pride sizes than food availability.

Genetic Evidence for Contrasting Wetland and Savannah Habitat Specializations in Different Populations of Lions (Panthera leo)

South-central Africa is characterized by an archipelago of wetlands, which has evolved in time and space since at least the Miocene, providing refugia for animal species during Pleistocene arid episodes. Their importance for biodiversity in the region is reflected in the evolution of a variety of specialist mammal and bird species, adapted to exploit these wetland habitats. Populations of lions (Panthera leo) across south-central and east Africa have contrasting signatures of mitochondrial DNA haplotypes and biparental nuclear DNA in wetland and savannah habitats, respectively, pointing to the evolution of distinct habitat preferences. This explains the absence of genetic admixture of populations from the Kalahari savannah of southwest Botswana and the Okavango wetland of northern Botswana, despite separation by only 500 km. We postulate that ancestral lions were wetland specialists and that the savannah lions evolved from populations that were isolated during arid Pleistocene episodes. Expansion of grasslands and the resultant increase in herbivore populations during mesic Pleistocene climatic episodes provided the stimulus for the rapid population expansion and diversification of the highly successful savannah lion specialists. Our model has important implications for lion conservation.