The reproductive success of black rhinoceroses in the Hluhluwe–iMfolozi Park, KwaZulu-Natal, South Africa

Zoliswa N Nhleko,Dan M Parker,Dave J Druce

doi:10.4102/koedoe.v59i1.1386

Abstract

Black rhinoceroses (Diceros bicornis) are endangered and the southern-central sub-species (Diceros bicornis minor) is considered critically endangered. We assessed the reproductive lifehistories of black rhinoceroses in Hluhluwe–iMfolozi Park (HiP), KwaZulu-Natal, South Africa, to determine whether this historically important donor sub-population was meeting regional reproductive targets. Detailed life-history information for known individuals (n = 79–120) was used to investigate reproductive parameters between 1998 and 2013. Mean age at sexual maturity was 12 years, which exceeded a target period of 7 years and 5 months. The mean inter-calving interval was 3 years and 8 months – 8 months longer than the recommended 3 years. The poor population performance of the HiP black rhinoceroses could be a result of poor habitat quality, poor animal condition, females losing their first calves, predation of calves or a negative social effect of annual live-harvesting of the population. However, we believe that the estimated ecological carrying capacity of black rhinoceroses at HiP (a figure used to ascertain whether the population can be harvested at all) may be incorrect, leading to the poor reproductive performance. We recommend that the accuracy of the ecological carrying capacity estimate be assessed as a matter of urgency and that a moratorium be placed on the live-harvesting of individuals until the estimate has been refined.Conservation implications: Our results provide key data which can be used to refine black rhinoceros breeding targets in South Africa and the region more broadly

Highlights

The conservation status of the southern-central black rhinoceros (Diceros bicornis minor) is critically endangered as a result of a population decrease of approximately 80% over the last three generations (International Union for Conservation of Nature [IUCN] 2012)
Our study shows that the current black rhino population at Hluhluwe–iMfolozi Park (HiP) consists of 63.2% adults, 25.5% subadults and 11.3% juveniles, suggesting that the population is stable (Owen-Smith 1988)
The black rhino population at HiP is an important donor population for the Black Rhino Range Expansion Programme (BRREP). This means that this population must perform well both genetically and demographically in order to continue contributing to the BRREP

Summary

Introduction

The conservation status of the southern-central black rhinoceros (Diceros bicornis minor) is critically endangered as a result of a population decrease of approximately 80% over the last three generations (International Union for Conservation of Nature [IUCN] 2012). With relevance to the southern-central black rhinoceros (hereafter black rhino), these were (1) to achieve a metapopulation growth rate of at least 5% per annum and (2) to increase the population to at least 2800 individuals by the end of 2020 These targets were to be achieved through sustainable metapopulation growth by annual live-harvesting and translocating 5% of individuals from certain sub-populations to populate additional sites (Goodman 2013). The expansion programme was dependent on the intensive monitoring of all sub-populations, including assessments of annual population sizes, population growth rates, fertility rates and mortality rates (Goodman 2013)

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Discussion

Conclusion