Endangered Greater One‐horned Rhinoceros Carry High Levels of Genetic Variation

Dinerstein, Eric; McCracken, Gary F.

doi:10.1111/j.1523-1739.1990.tb00316.x

Cited by 96 publications

(69 citation statements)

References 27 publications

(40 reference statements)

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“…Most endangered species have less genetic diversity than related nonendangered species (see references above; D. Spielman, B.W. Brook, and R. Frankham, unpublished data), although there are a few examples, e.g., the Indian rhinoceros (Dinerstein and McCracken 1990), that do not fit this general pattern. Because the proportionate loss of heterozygosity equals the inbreeding coefficient (Falconer and Mackay 1996), most endangered species are already inbred.…”

Section: Discussionmentioning

confidence: 84%

Contribution of Inbreeding to Extinction Risk in Threatened Species

Brook¹,

Tonkyn²,

O’Grady³

et al. 2002

212

189

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ABSTRACT. Wild populations face threats both from deterministic factors, e.g., habitat loss, overexploitation, pollution, and introduced species, and from stochastic events of a demographic, genetic, and environmental nature, including catastrophes. Inbreeding reduces reproductive fitness in naturally outbreeding species, but its role in extinctions of wild populations is controversial. To evaluate critically the role of inbreeding in extinction, we conducted realistic population viability analyses of 20 threatened species, with and without inbreeding depression, using initial population sizes of 50, 250, and 1000. Inbreeding markedly decreased median times to extinction by 28.5, 30.5, and 25% for initial populations of 50, 250, and 1000, respectively, and the impacts were similar across major taxa. The major variable explaining differences among species was initial population growth rate, whereas the impact of inbreeding was least in species with negative growth rates. These results demonstrate that the prospects for survival of threatened species will usually be seriously overestimated if genetic factors are disregarded, and that inappropriate recovery plans may be instituted if inbreeding depression is ignored.

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Section: Discussionmentioning

confidence: 84%

Contribution of Inbreeding to Extinction Risk in Threatened Species

Brook¹,

Tonkyn²,

O’Grady³

et al. 2002

212

189

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“…Some studies of small populations found no obvious losses. The Indian rhinoceros Rhinoceros unicornis was such a study (Dinerstein & McCracken, 1990). Many studies inferred low population size and impending declines from low genetic variability without providing population data to support the association (Pimm et al, 1989).…”

Section: General Arguments For and Against Rescuementioning

confidence: 99%

The genetic rescue of the Florida panther

Pimm

Dollar

Bass

2006

Animal Conservation

167

180

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We examine the consequences of panthers introduced from Texas into south Florida, an area housing a small, isolated, inbred and distinct subspecies (Puma concolor coryi). Once part of a continuous, widespread population, panthers became isolated in south Florida more than a century ago. Numbers declined and the occurrence of genetic defects increased. Hoping to reverse the genetic damage, managers introduced eight female panthers from Texas into south Florida in the mid-1990s. This action was highly controversial and we explain the arguments for and against the intervention. We synthesized data systematically collected on the Florida panthers from before, during and after this management intervention. These data include information on movements, breeding, mortality, survivorship and range. There is no evidence that purebred Florida females produce fewer kittens at a later age or less often than do hybrid cats (i.e. those with a Texas ancestor). Hybrid kittens have about a three times higher chance of becoming adults as do purebred ones. Hybrid adult females survive better than purebred females; there is no obvious difference between the males. Males die younger than females, are more often killed by other males and are more likely to disperse longer distances into habitats that are dangerous to them. Hybrids are expanding the known range of habitats panthers occupy and use.

