Hluhluwe-iMfolozi Park Research Articles

An investigation of the effects of secondary processing on Mycobacterium spp. in naturally infected game meat and organs

The risk for humans to contract bovine tuberculosis through the consumption of undercooked game meat as well as biltong (traditionally dried game meat) is a concern. The survival potential of Mycobacterium bovis during the cooking and drying processes was researched in a preceding study on beef and the positive results compelled the authors to investigate the results with a similar preliminary study on game meat. Muscular, lymphatic and visceral tissues from skin test positive African buffalo (Syncerus caffer) and greater kudu (Tragelaphus strepsiceros) with tuberculous lesions were collected from the Hluhluwe iMfolozi Park during the park's culling programme. The different tissues were exposed to cooking and the muscular tissue to the drying process prior to culture. All acid-fast isolates were analysed by polymerase chain reaction for the presence of Mycobacterium bovis. All tissues were found negative for Mycobacterium bovis but non-tuberculous mycobacteria were isolated from kidney, liver, heart and lymph nodes. The results showed that these processes will kill Mycobacterium bovis but the unexpected recovery of non-tuberculous mycobacteria suggests possible survival and resistance characteristics of these strains which might be of veterinary public health interest.

Occurrence of Theileria parva and other haemoprotozoa in cattle at the edge of Hluhluwe-iMfolozi Park, KwaZulu-Natal, South Africa

Theileria parva, the most important bovine theilerial species in sub-Saharan Africa, causes widespread mortality and morbidity in endemic areas. A survey was conducted using buffy-coat specimens from 60 apparently healthy adult communally herded Nguni-type cattle at the northeastern edge of the Hluhluwe-iMfolozi Park to determine, by means of PCR and Reverse Line Blot (RLB) hybridisation, the occurrence of Theileria and Babesia species. The presence of Trypanosoma species was determined using PCR-RFLP. Results showed that 6.7 % of the specimens were positive for Theileria parva. This significant finding suggests that cattle in South Africa, and not only African buffaloes (Syncerus caffer), may be subclinical carriers of T. parva. Other species identified were T. mutans (83.3%), T. velifera (70.0%), Theileria sp. (sable) (46.8%) and T taurotragi (1.7%). Two specimens (3.3%) were positive for Babesia bovis and single specimens (1.7%) positive for B. bigemina and B. rossi, respectively. Mixed infections, of up to 4 species, were common (65.0%). Only 1 specimen was found to be positive for Trypanosoma vivax, and 2 for T theileri, of which only the first species is pathogenic.

Black Rhinoceros are Slow to Colonize a Harvested Neighbour's Range

Live-harvests from source populations for translocation are key to rapid recovery for many species. Contrary to common assumption, however, reduced density might not Immediately Improve vital rates because animal recolonization is slow — creating management uncertainty about harvest adequacy or sustainability. Reports measuring animal recolonization are rare. We measured the response of the 19 same- or opposite-sex neighbours of 11 live-harvested black rhinoceros (Diceros bicornis minor) in Hluhluwe-iMfolozi Park, South Africa, by comparing the size and location of their activity areas for an average two years before and after harvest. The only significant change was a decolonization response by opposite-sex neighbours, especially males after the harvest of a female neighbour. Recolonization of habitat after harvest, at least by neighbours, might not Just be slow but also further delayed by the disruption of long-standing breeding relationships with Important Implications for the spatial pattern and frequ...

Annual and Seasonal Rainfall May Influence Progeny Sex Ratio in the Black Rhinoceros

Facultative sex allocation theories predict that animals will bias their offspring’s sex in response to environmental cues. Biased sex ratios can be a problem when managing small populations in the wild or captivity. Using rainfall and calving records from HluhluweiMfolozi Park in South Africa, we compared seasonal and annual rainfall with calving rates and sex of the calves. Between 1989–2004, 159 calves were sighted soon enough after birth to reliably attribute their conception to a particular season and year. Conceptions were strongly seasonal, with most (73.6%) occurring during rainy seasons and the remainder during dry seasons. Overall progeny sex ratio for the period 1989–2004 was 53.1% male. Mothers were more likely to be observed with male calves if they conceived during the wet season (57.3% male) than during the dry season (42.9% male) in accordance with the Trivers-Willard hypothesis. Similar numbers of conceptions that resulted in calves occurred during wet and dry years (52.2% of conceptions occurred during wet years). Mothers were more likely to raise male calves if they conceived during wet years (60.2% male) than during dry years (46.1% male). Removal of males from small populations might be particularly important after a sequence of wet years to facilitate greater population growth.

