Concept: Northern White Rhinoceros
White rhinoceros (rhinos) is a keystone conservation species and also provides revenue for protection agencies. Restoring or mimicking the outcomes of impeded ecological processes allows reconciliation of biodiversity and financial objectives. We evaluate the consequences of white rhino management removal, and in recent times, poaching, on population persistence, regional conservation outcomes and opportunities for revenue generation. In Kruger National Park, white rhinos increased from 1998 to 2008. Since then the population may vary non-directionally. In 2010, we estimated 10,621 (95% CI: 8,767-12,682) white rhinos using three different population estimation methods. The desired management effect of a varying population was detectable after 2008. Age and sex structures in sink areas (focal rhino capture areas) were different from elsewhere. This comes from relatively more sub-adults being removed by managers than what the standing age distribution defined. Poachers in turn focused on more adults in 2011. Although the effect of poaching was not detectable at the population level given the confidence intervals of estimates, managers accommodated expected poaching annually and adapted management removals. The present poaching trend predicts that 432 white rhinos may be poached in Kruger during 2012. The white rhino management model mimicking outcomes of impeded ecological processes predicts 397 rhino management removals are required. At present poachers may be doing “management removals,” but conservationists have no opportunity left to contribute to regional rhino conservation strategies or generate revenue through white rhino sales. In addition, continued trends in poaching predict detectable white rhino declines in Kruger National Park by 2016. Our results suggest that conservationists need innovative approaches that reduce financial incentives to curb the threats that poaching poses to several conservation values of natural resources such as white rhinos.
With only three living individuals left on this planet, the northern white rhinoceros (Ceratotherium simum cottoni) could be considered doomed for extinction. It might still be possible, however, to rescue the (sub)species by combining novel stem cell and assisted reproductive technologies. To discuss the various practical options available to us, we convened a multidisciplinary meeting under the name “Conservation by Cellular Technologies.” The outcome of this meeting and the proposed road map that, if successfully implemented, would ultimately lead to a self-sustaining population of an extremely endangered species are outlined here. The ideas discussed here, while centered on the northern white rhinoceros, are equally applicable, after proper adjustments, to other mammals on the brink of extinction. Through implementation of these ideas we hope to establish the foundation for reversal of some of the effects of what has been termed the sixth mass extinction event in the history of Earth, and the first anthropogenic one. Zoo Biol. XX:XX-XX, 2016. © 2016 Wiley Periodicals, Inc.
White rhinoceros ejaculates (n=9) collected by electroejaculation from four males were shipped (10°C, 12h) to develop procedures for the production of chilled and frozen-thawed sex-sorted spermatozoa of adequate quality for artificial insemination (AI). Of all electroejaculate fractions, 39.7% (31/78) exhibited high quality post-collection (≥70% total motility and membrane integrity) and of those, 54.8% (17/31) presented reduced in vitro quality after transport and were retrospectively determined to exhibit urine-contamination (≥21.0μg creatinine/ml). Of fractions analyzed for creatinine concentration, 69% (44/64) were classified as urine-contaminated. For high quality non-contaminated fractions, in vitro parameters (motility, velocity, membrane, acrosome and DNA integrity) of chilled non-sorted and sorted spermatozoa were well-maintained at 5°C up to 54h post-collection, whereby >70% of post-transport (non-sorted) or post-sort (sorted) values were retained. By 54h post-collection, some motility parameters were higher (P<0.05) for non-sorted spermatozoa (total motility, rapid velocity, average path velocity) whereas all remaining motion parameters as well as membrane, acrosome and DNA integrity were similar between sperm types. In comparison with a straw method, directional freezing resulted in enhanced (P<0.05) motility and velocity of non-sorted and sorted spermatozoa, with comparable overall post-thaw quality between sperm types. High purity enrichment of X-bearing (89±6%) or Y-bearing (86±3%) spermatozoa was achieved using moderate sorting rates (2540±498X-spermatozoa/s; 1800±557Y-spermatozoa/s). Collective in vitro characteristics of sorted-chilled or sorted-frozen-thawed spermatozoa derived from high quality electroejaculates indicate acceptable fertility potential for use in AI.
