Rhebok Research Articles

Facilitation of a free-roaming apex predator in working lands: evaluating factors that influence leopard spatial dynamics and prey availability in a South African biodiversity hotspot.

Apex predators ideally require vast intact spaces that support sufficient prey abundances to sustain them. In a developing world, however, it is becoming extremely difficult to maintain large enough areas to facilitate apex predators outside of protected regions. Free-roaming leopards (Panthera pardus) are the last remaining apex predator in the Greater Cape Floristic Region, South Africa, and face a multitude of threats attributable to competition for space and resources with humans. Using camera-trap data, we investigated the influence of anthropogenic land modification on leopards and the availability of their natural prey species in two contrasting communities-primarily protected (Cederberg) and agriculturally transformed (Piketberg). Potential prey species composition and diversity were determined, to indicate prey availability in each region. Factors influencing spatial utilisation by leopards and their main prey species were also assessed. Estimated potential prey species richness (Cederberg = 27, Piketberg = 26) and diversity indices (Cederberg-H' = 2.64, Ds = 0.90; Piketberg-H' = 2.46, Ds = 0.89), supported by both the Jaccard's Index (J = 0.73) and Sørensen's Coefficient (CC = 0.85), suggested high levels of similarity across the two regions. Main leopard prey species were present in both regions, but their relative abundances differed. Grey rhebok, klipspringer, and rock hyrax were more abundant in the Cederberg, while Cape grysbok, Cape porcupine, chacma baboon, and common duiker were more abundant in Piketberg. Leopards persisted across the agriculturally transformed landscape despite these differences. Occupancy modelling revealed that the spatial dynamics of leopards differed between the two regions, except for both populations preferring areas further away from human habitation. Overall, anthropogenic factors played a greater role in affecting spatial utilisation by leopards and their main prey species in the transformed region, whereas environmental factors had a stronger influence in the protected region. We argue that greater utilisation of alternative main prey species to those preferred in the protected region, including livestock, likely facilitates the persistence of leopards in the transformed region, and believe that this has further implications for human-wildlife conflict. Our study provides a baseline understanding of the potential direct and indirect impacts of agricultural landscape transformation on the behaviour of leopards and shows that heavily modified lands have the potential to facilitate mammalian diversity, including apex predators. We iterate that conservation measures for apex predators should be prioritised where they are present on working lands, and encourage the collaborative development of customised, cost-effective, multi-species conflict management approaches that facilitate coexistence.

Five small antelope species diets indicate different levels of anthrodependence in the Overberg Renosterveld, South Africa

AbstractThe Overberg area, Western Cape, South Africa is highly suitable for agricultural practices and has subsequently been severely transformed over the last four centuries. This has created a novel habitat for many wildlife species. The objective of this study was to determine the forage use of five antelope species and thereby assess their level of anthrodependence in terms of diet. The five species were bushbuck (Tragelaphus sylvaticus), Cape grysbok (Rhaphicerus melanotis), common duiker (Sylvicapra grimmia), grey rhebok (Pelea capreolus) and steenbok (Rhaphicerus campestris). To do this, we performed a histological analysis on dung samples collected. Our study indicated a high ratio of anthropogenic to natural vegetation in the diets of bushbuck, grey rhebok and steenbok, as anthropogenic vegetation presented a high nutrient food resource, which is easily accessible. However, Cape grysbok and common duiker indicated a higher use of natural vegetation. The results indicated that all the species benefit from the resources offered by the altered landscape and that some species may be dependent on these resources while others appear to be more dependent on the pockets of natural vegetation in the landscape.

Palaeoproteomics confirm earliest domesticated sheep in southern Africa ca. 2000 BP

We used palaeoproteomics and peptide mass fingerprinting to obtain secure species identifications of key specimens of early domesticated fauna from South Africa, dating to ca. 2000 BP. It can be difficult to distinguish fragmentary remains of early domesticates (sheep) from similar-sized local wild bovids (grey duiker, grey rhebok, springbok—southern Africa lacks wild sheep) based on morphology alone. Our analysis revealed a Zooarchaeology by Mass Spectrometry (ZooMS) marker (m/z 1532) present in wild bovids and we demonstrate through LC–MS/MS that it is capable of discriminating between wild bovids and caprine domesticates. We confirm that the Spoegrivier specimen dated to 2105 ± 65 BP is indeed a sheep. This is the earliest directly dated evidence of domesticated animals in southern Africa. As well as the traditional method of analysing bone fragments, we show the utility of minimally destructive sampling methods such as PVC eraser and polishing films for successful ZooMS identification. We also show that collagen extracted more than 25 years ago for the purpose of radiocarbon dating can yield successful ZooMS identification. Our study demonstrates the importance of developing appropriate regional frameworks of comparison for future research using ZooMS as a method of biomolecular species identification.