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“…1400 AD), the Indian rhinoceros occurred along flood plains from northwestern Burma, across the Gangetic Plain, to the Indus River Valley in northern Pakistan (Blanford 1891;Laurie 1979;Rookmaaker 2000). Since the nineteenth century, land clearings fragmented the habitat and hunting reduced the populations, eliminating the Indian rhinoceros from all areas except the Chitwan Valley, lowland Bhutan, the Teesta Valley, West Bengal, and the Brahmaputra Valley in Assam (Dinerstein and McCracken 1990;Rookmaaker 1999). The population in the Brahmaputra Valley, Assam, was further reduced in the following decades, and in 1908, when hunting was banned, probably fewer than 20 individuals were left in the area of today's Kaziranga National Park (Ryhiner 1961;Laurie et al 1983;Molur et al 1995).…”

Section: Introductionmentioning

confidence: 99%

Inbreeding, outbreeding, infant growth, and size dimorphism in captive Indian rhinoceros (Rhinoceros unicornis)

Zschokke¹,

Baur²

2002

Can. J. Zool.

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Effects of inbreeding and outbreeding on gestation period, birth mass, infant mortality, and growth, as well as the ontogeny of sexual size dimorphism, were analyzed in captive Indian rhinoceros (Rhinoceros unicornis L., 1758) using studbook data. Neither gestation period nor birth mass were affected by inbreeding. However, inbred calves grew slower and had a lower mortality rate than non-inbred ones. It is suggested that the severe bottleneck experienced in the early twentieth century by the Kaziranga population, from which most captive-born Indian rhinoceroses descend, resulted in strong inbreeding with consequent purging of recessive lethal alleles. Outbred individuals (offspring of matings between individuals from the Kaziranga and the Chitwan populations) had a higher infant mortality rate, suggesting that the two populations are genetically partially incompatible. Among captive individuals, adult males were found to be heavier (2300 kg) and larger (shoulder height = 172 cm) than females (1800 kg, 160 cm). There were, however, no sex differences in gestation period, birth mass, or infant growth. This suggests that sexual dimorphism in adults is the result of a longer growth period in males rather than a difference in growth rate between the sexes.Résumé : Nous avons tenté de déterminer, à l'aide du registre généalogique des animaux, les effets de l'endogamie et de l'exogamie sur la période de gestation, la masse à la naissance, la mortalité infantile et la croissance, de même que sur l'ontologie du dimorphisme sexuel de la taille chez des rhinocéros des Indes (Rhinoceros unicornis L., 1758) gardés en captivité. L'endogamie s'est révélée sans effet sur la période de gestation ou sur la masse des petits à la naissance. Cependant, les jeunes rhinocéros consanguins se développent plus lentement et ont un taux de mortalité moins élevé que celui des animaux non consanguins. Nous croyons que l'étranglement qui s'est produit chez la population de Kaziranga au début du vingtième siècle a eu pour résultat une forte endogamie qui a épuré la population de ses allèles récessifs létaux. Les animaux obtenus par exogamie (fécondation croisée d'animaux de la population de Kaziranga et de celle de Chitwan) ont des taux de mortalité infantile plus élevés, ce qui semble indiquer que ces deux populations sont en partie génétiquement incompatibles. Parmi les animaux en captivité, les mâles adultes se sont avérés plus lourds (2300 kg) et plus grands (hauteur au garrot = 172 cm) que les femelles (1800 kg, 160 cm). Cependant la durée de la gestation, la masse à la naissance et la croissance infantile sont semblables chez les mâles et les femelles. Cela semble indiquer que le dimorphisme sexuel chez les adultes est attribuable à la durée plus longue de la période de croissance des mâles plutôt qu'à une différence de taux de croissance entre mâles et femelles. [Traduit par la Rédaction] 2023Zschokke and Baur

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Endangered Greater One‐horned Rhinoceros Carry High Levels of Genetic Variation

Abstract: Abstract:The population of Rhinoceros unicornis in the Chitwan Valley, Nepal, was reduced to an estimated effective population size

Cited by 96 publications

References 27 publications

Contribution of Inbreeding to Extinction Risk in Threatened Species

Contribution of Inbreeding to Extinction Risk in Threatened Species

The genetic rescue of the Florida panther

Inbreeding, outbreeding, infant growth, and size dimorphism in captive Indian rhinoceros (Rhinoceros unicornis)

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