Southern Oribi

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Southern Oribi
Male and female Southern Oribi (Ourebia ourebi) in Gorongosa National Park, Mozambique

Male and female Southern Oribi ( Ourebia ourebi ) in Gorongosa National Park , Mozambique

Systematics
without rank: Forehead weapon bearer (Pecora)
Family : Horned Bearers (Bovidae)
Subfamily : Antilopinae
Tribe : Gazelle-like (antilopini)
Genre : Oribis ( Ourebia )
Type : Southern Oribi
Scientific name
Ourebia ourebi
( Zimmermann , 1783)

The Southern oribi or Bleichböckchen ( Ourebia ourebi) is an antelope species of the genus Oribis within the family Bovidae . It is widespread in southern Africa , where it inhabits open and dry landscapes in low-lying areas up to higher mountain regions. The animals are characterized by their small body size, their reddish brown fur, their long neck and the small and pointed horns that only male individuals wear. They live in small herds or appear as single animals. The respective social structure in a particular region is likely to be strongly influenced by external conditions. The main food is grasses and herbaceous plants. Not only the composition, but also the choice of certain parts of the plant varies with the seasons, so that the southern oribi can be viewed as a selective herbivore. Females usually give birth to one cub per birth which is independent after six months. The species was scientifically introduced in 1783. Originally, all Oribis were considered to belong to one species, but this was split up in 2011. The existence of the southern Oribi is at risk.

features

The southern oribi is a small to medium-sized antelope. Its head-torso length ranges from 89 to 115 cm, plus a 7.5 cm long tail. The shoulder height varies from 51 to 63.5 cm, the weight is 10.5 to 17.5 kg in males and 7.5 to 17 kg in females. As the only representative of the Oribis, the males of the Southern Oribi are larger than the females. Like all Oribis, the Southern Oribi is characterized by a slim build with a long neck and long limbs. The fur is reddish-brown in color on the back, but the speckled impact typical of the other Oribis is missing here. The underside appears whitish in color. Due to the seasonal fluctuations, the Southern Oribi has a difference between summer and winter fur, which is not the case with other Oribis. In summer the fur is short and soft, in winter it is thicker and more shaggy. The white hue of the underside is also found on the throat and chin. The tail, however, is tinted black. The white, rather long ears and the equally colored eye ring are also striking. A dark, hairless patch of skin appears below the ears as a feature of all Oribis. The pre-eye gland below the eyes stands out as a vertical fold and is particularly pronounced in the males, it takes up a larger part of the space between the eye and the mouth. The nasal mirror is generally bare. A black mark appears on the forehead mostly in females, less often in males. Horns are only found in the males, they are slender and pointed and have horizontal ridges at the base. In young animals, they are often wrapped in a layer of keratin that loses itself over time. Their length varies between 9.9 and 13.4 cm, with an average of 11.7 cm. The skull length varies from 14.6 to 17.3 cm.

distribution

The southern oribi occurs in southern Africa . There it has a spotty distribution south of the Zambezi . The northern areas extend from the extreme northeast of Namibia over the north of Botswana to the west of Zimbabwe . In Mozambique the species occurs in the province of Gaza and in the vicinity of the Sava River . In South Africa it inhabits the areas from the provinces Limpopo via KwaZulu-Natal to the south to the Eastern Cape . The southern limit is likely reached on the Great Fish River . Individual populations are also known from eastern Lesotho and Swaziland . The animals prefer open grasslands with Themada , Rendlia and Hyparrhenia grasses. The proportion of trees and bushes is usually small, denser undergrowth and woody areas usually lead to a decrease in a local population . Sometimes the animals also colonize regions with stony ground. The altitude distribution ranges from sea level to 2200 m in the South African province of Mpumalanga . The southern Oribi prefers gentle slopes of 0 to 10 °, which applies to both middle mountain areas around 600 to 1500 m and higher ones around 2000 m. In areas rich in food, such as in KwaZulu-Natal, the population density can be 4 to 18 individuals per square kilometer; in less productive landscapes it drops to 0.1 to 0.4 animals on a comparable area.