Phylogeny and vicariant speciation of the Grey Rhebok, Pelea capreolus

A South African endemic antelope, the Grey Rhebok (Pelea capreolus), has long been an evolutionary enigma in bovid systematics-its phylogenetic intractability attributed to its curious combination of derived and primitive morphological attributes and the consequences of a rapid radiation. By using a combination of DNA sequences, chromosomal characteristics and quantitative and qualitative morphological features we show that the species is a sister taxon to a clade that comprises the waterbuck, reedbuck and allies. Our finding of few unambiguous synapomorphies reinforces suggestions of a rapid radiation and highlights the effects of incomplete lineage sorting, including the hemiplasic nature of several chromosomal rearrangements. We investigate these data to address the general question of what may have led to Pelea being both genetically and ecologically distinct from the Reduncini. We argue that its adaptation to exposed habitats, free of standing water, arose by vicariance prompted by increasing aridity of the extreme south/southwestern region of the African continent in the Miocene. Ancestral lineages leading to the extant Redunca and Kobus, on the other hand, retreated to water-abundant refugia in the north during these mostly globally cool phases. The mosaic of water-rich environments provided by the Okavango and the drainage systems in the southwestern extension of the East African Rift system are considered to have facilitated speciation and chromosomal evolution within these antelope.

The social and spatial organisation of the beira antelope (Dorcatragus megalotis): a relic from the past?

We studied the social and spatial organisation of the beira (Dorcatragus megalotis) in arid low mountains in the South of the Republic of Djibouti. Beira was found to live in socio-spatial units whose ranges were almost non-overlapping, with a surface area of about 0.7 km2. Each unit included a single adult male, and from one to three adult females. On average, the members of a unit made up a single group during 76% of the observation time, 92% outside the periods when a neonate was in the “hider” stage and/or an adult female in oestrus. Collective sequences of linked urination–defecation were frequent. Members of neighbouring units rarely met and interacted, chasing behaviour occurring mainly between adult males. Overall, the social and spatial organisation of the beira appears to be intermediate between that of the dik-diks (Madoqua spp.), in which units exceptionally include more than one adult female, and that of the oribi (Ourebia ourebi), in which units can include several adult males. Moreover, it resembles those of the klipspringer (Oreotragus oreotragus) and rhebok (Pelea capreolus), two morphologically conservative species that do not belong to the tribe Antilopini. We suggest that the beira’s social and spatial organisation might be similar to that of the last common ancestor to the Antilopini, if not to most of the extant Antilopinae.

Home ranges of sympatric grey rhebok and mountain reedbuck in a South African highveld grassland

We investigated home ranges of grey rhebok and mountain reedbuck at Sterkfontein Dam Nature Reserve in South Africa. Minimum convex polygon (MCP) and adaptive kernel methods were used to estimate home ranges and core areas for six grey rhebok herds and ten territorial male mountain reedbuck. MCP (95%) areas for rhebok herds varied between 30 and 103 ha, while for territorial male mountain reedbuck they varied between 8 and 21 ha. There was <10% home range overlap between any two neighbouring rhebok herds and 5–35% overlap between any two neighbouring territorial male mountain reedbuck. There was complete overlap between the two species indicating no interspecific competitive exclusion. Both species used core areas that coincided with steep slopes. Crude densities were 6.4 rhebok/km2 and 11.5 mountain reedbuck/km2. Rhebok home ranges were smaller in areas with lots of steep slopes, but territorial male mountain reedbuck home ranges were not correlated with any tested ecological parameters. Instead, female occurrence was correlated to steep slopes, and males that held territories with more steep areas had greater access to females.

