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Background. It is well established that South Africa (SA) suffers an immense burden of violence and injuries. The responsibility of providing care for these injuries falls mainly on public health services, resulting in overloading of the health system. Prior to a recent intervention, the large burden had been exacerbated by limitations in the traditional referral system that highlighted the need for a better referral system. Vula’s smartphone app was introduced at Tygerberg Hospital in August 2016. This study evaluated the uptake, response times and outcomes using this app. Objectives. The main objectives of the study were to describe: ( i ) the number of referrals; ( ii ) referral response times; ( iii ) referring facilities; and ( iv ) referral outcomes. Secondary objectives were to: ( i ) evaluate whether the referral outcome pathway was appropriate; and ( ii ) assess professional conduct and evidence of upskilling. Methods. This retrospective, descriptive study investigated Vula app referrals to the Division of Orthopaedic Surgery at Tygerberg Hospital between 1 August 2016 and 31 March 2017. Vula was advertised to key facilities in the hospital’s referral network. All referrals to the division during the study period were systematically included in the analysis of operational outcomes, although some were excluded from the subsequent referral outcome analysis. Operational outcomes included the number of referrals, referring facilities and referral response times. Referral outcome analysis included the clinical diagnosis, referral pathway, whether the referral was used for upskilling and whether it was conducted in a professional manner. Results. A total of 2 275 referrals from 39 different facilities were received during the study period from 238 individual users; 50% of referrals received a response within 11 minutes, while a small percentage received no response. Clinical and demographic characteristics of 1 985 patients included in the referral outcome analysis indicated that the majority of trauma and emergency referrals involved males, with closed fractures being the most frequent clinical presentation. Although the most common referral outcome was immediate transfer, one-third of the patients were treated at the referring hospital with advice only. Conclusions. The large volume of orthopaedic referrals received through the Vula app suggests that Vula represents a successful alternative to traditional referral methods. Referrals managed by advice only could suggest that Vula facilitates some relief for the overburdened trauma services. Future research could further explore Vula’s role in strengthening the public health system, including interventions for high-volume referral areas and upskilling of referring health workers.

Penetration of matte into tap-hole bricks causes detrimental refractory wear, which can lead to furnace breakouts. The ability of the tap-hole clay to form a protective layer on the brick, thereby limiting matte penetration was investigated by examining the interaction between platinum group metal (PGM) matte, tap-hole clay, and alumina-chrome refractory bricks on a laboratory scale. Samples containing clay and brick as well as samples containing clay, brick, and matte were heated to different temperatures to establish the clay-brick interaction and the extent of matte penetration. The greatest degree of physical contact between the brick and clay was achieved at curing temperatures of 600°C. Poor clay-brick contact was observed in the sample that was heated to 900°C. Matte displaced the clay in the clay-brick-matte sample that was heated to 1350°C, with significant matte penetration into the brick. Less matte penetration was observed when the clay-brick-matte sample was heated to 1500°C. Less matte penetration was also observed in the clay-brick-matte sample in which the clay and brick were pre-baked at 800°C, and the sample then reacted with matte at 1350°C.

Background. The South African Rugby Union (SARU) has had a continual challenge to make the game representative of players of all ethnic groups at all levels of play. In response to this challenge SARU has implemented several programmes designed to accelerate the development of players from previously disadvantaged areas with the goal of making the game more representative. However, the success of these programmes to transform the player profile at different levels of rugby cannot be evaluated because the players representing different ethnic groups have not been quantified in a systematic way.Objectives. To quantify the number and playing time of South African professional players (Vodacom, Currie Cup, Super Rugby and Springboks) from different ethnic groups from 2007 to 2011 to determine whether there are any changes in the profile of the players over this period.Methods. Playing time was recorded for all players in sanctioned matches. Players were divided into the ethnic classifications used by SARU (i.e. white, coloured and black).Results. At all levels of competition there were proportionally more white players, followed by coloured players and then black players. This pattern did not change from 2007 to 2011. Based on the ratio of number of players v. playing time, the white players played more time than expected at the Springbok level, whereas the black players played less than expected for the number of players from 2007 to 2011. At the Vodacom level the white players played more than expected in 2007 and 2008 and played less than expected in 2010 and 2011, whereas the black players played more than expected in 2010 and the coloured players played more than expected at the 2011 tournament. The Super Rugby tournamenthad the most consistency between players and expected playing time for the different ethnic groups.Conclusions. Despite the effort to support players from disadvantaged backgrounds since 1998 with facilitative programmes and selection targets, the professional game is still dominated by white players at all levels.

The study pursued the hypothesis that bromine (Br) in drinking water at levels > 0.01 mg Br/L may have detrimental effects on the liver, kidneys and thyroid and the thyroid hormones T3 and T4 and that iodine (I) may alleviate the potential hazardous effect of Br. The research was done with mixed Ross broiler chickens over a 42-day post-hatch growth period. The trial design was six treatments, T1: 0 mg Br/L and 0 mg I/L; T2: 1 mg Br/L and 0 mg I/L; T3: 3 mg Br/L and 0 mg I/L; T4: 0 mg Br/L and 0.7 mg I/L; T5: 1 mg Br/L and 0.7 mg I/L; and T6: 3 mg Br/L and 0.7 mg I/L delivered via drinking water and three replicates per treatment with 30 birds per replicate. The effect of Br on T3 and T4 levels overall was non-significant, but T3 and T4 levels decreased between Weeks 4 and 6 with a significant effect at Week 6 on T3. Br had an overall effect on the thyroid gland (P = 0.0457), liver (P = 0.0025) and kidney (P = 0.0032), and had accumulated in these three organs. Histopathological assessment showed explicit damage to the livers that received the Br treatments. Iodine (0.07 mg/L) ameliorated the negative effects of high Br (3 mg/L Br) concentration and ingestion.