Way of life

Territorial behavior

The southern Oribi lives solitary or in smaller herds or in family groups. The social structure is relatively variable. In the Highmoor State Forest Land , a region with an altitude of around 2100 m in the Drakensberg in KwaZulu-Natal , the average group size consists of 2.2 individuals with a variation of one to six animals. More than half of all observations fall on couples with members of both sexes, sometimes with offspring. The second most common occurrence is single males in more than a quarter of all sightings, followed by single females in every tenth sighting. Larger groups, however, with one male and several females, so-called harems, could only be detected in around 19.5% of the cases. Similar conditions were determined in lower regions around 1200 m in the Drakensberg. A third occurs in pairs, and a further third is made up of solitary animals with equal proportions of males and females. Larger groups make up just under a quarter. The group formations of the Southern Oribi stand in clear contrast to the Oribis, which are further north and more tropical , where larger harems occur more frequently, which was documented in more than half of all cases observed. It can therefore be assumed that the social structure of the Oribis is heavily dependent on the richness of yield of a landscape and that the animals therefore tend to live in smaller groups or solitary in more moderate climates with greater seasonal fluctuations. The males of the southern oribi may show territorial behavior. According to investigations in the Highmoor State Forest Land, they occupy areas of 42 to 62  hectares in size. In the same region, females use land areas of around 36 hectares. The male animals mark their territorial boundaries with scented tags. This is done by rubbing the head with the pre-eye gland in the vegetation, which leaves a dark secretion . In some cases, they also cover the urine and feces of the female animals with their own feces or mark the corresponding places with scented secretions. They also chase away competing individuals. Sometimes, however, a dominant male tolerates a submissive sexual comrade in his own territory, which is then marked less often. This lowers the risk of being driven away by an equally dominant rival, but obviously accepts a reduced ability to reproduce that can result from the presence of the submissive animal. In this respect, the Southern Oribi is similar to the Serengeti Oribi .

nutrition

The main food of the southern Oribi consists mainly of grasses and herbaceous plants , occasionally it also consumes leaves . In the Gorongosa National Park in Mozambique , the food spectrum of the animals includes eleven grass species and seven tree species. In contrast, the diet of the Southern Oribi in the Golden Gate Highlands National Park in the South African province of Free State consists of around 22 different plant species. Among the most widely consumed grasses are representatives of Sporobolus and Themada , which reach proportions of 17.6 and 10.8%, respectively. Other grasses eaten in large quantities belong to the Monocymbium and the Zypergräsern . While grasses are ingested almost all year round, the proportion of herbaceous plants such as everlasting flowers or finials increases, especially in the period of southern summer . This also applies to the Sporobolus grasses, of which the southern oribi almost exclusively eats the flowers in the southern summer. In the same period of time, the Watsonia species prefers the leaves, but plucks out the tubers in southern winter . A total of 38 important food plant species of the species could be identified on individual private farms in KwaZulu-Natal. In addition to Themada , Andropogon , Monocymbium and Hyparrhenia dominate the grasses . Seasonal variations in the feeding behavior of the animals can also be seen here. In spring, Themada grasses predominate in the diet, the proportion of which decreases sharply in southern summer and autumn in favor of andropogon and hyparrhenia . According to investigations in the Mount Sheba National Reserve in the South African province of Mpumalanga , andropogon is the main food of the southern Oribi, followed by love grasses . However, after larger bushfires, the animals quickly switch to other freshly growing grasses, which then have a higher nutrient content. If andropogon grasses make up more than two thirds of the total food in the time before a bush fire , their proportion drops to zero after a fire and Themada , Rendlia or fescue grasses predominate by far . The former may then cover almost the entire nutritional requirement. Overall, the southern oribi can be seen as clearly selective in its food intake.

As a rule, the animals spend around 20 to 38% of their daily occupation with food. Most often they feed in the early morning hours and late evening. The southern Oribi avoids forest edges and prefers areas in the middle of taller grass areas for a possible quick retreat in the event of an approaching danger. It only eats in tree-covered areas when there is a very high supply of food. It can be assumed that in such cases the possibility of a faster and higher energy supply opposes the risk of predation by predators . Most of the time, the animals withdraw into thick grass after eating.

Reproduction

Most mother and young groups are observed in the southern summer from December to May, which indicates a seasonally restricted reproductive phase. According to studies in the Highmoor State Forest Land, mating activities take place between April and May, so that with a gestation period of around 210 days, the birth of the offspring occurs in the beginning of southern summer. The cubs spend the first month lying in the grass close to their mother. From the age of three months, the young follow the mother animal. They become independent at about six months. Observations in KwaZulu-Natal have shown that the Southern Oribi has different reproductive strategies. In regions with a higher quality of food resources and thus larger group formations, a male mates with several females and thus lives polygynously . However, these communities are largely unstable. At higher altitudes, with often poorer food supply, mostly monogamous couples appear. In a certain way, the number and density of predators in a region also has an impact on general reproductive behavior.