Home ranges of sympatric grey rhebok and mountain reedbuck in a South African highveld grassland

ABSTRACT We investigated home ranges of grey rhebok and mountain reedbuck at Sterkfontein Dam Nature Reserve in South Africa. Minimum convex polygon (MCP) and adaptive kernel methods were used to estimate home ranges and core areas for six grey rhebok herds and ten territorial male mountain reedbuck. MCP (95%) areas for rhebok herds varied between 30 and 103 ha, while for territorial male mountain reedbuck they varied between 8 and 21 ha. There was <10% home range overlap between any two neighbouring rhebok herds and 5–35% overlap between any two neighbouring territorial male mountain reedbuck. There was complete overlap between the two species indicating no interspecific competitive exclusion. Both species used core areas that coincided with steep slopes. Crude densities were 6.4 rhebok/km2 and 11.5 mountain reedbuck/km2. Rhebok home ranges were smaller in areas with lots of steep slopes, but territorial male mountain reedbuck home ranges were not correlated with any tested ecological parameters. Instead...

The activity budgets and activity patterns of sympatric grey rhebok and mountain reedbuck in a highveld grassland area of South Africa

AbstractBehavioural observations were carried out on grey rhebok and mountain reedbuck at Sterkfontein Dam Nature Reserve, South Africa, for a period of 1 year between May 2001 and April 2002. Four harem herds of grey rhebok, five territorial male mountain reedbuck and female mountain reedbuck (herds grouped as one individual) were monitored to determine activity budgets and activity patterns. Both species spent more time feeding in the late afternoon during relatively cool temperatures, and more time resting in the middle of the day during relatively high temperatures. Statistical comparisons between the two species of the percentage time feeding and resting found no differences between them, although mountain reedbuck spent more time resting overall than grey rhebok. Both species were active at night.

Population dynamics of two sympatric antelope species, grey rhebok (Pelea capreolus) and mountain reedbuck (Redunca fulvorufula), in a highveld grassland region of South Africa

AbstractPopulation dynamics of grey rhebok Pelea capreolus and mountain reedbuck Redunca fulvorufula were monitored at Sterkfontein Dam Nature Reserve in South Africa over three breeding seasons. Birth and death rates were recorded in both species, and causes of death were investigated. Immigration and emigration were monitored in grey rhebok. Grey rhebok bred seasonally, with 91% of lambs being born between November and February. The average fecundity rate was 74% and lamb sex ratios were 22M:19F. Mountain reedbuck also bred seasonally, with a birth peak between October and December. The average fecundity rate was 92%, and lamb sex ratios were 12M:8F. Most deaths in both species occurred between June and November each year. Sixteen grey rhebok deaths occurred during the study, of which 10 resulted from hypothermia during one spring snowfall event. This represented 27% of the population at the time. Males and females were affected to the same degree by the snow, but juveniles suffered more than adults. There was no evidence of infectious disease or predation. Forty‐three mountain reedbuck deaths occurred during the study, of which 32 resulted from hypothermia following the snowfall. This represented 51% of the population at the time. Females were affected by hypothermia more than males. There was no evidence of disease in the population from the examination of 41 culled animals, and no evidence of predation. Immigration and emigration within the grey rhebok population were uncommon, but dispersal of yearling males occurred every year between October and December when they were evicted from their natal herds. Herd structure of adult animals was very stable. In mountain reedbuck, emigration was very hard to detect.

A review of the social organisation of mountain reedbuck, Redunca fulvorufula, and grey rhebok, Pelea capreolus, in relation to their ecology

The social organisation of southern mountain reedbuck (Redunca fulvorufula fulvorufula) and grey rhebok (Pelea capreolus) is reassessed and categorised according to ecological factors. Both species generally fit well into social class B, as used by Jarman (1974). Both feed selectively without changing plant types all year, with mountain reedbuck being grazers and grey rhebok browsers. Both stay within a single home range. Their selective feeding style results in fairly small body size, and restricts group size to small herds. The two species differ in social structure, with territorial male mountain reedbuck using a system of resource defence polygyny, and grey rhebok using a system of female defence polygyny. Mountain reedbuck do not have permanent access to females, so test all females that move into their territories, while harem male grey rhebok do have permanent access to females and can secure all mating rights. The anti-predator behaviour of mountain reedbuck is to lie down and freeze, while that of grey rhebok is to run away. Newborn lambs of both species are hidden for up to four weeks to avoid predation.