Scat analysis is one of the most frequently used methods to assess carnivoran diets and Global Positioning System (GPS) cluster methods are increasingly being used to locate feeding sites for large carnivorans. However, both methods have inherent biases that limit their use. GPS methods to locate kill sites are biased towards large carcasses, while scat analysis over-estimates the biomass consumed from smaller prey. We combined carcass observations and scats collected along known movement routes, assessed using GPS data from four African lion (Panthera leo) prides in the Kruger National Park, South Africa, to determine how a combination of these two datasets change diet estimates. As expected, using carcasses alone under-estimated the number of feeding events on small species, primarily impala (Aepyceros melampus) and warthog (Phacochoerus africanus), in our case by more than 50% and thus significantly under-estimated the biomass consumed per pride per day in comparison to when the diet was assessed using carcass observations alone. We show that an approach that supplements carcass observations with scats that enables the identification of potentially missed feeding events increases the estimates of food intake rates for large carnivorans, with possible ramifications for predator-prey interaction studies dealing with biomass intake rate.

The dilemma of conservation practice lies in weighing the urgency for action against the need for sustainable long-term solutions, with urgent responses incurring the risk of failure and long-term solutions incurring the cost of time. Wisdom of hindsight reveals that sustainable solutions are not achieved when conservation action is initiated at an inappropriate scale. Here, I review recent studies that have included considerations of scale to illustrate how conservation problems and solutions might be unapparent, or even counterintuitive, to conservation practitioners responding to issues at the scales at which they were first perceived. Case studies cover the conservation of ecosystems, ecosystem services, species and populations. These studies collectively illustrate how most biodiversity conservation efforts can be improved by considering the problem at a broader spatiotemporal scale than that at which local natural resource management has traditionally operated. Globalization is increasingly challenging conservation practitioners to search for solutions across an ever-wider range of spatiotemporal scales and institutional levels. Identifying real problems and threats at relevant scales is part of conservation triage, when opportunity costs and cost efficiencies of alternative interventions are evaluated and ranked, before action is implemented through the appropriate institutional levels.

Summary 1. Understanding the effects of disease is critical to determining appropriate management responses, but estimating those effects in wildlife species is challenging. We used bovine tuberculosis (BTB) in the African buffalo Syncerus caffer population of Kruger National Park, South Africa, as a case study to highlight the issues associated with estimating chronic disease effects in a long-lived host. 2. We used known and radiocollared buffalo, aerial census data, and a natural gradient in pathogen prevalence to investigate if: (i) at the individual level, BTB infection reduces reproduction; (ii) BTB infection increases vulnerability to predation; and (iii) at the population level, increased BTB prevalence causes reduced population growth. 3. There was only a marginal reduction in calving success associated with BTB infection, as indexed by the probability of sighting a known adult female with or without a calf ( P = 0·065). 4. Since 1991, BTB prevalence increased from 27 to 45% in the southern region and from 4 to 28% in the central region of Kruger National Park. The prevalence in the northern regions was only 1·5% in 1998. Buffalo population growth rates, however, were neither statistically different among regions nor declining over time. 5. Lions Panthera leo did not appear to preferentially kill test-positive buffalo. The best (Akaike’s Information Criterion corrected for small sample size) AIC c model with BTB as a covariate [exp( β ) = 0·49; 95% CI = (0·24‐1·02)] suggested that the mortality hazard for positive individuals was no greater than for test-negative individuals. 6. Synthesis and applications . Test accuracy, time-varying disease status, and movement among populations are some of the issues that make the detection of chronic disease impacts challenging. For these reasons, the demographic impacts of bovine tuberculosis in the Kruger National Park remain undetectable despite 6 years of study on known individuals and 40 years of population counts. However, the rainfall and forage conditions during this study were relatively good and the impacts of many chronic diseases may be a non-linear function of environmental conditions such that they are only detectable in stressful periods.

We studied the composition of a savanna woody plant community across a natural herbivory gradient maintained by both browsing and grazing ungulates in an arid part of the Kruger National Park, South Africa. We focused on (1) short-term browsing effects on reproductive and morphological traits of a dominant-palatable woody species, Acacia nigrescens, Miller, (2) the relationship between browsing–grazing intensity and soil parameters, (3) the effects of herbivore–soil interactions on woody species richness and composition, and (4) browser-induced effects on the representation of woody plant functional traits. We show that the number of pods carried by A. nigrescens trees as well as the internode length of external tree branches both decreased significantly at high browsing intensity. Moreover, we found that total soil nitrogen (N) and soil cation (Ca, Na, Mg, and K) concentrations varied significantly according to grazing rather than browsing intensity with soil nutrients decreasing at heavily grazed sites. Although herbivory and soil

