Black Rhino (Diceros Bicornis)

Rev. 21 July 2021

Black Rhino (Diceros bicornis)

IMPACTS OF TROPHY HUNTING QUICK FACTS:

■ Offtakes are not biologically sustainable Population 3,142 mature individuals, estimated ■ Decreased genetic diversity Size: decline of 85% in last three genera- ■ Social disruption tions (43.5 years)

POPULATION Range: More than 98% of historical range lost The population size of the black rhinoceros (also IUCN Red Critically Endangered (2020) known as the black rhino) is estimated as 3,142 ma- List: ture individuals as of 2017.1 The population declined CITES: Appendix I (since 1977) by 85% in the last three generations (43.5 years), 1973 to 2017.2 International 80 black rhino trophies traded inter- Trade: nationally from 2009-2018 The black rhino has experienced steep long-term population declines with recent small increases Threats: Poaching for horns, habitat loss (Figure 2).2 During the 20th century, regional populations were hunted to low numbers or extinction.3 By 1960, only 100,000 remained due to ‘relentless hunting’ and habitat loss.1 From 1973 to 1983, black rhino declined from 37,807 to 9,444 due to heavy poaching.2 Overall, from 1960 to 1995, large-scale poaching caused a 98% collapse in population numbers.1

The black rhino has been classified as Critically En- dangered by IUCN since 1996, which was recently reconfirmed in the species’ 2020 assessment, high- lighting long-term concerns about the conservation status of this species. Species are classified as Criti- cally Endangered if they face an extremely high risk of extinction in the wild in the immediate future. Geographic Range of D. bicornis RANGE Current* range (1987) in red, historical range (ca. 1700) in blue Source: Ripple et al. 2015 * More recent range not shown due to threats from poaching. The black rhino has lost more than 98% of its historical range (ca. 1700).1,4,5 The majority (94%) of black rhinos reside in four range States: South Afri- native range States: Angola, Mozambique, Tanzania, ca, Namibia, Kenya, and Zimbabwe (in order or pop- and have been reintroduced to Botswana, Eswati- ulation size).6 They are also extant in three other ni, Malawi, Rwanda, and Zambia.1 Due to habitat loss

There has also been an effort to translocate black rhino to areas outside their historic range in order to establish new populations.1 Translocations have been important to the recovery of the black rhino, especially in South Africa; however, translocations vary in success.7 Many factors determine the success of translocations, including rhino age,7 reserve size,8 habitat quality,9 and group size.9 In addition, population growth may be slow as it can take at least three years following a translocation for a male to establish a home rage.10 Due to the complexities of spatial and social interactions, removing black rhinos from their range can disrupt social interactions and adult male-female breeding relationships.11,12,13,14 Therefore, both social and ecological conditions must be favor- 9 able for successful translocation. Estimated population of D. bicornis Over three generations by subspecies/genetic Translocation comes at a biological cost to black rhi- management cluster nos, as indicated by increased stress after capture Source: IUCN (2020) and during captivity in preparation for translocation.15 Post-mortality rates vary but can be as high as 18%.7 Translocation is associated with post-release Calves are weaned around two years old but remain distress, suppressed gonad function, and delayed in contact with their mothers for an additional 2-3 reproduction, consistent with poor reproductive years until their mothers give birth again.22 During output observed in captive and translocated rhino.15 this time, mothers have been observed maintaining Stress from translocation is believed to be the cause close proximity to their calves and protecting calves of reduced breeding performance of mothers and from predators.22 low survival rates in young rhinos.7,16 Stress experienced during immobilization, capture, transloca- Female reproduction is influenced by a number of tion, and dehorning can have immunosuppressive environmental factors, such as season, vegetation, effects and increase susceptibility to disease.17 Re- rainfall, and resource availability.24,25,26 This research peated mobilizations greatly reduce growth rates by has shown that there are clear links between female negatively affecting multiple fertility parameters.18 nutritional condition and reproduction. Peak calving Translocations, especially to restock existing popu- occurs during the wettest months,25 and shorter in- lations, are associated with high rates of male-male ter-calf intervals are correlated with higher rainfall.26 conflict and mortality.7 Both of these measures indicate that black rhino females reach greater reproductive potential during LIFE HISTORY AND wetter seasons when resources and vegetation are REPRODUCTION more abundant. Females are sensitive to heat stress, and reproduction is lower during the hottest time Black rhino population growth is slow due to low of the year.25 This is especially concerning as climate reproductive rates, long generation times, and high change will lead to warmer and drier periods in the calf mortality. Females give birth for the first time future. at 7-9 years old, but can be as late as 12 years for some populations.19,20 Males do not hold home rang- In the wild, maximum lifespan is approximately 42 es necessary for mating until 9 years old.21 Gestation years.2 Older black rhinos, both male and female, lasts approximately 15 months, and females produce have higher reproductive hormone levels.27 There one calf at a time.19 The average calving interval is no evidence of a post-reproductive period for is 2.25-4 years, depending on the population19,20,22 females, as they continue to give birth late into but can be up to 6 years with poaching pressure.23 life.20,25,28 In females, the only significant predictor of

