Roan Antelope Hippotragus Equinus Research Articles

Roan antelope Hippotragus equinus in Africa: a review of abundance, threats and ecology

Abstract The roan antelope Hippotragus equinus, Africa's second largest antelope species, is widely distributed throughout Africa. Many populations are isolated, occur at low densities, and are declining. The species' interactions with and adaptations to the diverse environmental conditions throughout its geographic range remain largely unknown. Most studies have taken place in southern Africa, near the range limit for the species; few studies have been conducted on the historically large Central and West African populations. We reviewed available published and accessible unpublished data related to the ecology of roan antelope. We aim to: 1) review available taxonomic, abundance, distribution, and population trend data; 2) describe the threats faced by the roan antelope, and establish whether sufficient data exist to describe its ecological requirements; and 3) highlight the relevance of conserving this species throughout Africa and suggest where research on survival requirements should be focussed. Roan antelope populations throughout Africa are declining due to natural and anthropogenic threats. Methodological irregularities result in uncertainty and non‐comparable population data between studies. Large gaps exist in our knowledge of roan antelope diet and regional movements. Information on the population genetics of roan antelope is needed in order to assess the connectedness of different populations. Data deficiency severely impedes our ability to employ powerful analytical methods aimed at understanding and predicting population persistence and viability, and to model envisaged threats from impending climate change. A unified approach to fundamental ecological research is required to inform the conservation and management of large rare mammalian ungulates such as the roan antelope in Africa.

Diets of savanna ungulates from stable carbon isotope composition of faeces

AbstractHypotheses to explain diversity among African ungulates focus largely on niche separation along a browser/grazer continuum. However, a number of studies advocate that the browser/grazer distinction insufficiently describes the full extent of dietary variation that occurs within and between taxa. Disparate classification schemes exist because of a lack of uniform and reliable data for many taxa, and failure to incorporate spatio‐temporal variations into broader assessments of diet. In this study, we tested predictions for diet and dietary niche separation of African savanna ungulates using stable carbon isotope evidence from faeces for proportions of C3 (browse) to C4 (grass) intake among 19 species from the Kruger National Park, South Africa. Dietary predictions from the literature are confirmed in the case of browsers (black rhinoceros Diceros bicornis, giraffe Giraffa camelopardalis, bushbuck Tragelaphus scriptus, kudu Tragelaphus strepsiceros), mixed‐feeders (impala Aepyceros melampus, nyala Tragelaphus angasii), and most grazers (white rhinoceros Ceratotherium simum, Burchell's zebra Equus burchellii, warthog Phacochoerus africanus, hippopotamus Hippopotamus amphibius, blue wildebeest Connochaetes taurinus, tsessebe Damaliscus lunatus, waterbuck Kobus ellipsiprymnus). In contrast, several species showed results differing from most expectations derived from the available literature, including eland Taurotragus oryx, steenbok Raphicerus campestris, grey duiker Sylvicapra grimmia, buffalo Syncerus caffer, roan antelope Hippotragus equinus and sable antelope Hippotragus niger. Many of these discrepancies can be accounted for by seasonal and/or regional dietary differences. Cluster analysis based on a data matrix that incorporates the extent of spatio‐temporal dietary variation among Kruger Park ungulates reveals several distinct categories of feeding preferences that extend beyond a two‐edged browser/grazer dichotomy, such as mixed‐feeders with a preference for either forage class, and spatial/seasonal shifts between uniform and mixed‐feeding styles among variable browsers (e.g. grey duiker) and variable grazers (e.g. buffalo). These results highlight the need for approaches that are sensitive to spatio‐temporal variations and the continuity of diet.

Challenges faced in the conservation of rare antelope: a case study on the northern basalt plains of the Kruger National Park

