Comparative parasitological examination on sympatric equids in the Great Gobi “B” Strictly Protected Area,Mongolia

The Przewalski’s horse (Equus caballus przewalskii) became extinct in the wild during the 1960s. Based on a successful captive breeding program, Przewalski’s horses were reintroduced to the Great Gobi Part “B” strictly protected area (SPA) in SW Mongolia in the late 1990s. The Asiatic wild ass (Equus hemionus hemionus), Przewalski’s horse, and sometimes domestic horses live sympatricly in the Gobi B SPA. Previously published data demonstrates that, as a result of their different requirements and utilization of the park’s resources, their home-range size and social structure differ. Parasitological examinations in the three equid species show how the factors “home range, social structure, and resource selection” significantly impact parasitic burden. Asiatic wild asses are potentially exposed to a higher risk of parasite re-infection due to their temporal aggregation in very large groups. This study demonstrates a highly significant greater parasite load in the Asiatic wild ass for the majority of parasites evaluated (Dictyocaulus arnfieldi, Trichostrongylus axei, Strongyloides westeri, Parascaris equorum) compared to Przewalski’s horses and domestic horses in the same habitat. Domestic horses had higher parasite loads for eggs of strongylids, eggs of anoplocephalidae, and Eimeria leuckarti. The potential risk of cross infection between sympatric living equids is high, as is the cross infection between ruminants and equids. Furthermore, this study reports for the first time the occurrence of lungworms in free-ranging Przewalski’s horses. Whereas, Asiatic wild asses and Przewalski’s horses seem to cope very well with the sometimes high parasite burden, Mongolian domestic horses manifested typical parasite burden symptoms.     

Characterization of a novel variant of amino acid transport system asc in erythrocytes from Przewalski's horse (Equus przewalskii).

In thoroughbred horses, red blood cell amino acid transport activity is Na(+)-independent and controlled by three codominant genetic alleles (h, l, s), coding for high-affinity system asc1 (L-alanine apparent Km for influx at 37 degrees C congruent to 0.35 mM), low-affinity system asc2 (L-alanine Km congruent to 14 mM), and transport deficiency, respectively. The present study investigated amino acid transport mechanisms in red cells from four wild species: Przewalski's horse (Equus przewalskii), Hartmann's zebra (Zebra hartmannae), Grevy's zebra (Zebra grevyi), and onager (Equus hemonius). Red blood cell samples from different Przewalski's horses exhibited uniformly high rates of L-alanine uptake, mediated by a high-affinity asc1-type transport system. Mean apparent Km and Vmax values (+/- SE) for L-alanine influx at 37 degrees C in red cells from 10 individual animals were 0.373 +/- 0.068 mM and 2.27 +/- 0.11 mmol (L cells.h), respectively. As in thoroughbreds, the Przewalski's horse transporter interacted with dibasic as well as neutral amino acids. However, the Przewalski asc1 isoform transported L-lysine with a substantially (6.4-fold) higher apparent affinity than its thoroughbred counterpart (Km for influx 1.4 mM at 37 degrees C) and was also less prone to trans-stimulation effects. The novel high apparent affinity of the Przewalski's horse transporter for L-lysine provides additional key evidence of functional and possible structural similarities between asc and the classical Na(+)-dependent system ASC and between these systems and the Na(+)-independent dibasic amino acid transport system y+. Unlike Przewalski's horse, zebra red cells were polymorphic with respect to L-alanine transport activity, showing high-affinity or low-affinity saturable mechanisms of L-alanine uptake. Onager red cells transported this amino acid with intermediate affinity (apparent Km for influx 3.0 mM at 37 degrees C). Radiation inactivation analysis was used to estimate the target size of system asc in red cells from Przewalski's horse. The transporter's in situ apparent molecular weight was 158,000 +/- 2500 (SE).     

Molecular phylogeny and evolution of the Perissodactyla

The evolution of perissodactyls (rhinoceroses, tapirs, and horses) has been well studied primarily because of their extensive fossil record. Nevertheless, controversy persists regarding relationships of some of the extant taxa, reflecting inconsistencies between molecular and morphological studies. Here we examine the phylogenetic relationships of 16 living perissodactyl species by concatenating two mitochondrial and nine nuclear genes, and we estimate their divergence times using a relaxed Bayesian molecular clock approach. Our analyses recovered the monophyly of the suborders Ceratomorpha and Hippomorpha, and the families Rhinoceratidae, Tapiridae, and Equidae. We supported the early divergence of the Indian rhinoceros in the late Oligocene (26 Mya) relative to the Sumatran and African rhinoceroses, and the split of caballine (domestic horse and Przewalski's wild horse) and noncaballine equids (zebras and African and Asiatic asses) in the Pliocene (4 Mya). An important implication of this study is that Equus asinus, the African wild ass was found to be the sister taxon of Asiatic asses and zebras, diverging from the common ancestor with caballine horses 2 Mya. Rates of chromosome rearrangements were also evaluated in perissodactyls, placing a notably high rate of variation amongst equids, particularly within the zebra clade. The robust phylogenetic results presented here are relevant in terms of understanding the evolutionary history of this highly threatened group of mammals. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163 , 1289–1303.     