We investigated the linkages between leaf litter quality and decomposability in a savanna plant community dominated by palatable-spinescent tree species. We measured: (1) leaf litter decomposability across five woody species that differ in leaf chemistry; (2) mass decomposition, nitrogen (N); and carbon (C) dynamics in leaf litter of a staple browse species (Acacia nigrescens) as well as (3) variation in litter composition across six sites that experienced very different histories of attack from large herbivores. All decomposition trials included litter bags filled with chopped straw to control for variation in site effects. We found a positive relationship between litter quality and decomposability, but we also found that Acacia and straw litter mass remaining did not significantly vary between heavily and lightly browsed sites. This is despite the fact that both the quality and composition of litter returned to the soil were significantly different across sites. We observed greater N resorption from senescing Acacia leaves at heavily browsed sites, which in turn contributed to increase the C:N ratio of leaf litter and caused greater litter N immobilization over time. This, together with the significantly lower tree- and herb-leaf litter mass beneath heavily browsed trees, should negatively affect decomposition rates. However, estimated dung and urine N deposition from both browsers and grazers was significantly greater at high- than at low-herbivory sites. We hypothesize that N inputs from dung and urine boost litter N mineralization and decomposition (especially following seasonal rainfall events), and thereby offset the effects of poor leaf litter quality at chronically browsed sites.

Allogrooming among primates has been suggested as a strategy for enhancing reproductive success, by allowing males to enhance their proximity to oestrous females, or by influencing female choice through the development of affiliative relationships with males. Female chimpanzees have swollen anogenital regions signalling receptivity and by adapting their grooming investment accordingly, males could increase their copulatory success whilst females may increase chances of copulations with preferred males. Five and a half years of data from chimpanzees in the Budongo Forest, Uganda, were examined to investigate how sexual swellings influence grooming behaviour between males and females of different age classes. Based on the availability of oestrous females, significantly less grooming than expected occurred between anoestrous females and adult males, as well as between adult (anoestrous and oestrous) females and subadult males, but significantly more grooming than expected occurred between oestrous females and adult males or subadult males. Both oestrous adult and subadult females devoted more time to grooming interactions with adult males than did anoestrous females. Grooming interactions between adult males and oestrous adult females were initiated and terminated significantly more often by males, but those between anoestrous subadult females and adult males were initiated significantly more frequently by females.

We investigated the variation in birth synchrony displayed by impala Aepyceros melampus populations across their distribution from southern to eastern Africa. Our analysis was based on field data from Chobe National Park in Botswana and Mala Mala Private Game Reserve in South Africa (4 and 13 years of monitoring, respectively). We compared our results with those from other studies conducted across the impala species range. Impala lambing was highly synchronized in Chobe with 90% of lambs born within 2 weeks in mid-November. Variation in rainfall in the preceding wet season explained 74% of variation in the dates of the first lamb observation in Mala Mala. In Chobe, the earliest birth peak occurred after the highest rainfall and the body condition of lambs in that cohort was also best for both males and females. No association was found between the lunar cycle and the estimated onset of the conception period, despite previous studies having found an association between the lunar cycle and the rutting behaviour in males. On a regional scale, impalas in areas with a marked dry season (several months with no rain) tend to synchronize births with the onset of the rains, when grass quality is highest. Number of months with rain explained 78% of the regional variation in birth synchrony. Neither latitude nor total rainfall contributed significantly to a stepwise multiple regression model. These data support the theory that impalas synchronize births in areas with a highly seasonal food supply, and temporally space births in less seasonal (equatorial) areas to reduce predation risks.

We measured browsing-induced responses of Acacia trees to investigate "browsing lawns" as an analogy to grazing lawns in a semiarid eutrophic African savanna. During the two-year field study, we measured plant tolerance, resistance, and phenological traits, while comparing variation in leaf nitrogen and specific leaf area (SLA) across stands of Acacia nigrescens, Miller, that had experienced markedly different histories of attack from large herbivores. Trees in heavily browsed stands developed (1) tolerance traits such as high regrowth abilities in shoots and leaves, high annual branch growth rates, extensive tree branching and evidence of internal N translocation, and (2) resistance traits such as close thorn spacing. However, phenological "escape" responses were weak even in heavily browsed stands. Overall, browsing strongly affected plant morpho-functional traits and decreased both the number of trees carrying pods and the number of pods per tree in heavily browsed stands. Hence, there is experimental evidence that tolerance and resistance traits may occur simultaneously at heavily browsed sites, but this comes at the expense of reproductive success. Such tolerance and resistance traits may coexist if browsers trigger and maintain a positive feedback loop in which trees are continually investing in regrowth (tolerance), and if the plant's physical defenses (resistance) are not nutritionally costly and are long-lived. Our results confirm that chronic browsing by ungulates can maintain A. nigrescens trees in a hedged state that is analogous to a grazing lawn. Further research is needed to fully understand the long-term effects of chronic browsing on reproduction within such tree populations, as well as the overall effects on nutrient cycling at the ecosystem level.

African wild dog Lycaon pictus populations are declining due to persecution as well as habitat destruction and fragmentation. Understanding the natural mechanisms driving population dynamics is important for conservation management as it clarifies natural from human-induced factors. Therefore, this understanding is essential to compensate for disadvantaging ecological factors and successfully apply conservation actions. Juvenile survival is important in driving wild dog population dynamics, and therefore this study investigated the influence of rainfall and pack size on the survival of juveniles up to the age of 12 months. We found that past rainfall significantly influenced pup survival up to 9 months of age, such that pups benefited from preceding dry periods. The positive effects of pack size on juvenile survival only became evident for pups older than 9 months and, despite this delayed Allee effect, we found no evidence of reproductive failure in small packs as compared with larger ones.