The conservation of rare antelope has long been one of the goals of the Kruger National Park. The roan antelope Hippotragus equinus, and to a lesser extent the tsessebe Damaliscus lunatus, represent low-density species or rare antelope in the park. Specific management approaches representing the older equilibrium approach, have been employed to conserve these antelope. Of these, the supply of artificial water over many decades was the most resource intensive. The sudden, severe drop in the roan antelope population towards the end of the 1980s was unexpected and, retrospectively, attributed to the development of a high density of perennial waterpoints. The postulated mechanism was that the perennial presence of water allowed Burchell’s zebra Equus burchelli to stay permanently in an area that was previously only seasonally accessible. The combined effect of a long, dry climatic cycle, high numbers of zebra and their associated predators was proposed to be the cause of this decline. As part of the new nature evolving or ecosystem resilience approach, twelve artificial waterpoints were closed in the prime roan antelope habitat in 1994 in an attempt to move the zebra out of this area. The zebra numbers declined as the rainfall increased. Closure of waterholes clearly led to redistribution of zebra numbers on the northern plains, zebra tending to avoid areas within several kilometres of closed waterpoints. However, at a larger scale, regional densities appeared similar in areas with and without closed waterpoints. There was an initial drop in the lion numbers in 1995, after which they stabilised. In spite of an improvement in the grass species composition and an increase in biomass the roan antelope population did not increase. The complexity of maintaining a population at the edge of their distribution and the problems associated with the conservation of such populations are discussed in terms of management options and monitoring approaches that may be employed in this process.

Establishing the causes of the roan antelope decline in the Kruger National Park, South Africa

Between 1986 and 1993, the roan antelope Hippotragus equinus population in the Kruger National Park, South Africa, declined from about 450 to ca.45 animals. Data from long term monitoring of herbivore numbers, sex, age and herd structure and of vegetation condition, supported by spatial and demographic modelling and predator sighting records, were used to evaluate potential causes of the population decrease, including: (1) competition from zebra and wildebeest, which moved into the roan’s range after the introduction of waterpoints; (2) increased predation following the influx of zebra and wildebeest; (3) habitat deterioration due to an extended period of low rainfall; (4) outbreaks of the disease anthrax; and (5) stress associated with immunisation against anthrax. Evidence did not support the latter two causes. Drought alone was inadequate as an explanation, although progressive desiccation over a sequence of low rainfall years, and resultant grassland deterioration, may have been contributory. Grassland recovery may have been suppressed by grazing pressure from zebra and wildebeest. The population crash was associated with an increase in adult mortality, but little apparent change in calf survival, suggesting that nutritional factors were not the prime cause. Increased predation on adult roan due to a build-up in lion numbers, following the zebra and wildebeest influx, seemed to be the proximate cause of the initial sharp decline in the roan population. However, the ultimate cause was the provision of numerous artificial waterpoints in the roan range, which attracted the influx of zebra and wildebeest, particularly during drought conditions. Following the closure of waterpoints in a section of the roan range, the roan herds in the vicinity are recovering. Deficiencies in current monitoring programmes in the Kruger Park are identified.

Evaluating population persistence of censused and unmanaged herbivore populations from the Kruger National Park, South Africa

The application of the Dennis et al. ( Ecol. Monogr., 61, 1991) model to data from 12 herbivore populations from the Kruger National Park, South Africa, introduces ‘risk assessment’ procedures into the conservation management of free-ranging species. The model enables one to predict the probability of reaching an arbitrarily defined threshold population size using census figures from censused and unmanaged populations. It also provides an objective evaluation of population persistence based on past performance. Of the 12 species investigated, five (impala Aepyceros melampus, blue wildebeest Connochaetes taurinus, zebra Equus burchelli, white rhinoceros Ceratotherium simum, giraffe Giraffa camelopardalis) appear to be secure, four (kudu Tragelaphus strepsiceros, waterbuck Kobus ellipsiprymnus, warthog Phacochoerus aethiopicus, sable antelope Hippotragus niger) are vulnerable and three species (tsessebe Damaliscus lunatus, eland Taurotragus oryx, roan antelope Hippotragus equinus) are at risk of declining by an order of magnitude within 100 years. Therefore, within data limitations, the KNP appears not to offer sufficient suitable habitat for a number of herbivore species despite its considerable size, and a metapopulation approach may be required for the effective conservation of some species. The model also allows the principle of ‘complementarity’ to be extended beyond that of species composition. Objective evaluations of population persistence, of censused and unmanaged populations, as demonstrated here, mean that the principle of ‘population viability’ can help the design of efficient regional reserve networks.