Reproductive tract tumours, specifically leiomyoma, are commonly found in female rhinoceroses. Similar to humans, tumour growth in rhinoceroses is thought to be sex hormone dependent. Tumours can form and expand from the onset of ovarian activity at puberty until the cessation of sex-steroid influences at senescence. Extensive tumour growth results in infertility. The aim of this study was to down regulate reproductive function of tumour-diseased and infertile females to stop further tumour growth using a Gonadotropin releasing factor (GnRF) vaccine. Four infertile southern white (Ceratotherium simum simum) and three Greater one-horned rhinoceroses (rhinoceros unicornis) with active ovaries and 2.7 ± 0.9 and 14.0 ± 1.5 reproductive tract tumours respectively were vaccinated against GnRF (Improvac®, Zoetis, Germany) at 0, 4 and 16 weeks and re-boostered every 6-8 months thereafter. After GnRF vaccination ovarian and luteal activity was suppressed in all treated females. Three months after vaccination the size of the ovaries, the number of follicles and the size of the largest follicle were significantly reduced (P<0.03). Reproductive tract tumours decreased significantly in diameter (Greater-one horned rhino: P<0.0001; white rhino: P<0.01), presumably as a result of reduced sex-steroid influence. The calculated tumour volumes were reduced by 50.8 ± 10.9% in Greater one-horned and 48.6 ± 12.9% in white rhinoceroses. In conclusion, GnRF vaccine effectively down regulated reproductive function and decreased the size of reproductive tract tumours in female rhinoceros. Our work is the first to use down regulation of reproductive function as a symptomatic treatment against benign reproductive tumour disease in a wildlife species. Nonetheless, full reversibility and rhinoceros fertility following GnRF vaccination warrants further evaluation.
Identification of Policies for a Sustainable Legal Trade in Rhinoceros Horn Based on Population Projection and Socioeconomic Models
- Conservation biology : the journal of the Society for Conservation Biology
- Published over 6 years ago
Between 1990 and 2007, 15 southern white (Ceratotherium simum simum) and black (Diceros bicornis) rhinoceroses on average were killed illegally every year in South Africa. Since 2007 illegal killing of southern white rhinoceros for their horn has escalated to >950 individuals/year in 2013. We conducted an ecological-economic analysis to determine whether a legal trade in southern white rhinoceros horn could facilitate rhinoceros protection. Generalized linear models were used to examine the socioeconomic drivers of poaching, based on data collected from 1990 to 2013, and to project the total number of rhinoceroses likely to be illegally killed from 2014 to 2023. Rhinoceros population dynamics were then modeled under 8 different policy scenarios that could be implemented to control poaching. We also estimated the economic costs and benefits of each scenario under enhanced enforcement only and a legal trade in rhinoceros horn and used a decision support framework to rank the scenarios with the objective of maintaining the rhinoceros population above its current size while generating profit for local stakeholders. The southern white rhinoceros population was predicted to go extinct in the wild <20 years under present management. The optimal scenario to maintain the rhinoceros population above its current size was to provide a medium increase in antipoaching effort and to increase the monetary fine on conviction. Without legalizing the trade, implementing such a scenario would require covering costs equal to approximately $147,000,000/year. With a legal trade in rhinoceros horn, the conservation enterprise could potentially make a profit of $717,000,000/year. We believe the 35-year-old ban on rhinoceros horn products should not be lifted unless the money generated from trade is reinvested in improved protection of the rhinoceros population. Because current protection efforts seem to be failing, it is time to evaluate, discuss, and test alternatives to the present policy.
The population of free-roaming white rhinoceroses (Ceratotherium simum) is under serious threat. Captive breeding of this species is therefore becoming more important, but this is challenging and often not successful. Obtaining reproductive reference values is a crucial aspect of improving these breeding results. In this study performed between 2008 and 2016, reproductive performance was analysed in 1,354 animals kept in a 8000 hectares game-ranched environment. Descriptive statistics of this captive population showed an average annual herd growth (%) of 7 .0±0.1 (min -9 -max 15). Average calving rates were calculated as an annual calving rate of 20% and biennial calving rate of 37% adult females calving per year. Females had a median age of 83.2 months at first calving (IQR 72.9-110.7) and inter-calving intervals of 29.2 (IQR 24.6-34.8) months. Furthermore, translocations of animals did not interfere with reproductive success in terms of inter-calving periods or age at first calving. Multivariate models showed a clear seasonal calving pattern with a significant increase of the number of calvings during December-April when compared to April-December. Our results did not show any significant skewed progeny sex ratios. Weather observations showed no significant influence of rain or season on sex ratios of the calves.
A young male southern white rhinoceros (Ceratotherium simum), which was resident in a zoo as part of a multi-rhinoceros group, died suddenly. Necropsy and histopathological findings supported a diagnosis of death from acute hepatic necrosis. The microscopic distribution of liver lesions was suggestive of hepatotoxicosis. Further investigation revealed potential exposure to a mycotoxin, sterigmatocystin, present in spoiled lucerne hay contaminated with Aspergillus nidulans. It was concluded that mycotoxicosis was the likely cause of the hepatic necrosis and death in this animal.