Predators and parasites

The black-backed jackal is one of the most important predators . In a total of 154 investigated droppings from KwaZulu-Natal, the antelope species only accounts for a small proportion of around 1%, with no differences between summer and winter. So far, roundworms such as Trichostrongylus and Cooperia have been documented on parasites . Impalaia and Oesophagostomum could also be diagnosed in some animals from the Kruger National Park , where the southern oribi no longer occurs today .

Systematics

The southern Oribi is a kind from the kind of Oribis ( Ourebia ) within the family of Bovidae (Bovidae). The genus is included in the Antilopinae subfamily . Their position within the Antilopinae is not entirely clear. Sometimes the Oribis were classified together with the small ram ( Neotragus ), the ram ( Nesotragus ), the cliff jumpers ( Oreotragus ), the dikdiks ( Madoqua ) and other small antelopes in the tribe of the Neotragini . Common features were often the short, spear-like horns and a similar social structure. In molecular genetic studies, however, this community turned out to be not self-contained and, from today's point of view, is limited to the small ram, while the male goats are more closely related to the impalas (Aepycerotini), the klipspringer are close to the small ram, but have their own group ( Oreotragini) and the dikdiks belong to the gazelle-like (antilopini). The latter also applies to the Oribis, which is evident from numerous recent genetic analyzes. The Oribis either form the sister group of the actual gazelle-like (Untertribus Antilopina ) or they cluster together with the short-tailed gazelles ( Procapra ) relatively basally within the Antilopini. As a rule, the Oribis are assigned their own sub- tribus within the Antilopini, the Ourebiina . Occasionally, however, some authors see the Oribis outside of the Antilopini and group them into a separate tribe, which is then referred to as Ourebiini. The long drawn out rostrum , which does not noticeably narrow at the front , the widened inner incisors and the high-crowned molars with extensive enamel surfaces can be mentioned as special characteristics of the Oribis . Outwardly striking is the hairless, dark patch of skin under the ears, which is somewhat reminiscent of a similar formation in the not closely related reedbucks .

Until the beginning of the 21st century, the Oribis were considered to belong to a species that bore the scientific name Ourebia ourebi and was trivially referred to in German as "Oribi". Within this species there were between eight and 13 subspecies, but some of them have become extinct. A 2011 revision of the ungulates by Colin P. Groves and Peter Grubb split the species into four species, mainly using morphometric features. In addition to the southern oribi , the Sudan oribi ( Ourebia montana ), the Senegal oribi ( Ourebia quadriscopa ) and the Serengeti oribi ( Ourebia hastata ) received species status as a nominate form of the genus . The remaining subspecies were largely synonymous with the Sudan and the Serengeti Oribi . The southern Oribi therefore does not contain any subspecies. The division of the Oribis into four species is not followed in all cases. However, genetic studies from 2017 showed that at least the Southern Oribi differs significantly from the Serengeti Oribi. Both forms show a difference of about 13% in cytochrome b , which is just as high as between the southern oribi and the ibex ( Raphicerus campestris ). Variances of around 2% occur within Southern Oribis. The authors of the study therefore advocate the classification of the southern Oribis as an independent taxonomic unit, without defining the species or subspecies level.

The southern Oribi was first scientifically described in 1783 by Eberhard August Wilhelm von Zimmermann . He used the species name antelope ourebi . Zimmermann identified the short, straight horns and the long neck as outstanding features. He noted the type area with " Cafferen ", which today largely corresponds to the South African province of Eastern Cape . Bruintjieshoogte near Somerset East in said province is given as a locality for a syntype of the species .

Danger

The IUCN does not currently differentiate between the different types of Oribis. The environmental protection organization classifies the entire portfolio as “not at risk” ( least concern ). The population is threatened by the expansion of agricultural and grazing areas, the expansion of human settlements and the increase in hunting, especially with dogs . In South Africa , the population decreased by 13% between 1996 and 2014 . The total number of individuals for 2015 was estimated to be a minimum of 1860 to 2170 and a maximum of 3100 adults. The largest proportion can be found in the Maloti Drakensberg Park in KwaZulu-Natal , but here too the population decreased from around 496 to 375 individuals. It is possible that no sub-population comprises more than 250 adult individuals. The species is present in numerous nature reserves, including the Golden Gate Highlands National Park in South Africa, the Gorongosa National Park in Mozambique and the Sehlabathebe National Park in Lesotho . The focus of research is on population development and the influence of hunting on it, also in relation to landscape fragmentation, in addition, the interactions with other, competing grass nutrition specialists such as the blessbock or the white-tailed wildebeest or with grazing animals as well as the role of grassland corridors in the migration of animals are examined. Another topic includes the effects of resettlement measures of individual groups in the southern Oribi, in the past not all release projects have been successful. In general, the southern Oribi is considered to be endangered in its area of ​​distribution.