Assessing the risks of extinction for local populations of roan antelope Hippotragus equinus

We estimated the minimum size of the roan antelope Hippotragus equinus population in the Parc National de l'Akagera in Rwanda to be at least 144 animals, based on a two and a half year study of individually recognized stable social groups. Data from the same study were used to estimate the annual birth rate, and the survival rate of male calves, female calves, adult females and juvenile females; and to identify factors which would result in year-to-year variations in survival. The results of this analysis were incorporated into an age-structured model of the population's dynamics which took account of demographic and environmental stochasticity. This model was then used to determine the viability of the roan population in the park and to identify demographic characteristics whose occurrence could be used to predict when the population was most at risk of extinction. The risk of extinction could be predicted if the number of stable groups within the park was monitored in September of each year. This risk could be greatly reduced if a reciprocal arrangement was established with other protected areas such that the population in the park could be reinforced with new stable groups when the number of stable groups fell below three. However, the risks—particularly of disease transfer—associated with such reinforcement programmes should be clearly recognized.

Basic haematological values in antelopes—II. the hippotraginae and the tragelaphinae

1. 1. Basic haematological values in 49 animals of five species of the subfamily Hippotraginae, namely the roan antelope Hippotragus equinus, sable antelope Hippotragus niger, adax antelope Addax nasomaculatus, gemsbok oryx Oryx gazella gazella and scimitar horned oryx Oryx damah and in 51 individuals of five species in the subfamily Tragelaphinae, including the bushbuck Tragelaphus scriptus, nyala Tragelaphus angasi, greater kudu Tragelaphus strepsiceros, cape eland Tautotragus oryx and bongo Bocercus euryceros are reported. 2. 2. The erythrocyte counts were in the range of 12.62 × 10 12/1 in the gemsbok oryx to 6.44 × 10 12/l in the bongo, the haematocrit values varied from 0.488 in the nyala to 0.380 in the roan antelope and for the haemoglobin highest levels (164.0 g/l) were noted in the adax antelope, and the lowest (105.5 g/l) in the bongo. 3. 3. Leukocyte counts were found mostly in the normal human range and varied from 7.17 × 10 9/l in the adax antelope to 4.05 × 10 9/l in the nyala, only in the greater kudu decreased values of 3.02 × 10 9 were estimated. 4. 4. These results are compared with findings taken from the literature, and with the normal human range.

An outbreak of dermatophilosis in sable <I>Hippotragus niger</I> and roan <I>Hippotragus equinus</I> in the Kruger National Park

A severe skin disease diagnosed as dermatophilosis took on alarming proportions in roan antelope Hippotragus equinus and sable antelope Hippotragus niger herds, which were kept in a 256 ha enclosure in the Kruger National Park, Republic of South Africa. Only calves were effected. Numerous Dermatophilus organisms were identified in skin biopsies taken from affected areas and examined histologically. Complete recovery followed a single treatment of intramuscular injections of a combination of a long-acting penicillin and streptomycin and the topical application of a preparation which included copper sulphate and benzene hexachloride. Factors which probably contributed to the outbreak included prolonged wetness, flies, a high density of susceptible animals and playful butting behaviour of the calves. This is the first report of the occurrence of dermatophilosis as a disease entity in wildlife species in southern Africa.

Anthrax immunization of free-ranging Roan Antelope <i>Hippotragus Equinus</i> in the Kruger National Park

An aerial method of immunization is presented as afeasible means of vaccinating free-ranging roan antelope Hippotragus equinus against anthrax in the Kruger National Park. Themethod is described in detail and the results, obtained aftertwo consecutive years of application, are noted, tabulated andevaluated. A helicopter and a fixed wing aircraft were success-fully utilized in the location of widely dispersed roan antelopeherds and to bring the operator within effective firing rangeof the animal to be darted. A disposable projectile syringe,which simultaneously administers vaccine and effectively marksthe animal for later identification, is considered a vital part inthe successful implementation of the aerial method of immunization.

Breeding the Roan antelope Hippotragus equinus at Hanover Zoo

International Zoo YearbookVolume 9, Issue 1 p. 116-116 Breeding the Roan antelope Hippotragus equinus at Hanover Zoo LOTHAR DITTRICH, LOTHAR DITTRICH Scientific Director, Zoologischer Garten Hannover, GermanySearch for more papers by this author LOTHAR DITTRICH, LOTHAR DITTRICH Scientific Director, Zoologischer Garten Hannover, GermanySearch for more papers by this author First published: January 1969 https://doi.org/10.1111/j.1748-1090.1969.tb02649.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume9, Issue1January 1969Pages 116-116 RelatedInformation