The Southern white rhinoceros (Ceratotherium simum) is a threatened species, central to the tourism appeal of private game reserves in South Africa. Privately owned reserves in South Africa tend to be smaller than government run reserves such as Kruger National Park. Because of their relatively small size and the often heterogeneous nature of the landscape private game reserve managers benefit from detailed knowledge of white rhinoceros terrain selection preferences, which can be assessed from their ranging behaviours. We collected adult and sub-adult white rhinoceros distribution data over a 15 month period, calculating individual range size using kernel density estimation analysis within a GIS. From this, terrain selectivity was calculated using 50% and 95% kernels to extract terrain composition values. Jacob’s correction of the Ivlev’s selectivity index was subsequently applied to the terrain composition of each individual to identify trends in selectivity. Results reveal that adult males hold exclusive territories considerably smaller than those found in previous work conducted in “open” or large reserves. Similarly, results for the size of male versus female territories were also not in keeping with those from previous field studies, with males, rather than females, having the larger territory requirement. Terrain selection for both genders and age classes (adult and sub-adult) showed a strong preference for open grassland and avoidance of hill slope and riparian terrains. This research reveals white rhinoceros terrain selection preferences and how they influence range requirements in small, closed reserves. We conclude that this knowledge will be valuable in future white rhinoceros conservation management in small private game reserves, particularly in decisions surrounding removal of surplus individuals or augmentation of existing populations, calculation of reserve carrying capacity and future private reserve acquisition.
Ninety-four subadult and adult white rhinoceroses (Ceratotherium simum) were captured between February and October, 2009-11, in Kruger National Park and placed in holding bomas prior to translocation to other locations within South Africa. A simple three-category system was developed based on appetite, fecal consistency/volume, and behavior to assess adaptation to bomas. Individual animal and group daily median scores were used to determine trends and when rhinoceroses had successfully adapted to the boma. Seventeen rhinoceroses did not adapt to boma confinement, and 16 were released (1 mortality). No differences in boma scores were observed between rhinoceroses that adapted and those that did not, until day 8, when the first significant differences were observed (adapted score=13 versus nonadapted score=10). The time to reach a boma score determined as successful adaptation (median 19 d) matched subjective observations, which was approximately 3 wk for most rhinoceroses. Unsuccessful adaptation was indicated by an individual boma score of less than 15, typically during the first 2 wk, or a declining trend in scores within the first 7-14 d. This scoring system can be used for most locations and could also be easily adapted to other areas in which rhinoceroses are held in captivity. This tool also provides important information for assessing welfare in newly captured rhinoceroses.
Butorphanol with oxygen insufflation improves cardiorespiratory function in field-immobilised white rhinoceros (Ceratotherium simum)
- Journal of the South African Veterinary Association
- Published over 5 years ago
Opioid-induced immobilisation results in severe respiratory compromise in the white rhinoceros (Ceratotherium simum). The effectiveness of oxygen insufflation combined with butorphanol in alleviating respiratory depression in free-ranging chemically immobilised white rhinoceroses was investigated. In this prospective intervention study 14 freeranging white rhinoceroses were immobilised with a combination of etorphine, azaperone and hyaluronidase. Six minutes (min) after the animals became recumbent, intravenous butorphanol was administered and oxygen insufflation was initiated. Previous boma trial results were used for comparison, using repeated measures two-way analysis of variance. The initial immobilisation-induced hypoxaemia in free-ranging rhinoceroses (arterial partial pressure of oxygen [PaO2] 35.4 mmHg ± 6.6 mmHg) was similar to that observed in bomaconfined rhinoceroses (PaO2 31 mmHg ± 6 mmHg, n = 8). Although the initial hypercapnia (PaCO2 63.0 mmHg ± 7.5 mmHg) was not as severe as that in animals in the boma trial (79 mmHg ± 7 mmHg), the field-immobilised rhinoceroses were more acidaemic (pH 7.10 ± 0.14) at the beginning of the immobilisation compared with boma-immobilised rhinoceroses (pH 7.28 ± 0.04). Compared with pre-intervention values, butorphanol with oxygen insufflation improved the PaO2 (81.2 mmHg ± 23.7 mmHg, p < 0.001, 5 min vs 20 min), arterial partial pressure of carbon dioxide (55.3 mmHg ± 5.2 mmHg, p < 0.01, 5 min vs 20 min), pH (7.17 ± 0.11, p < 0.001, 5 min vs 20 min), heart rate (78 breaths/min ± 20 breaths/min, p < 0.001, 5 min vs 20 min) and mean arterial blood pressure (105 mmHg ± 14 mmHg, p < 0.01, 5 min vs 20 min). Oxygen insufflation combined with a single intravenous dose of butorphanol improved oxygenation and reduced hypercapnia and acidaemia in immobilised free-ranging white rhinoceroses.