© 2021 Humane Society International 2 reproductive success is age, with older females pro- ing, poaching) will likely increase social conflict.34 ducing more calves.29 This highlights the importance of older females for population growth. There is lit- SOCIAL STRUCTURE tle available research on male reproduction. There is no scientific evidence that males stop reproduc- Black rhinos were once believed to be mostly sol- ing at older ages. One study found that the majority itary; however scientists suggest that was a mis- of calves were fathered by a male 25-37 years old.30 conception due to intense population declines.33,19 In addition, males 25 years and older produce an- Instead, black rhinos exhibit social structure based drogens, important reproductive hormones, at con- on spatial organization, where females have overlap- centrations comparable to younger males.31 ping home ranges, and males defend home ranges encompassing many females.33 There is also evi- Black rhinos are polygynous, and males exhibit high dence of loose family structures.30 variance in reproductive success.29,19,30 Males compete for home ranges that overlap with the home Social interactions are largely based on the degree ranges of several adult females. Once males reach of home range overlap, which is heavily influenced the age of nine, they begin to hold home ranges nec- by age, sex, and neighboring rhinos.11,12,13,14 Social essary for mating.21 Males compete with one anoth- groupings of black rhinos are typically referred to er for the best home ranges and access to females. as clusters.11,14 Female home ranges typically over- Male-male competition is intense and can be fatal.7 lap and occur in clusters of three or more females.11 Among males, horn mass is positively correlated Female clusters may consist of both related or un- with higher rank.32 Therefore, trophy hunting that related individuals,11 and mothers may share part of targets males with the largest horns threatens to their home ranges with adult female offspring.12,23 eliminate the most prolific male and can negatively Female home ranges also overlap male home rang- affect reproduction. For males, home range size is es, consistent with adult male-female breeding re- correlated with greater heterozygosity (indicating lationships.11,12,13,14 While adult males do not share lower levels of inbreeding), which is the strongest home ranges with other adult males; young males predictor of reproductive success.29 Reproductive frequently overlap ranges of males nine years and success is highly skewed among males, meaning older.11,14 This suggests that young males roam and that a few individuals are responsible for the major- regularly associate with older males. ity of matings.19,30 Population declines across their range have resulted in decreases in genetic diversi- Black rhinos exhibit varying levels of social complex- ty.3 Therefore, the removal of males due to poaching ity. At the simplest level, temporary aggregations or trophy hunting could have detrimental effects on form in habitats with low-lying vegetation and pre- population growth if those males are highly success- ferred forage species.11 Neighboring adult males and ful or genetically important. In captivity, testoster- adult females form longer breeding relationships, one concentrations are higher with an increasing which determine individual habitat use and spatial number of female rhinos present.33 In addition, iso- overlap.13 There is also some added complexity to lated males had lower testosterone concentrations these relationships in the form of social dominance than males housed with other males.33 This indicates based on sex and horn size.32 Among males, larger that the presence of neighbors, especially many fe- horns are associated with higher dominance.32 Be- male neighbors, is important for stimulating repro- tween the sexes, females exhibit dominance over duction. males, regardless of horn size.32 Scientists also be- lieve that olfactory communication plays an import- Population age structures reveal low numbers of ant role in social relationships.27 subadults and juveniles, which is problematic for future population growth.20 There is also evidence In addition, social relationships clearly play some that females experience spontaneous natural abor- beneficial role, as evidenced by the importance of tions, which would further slow growth rates.25 Nat- group size for relocation success.9 Scientists sug- ural deaths occur due to illness, male-male fighting, gest that social peers could play an important role accidents (such as falls), and predation.21 Injuries in resource acquisition, especially in unfamiliar low and mortalities from fighting are more common in quality habitats.9 Navigating the social environment smaller reserves.8 Scientists say that social disrup- is also important for establishing new home ranges tion due to removal (e.g., relocation, trophy hunt- and must be considered in management decisions.35