HELMINTHS IN SYMPATRIC POPULATIONS OF MOUNTAIN REEDBUCK (REDUNCA FULVORUFULA) AND GRAY RHEBOK (PELEA CAPREOLUS) IN SOUTH AFRICA

Helminths of mountain reedbuck (Redunca fulvorufula fulvorufula) and gray rhebok (Pelea capreolus) were investigated in South Africa between June 1999 and February 2002. Forty-one mountain reedbuck were culled at Sterkfontein Dam Nature Reserve over 8 different periods, and 25 mountain reedbuck were culled at Tussen die Riviere Nature Reserve over 3 different periods. A total of 17 kinds of helminths were found at the 2 sites, including 15 nematodes, 1 trematode, and 1 cestode. At Sterkfontein, the most prevalent and abundant species were Cooperia yoshidai, Longistrongylus schrenki, and Haemonchus contortus, with the latter 2 being more abundant during November/December than at other times of the year, probably because infective larvae increased on pasture at that time. No statistical differences were found in parasite loads between male and female mountain reedbuck. No correlation was found between fecal egg counts and adult worm counts or between parasite counts and body condition. At Tussen die Riviere, helminths in mountain reedbuck were less prevalent and abundant than at Sterkfontein. The most important species were Nematodirus spathiger, Trichostrongylus falculatus, and Cooperia rotundispiculum. Four gray rhebok died of natural causes at Sterkfontein, from which 5 kinds of helminths were recovered, including C. yoshidai and Paracooperioides peleae.

Systemic Disease in Vaal Rhebok ( Pelea capreolus ) Caused by Mycoplasmas in the Mycoides Cluster

Systemic Disease in Vaal Rhebok ( <i>Pelea capreolus</i> ) Caused by Mycoplasmas in the Mycoides Cluster

Systemic Disease in Vaal Rhebok ( Pelea capreolus ) Caused by Mycoplasmas in the Mycoides Cluster

In the winter of 2002, an outbreak of mycoplasma infection in Vaal rhebok (Pelea capreolus) originating from South Africa occurred 15 weeks after their arrival in San Diego, Calif. Three rhebok developed inappetence, weight loss, lethargy, signs related to pulmonary or arthral dysfunction, and sepsis. All three rhebok died or were euthanized. Primary postmortem findings were erosive tracheitis, pleuropneumonia, regional cellulitis, and necrotizing lymphadenitis. Mycoplasmas were detected in numerous tissues by electron microscopy, immunohistochemistry, and PCR. The three deceased rhebok were coinfected with ovine herpesvirus-2, and two animals additionally had a novel gammaherpesvirus. However, no lesions indicative of herpesvirus were seen microscopically in any animal. The rheboks' mycoplasmas were characterized at the level of the 16S rRNA gene, the 16S-23S intergenic spacer region, and the fructose biphosphate aldolase gene. Denaturing gradient gel electrophoresis was carried out to address the possibility of infection with multiple strains. Two of the deceased rhebok were infected with a single strain of Mycoplasma capricolum subsp. capricolum, and the third animal had a single, unique strain most closely related to Mycoplasma mycoides subsp. mycoides large-colony. A PCR survey of DNA samples from 46 other ruminant species demonstrated the presence of several species of mycoplasmas in the mycoides cluster, including a strain of M. capricolum subsp. capricolum identical to that found in two of the rhebok. These findings demonstrate the pervasiveness of mycoplasmas in the mycoides cluster in small ruminants and the potential for interspecies transmission and disease when different animal taxa come in contact.

CHEMICAL IMMOBILIZATION OF RHEBOK (PELEA CAPREOLUS) WITH CARFENTANIL–XYLAZINE OR ETORPHINE–XYLAZINE

Twelve adult rhebok (Pelea capreolus) were immobilized using a combination of 0.4 mg/kg xylazine and either 0.01 mg/kg of carfentanil (n = 6) or 0.01 mg/kg etorphine (n = 6), delivered i.m. using a remote injection system. Induction and recovery times, heart rate, respiratory rate, rectal temperature, oxygen saturation, end-tidal CO2 (ETCO2), anesthetic depth, indirect blood pressure, and arterial blood gases were recorded. Rhebok were not intubated but nasal oxygen was administered. Forty minutes after induction, anesthesia was antagonized with naltrexone and yohimbine. Mean initial heart rate was significantly higher in the carfentanil group than in the etorphine group. Mean initial oxygen saturation was consistent with hypoxia in both the carfentanil group and the etorphine group. In both groups, arterial pH decreased and partial pressure of carbon dioxide increased during the first 15 min of anesthesia, and values were similar in both groups. These findings were consistent with respiratory acidosis and decreased ventilation. Values for respiratory rate, temperature, oxygen saturation, ETCO2, and blood pressure were similar for both groups at all time periods. During the first 5 min of anesthesia, rhebok in the carfentanil group were more responsive to stimuli than rhebok in the etorphine group. After administration of antagonists, time to first arousal was significantly shorter in the etorphine group than in the carfentanil group. Although cardiopulmonary values were similar for the two groups, rhebok in the carfentanil group were at a comparatively lighter plane of anesthesia, and some individuals in this group required additional manual and chemical restraint for medical procedures to be performed. In conclusion, for captive adult rhebok, 0.01 mg/kg of etorphine and 0.4 mg/kg of xylazine are recommended over 0.01 mg/kg carfentanil and 0.4 mg/kg xylazine because of qualitatively better anesthetic episodes and shorter recovery times.

