Aspects of the biology, population ecology and behaviour of the sable antelope, Hippotragus niger niger, (Harris, 1838) in the Rhodes Matopos National Park, Rhodesia

Abstract

The study set out to determine some of the bioecological relationships of the sable antelope Hippotragus niger niger (Harris, 1838) in the Rhodes Matopos National Park, Rhodesia. The vegetation of the area is divided into seven categories each of which is discussed. The population in the study area (approximately 200) had three major components as follows: the breeding groups, the bachelor male groups and territorial males. The structure of the breeding groups varied seasonally. Bachelor male groups of two to 12 consisted of younger males which had as yet not established territories. Territorial males fell into three classes depending on status:- class I: central territorial; class II: peripheral territorial and class III: outer territorial males, in relation to the breeding group home ranges. The population had a recruitment rate of 26 - 29 per cent fron young of the year and a calving percentage of 56 - 67 per cent, calculated towards the end of the year for 1971 and 1972. The male to fenale sex ratio was not significantly different from a l:l ratio for calves and yearlings but in adults the females outnumbered the males significantly. Breeding groups were found to have home ranges ranging in area from 240 ha to 280 ha though this did not apply in the strictest sense. The territories of territorial males were marked by branch breaking on shrubs and were equivalent to home ranges. The territories ranging from 25 ha to 40 ha in size were defended against other territorial males though bachelor males were tolerated. Social organisation of the ropulation wns based on intraspecific aggressiveness and intolerance and the dominance of one individual over another. Various dominance displays are discussed. Although difficult to determine exactly, the gestation period was about 270 days, the peak calving period being early February. The peak rut took place during May and June although fenales were mated at other times during the year. Measurements and mass are given for 47 young calves which were captured, marked and released for field studies. The sable were found to be selective grazers of nediun height grass showing preference for new growth. Sable appeared to be water dependent, drinking mostly from l3h00 to l4h00. Twenty-eight plant species were recorded as food plants, four of which were dicotyledonous. Seasonal use of different habitats was recorded. Mortality factors in the study area included predation, accidental deaths and illegal hunting, with possible mortality from parasite infestation and fighting. Management of the species involves management of the sable population itself and managenent of the habitat in which they live. Management inplications are discussed. AFRIKAANS : Die doel van die huidige studie was om sekere bioekologiese verwantskappe van die Swrartwitpens Hippotragus niger niger (Harris, 1838) te bestudeer in die Rhodes Matopos Nationale Park in Rhodesië. Die plantetgroei van die area is in sewe subklasse verdeel en elk van die subklasse is bespreek. Die bevolking van ongeveer 200 Swartwitpense het uit drie hoof groepe bestaan, nl., die teelgroepe, vrygesel bulgroepe en territoriale bulle. Die samestelling van die teelgroepe het gewissel van seisoen tot seisoen. Die vrygesel bulgroepe het uit twee tot 12 jonger bulle bestaan wat nog nie 'n territoriale gebied afgebaken het nie. Die territoriale bulle kan volgens status in drie groepe verdeel word nl. klas I: sentraal territoriaal; klas II: aangrensend territoriaal en klas III: rand territoriaal ten opsigte van die weidingsgebied van die teelgroepe. Die Swartwitpens bevolking het 'n jaarlikse aanvas van tussen 26 - 29 persent gehad en die kalfpersentasie was tussen 56 - 67 persent. Die syfers is gebaseer op gegewens ingewin gedurende Oktober tot Desember vir die 1971 en 1972 seisoene. Die geslagsverhouding het nie betekenisvol afgewyk van 'n 1:1 verhouding vir kalwers en een tot twee jaar oud diere nie, maar by volwasse diere was daar betekenisvol meer koeie as bulle.