Aside from Kruger National Park, no other suitable reserves of sufficient size exist in South Africa that will hold a viable population of wild dogs (Lycaon pictus). Consequently, conservation efforts have been focused on creating a metapopulation through a series of wild dog reintroductions into isolated fenced reserves. Additional potential exists for conserving wild dogs on private ranch land. Establishing the metapopulation wa sa ne xpensive process, accounting for approximately 75% of the US$380,000 spent on wild dog conser- vation in South Africa during 1997-2001. The principal goal of the metapopulation project was to reduce the risk of catastrophic population decline. Now that this has been achieved, we developed a uniform cost- efficiency index to estimate the cost efficiency of current and potential future conservation strategies in South Africa. Conserving wild dogs in large protected areas was predicted to be the most cost-efficient conserva- tion strategy (449 packs/$100,000 expenditure). Establishing the metapopulation has been less cost efficient (23 packs/$100,000), and expansion of the metapopulation was predicted to be even less cost efficient if preda- tion by wild dogs results in additional costs, as is to be expected if private reserves are used for reintroductions (3-13 packs/$100,000). Because of low logistical costs, conserving wild dogs in situ on private ranch land was potentially more cost efficient than reintroducing wild dogs (14-27 packs/$100,000). We recommend that donor funding be used to reintroduce wild dogs into transfrontier parks, when they are established, to maintain the existing metapopulation and to establish conservation programs involving wild dogs on private ranch land. Investing in the expansion of the metapopulation should be limited to state-owned nature reserves willing to carry predation costs without compensation.

Longer-term ecosystem level dynamics are often neglected in conservation studies involving single species. In this study, a retrospective analysis is presented on the feeding performance of African wild dogs Lycaon pictus in the Serengeti in relation to a competing species, the spotted hyena Crocuta crocuta, to test whether hyenas had an effect on feeding performance of wild dogs in this ecosystem. Our analysis is based on observations of over 700 wild dog kills recorded over a 20-year period (from 1964 to 1987) during which time there was a decline in wild dog numbers (ending with their local extinction in 1991) and a twofold increase in hyena density. Overall, the amount of time that dogs had access to the kill (access time) decreased with increasing numbers of hyenas attending kills, but access time increased with increasing hunting-group size of dogs and carcass mass. In addition, in the 1980s, dogs spent longer at kills than in the 1970s for a given set of conditions, including when hyenas were absent. Our analysis demonstrates a greater potential for group benefits than was found in a previous study (Carbone, Du Toit et al., 1997). Hunting-group sizes of between two and six dogs performed best when hyenas attended dog kills because the benefits of increased defence outweighed the costs of having to share the carcass with more dogs. Hunting-group sizes of wild dog and levels of hyena attendance at the kill broadly paralleled the population trends in these species, with hunting-group sizes of wild dog declining, followed by hyena attendance increasing. Despite the combined effects of increased hyena attendance and reduced hunting-group size, dogs in the 1980s typically spent longer feeding and consumed more of the carcass including the poorest sections. This suggests that dogs in the 1980s may have been under greater energetic stress.

Radio-tracking locations of 25 individuals (13 females; 12 males) and visual observations of nine habituated individuals were used to investigate the spatial organization and movement patterns of the honey badger Mellivora capensis in the southern Kalahari. The home ranges of adult male honey badgers (541 ± 93 km2) were significantly larger than the home ranges of adult females (126 ± 13 km2). Female home-range size was five times larger than predicted from body mass. The extensive home ranges of females were likely to be a function of relatively low prey availability in the semi-arid Kalahari and the long period of cub dependence (12–16 months). While mean home-range overlap in females was moderate (13%) and home-range centres were regularly spaced, females did not appear to actively defend a territory and no direct interactions between females were observed. Scent marking appears to mediate spatio-temporal separation and females show a loosely territorial spacing pattern. In contrast, males did not support the typical mustelid pattern of intra-sexual territoriality but instead encompassed the overlapping home ranges of up to 13 females. Males and females differed significantly in their rate of travel (3.8 ± 0.3 km/h vs 2.7 ± 0.2km/h), straight line (6.2 ± 0.5 km vs 2.4 ± 0.2 km) and actual distance (13.8 ± 0.9 km vs 7.7 ± 0.7 km) moved during an active period but do not differ in the percentage of their home-range area traversed in a single day (3%). Young males tended to have smaller home ranges (151 ± 45 km2) than adult males and showed a spacing pattern more similar to adult females than adult males. In common with other solitary mustelids, the spatial organization suggests a polygynous or promiscuous mating system.

The honey badger, or ratel, Mellivora capensis has not been well studied and data on life-history variables have previously been incomplete and contradictory. Here we present data on life-history variables that were collected from visual observations as part of the first intensive study of free-living honey badgers (25 radio-marked individuals) and we make comparisons with other similarly sized mustelids (5–25 kg). The honey badger is a non-social species and only the mother rears the young. The data do not support delayed implantation as gestation was a maximum of 50–70 days with the unusually small litter size of one cub. The long time to independence of both male and female cubs (12–16 months) resulted in birth intervals longer than 12 months with no distinct breeding season. Overall the honey badger appears to have a more K-selected life history compared to other species within the Mustelidae.