© 2021 Humane Society International 3 HABITAT AND ECOLOGY rare large herbivores, like black rhino.5 Black rhinos are also economically important. They bring in sig- Black rhinos are herbivorous browsers and prefer nificant revenue in the photo safari industry.5 Black small acacias and other palatable woody species, rhinos are highly sought by tourists who will pay as well as herbs and succulents.1 However, many high prices to observe a black rhino in the wild.40,41 woody species are unpalatable due to high levels of plant chemicals.1 Black rhinos are highly selective DIRECT ANTHROPOGENIC foragers, and while they may eat over 80 species, a THREATS small number of species account for the majority of their diet.36 Previous calculations have over-estimat- The greatest human-caused, or anthropogenic, ed carrying capacities due to failure to acknowledge threat is illegal killing for the rhino horn trade.1 Af- this.1 Carrying capacity is driven by rainfall, soil nutri- rican rhino horns are one of the most expensive ent status, fire histories, levels of grass interference, goods in the world.42 In 2013-2014, the price of rhino extent of frost, and densities of other large brows- horn ranged between US$25,000 and US$65,000 ers.1 per kilogram.43 As of 2017, the price of rhino horn had increased to US$45,000 and US$120,000 per Black rhinos are found in a wide variety of habitats, kilogram.42 Since rhino horn has long been a highly although the highest densities reside in savanna valued good, there is a history of unregulated and habitats.1 Home ranges are highly variable, shift over excessive hunting.42 Between 1960 and 1995, large- time, and depend on several factors, such as sea- scale poaching caused a dramatic 98% collapse in son, resource availability, habitat type, human dis- population numbers.1 Although black rhino poach- turbance, and neighboring rhinos.11,14,37 Surface water ing peaked in 2015 and has declined, poaching has may be the primary limiting factor for female black continued to slow population growth.1 Poaching also rhino habitat use.37 Home ranges not only reflect threatens black rhino conservation efforts because resource availability, but black rhinos tend to shift many private landowners find it too costly and risky and reconfigure their home ranges to avoid human to maintain the species.1 disturbances.14 Mean home range sizes vary from 12 There are multiple corrupt networks involved in km2 to 89.9 km2 and are highly dependent on loca- black rhino poaching.42,44 Poaching networks range tion, methodology, season, and resource availabili- in sophistication and include organized crime syn- ty.11,38 Home ranges are also important predictors dicates that use high tech methods to poach rhi- of social interactions and adult male-female breed- nos and smuggle horns.44 Pseudo-hunting networks ing relationships.11,12,13,14 In males, home range size is involve a scheme where people apply for trophy also correlated with greater genetic heterozygosi- hunting permits as a cover for obtaining and trad- ty, which is the strongest predictor of reproductive ing rhino horns.44 Pseudo-hunting is a regulatory success.29 loophole where ‘hunters’ from atypical countries for trophy hunting, such as Viet Nam, trophy hunt Many remaining black rhinos reside in fenced re- for the sole intent of obtaining rhino horn. This is serves and intensive protection zones.1 Fenced one way in which seemingly legal products end up in reserves may also limit future population genetic illegal markets. South Africa is currently the primary diversity due to isolation of subpopulations. In addi- supplier of illegal rhino horn through poaching and tion, injuries and mortalities from male-male fighting pseudo-hunting.45 Pseudo-conservation networks are more common in smaller reserves.8 Therefore, are where groups obtain live rhinos and trade them reserve size and location are critical for survival and domestically under the guise of conservation, only reproduction. to kill and dehorn the animals for illegal trade.44 Theft networks are also common, where black rhino Black rhinos play an important role in the ecosys- horns are stolen from both private and government tem as grazers, which shapes the local landscape. stockpiles, as well as institutions and museum col- Megaherbivores, such as rhino, are unique in their lections.44 ecosystem in their ability to alter nutrient cycles, soil properties, fire regimes, and primary produc- The Groenewald gang or the “Musina group” is tion.5,39 These roles cannot be taken over by smaller a well-known rhino poaching syndicate that was herbivores. Due to their importance, scientists rec- charged with 1,736 counts of racketeering, money ommend a global government-funded scheme for laundering, fraud, intimidation, illegal hunting, and