Heterogeneity in the density of spotted hyaenas in Hluhluwe-iMfolozi Park, South Africa

Animal population sizes and trends, as well as their distributions, are essential information to the understanding and conservation of ecosystems. During this study in Hluhluwe-iMfolozi Park, South Africa, a spotted hyaena Crocuta crocuta Erxleben, 1777 (Hyaenidae) population was surveyed by attracting individuals with pre-recorded sounds. The hyaena population (excluding cubs) is substantially larger (321 individuals) than the previous estimate of 200 and this population is the second largest protected population in South Africa. Average hyaena density, at 0.357 individuals/km2, was relatively high compared to other southern African conservation areas, and range from 0 to 1.25 individuals/km2 across sampling stations. For short periods, spatial heterogeneity in density was marked at small and large spatial scales, but decreased when averaged over a longer period. This heterogeneity may be important in promoting the coexistence of other large and mobile carnivores in Hluhluwe-iMfolozi Park by creating potential dynamic competition refugia in space and time. Furthermore, heterogeneity of hyaena density at smaller scales should influence studies investigating the avoidance of hyaenas by competitively inferior carnivores.

Grazing and landscape controls on nitrogen availability across 330 South African savanna sites

AbstractThe availability of nitrogen (N) is an important determinant of ecosystem and community dynamics for grasslands and savannas, influencing factors such as biomass productivity, plant and herbivore composition, and losses of N to waters and the atmosphere. To better understand the controls over N availability at landscape to regional scales, we quantified a range of plant and soil characteristics at each of 330 sites in three regions of South Africa: Kruger National Park (KNP), private game reserves adjacent to KNP (private protected areas – PPAs) and Hluhluwe‐iMfolozi Park (HiP). In comparing regions and sites within regions, grazing appeared to have a strong influence on N availability. Sites in the PPAs adjacent to KNP as well as sodic and alluvial sites in general typically had the highest N availability. The high N availability of these sites was not generally associated with greater potential N mineralization, but instead with less grass biomass and more forb biomass that indicated greater grazing pressure. Whereas sodic sites had a long history of high N availability as evidenced by their high soil δ15N, the greater N availability in the PPAs over the two parks appeared to be relatively recent. Grazer biomass, average potential mineralization rates and grass biomass for HiP were greater than KNP, yet there were no differences in N availability as indexed by soil and foliar δ15N between sites in the two parks. Although the short‐term increase in N availability in PPAs is not necessarily deleterious, it is uncertain whether current productivity levels in those ecosystems is sustainable. With differences in management causing herbivore biomass to be 150% greater in the PPAs than the adjacent KNP, changes in plant communities and nitrogen cycling might lead to long‐term degradation of these ecosystems, their ability to sustain herbivore populations, and also serve as an economic resource for the region.

Browsing and fire interact to suppress tree density in an African savanna

Disturbances from fire and herbivory strongly affect savanna vegetation dynamics. In some savannas, fire especially may be instrumental in preserving the coexistence of trees and grasses. The role of herbivory by large mammals is less clear; herbivory has been shown variously to promote and to suppress tree establishment. Here we ask how interactions between herbivory and fire act to shape savanna vegetation dynamics via their effects on tree populations in Hluhluwe iMfolozi Park in KwaZulu Natal, South Africa, a savanna with a full complement of native large mammals. We examined the effects of herbivore exclusion on tree growth, mortality, and seedling establishment from 2000 to 2007 at 10 sites located in areas of low and high herbivore pressure throughout the park. Results were analyzed statistically and using Leslie matrix models of population dynamics. Herbivory and fire acted primarily to suppress sapling growth rather than on sapling mortality or seedling establishment. This indicates that browsing, like fire, suppresses tree density by imposing a demographic bottleneck on the maturation of saplings to adults. Model results suggest that, while browsing and fire each alone impacted growth, a combination of browsing and fire had much greater effects on tree density. Only fire and browsing together were able to prevent increases in tree density. These results suggest that, while soil resources, including nutrients and moisture, are probably instrumental in determining tree growth rates, disturbances from fire and herbivory may be instrumental in limiting tree cover and facilitating the coexistence of trees and grasses in savannas.