Haemonchus horaki n. sp. (Nematoda: Trichostrongyloidea) from the grey rhebuck Pelea capreolus in South Africa.

In the course of a revision of species of Haemonchus Cobb, 1898 (Nematoda), commonly referred to as large stomach worms and significant pathogens of ruminants, a new species was discovered in the grey rhebuck Pelea capreolus, and the bontebok Damaliscus pygarthus, in South Africa. The new species, Haemonchus horaki, was previously reported as a long-spicule form of H. contortus (Rudolphi, 1803) Ransom, 1911. The new species, compared with H. contortus, can be distinguished by significantly longer spicules (555-615 microm vs. 383-475 microm); a synlophe with fewer ridges (26 vs. 30 in the region of the posterior part of the esophagus) that extend more posteriorly (within 1 mm of the copulatory bursa in males and postvulvar in females, vs. 2/3 to 3/4 of prebursal and prevulvar lengths); and an asymmetrical dorsal lobe with a long dorsal ray divided for more than half of its length, forming 2 branches of unequal length (vs. a dorsal ray divided for less than half of its length and forming 2 equal branches in H. contortus).

Molecular Systematics and Phylogeny of the Reduncini (Artiodactyla: Bovidae) Inferred from the Analysis of Mitochondrial Cytochrome b Gene Sequences

The evolutionary relationships within the bovid tribe Reduncini were investigated by comparing complete nucleotide sequences of the mitochondrial cytochrome b gene (1140 bp) among 11 extant taxa. With a few exceptions, the molecular data are in agreement with previous morphologically-based studies. Based on our cytochrome b data, the kob and puku are only 0.3% divergent, suggesting that the species level status of the puku is questionable. Bootstrap analyses and the likelihood ratio test support a sister relationship of the waterbuck (Kobus ellipsiprymnus) to the kob (K. kob) and puku (K. vardoni) clade rather than a possible sister relationship with the lechwe (K. leche) and Nile lechwe (K. megaceros) clade suggested by morphological investigations. We also investigated the affinity of the vaal rhebuck (Pelea capreolus) to the reduncines. Our data do not resolve the placement of the vaal rhebuck among the reduncines. The data support the currently designated subspecies of the waterbuck (K. e. ellipsiprymnus and K.e. defassa) and the lechwe (K.l. leche, K.l. kafuensis and K.l. smithemani), the descriptions of which have been based essentially on morphology and geographic distribution. We detected nuclear homologs of mitochondrial genes and suggest that critical sequence analysis is of importance to avoid erroneous interpretations of mitochondrial phylogenies.

Interrelationships Between Fire, Grazing and Grass Cover at the Bontebok National Park

Point surveys of permanently marked plots were conducted with the aim of (i) determining the change in grass height, cover and degree of defoliation with increasing time after veld burning and (ii) determining which plant species are most intensively defoliated by herbivores (mainly bontebok and grey rhebok). Grass was the most heavily defoliated component of the vegetation, whereas Restionaceae and Cyperaceae were generally avoided. No grass species was consistently avoided by herbivores, and no species was consistently favoured. Instead selection among species varied with growth stage. The tall, coarse species were favoured on new burns when the vegetation was still short. The short species came into favour once the sward had grown taller. Defoliation was heaviest within the first year after burning and thereafter decreased substantially. The introduction of coarse grass grazers such as mountain zebra to the park might lead to greater use of the mature veld. Those grass species that underwent the heaviest defoliation on new burns (over 50 of leaves severed) showed three- to seven-fold increases in canopy spread cover over subsequent years. Thus heavy use of recently burnt veld is not necessarily deleterious.