© 2021 Humane Society International 4 dealing in rhino horns in South Africa.42 Working at Hunting organizations argue that individuals must the interface of legal and illegal markets, they were be removed from the population in order to reduce also accused of selling fake trophy hunting permits density and stimulate population growth, although and illegal dehorning of rhinos.42 The Groenewald there is also no evidence that manipulation of age gang allegedly was socially well-connected with the or sex structures stimulates population growth.17 African wildlife industry, and Dawie Groenewald al- Black rhinos exhibit similar birth rates at different legedly obtained rhinos and rhino horns from other population densities.50 Further, rhinos are poor dis- farmers, as well as illegally hunted rhinos on his own persers and are unlikely to colonize recently vacated land.42 The privatization of rhinos allowed for the home ranges. Following the removal of a neighbor Groenewald gang, and others, to appear legitimate for translocation purposes, rhinos are slow to recol- and go undetected. onize the habitat that was occupied by their former neighbor.13 Female and male rhinos form breed- Black rhinos have two prominent horns, which grow ing relationships that influence habitat use; there- throughout their lifetime and naturally vary in size.32 fore, removal of an individual results in the loss of Males and females have similarly sized horns; there- a breeding relationship that is not immediately re- fore, both are targeted by poachers. In fact, poach- placed. Decreased home range overlap also reduces ers target all age and sex classes.46 However, males interactions between the sexes, which is especially are disproportionately targeted by poachers, which concerning in populations with low density. Scien- significantly alters sex ratios.47 Populations protect- tists say that social behavior of black rhino must be ed from poaching exhibit more equal sex ratios considered when removing individuals from a pop- than those with heavy poaching pressure.47 Males ulation; otherwise, an unbalanced social structure are constrained in the distance they are able to flee could shift home ranges and reduce reproductive from poachers due to the importance of established rates because rhinos are expending more energy home ranges, which leaves them at greater risk of on establishing new home ranges rather than on re- being killed.47 Females travel further than males, up production.34 Trophy hunting random individuals in to 40 km a day, in response to poaching pressure,47 the population does not consider these impacts and which may be energetically costly, result in loss of can further slow population growth. resources, and negatively affect survival. Poaching also decreases future population growth by altering In addition, hunting organizations also argue that age structures and reproductive rates.23,48 In Kruger “excess” older males can be removed as they no National Park, South Africa, a stronghold for black longer contribute to reproduction; however, there rhinos, the poaching rate is double the recruit- is no evidence that males stop reproducing in old ment rate.48 Poaching can also decrease population age. Hunting organizations argue that removing growth through suppressed recruitment, increased males from a population decreases injury or death calving intervals, and leaving orphaned calves.23 Af- due to male-male fighting. Yet, scientists say social ter only four years of heavy poaching pressure, the disruption that is not specifically planned based on black rhino population in Kruger National Park ex- rhino social networks will increase conflict.34 In ad- hibited a significantly different age structure and dition, scientists worry that lower population densi- a decrease in the proportion of calves.23 Poaching ties will result in fewer breeding opportunities and creates ecological traps, where prime habitat is also higher calf predation.23 Thus, trophy hunting can ac- associated with a high risk of poaching.49 These eco- tually have the opposite effect of what they claim. logical traps, in combination with poor recoloniza- Genetic diversity is the most important predictor tion behavior, means that poaching is likely to cause of male reproductive success; therefore, every in- local extinctions of black rhinos.49 dividual is important to the population. Low levels of genetic diversity across much of the black rhino’s Due to drastic population declines and small frag- range can be explained by the onset of trophy hunt- mented populations, each black rhino is important ing in the latter half of the 19th century.3 Relentless for maintaining genetic diversity, which is essential hunting throughout the 20th century also contrib- for reproductive success.29 In addition, because re- uted to large population declines.1 Further, trophy productive success is highly skewed, where select hunters are likely targeting the most important males are responsible for the majority of breeding, males given their preference for large horns, which offtake of these successful males would have dele- belong to the most dominant males.32 According to terious impacts on population growth.19 experts, “[c]urrent understanding of black rhinoc-

