Small populations are vulnerable to the consequences of breeding within closed groups as the loss of genetic variability can lead to inbreeding depression. Here, we use microsatellite genotypes to assess variability and parentage within a small, managed population of southern white rhinoceros in northern Namibia. Tissue samples gathered from either a modified biopsy darting technique or ear notches allowed us to obtain genotypic data for all individuals in the population. As expected for this species, genetic variability in the population was relatively low (overall H obs 0.45). In combination with detailed management records for the period 1993-2009, we were able to assign both parents for all 23 offspring. Only one calf of seven in the F 2 generation arose from father-daughter inbreeding within the population. Our analysis revealed that paternity was initially dominated by a single founder bull siring 10 of 13 calves over nine years; paradoxically, the other founder bull was selected for removal based on observations suggesting he was behaviourally dominant and therefore the likely sire of most calves. We also found that young introduced bulls were breeding successfully within six months of their arrival, well before having established their home ranges. We argue that in order to optimally manage and conserve the southern African rhino metapopulation it is essential to have accurate pedigree information and genetic data for all individuals in the numerous small populations that are key to the survival of the species.(379 words) Keywords Microsatellites, tissue biopsy, biopsy dart method, inbreeding, Ceratotherium simum simumElectronic supplementary material The online version of this article (doi: to come) contains supplementary material, which is available to authorized users.

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Estimating the population parameters, performance and factors that influence reproduction from long-term, individual-based monitoring data is the gold standard for effective wildlife management and conservation. Yet this information is often difficult and costly to collect or inaccessible to managers. We synthesized a 20-year set of individual-based monitoring data from a subset of black rhinoceros Diceros bicornis subpopulations across a range of environmental conditions in Namibia. Our findings demonstrate that despite the relatively arid landscape in Namibia, the black rhinoceros metapopulation is performing well, measured by age at first reproduction, inter-birth interval, population growth and survivorship. Information-theoretic modelling revealed that a univariate model including normalized differential vegetative index had a greater influence upon age at first reproduction than population density. The inter-birth interval model set identified cumulative rainfall during the 15 months prior to the birth month as the top model, although the mean normalized differential vegetative index during the inter-birth interval was comparable. There was little evidence for density-dependence effects on reproduction. These findings suggest that although browse quality could have a greater impact on parameters spanning multiple years, shorter-term parameters could be more influenced by rainfall. Our analysis also revealed a synchronous pattern of conceptions occurring in the rainy season. Our study provides a set of population parameter estimates for Namibian black rhinoceros subpopulations and preliminary insights on factors driving their reproduction. These expand our collective knowledge of global black rhinoceros population dynamics and improve our confidence and capability to adaptively manage the black rhinoceros metapopulation of Namibia.

Current management models for many endangered species focus primarily on demographic recovery, often ignoring their intrinsic ecological requirements. Across the protected area network of southern Africa, most southern white rhinoceros are managed in populations of less than 50 individuals, experiencing restricted dispersal opportunities, and limited breeding male numbers due to their exclusive home range requirements. In the absence of information on the breeding structure of these populations, poor management decisions may require females to either forego a breeding opportunity or select to inbreed with close relatives. Here, we use a combination of social pedigree data together with genetic analyses to reconstruct the parentage of all 28 offspring produced in a 5-year period in a managed free-ranging southern white rhinoceros population. During this period, all breeding females (founders and first-generation daughters) had access to both a founder male (father to most of the daughters) and two recently introduced inexperienced males. We report that while founder females were more likely to breed with the founder male, their daughters, in contrast, were more likely to breed with the introduced males, thus avoiding inbreeding. However, we also found evidence of father–daughter inbreeding in this population, and contend that in the absence of choice, rather than forego a breeding opportunity, female white rhinoceros will inbreed with their fathers. We argue that to effectively conserve the southern white rhinoceros, managers need to understand the breeding structure of these small populations, particularly in terms of parentage and kinship.