Black Rhinoceros (Diceros bicornis) Calf Succumbs After Lion Predation Attempt: Implications for Conservation Management

Actual observations of black rhinoceros predation are rarely reported and are limited to two incidences involving subadults. Nevertheless, some authors attribute tail and ear deformities in up to 7.1% of some populations to predation attempts. In August 2008 we observed a mother with dependent c. 8-month-old female black rhinoceros calf in Hluhluwe-iMfolozi Park, South Africa. The calf had a recently amputated tail, wounds to the anogenital region, right posterior flank and right side of the neck resembling a lion attack. Thirteen days later and on three subsequent occasions, the mother was sighted alone, suggesting that the calf had succumbed to its injuries. This incident provides evidence to suggest a link between attempted lion predation and tail amputation in black rhinoceros. Significantly, it implies that amputated tails and ears throughout Africa may represent failed depredation attempts and that calf predation may be more prevalent than previously appreciated. Predation is seldom considered in the management of black rhinoceros but should be when attributing cause to poor population performance of this critically endangered species.

Effects of large herbivores on murid rodents in a South African savanna

Abstract:Our study presents experimentally based results on how large herbivore species affect savanna vegetation and thus murid rodents in the Hluhluwe-iMfolozi Park in KwaZulu-Natal, South Africa. We permanently excluded groups of large herbivore guilds of various body sizes (ranging from white rhino to hares) from sixteen 40 × 40-m plots of vegetation by using different fence types. We determined grass species composition and vegetation height and collected capture–mark–recapture data on murid rodents. Nutrient concentrations of the dominant grass species and rodent diet compositions were analysed. We found that herbivore species of different body sizes had different effects on murid rodents. The exclusion of medium-sized herbivores, such as warthog, impala and nyala increased the abundance of high-quality grass species, especiallyPanicum maximum. However, the dominant rodent speciesLemniscomys rosaliapreferred the most abundant grass species, rather than high-quality grasses. The absence of large bulk feeders, such as zebra, buffalo and white rhino led to an increase in vegetation height. In response, tall vegetation promoted both rodent abundance and species diversity and altered rodent species composition. Ultimately, our results indicate that the greatest effect on murid rodents came from the reduction of vegetation cover by large bulk feeders, which likely increased rodent predation risk.

Dogs on the catwalk: Modelling re-introduction and translocation of endangered wild dogs in South Africa

In South Africa, a plan was launched to manage separate sub-populations of endangered African wild dogs ( Lycaon pictus) in several small, geographically isolated conservation areas as a single meta-population. This intensive management approach involves the re-introduction of wild dogs into suitable conservation areas and periodic translocations among them. Despite the initial failures and high costs associated with wild dog re-introductions and translocations, there is no predictive framework available to quantify which management protocol is the most efficient. We therefore developed an individual-based model of wild dog population and pack dynamics, which accounts for the wild dogs’ social complexity. The model appeared to capture the essential characteristics of a real wild dog population from Hluhluwe-iMfolozi Park, South Africa and to be relatively robust to parameter uncertainty, suggesting that the model is valid enough for addressing management problems. The model enabled us to quantify a critical initial number of packs (two) and individuals per pack (six) necessary for a re-introduced wild dog population to establish itself in the release area. We also found a practically feasible intervention regime at which a re-introduced wild dog population had the best chance of persistence: intermittently adding packs (at least every 6 years) and harvesting disperser groups (as often as every 4 years) for translocation to other release sites, without threatening the small source population. This study demonstrates that individual-based models can be a powerful decision-support tool in re-introduction planning and provides insight into how populations made up of social groups have dynamics, and ultimately persistence, determined by individual behaviour.