© 2021 Humane Society International 5 eros (Diceros bicornis) demography and population veterinarians, nature conservation officials, and oth- dynamics remains poor.”51 Therefore, allowing tro- ers are involved in the illicit ‘production’ and traf- phy hunting without adequate evidence and under- ficking of rhino horn.”42 Wildlife professionals have standing of how offtake will affect the species could also been involved in poaching rhinos.45 be detrimental to future survival. Critically Endangered species should not be tro- Due to their rarity, black rhino trophies fetch one phy hunted, especially when facing ongoing and in- of the highest prices of any species.52 However, creasing threats, such as poaching and habitat loss. considering the small population size and potential With such high levels of poaching and slow popu- negative impacts, there are serious concerns about lation growth, no levels of hunting offtake can be whether such a rare and Critically Endangered spe- considered sustainable, especially given such a poor cies should be hunted as a trophy. Further, the rarity understanding of demography and population dy- of the black rhino, and the high trophy fees, may in- namics.51 Management plans aim for 5% annual pop- centivize unsustainable trophy hunting. ulation growth; however, due to poaching, some of those targets have been lowered to 1%.54,55,56 If such Black rhinos may also be used in ‘put-and-take’ hunt- low population growth targets are not feasible, then ing, where animals from highly managed areas are trophy hunting should not be allowed to contribute released onto a property for the sole purpose of be- to the problem. In addition, maintenance of genetic ing immediately shot and then restocked again.45,53 diversity is critical in the face of severe population This often occurs in very unnatural settings, where declines and habitat fragmentation. Trophy hunters wildlife production units are too small to support and poachers target rhinos with the largest horns, self-sustaining wildlife populations.53 Offtake from which are also the most dominant males. Males ‘put-and-take’ is excessive and feeds into illegal reproductive success is highly variable, meaning trade.45 ‘Put-and-take’ hunting threatens biodiversi- that the most important breeding males could be ty due to disease transmission, genetic mixing, and removed, leaving less successful breeders. A long releasing subpar individuals.53 Experts say that this history of trophy hunting has been linked to loss of practice should be prohibited as it “compromise[s] vital genetic diversity.3 Removal of dominant males the principles of fair chase and the humane treat- with large horns removes important genetic diver- ment of animals.”53 By way of pseudo-hunting, ‘put- sity from the population that may be detrimental to and-take,’ and other loopholes, trophy hunting can future population growth. provide an avenue for illegal trade.42 Yet, some countries are increasing their trophy MANAGEMENT IMPLICATIONS hunting quotas for black rhinos. South Africa recently increased its quota from 5 individuals to 0.5% Black rhino populations have drastically declined of the population. Based on the most recent (2017) over the last 50 years, primarily due to illegal hunt- population estimates, that would double the num- ing for their horns and habitat loss. Poaching rhino ber of black rhinos hunted from 5 to 10 annually. for their horns is an organized crime problem, which This system requires extremely precise and current is very difficult to address without full government population counts, which are not available. In addi- support within and between range States.6 Prosecu- tion, management based on population size should tion of those engaged in rhino horn trafficking is im- also consider demographic factors. For example, proving; however, there are still problems with trial a high percentage of older individuals or a skewed postponements, granting bail, and light sentences sex ratio would indicate slowed future population for poachers and traffickers.6 growth, which would not be captured by simply counting individuals in the population. Therefore, Pseudo-hunting and ‘put-and-take’ hunting are at there are concerns about how this system will im- the nexus of legal and illegal markets.45 Both involve pact black rhino populations in the future.57 corruption by multiple agents that exploit regulatory loopholes and “belong to influential and trans- Despite arguments from hunting organizations, national social networks with links to political and there is no evidence that older males or females economic elites in supply, transit and consumer are redundant in the population. In fact, hunters are countries.”45 Beyond that, South African court cases likely targeting the most important males for pop- indicate that “rhino breeders, professional hunters, ulation growth, given their large horn size, social