We compared the diurnal activity budgets of four syntopic species of African browsing ruminant that differ widely in body size. These were concurrently studied through all phases of the seasonal cycle, in the same area, using the same methods. We tested five predictions from the literature on how body size is expected to influence the behaviour of tropical ungulates: the smallest members of the browsing ruminant guild exhibit (1) the lowest allocation of diurnal time to activity; (2) the greatest hour-to-hour variation in activity and resting time; (3) the greatest reduction in activity time during the hottest days; (4) the least change between wet and the dry seasons in the ratio of feeding: ruminating time; and (5) the greatest time budget allocation to vigilance. Prediction 1 was supported in that the smaller species spent less time being active during the day. Prediction 2 was also supported in that the smaller species were more variable in their relative allocations of time to activity and resting through successive hours of the day. Contrary to Prediction 3, however, the greatest reduction in activity with increasing temperature was found for the largest guild member. The smaller species can achieve their daily food intake requirements by feeding at night and in the cool hours of the day, while the larger species have to feed during all hours of the day and are thus more susceptible to thermoregulatory constraints on foraging. Prediction 4 was partially upheld in that the largest species (giraffe) displayed the widest variation in feeding: ruminating time through the seasonal cycle. Prediction 5 was not supported, indicating that multiple factors interact with body size in determining vigilance behaviour.

Domestic dogs (Canis familiaris) arrived in Zimbabwe ca. 1000 years ago. Numbers of free-ranging dogs have reached unprecedented levels in communal lands (agro-pastoralist rural areas), and interact with large wild carnivores along boundaries with wildlife reserves as predators and prey. This study examined a population of 236 dogs in a 33-km2 section of Gokwe Communal Land (GCL) bordering the Sengwa Wildlife Research Area (SWRA) in north-western Zimbabwe in 1995–1996. Dogs were found up to 6 km within the SWRA, and were the most common carnivore on the GCL–SWRA boundary. Observations of 16 radio-collared dogs showed that they were inefficient predators. Only 20 kills were recorded amongst the remaining dog population, of which three were wild ungulates. Dogs were unsuccessful predators due to their small group size (mean 1.7) and body mass (mean 14.7 kg), and the abundance of alternative food. It is therefore unlikely that they compete with large carnivores for wild prey. However, leopards (Panthera pardus), lions (P. leo) and spotted hyaenas (Crocuta crocuta) preyed on dogs in GCL, removing ⩾6% of the dog population in 1993. Such predation provides ideal circumstances for disease transmission. Canid disease was prevalent in the study area; including rabies and probably distemper. The risk of infection is greatest during the dry season (May–October), when peaks in rates of disease, carnivore incursions into GCL, and predation on dogs coincided. The role of jackals (Canis adustus and Canis mesomelas) and spotted hyaena predation of dogs is discussed in relation to disease epidemics within wildlife reserves. With a dog population growth rate of 6.5% per annum, and the prevalence of canid diseases, the conservation threat posed by dogs is escalating on communal land–wildlife reserve boundaries in Zimbabwe. Measures to control dog numbers and improve vaccination coverage of dogs are discussed.

We investigated sexual and seasonal patterns in scent-marking behaviour of the honey badger, by direct observations of habituated individuals (five females, four adult males, two young males). Four categories of scent-marking behaviour were identified: (1) scent marking at latrines; (2) token urination in holes along the foraging path; (3) squat marking at single-use sites; and (4) functional excretion. Females and young males used all four types of scent marking, but adult males were not observed to use token urination. A strategy of hinterland scent marking was used, as was predicted from the large home ranges of both male and female honey badgers. There were significant sexual differences in marking rate: adult males primarily used latrines and adult females favoured token urination. Latrine scent marking in adult male honey badgers provides support for the ‘scent-matching’ hypothesis. Females visited latrines when they were in oestrus. However, the low level of marking activity during a visit and the intensive smelling suggested a scent-matching function rather than reproductive advertisement. Token urination appeared to be related to the maintenance of spatiotemporal separation in females, although we also observed token urination in young males. While the placement of urine in foraging holes and its relation with successful digging attempts offer some support for the foraging efficiency hypothesis, we consider this unlikely, because we did not observe it in adult males and there was no seasonal pattern. Squat marking occurred under a wide range of conditions in both males and females and may be related to marking valuable resources. It is likely that scent marking in honey badgers has many functions.  2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.

Cheetah Acinonyx jubatus home-range size and habitat use were analysed using radio-tracking data collected in the southern district of the Kruger National Park (KNP) between 1987 and 1990. Meaningful estimates of home-range size, using the 95% minimum convex polygon method, were 126 km2 for a three-male cheetah coalition, 195 km2 for a solitary male, and 150 km2 and 171 km2 for two female cheetahs. Although cheetahs used all habitats according to their availability, they did show a preference for open savanna habitat because their core or total home ranges centred on these habitats. Female cheetahs used denser woodland habitat more frequently than males, as they seemed to be influenced by the distribution of their main prey, impala Aepyceros melampus, which also preferred denser woodland habitat.