literature

  • Justin S. Brashares and Peter Acrese: Ourebia ourebi Oribi. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume VI. Pigs, Hippopotamuses, Chevrotain, Giraffes, Deer and Bovids. Bloomsbury, London, 2013, pp. 406-413
  • Colin P. Groves and David M. Leslie Jr .: Family Bovidae (Hollow-horned Ruminants). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 2: Hooved Mammals. Lynx Edicions, Barcelona 2011, ISBN 978-84-96553-77-4 , p. 660
  • JT du Toit: Order Ruminantia. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, pp. 696-698

Individual evidence

  1. ^ A b c Colin Groves and Peter Grubb: Ungulate Taxonomy. Johns Hopkins University Press, 2011, pp. 1–317 (SS 179–183)
  2. ↑ a b c d e J. T. du Toit: Order Ruminantia. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, pp. 696-698
  3. ↑ a b c d e f Colin P. Groves and David M. Leslie Jr .: Family Bovidae (Hollow-horned Ruminants). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 2: Hooved Mammals. Lynx Edicions, Barcelona 2011, ISBN 978-84-96553-77-4 , p. 660
  4. ↑ a b c d e f g h i Justin S. Brashares and Peter Acrese: Ourebia ourebi Oribi. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume VI. Pigs, Hippopotamuses, Chevrotain, Giraffes, Deer and Bovids. Bloomsbury, London, 2013, pp. 406-413
  5. ^ KE van Teylingen and GIH Kerley: Habitat characteristics of increasing and decreasing oribi subpopulations in Eastern Cape Province, South Africa. South African Journal of Wildlife Research 25 (4), 1995, pp. 118-122
  6. ^ DT Rowe-Rowe: Habitat preferences of five Drakensberg antelopes. South African Journal of Wildlife Research 13, 1982, pp. 1-8
  7. ↑ Michael R. Perrin and Peter S. Everett: Habitat use by oribis at midlands elevations in KwaZulu-Natal, South Africa. South African Journal of Wildlife Research 29 (2), 1999, pp. 10-14
  8. ^ A b Adrian M. Shrader, Ian Little, Brent Coverdale and Tamanna Patel: A conservation assessment of Ourebia ourebi ourebi. In MF Child, L. Roxburgh, E. Do Linh San, D. Raimondo and HT Davies-Mostert (Eds.): The Red List of Mammals of South Africa, Swaziland and Lesotho. South African National Biodiversity Institute and Endangered Wildlife Trust, South Africa, 2016
  9. ↑ a b c d M. DN Oliver, NRM Short and J. Hanks: Population ecology of oribi, gray rhebuck and mountain reedbuck in Highmoor State Forest Land, Natal. South African Journal of Wildlife Research 8, 1978, pp. 95-105
  10. ↑ DT Rowe-Rowe, PS Everett and MR Perrin: Group size of oribis in different habitats. South African Journal of Wildlife Research 27 (3), 1992, pp. 140-143
  11. ^ BK Reilly, GK Theron and J. Du P. Bothma: Food preferences of oribi Ourebia ourebi in the Golden Gate Highlands National Park. Koedoe 33 (1), 1990, pp. 55-61
  12. ^ PS Everett, MR Perrin and DT Rowe-Rowe: Diet of oribi on farmland in Natal. South African Journal of Wildlife Research 22 (1), 1992, pp. 7-10
  13. ↑ C. Shackleton and BH Walker: Habitat and dietary species selection by oribi antelope at Mount Sheba Nature Reserve. South African Journal of Wildlife Research 15, 1985, pp. 49-53
  14. ↑ Keenan Stears and Adrian M. Shrader: Increases in food availability can tempt oribi antelope into taking greater risks at both large and small spatial scale. Animal Behavior 108, 2015, pp. 155-164
  15. ↑ Vera G. Adamczak and Robin Ian MacDonald Dunbar: Variation in the mating system of oribi and its ecological determinants. African Journal of Ecology 46 (2), 2008, pp. 197-206
  16. ↑ Bruce D. Humphries, Tharmalingam Ramesh and Colleen D. Downs: Diet of black-backed jackals (Canis mesomelas) in farmlands in the KwaZulu-Natal Midlands, South Africa. Mammalia 80 (4), 2016, pp. 405-412
  17. ↑ J. Boomker, ME Keep, JR Flamand and IG Horak: The helminths of various antelope species from Natal. Onderstepoort Journal of Veterinary Research 51, 1984, pp. 253-256