Herbivore and nutrient control of lawn and bunch grass distributions in a southern African savanna

In African savannas, bottom-up soil nutritional factors and top-down herbivory have both been suggested to control the distribution patterns of bunch and lawn grasses. We tested the separate and combined roles of these factors on grassland distribution in a South African savanna by focusing on three main objectives, namely (1) are grazing patches and lawns restricted to specific soils or sites, (2) does herbivory alter rates of nutrient cycling which facilitates lawns and (3) are there any differences in foliage quality between lawn and bunch grass-dominated sites that might influence animals in choosing to feed on lawns? We set up ten sites along a grazing gradient in the Hluhluwe-iMfolozi Park in KwaZulu-Natal, South Africa. At these sites, we measured total soil nutrients, soil nutrient turnover rates and grass foliage nutrient concentrations. We found that in the Hluhluwe-iMfolozi Park the spatial distribution of lawn and bunch grassland types appears to be an animal-driven phenomenon and not dependent on specific soil properties. The short-structured and distinct species found in lawns do not appear to be restricted to nutrient-enriched patches. However, the grasses of these lawns had significantly higher nutrient concentrations, in their foliage, which might explain the high attraction to these patches by herbivores. We also did not find any animal-induced stimulation of nutrient cycling rates that are often associated with lawn grass species.

Sexual and vegetative regeneration of three leguminous tree species in South African savannas

The legume trees Dichrostachys cinerea, Acacia karroo and Acacia nilotica are encroaching a number of African savannas. I quantified the extent to which these species regenerated by seeds and root suckers respectively, and how land management affects the mode of regeneration. I used transects at three sites inside the Hluhluwe-iMfolozi Park and at three sites in adjacent villages outside the park to score all individuals shorter than 20 cm. I also excavated the roots to determine whether the plant was a gamete or a ramet connected to an established mother tree. I found D. cinerea regenerated to equal extent vegetatively and sexually, while A. karroo and A. nilotica mainly regenerated sexually. The present results suggest that the capacity of sexual regeneration of trees is important to consider in future management of bush encroachment in southern African savannas.

EVALUATION OF HEMATOLOGIC VALUES IN FREE-RANGING AFRICAN BUFFALO (SYNCERUS CAFFER)

As part of a large-scale disease screening program, blood samples were collected from 534 African buffalo (Syncerus caffer) in South Africa's Hluhluwe-iMfolozi Park in October 2005 and May 2006 to establish age- and sex-specific reference intervals for erythrogram and leukogram values. Sixty-seven of the animals were positive for bovine tuberculosis (TB), allowing for comparisons between TB-positive and TB-negative groups. Positive animals had basopenia and slight lymphopenia compared to TB-negative animals. Blood values were compared to those reported for captive African buffalo, American bison (Bos bison), and cattle (Bos taurus). The free-ranging buffalo sampled in this study had higher white blood cell counts than captive buffalo, and this difference was driven by lymphocytes. Free-ranging buffalo also had higher red blood cell counts, mean corpuscular hemoglobin concentration (MCHC), white blood cell counts, neutrophils and lymphocytes, and lower mean corpuscular volume (MCV) than cattle. Demographic and environmental factors strongly affected hematologic values in the study population. Older animals had significantly higher hemoglobin, hematocrit, MCV, and mean corpuscular hemoglobin (MCH), while younger animals had a higher red blood cell count, red cell distribution width (RDW), and white blood cell count, which was due to lymphocytes and basophils. Females had a higher hemoglobin concentration, hematocrit, MCV, MCH, and basophils than males. At the end of the wet season, hemoglobin, red blood cell count, hematocrit, MCHC, RDW, white blood cell count, and neutrophils were all significantly higher, while basophils and MCV were lower, than at the end of the dry season. Our results emphasize the need to use species-specific data when interpreting hematologic values and point to important differences in hematology between captive and free-ranging animals of the same species. Strong variability in hematologic values with animal age and sex, season, and herd affiliation indicates that ''normal'' hematologic values in wild animals vary throughout their lives and subject to fluctuating environmental conditions.