The honey badger, or ratel, Mellivora capensis has not been well studied despite its extensive distribution. As part of the first detailed study, visual observations of nine habituated free-living individuals (five females, four males) were used to investigate seasonal, annual and sexual differences in diet and foraging behaviour. Theory predicts that generalist predators ‘switch’ between alternative prey species depending on which prey species are currently most abundant, and diet breadth expands in response to decreased availability of preferred food types. There were significant seasonal differences in the consumption of eight prey categories related to changes in prey availability but no seasonal differences in food intake per kg of body mass. As predicted, the cold-dry season diet was characterized by low species richness and low foraging yield but high dietary diversity, while the reverse was true in the hot-dry and hot-wet seasons. In accordance with these predictions, results suggest that the honey badger maintains its intake level by food switching and by varying dietary breadth. Despite marked sexual size dimorphism, male and female honey badgers showed no intersexual differences in prey size, digging success, daily food intake per unit body weight or foraging behaviour. Results do not support the hypothesis that size dimorphism is primarily an adaptation to reduce intersexual competition for food.

The objective of the study was to develop a bait and baiting system capable of delivering one effective dose of oral rabies vaccine to each member of a free-ranging African wild dog (Lycaon pictus) pack. Trials were conducted between June and October 2000. The results of cafeteria-style bait preference trials testing seven candidate baits in captive wild dogs revealed a significant preference for chicken heads (June trials: P = 0.023, September trials: P = 0.021). Trials using a topical biomarker (rhodamine B) showed that chicken head baits were sufficiently chewed on most occasions to rupture the vaccine container. Free-ranging wild dogs and young pups ingested chicken head baits. Significant dominance of bait intake by a single individual was seen in four of six study packs and in the three packs in which an alpha pair could be distinguished, the dominant feeder was an alpha animal. Pattern of bait distribution and degree of satiation had no effect on pack coverage (proportion of pack ingesting at least one bait). Pack coverage was significantly related to trial number (r = 0.71, P < 0.001), with pack coverage increasing with increased exposure of the pack to the baits. During 46 hr of diurnal observations of free-ranging wild dogs only two baits were lost to non-target species. A baiting system for the oral vaccination of captive and free-ranging wild dogs is proposed.

Numbers of free-ranging dogs (Canis familiaris) have reached unprecedented levels in Zimbabwean communal lands (agropastoralist rural areas). This study examined the potential competitive interactions between dogs and wild scavengers on the boundary of Gokwe Communal Land (GCL) and the Sengwa Wildlife Research Area (SWRA) in 1995–96. Dietary studies showed that dogs were primarily scavengers of human waste and animal carcasses. Twelve experimental carcasses indicated that dogs were the most successful species in the vertebrate scavenger guild, consuming 60% of available biomass and finding 66.7% of carcasses. Dogs monopolized the supply of domestic animal carrion within GCL, but also consumed wild carrion up to 1 km within the SWRA, and were seen 3 km inside the reserve. Their principal competitors for carcasses were vultures, and to a lesser degree lions (Panthera leo), leopards (P. pardus) and spotted hyaenas (Crocuta crocuta). Dogs outcompete vultures on wildlife reserve boundaries owing to their high densities, nocturnal and diurnal activity, physical dominance and greater tolerance of human disturbance. With a population growth rate of 6.5% per annum the influence of dogs will intensify on the peripheries of reserves, exacerbating their existing threat to wild scavengers. This scenario is probably occurring in many other African countries.

To understand ecosystem structure and dynamics we need more knowledge of how common species affect ecosystem dynamics. In this context, impala are especially interesting in the Chobe ecosystem, whe ...

Differences in feeding patterns of the African elephant were examined by sex and age during the dry season in a dystrophic savanna-woodland ecosystem in northern Botswana. Adult males had the least diverse diet in terms of woody plant species, but they consumed more plant parts than family units. The diameter of stems of food plants broken or bitten off was also greater for adult males than for females and subadult males. Adult males spent more time foraging on each woody plant than did females. The number of woody plant species and individuals present were higher at feeding sites of family units than at feeding sites of adult males, indicating that family units positioned themselves at feeding sites with higher species diversity than those of males. We argue that the most likely explanation for these differences is related to the pronounced sexual size dimorphism exhibited by elephants, resulting in sex differences in browsing patterns due to the allometric relationships that govern the tolerance of herbivores for variation in diet quality. From our results this Body Size Hypothesis is accepted rather than the alternative Scramble Competition Hypothesis, which predicts that adult male elephants consume lower quality browse because they are displaced from preferred browse as an outcome of scramble competition with adult females and their offspring. If the feeding patterns of adult male elephants were affected by intersexual scramble competition, we would expect adult males to browse at a higher level in the canopy than the smaller-bodied females and their offspring. No evidence was found for this, although adult females were found to browse at a higher level in the canopy when feeding in close proximity to subadults and juveniles than when feeding alone. Sex differences in elephant browsing patterns are, we propose, of relevance to understanding and managing elephant impacts on African woodlands.

The African savanna biome supports a higher diversity of ungulate species than is found in any other biome or continent. This exceptional faunal diversity and herbivore biomass density is directly linked to the high spatial heterogeneity of African savanna ecosystems. The dependence of herbivore dietary tolerance on body size translates into important size-related differences between savanna ungulate species in terms of habitat specificity, geographical range, and the share of community resources exploited. Intact savanna ungulate communities, with species distributed across body size classes and feeding guilds (grazer/browser), have strong regulatory influences on savanna ecosystem structure and function. Replacement with livestock systems of low diversity and high biomass density within a narrow body size range has occurred through the removal of competitors, pathogens, and predators, and the widespread provisioning of water. Overgrazing by livestock, coupled with episodic droughts, has caused widespread rangeland degradation and loss of floristic and faunal diversity which, by current models, is unlikely to recover to 'climax’ conditions even with destocking. In selected regions where potential still exists, African savanna biodiversity and human economic development will both be best served by the integration of sustainable wildlife utilization into multispecies animal production systems.