© 2021 Humane Society International 6 dominance, and variability in reproductive success. radio telemetric study on the black rhinoceros Trophy hunting fees have not provided protection in Hluhluwe Game Reserve, Zululand. Proc. a for black rhinos as populations are still plummeting, Symp. Biotelemetry, Pretoria, 79–100. even in protected areas. Given that black rhino tro- 13. Linklater W.L. & Hutcheson I.R. (2010) Black rhi- phy fees are among the highest of all species, there noceros are slow to colonize a harvested neigh- should be some evidence of population protection bour’s range. African J. Wildl. Res. 40, 58–63. and recovery if trophy hunting were contributing 14. Odendaal-Holmes K. et al. (2014) Disturbance to conservation. There is also concern that trophy and habitat factors in a small reserve: space use hunting provides a legal pathway for trafficking black by establishing black rhinoceros (Diceros bicor- rhino horns and encouraging further poaching. nis). African J. Wildl. Res. 44, 148–160. 15. Linklater W.L. et al. (2010) Declining and low fe- REFERENCES cal corticoids are associated with distress, not acclimation to stress, during the translocation 1. Emslie R. (2020) Diceros bicornis. The IUCN of African rhinoceros. Anim. Conserv. 13, 104– Red List of Threatened Species. 8235, e. 111. T6557A152728945. 16. Patton F. et al. (2008) Biological management 2. Emslie R. (2020) Diceros bicornis. The IUCN of the high density black rhino population in Red List of Threatened Species - Supplemental. Solio Game Reserve, central Kenya. Pachyderm 3. Moodley Y. et al. (2017) Extinctions, genetic 44, 72–79. erosion and conservation options for the black 17. Balfour D. et al. (2019) Concise best practice rhinoceros (Diceros bicornis). Sci. Rep. 7, 1–16. guidelines for the biological management of Af- 4. Ceballos G. & Ehrlich P.R. (2002) Mammal pop- rican rhino. WWF-SA. 123pp. ulation losses and the extinction crisis. Science. 18. Alibhai S.K. et al. (2001) Effects of immobiliza- 296, 904–907. tion on fertility in female black rhino (Diceros 5. Ripple W.J. et al. (2015) Collapse of the world’s bicornis). J. Zool. 253, 333–345. largest herbivores. Sci. Adv. 1, e1400103. 19. Freeman E.W. et al. (2014) Impacts of environ- 6. Emslie R.H. et al. (2019) African and Asian Rhi- mental pressures on the reproductive physi- noceroses – Status, Conservation and Trade: A ology of subpopulations of black rhinoceros report from the IUCN Species Survival Com- (Diceros bicornis bicornis) in Addo Elephant mission (IUCN/SSC) African and Asian Rhino National Park, South Africa. Conserv. Physiol. 2, Specialist Groups and TRAFFIC to the CITES 1–13. Secretariat pursuant to Resolution Conf. 9.14 20. Nhleko Z.N. et al. (2017) The reproductive suc- (Rev. CoP17). In CoP18 Doc. 83.1 Annex 2. CITES cess of black rhinoceroses in the Hluhluwe–iM- Secretariat, Geneva, Switzerland. folozi Park, KwaZulu-Natal, South Africa. Koe- 7. Linklater W.L. et al. (2011) Guidelines for large doe 59, 1–10. herbivore translocation simplified: black rhi- 21. Hitchins P.M. & Anderson J.L. (1983) Reproduc- noceros case study. J. Appl. Ecol. 48, 493–502. tion, population characteristics and manage- 8. Linklater W.L. & Swaisgood R.R. (2008) Reserve ment of the black rhinoceros Diceros bicornis size, conspecific density, and translocation suc- minor in the Hluhluwe/Corridor/Umfolozi game cess for black rhinoceros. J. Wildl. Manage. 72, reserve complex. South African J. Wildl. Res. 13, 1059–1068. 78–85. 9. Linklater W.L. et al. (2012) Translocations as ex- 22. Owen-Smith R.N. (1988) Megaherbivores: the periments in the ecological resilience of an aso- influence of very large body size on ecology cial mega-herbivore. PLoS One 7. Cambridge University Press. 10. Adcock K. et al. (1998) Lessons from the intro- 23. le Roex N. & Ferreira S.M. (2020) Age structure duced black rhino population in Pilanesberg changes indicate direct and indirect population National Park. Pachyderm 26, 40–51. impacts in illegally harvested black rhino. PLoS 11. Lent P.C. & Fike B. (2003) Home ranges, move- One 15, e0236790. ments and spatial relationships in an expanding 24. Okita-Ouma B. et al. (2020) Relationships of re- population of black rhinoceros in the Great Fish productive performance indicators in black rhi- River Reserve, South Africa. African J. Wildl. noceros (Diceros bicornis michaeli) with plant Res. 33, 109–118. available moisture, plant available nutrients and 12. Hitchins P.M. (1971) Preliminary findings in a woody cover. Afr. J. Ecol., 1–15.

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