Home ranges, movements and spatial relationships in an expanding population of black rhinoceros

Abstract

Over 3000 sightings and fixes of individually identified black rhinoceros (Diceros bicornis minor ) over a 14-year period provided information on the spatial organization and movements of these introduced animals and their offspring in the Great Fish River Reserve, South Africa. Core home ranges based on 50% adaptive kernel calculations proved useful for depicting spatial associations among individuals and shifts in areas of occupation. The mean home range size (minimum convex polygon) was 11.7 km 2 and that of core adaptive kernel 6.8 km 2 . Annual and individual variations in home range size were great and social factors clearly affected size. For these and other reasons great caution is recommended in interpretation and inter-population comparisons of home range sizes. Most individuals in this expanding population showed mobility, with home ranges shifting over time. Although clearly exhibiting individual home ranges, most females associated in clusters of three or more individuals. Calves generally moved away from their mothers at the time of her next calving, but some subsequently moved back into their mothers' core home range. In addition to mother-offspring pairs, some females also showed multiple-year associations in these clusters. Male home ranges overlapped, and individuals showed multiple-year associations until they reached approximately nine years of age. Males over age 8 were rarely sighted in the core home range of other similarly aged males

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