Levels of bromine (Br) in groundwater that exceeded guideline concentrations of 0.01 mg/L prompted the investigation of the effect Br and iodine (I) in drinking water on the production parameters of broilers. The research was done over a 42-day growth period, post-hatch, in which the trial design was: Control: 0 mg Br/L and 0 mg I/L; 1 mg Br/L and 0 mg I/L; 3 mg Br/L and 0 mg I/L; 0 mg Br/L and 0.7 mg I/L; 1 mg Br/L and 0.7 mg I/L; 3 mg Br/L and 0.7 mg I/L, by 3 replicates with 30 birds/replicate, using mixed Ross broiler chickens. Br and I were administered as NaBr and KI. Mortalities, water and feed intakes were recorded daily and live weight once a week. Average daily gains and feed conversion rations were calculated. Different treatments of Br, irrespective of I, decreased water and feed intake significantly. The interaction of Br and I had no significant effect on intake of water or feed. I had an effective ameliorating effect on Br. Bromine administered at 1 and 3 mg Br/L or at ingestion rates of 1.59 and 4.44 mg Br/day affected production parameters.

The Mkuze Game Reserve (MGR), in north-eastern KwaZulu-Natal Province, South Africa is an African swine fever virus (ASF) controlled area. In a survey conducted in 1978, ASF prevalence in warthogs and Ornithodoros ticks in MGR was determined to be 2 % and 0.06 %, respectively. These values, acknowledged as being unusually low compared to other East and southern African ASF-positive sylvatic-cycle host populations, have not been assessed since. The availability of a sensitive PCR-based virus detection method, developed specifically for the sylvatic tampan host, prompted a re-evaluation of ASF virus (ASFV) prevalence in MGR ticks. Of the 98 warthog burrows inspected for Ornithodoros presence, 59 (60.2 %) were found to contain tampans and tick sampling was significantly male-biased. Whilst gender sampling-bias is not unusual, the 27 % increase in infestation rate of warthog burrows since the 1978 survey is noteworthy as it anticipates a concomitant increase in ASFV prevalence, particularly in light of the high proportion (75 %) of adult ticks sampled. However, despite DNA integrity being confirmed by internal control amplification of the host 16S gene, PCR screening failed to detect ASFV. These results suggest that ASFV has either disappeared from MGR or if present, is localized, occurring at exceptionally low levels. Further extensive surveys are required to establish the ASFV status of sylvatic hosts in this controlled area.

Mammals must overcome several challenges to exploit woody plants; these include variation among plant species, individuals, growth stages, and parts in their nutritional value and mechanical and chemical defenses (91). The latter are especially significant because woody plants produce a variety of secondary metabolites (56), many of which are chemical defenses against browsing by mammals and some of which appear to be an evolutionary 431 0066-4162/91/1120-043 1$02.00

This study determined the proportion of captive juvenile and adult African wild dogs (Lycaon pictus) that developed protective titres of rabies neutralising antibodies following ingestion of a chicken head bait/SAG-2 oral rabies vaccine combination. A single chicken head containing 1.8 ml of SAG-2 vaccine (10(8.0) TCID50/ml) in a plastic blister was fed to each of eight adult and three juvenile wild dogs. Bait ingestion resulted in a significant rise in serum neutralising antibody titres. Overall seroconversion rate was eight out of 11 (72.7%), and all the puppies and five out of eight (62.5%) adults showed potentially protective levels of antibodies on day 31. The mean post-vaccination neutralising antibody titre was within the range reported to be protective against challenge with virulent rabies virus in other species.

We investigated whether the food quality of tree foliage for African savanna browsers varies across the feeding height range of the guild. This was to address the question of why giraffes (Giraffa camelopardalis) generally feed at a higher level in the canopy than is accessible to all other browsers. We defined a giraffe browse unit (GBU) as the length of twig corresponding to the average "bite" taken by giraffes from two staple browse plants: Acacia nigrescens and Boscia albitrunca. We sampled at three study sites in South Africa in the late dry season, at each site clipping GBUs at three heights above ground: 0.5 m, 1.5 m and 2.5 m; these representing the levels typically browsed by small, medium and large-bodied browsing ungulates respectively. For each GBU we measured leaf dry mass, total N, neutral detergent fibre and condensed tannin, using near-infrared spectroscopy calibrated by conventional laboratory analyses. We found no differences between height levels with regard to leaf chemistry concentrations, but leaf biomass per GBU was significantly higher at the 1.5-m and 2.5-m levels than at the 0.5-m level. The larger browsers thus gain a bite-size advantage by browsing above the reach of the smaller species. A likely reason for the reduced leaf biomass per GBU at the low browsing level is the tendency for small browsers to pluck individual leaves from shoots, while large browsers prune off whole shoots. We contend that our findings are analogous to those from parallel studies on the grazing guild, and are consistent with the hypothesis that the smaller members of ungulate guilds competitively displace the larger ones from shared feeding sites when resources become restricted. A prediction of this hypothesis is that the smaller members of each guild drive the grazing succession from behind and maintain browsing height stratification from below.