  18. ↑ J. Boomker, IG Horak and V. de Vos: The helminth parasites of various artiodactylids from some South African nature reserves. Onderstepoort Journal of Veterinary Research 53, 1986, pp. 93-102
  19. ↑ J. Boomker and RK Reinecke: A nematode parasite Trichostrongylus deflexus n. Sp. from several South African antelope species. South African Journal of Wildlife Research 19 (1), 1989, pp. 21-25
  20. ^ A b Eva V. Bärmann and Tim Schikora: The polyphyly of Neotragus - Results from genetic and morphometric analyzes. Mammalian Biology 79, 2014, pp. 283-286
  21. ↑ a b Alexandre Hassanin, Frédéric Delsuc, Anne Ropiquet, Catrin Hammer, Bettine Jansen van Vuuren, Conrad Matthee, Manuel Ruiz-Garcia, François Catzeflis, Veronika Areskoug, Trung Thanh Nguyen and Arnaud Couloux: Pattern and timing of diversification of Cetartiodactyla (Mammalia , Laurasiatheria), as revealed by a comprehensive analysis of mitochondrial genomes. Comptes Rendus Palevol 335, 2012, pp. 32-50
  22. ↑ Fayasal Bibi: A multi-calibrated mitochondrial phylogeny of extant Bovidae (Artiodactyla, Ruminantia) and the importance of the fossil record to systematics. BMC Evolutionary Biology 13, 2013, p. 166
  23. ↑ a b Eva Verena Bärmann, Gertrud Elisabeth Rössner and Gert Wörheide: A revised phylogeny of Antilopini (Bovidae, Artiodactyla) using combined mitochondrial and nuclear genes. Molecular Phylogenetics and Evolution 67 (2), 2013, pp. 484-493
  24. ↑ Chengzhong Yang, Changkui Xiang, Wenhua Qi, Shan Xia, Feiyun Tu, Xiuyue Zhang, Timothy Moermond and Bisong Yue: Phylogenetic analyzes and improved resolution of the family Bovidae based on complete mitochondrial genomes. Biochemical Systematics and Ecology 48, 2013, pp. 136-143
  25. ↑ Juan P. Zurano, Felipe M. Magalhães, Ana E. Asato, Gabriel Silva, Claudio J. Bidau, Daniel O. Mesquita and Gabriel C. Costa: Cetartiodactyla: Updating a time-calibrated molecular phylogeny. Molecular Phylogenetics and Evolution 133, 2019, pp. 256-262
  26. ↑ Taghi Ghassemi-Khademi: Evaluation of phylogenetic relationships of Antilopini and Oreotragini tribes (Bovidae: Artiodactyla) based on complete mitochondrial genomes. Journal of Wildlife and Biodiversity 1 (1), 2017, pp. 1–11
  27. ↑ Jonathan Kingdon: Tribe Ourebiini Oribi. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume VI. Pigs, Hippopotamuses, Chevrotain, Giraffes, Deer and Bovids. Bloomsbury, London, 2013, pp. 404-405
  28. ↑ Peter Grubb: Genus Ourebia Oribi. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume VI. Pigs, Hippopotamuses, Chevrotain, Giraffes, Deer and Bovids. Bloomsbury, London, 2013, p. 405
  29. ↑ a b Don E. Wilson and DeeAnn M. Reeder (eds.): Mammal Species of the World. A Taxonomic and Geographic Reference. Johns Hopkins University Press, 2005 ( [1] )
  30. ↑ Bettine Jansen van Vuuren, Ian Rushworth and Claudine Montgelard: Phylogeography of oribi antelope in South Africa: evolutionary versus anthropogenic panmixia. African Zoology 52 (4), 2017, pp. 189-197
  31. ↑ Eberhard August Wilhelm von Zimmermann: Geographical history of humans, and the generally widespread four-footed animals and a corresponding zoological world chart. Third volume. including appendix: Brief explanation of the zoological world chart. Leipzig, 1783, pp. 1–278 and pp. 1–32 (p. 268) ( [2] )
  32. ^ IUCN SSC Antelope Specialist Group: Ourebia ourebi. The IUCN Red List of Threatened Species 2016. e.T15730A50192202 ( [3] ); last accessed on January 7, 2020
  33. ↑ Rebecca Gray-Ross, Colleen T. Downs and Kevin Kirkma: Reintroduction Failure of Captive-Bred Oribi (Ourebia ourebi). South African Journal of Wildlife Research 39 (1), 2009, pp. 34-38

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