A demographic perspective on bush encroachment by Acacia karroo in Hluhluwe-Imfolozi Park, South Africa

Acacia karroo has invaded large areas of the Hluhluwe part of the Hluhluwe-Imfolozi Park, despite the relatively frequent fire regime (mean and median fire frequency of 2.9 and 1.3 years, respectively) of this area. We surveyed A. karroo demography and post-fire responses to determine what is facilitating this encroachment. We found no seedlings and few individuals with small lignotubers. This suggests that encroachment is due to release of already established individuals, rather than recent or continuous recruitment of new individuals. Post-fire height growth rates of basal resprouts is about 0.5 m y− 1, which is too slow for escape from damage by fire, given the present frequent fire regime. Analysis of post-fire responses suggests that individuals can resprout from the stem at relatively small sizes (1.2–2.2 m tall). We suggest that stems can incrementally grow beyond the zone of fire influence because post-fire resprouting does not only take place from the base, after individuals are above 1.2 m in height. Bush encroachment is suggested to be due to low fire intensity, which allows relatively small plants to resprout from the stem and thus incrementally grow in size until escape size.

Resource partitioning by grass height among grazing ungulates does not follow body size relation

We compared the grass height grazed by white rhino, wildebeest, zebra and impala through the dry season months in the Hluhluwe–iMfolozi Park in South Africa. We expected that the grass height grazed would increase with the body size of the herbivore species, as suggested from past studies of resource partitioning among large mammalian herbivores. Instead we found that the largest of these species, white rhino, concentrated on the shortest grass, while the smallest species, impala, grazed heights intermediate between those grazed by wildebeest and zebra. Results suggest that the scaling of mouth width relative to body size, and hence to metabolic demands, may be the primary factor governing grass height selection, rather than body size alone. This calls into question the widespread assumption that smaller herbivores are superior competitors through being able to persist on sparser vegetation. Furthermore, there was considerable overlap in grass height grazed among these four species, indicating that niche separation by grass height is inadequate alone to explain their coexistence.

Monitoring large herbivore diversity at different scales: comparing direct and indirect methods

Monitoring of large herbivores is central to research and management activities in many protected areas. Monitoring programs were originally developed to estimate (trends in) population sizes of individual species. However, emphasis is shifting increasingly towards conservation of diversity and communities instead of individual species, as a growing literature shows the importance of herbivore diversity for ecosystem functioning. We argue that the design of monitoring programs has not yet been adapted well to this new conservation paradigm. Using large herbivore census data from Hluhluwe-iMfolozi Park, South Africa, we studied how monitoring methodology (observational counts vs. dung counts) and spatial scale interact in influencing estimates of large herbivore species richness and diversity. Dung counts resulted in higher herbivore species richness and diversity estimates than direct observational counts, especially at finer monitoring resolutions (grid cells smaller than 25 km2). At monitoring resolutions coarser than 25 km2 both methods gave comparable diversity estimates. The methods also yielded different spatial diversity estimates, especially at finer resolutions. Grid cells with high diversity according to the dung count data did not necessarily have high diversity according to the observational counts, as shown by low correlation of grid cell values of both methods. We discuss these results in the light of estimates of the sampling effort of each method and, hence, suggest new monitoring designs that are more suitable for tracking temporal and spatial trends in large herbivore diversity and community composition.

Dynamics of a small re-introduced population of wild dogs over 25 years: Allee effects and the implications of sociality for endangered species’ recovery

We analysed 25 years (1980-2004) of demographic data on a small re-introduced population of endangered African wild dogs (Lycaon pictus) in Hluhluwe-iMfolozi Park (HiP), South Africa, to describe population and pack dynamics. As small populations of cooperative breeders may be particularly prone to Allee effects, this extensive data set was used to test the prediction that, if Allee effects occur, aspects of reproductive success, individual survival and population growth should increase with pack and population size. The results suggest that behavioural aspects of wild dogs rather than ecological factors (i.e. competitors, prey and rainfall) primarily have been limiting the HiP wild dog population, particularly a low probability of finding suitable mates upon dispersal at low pack number (i.e. a mate-finding Allee effect). Wild dogs in HiP were not subject to component Allee effects at the pack level, most likely due to low interspecific competition and high prey availability. This suggests that aspects of the environment can mediate the strength of Allee effects. There was also no demographic Allee effect in the HiP wild dog population, as the population growth rate was significantly negatively related to population size, despite no apparent ecological resource limitation. Such negative density dependence at low numbers indicates that behavioural studies of the causal mechanisms potentially generating Allee effects in small populations can provide a key to understanding their dynamics. This study demonstrates how aspects of a species' social behaviour can influence the vulnerability of small populations to extinction and illustrates the profound implications of sociality for endangered species' recovery.