Home range data were collected concurrently from four syntopic browsing ruminant species in a conserved savanna ecosystem. Mean home range areas were: giraffe (Giraffa camelopardalis) 282 km2; kudu (Tragelaphus strepsiceros) 21.9 km2; impala (Aepyceros melampus) 5.82 km2; steenbok (Raphicerus campestris) 0.62 km2. Home range area (A hr) scaled on body mass (M) as: A hr=0.024 M 1.38 (r 2=0.99).

1. Group hunting in social carnivores is generally thought to have evolved through natural selection for improved efficiency of prey capture, increased prey size apprehended or defence of the kill against intra- and interspecific kleptoparasitism. 2. We used a simple model to explore how variation in hunting group size or wild dogs in the Serengeti influences defence of kills against kleptoparasitism from spotted hyenas and the trade-off effects this has on intake rate per dog for a given prey size selected. 3. The analysis presented suggests that while kleptoparasitism substantially influences the amount of time a hunting group can access a kill, increases in access rime with increased hunting group size rarely fully compensate Cor the reduction in each dog's share of the carcass due to scramble competition among the dogs. 4. A profitability index, which includes limitations of the probability of capturing different sized prey, gut capacity, food depletion and access time, suggests that small hunting groups (1-2) would be particularly vulnerable to kleptoparasitism because they are usable to fully satiate themselves before spotted hyenas take over their kills. Intermediate-sized hunting groups may be most effective at meeting nutritional demands over a range of prey sizes. 5. While reasons for the recent extinction of the Serengeti wild dog population remain speculative, this paper contributes lo the debate by proposing that kleptoparasitism by spotted hyenas would have placed a major constraint on the ability of individual wild dog packs to recover from episodic disasters.

Large species generally occur at lower population densities than small species but, being larger, use more energy per individual. The balance between population density and energy use per individual determines how evenly community resources are shared by species of different size. Analyses of large data sets, covering a wide range of body sizes, have found that population metabolism (the product of population density and energy use per individual) scales either neutrally (Damuth 1981, 1987) or negatively (Peters 1983) with body mass. However, different scaling relationships may occur in certain communities within specific biogeographic regions. Brown and Maurer (1986) found that population metabolism scales positively with body mass among North American land birds, granivorous desert rodents, marine fishes, and perennial desert plants. A comprehensive study of the relationships between mammalian population density and body mass (Peters and Raelson 1984) indicates that population metabolism scales positively with body mass among "smaller tropical" herbivores (αM0.26), "larger tropical" herbivores (αM0.45), and "larger tropical" carnivores-omnivores (αM0.28), but not among North American species (herbivores, αM0.09 ; carnivores-omnivores, αM-0.39).

Nutrient concentrations in intertidal rockpools on the shores of seabird breeding islands off the west coast of South Africa are significantly higher than concentrations in similar pools on mainland shores. This is due to the presence of terrestrial and upper intertidal guano deposits which are washed through the intertidal zone. Growth rates of intertidal macroalgae are significantly faster on the rocky shores of seabird breeding islands than on mainland rocky shores, and the extensive, permanent algal mats that develop on island shores are absent from mainland shores. The hypothesis that guano run-off enhances intertidal algal growth was tested experimentally at a site on the west coast of South Africa where no seabird colonies exist. Seawater, artificially enriched with guano, was trickled down an intertidal rocky slope during a period of two months. Algal settlement and growth on artificial surfaces were significantly enhanced by the guano treatment when compared with controls. The conclusion is that increased intertidal primary production on seabird islands, and the consequent modification of intertidal community structure, are due in part to nutrients which are introduced into the intertidal zone by run-off from the guano cap and by direct deposition of guano in the high-shore region by roosting birds.

At 22°C the resting oxygen consumption of G. capensis is 1.13±0.05 cm3O2·g-1·h-1 (mean± S.E.). In loose sandy soil the burrowing metabolic rate was approximately three times that of resting (3.41±0.19 cm3O2·g-1· h-1). Rate of oxygen consumption while burrowing bears a linear relationship with rate of burrowing. The equation of the regression line describing this relationship was used to construct a model for calculating energy expenditure of burrowing in free-living mole-rats. The diet of G. capensis consists of some green plant material and geophyte corms. The latter has a mean gross energy content of 16.36 kJ·g-1 dry weight. The digestibility coefficient for captive G. capensis fed on sweet potato, was 97.42±0.41%. Data collected from an excavated burrow system revealed that the total energetic cost of constructing the burrow amounted to 79% of the estimated digestible energy available from geophyte corms in the area. A food store in the same burrow system was sufficient to meet the maintenance requirements of an adult G. capensis, resting at 22°C, for approximately 80–85 days. Soil samples taken at random adjacent to the burrow contained corms with a mean estimated digestible energy value of 2084 kJ per m3 of soil. A comparison of energetic cost of burrowing and randomly available digestible energy in the field suggests that foraging patterns are not random.

Uittreksel Die produksie‐ en morfologiese reaksie van Cenchrus ciliaris cv. Molopo is, oor ‘n periode van een jaar, onder glashuistoestande bestudeer. Die resultate dui op ‘n groot buigbaarheid in die benuttingsprogram van die gras. Ten opsigte van wortelmassa skyn frekwensie van ontblaring egter meer krities te wees as intensiteit van ontblaring.