Molecular epidemiology of Mycobacterium bovis isolates from free-ranging wildlife in South African game reserves

Bovine tuberculosis is endemic in African buffalo and a number of other wildlife species in the Kruger National Park (KNP) and Hluhluwe-iMfolozi Park (HiP) in South Africa. It was thought that the infection had been introduced into the KNP ecosystem through direct contact between cattle and buffalo, a hypothesis which was confirmed in this study by IS 6110 and PGRS restriction fragment length polymorphism (RFLP) typing. The molecular characterisation of 189 Mycobacterium bovis isolates from nine wildlife species in the HiP, including three smaller associated parks, and the Kruger National Park with adjacent areas showed that the respective epidemics were each caused by an infiltration of a single M. bovis genotype. The two M. bovis strains had different genetic profiles, as demonstrated by hybridisation with the IS 6110 and PGRS RFLP probes, as well as with regard to evidence of evolutionary changes to the IS profile. While the M. bovis type in HiP was transmitted between buffaloes and to at least baboon, bushpig and lion without obvious genetic changes in the RFLP patterns, in the KNP a dominant strain was represented in 73% of the M. bovis isolates, whilst the remaining 27% were variants of this strain. No species-specific variants were observed, except for one IS 6110 type which was found only in a group of five epidemiologically related greater kudu. This finding was attributed to species-specific behaviour patterns rather than an advanced host–pathogen interaction.

Translocating lions into an inbred lion population in the Hluhluwe‐iMfolozi Park, South Africa

AbstractA fundamental problem in conservation biology is the risk of inbreeding in fragmented and declining populations. In the Hluhluwe‐iMfolozi Park (HiP), a small, enclosed reserve in South Africa, a large lion Panthera leo population arose from a founder group of five individuals in the 1960s. The HiP lion population went through a persistent decline and showed indications of inbreeding depression. To restore the genetic variation of the inbred HiP lion population, new lions were translocated into the existing population. Translocated females formed stable associations and established enduring pride areas with other translocated lionesses, but did not bond into native female prides. The translocated male coalition was more successful in gaining and maintaining residence in a pride than the translocated lone male that split off on his own from the male coalition. Litter size and cub survival was about twice as high for pairings involving at least one translocated parent than for pairings of two native lions. It is therefore possible to infuse new genes rapidly and successfully into a small, isolated lion population. Such translocations may become an important adaptive management tool as lion populations become increasingly fragmented.

Conflicting human interests over the re-introduction of endangered wild dogs in South Africa

In South Africa, a plan was launched to manage separate sub-populations of endangered African wild dogs (Lycaon pictus) in several small, geographically isolated, conservation areas as a single meta-population. This intensive management approach involves the re-introduction of wild dogs into suitable conservation areas and periodic translocations among them. To assess the attitudes towards re-introduced wild dogs, we conducted a questionnaire survey of multiple stakeholders—local community members, private landowners and tourists—in and around Hluhluwe-iMfolozi Park (HiP), one of the meta-population conservation areas. Here, we document conflicting human interests over the re-introduced wild dogs. Tourists in HiP, on the one hand, expressed overwhelmingly positive opinions about wild dogs across personal details of the respondents, but especially after having seen free-ranging wild dogs. On the other hand, we found misconceptions and perceptions that were more negative among the rural population around HiP, again largely independent of personal details of the participants, although educated respondents voiced more favourable views of wild dogs. These negative attitudes were in particular due to perceived and real threats of livestock losses. In a follow-up questionnaire survey, we also discovered apparent shortcomings of a previous short-lived conservation education programme among the local communities adjacent to HiP. Consequently, the mitigation of the conflict between wild dogs and rural people requires an understanding of the conditions under which livestock predation occurs, the encouragement of practices that prevent such predation, and increasing local tolerance of co-existence with wild dogs through both economic and non-monetary incentive schemes as well as continued conservation education.