Effects of grazing by re-introduced Equus hemionus on the vegetation in a Negev desert erosion cirque

Abstract. Asiatic wild asses, Equus hemionus, were driven to extinction in Israel in the early 20th century. In 1983, a herd of these animals was re-introduced to the wild in Makhtesh Ramon, a large erosion cirque in the central Negev desert, Israel. The population has grown steadily ever since and now numbers some 100 animals. In order to determine whether the wild asses are having a significant impact on the vegetation, we have monitored the plant communities in Makhtesh Ramon since 1992, using McAuliffe's log-series survey method. Our study involves 11 pairs of plots along the length of the altitudinal gradient in Makhtesh Ramon. The altitudinal gradient results in a rainfall gradient from an average of 95 mm rain per year to an average of about 40 mm per year. Each pair of plots consists of: (1) an unfenced plot, and (2) a fenced plot that excludes wild asses but not the other large mammalian herbivore, the dorcas gazelle Gazella dorcas. The wild asses have not had a significant impact on vegetation cover, species richness, diversity or dominance. Three plant species showed significant increases in percentage cover in fenced plots, while one species showed a significant increase in percentage cover in unfenced plots. Furthermore, eight plant species invaded fenced plots, three species invaded unfenced plots and one species disappeared from unfenced plots during the study. Using Detrended Correspondence Analysis, we found that the major differences among plots are due to position along the altitudinal gradient. The Detrended Correspondence Analyses indicated that the wild asses have had no significant effect on vegetation community structure.     

Equine piroplasmoses at the reintroduction site of the Przewalski's horse (Equus ferus przewalskii) in Mongolia

Piroplasmosis has been identified as a possible cause of mortality in reintroduced Przewalski's horses (Equus ferus przewalskii) in the Dsungarian Gobi (Mongolia). A cross-sectional and a longitudinal study were conducted in a representative sample (n = 141) of the resident domestic horse population and in 23 Przewalski's horses to assess the prevalence of Theileria equi and Babesia caballi. Piroplasms were detected in blood by light microscopy in 6.7% (95% confidence interval [CI]: 3.6-12.2%) of the domestic horse samples. Antibody prevalence was 88.6% (95% CI: 82.4-92.9%) for T. equi and 75.2% (95% CI: 67.4-81.6%) for B. caballi. Antibody prevalence did not change over time, but antibody prevalence for both piroplasms were significantly lower in animals less than 1 yr of age. For both piroplasms, the prevalence of presumably maternal antibodies (falling titers) in foals was 100%. Only one of 16 foals seroconverted against T. equi during the study period, despite that piroplasms were found in two other individuals. The incidence density (ID) of T. equi in foals was therefore 0.0012 seroconversions per horse day (95% CI: 0.00029-0.0057). In contrast, yearlings had an ID of 0.0080 (95% CI: 0.0049-0.010) for T. equi and 0.0064 (95% CI: 0.0036-0.0093) for B. caballi, and in seven individuals piroplasms were detected. The seroprevalence of both piroplasms rose from 20% in spring to 100% in autumn. Comparison of domestic and Przewalski's horses resulted in a standardized prevalence ratio (SPR) of 0.98 (95% CI: 0.80-1.24, not significant) for B. caballi; in contrast, the prevalence of T. equi in Przewalski's horses was significantly lower than expected (SPR = 0.51, 95% CI: 0.50-0.64).     

Hemoglobin polymorphism in Equus przewalskii and E. caballus analyzed by isoelectric focusing.

1. Through the use of isoelectric focusing and peptide analysis, the hemoglobins of Przewalski's horse. Equus przewalskii and the domestic horse, E. caballus have been compared. 2. Przewalski's horses have two separate alpha-globin chain polymorphisms similar to domestic horses. Each hemoglobin phenotype could be accurately determined by isoelectric focusing. 3. Confirmation of the electrofocusing hemoglobin determinations was made by comparison to amino acid composition analyses of purified tryptic peptides and by analysis of the rare hemoglobins phenotypes observed in a family of Norwegian trotting horses. 4. Hemoglobin genotypes of fifteen Przewalski's horses were determined and inheritance of hemoglobin haplotypes has been observed.     

Horse domestication and conservation genetics of Przewalski's horse inferred from sex chromosomal and autosomal sequences

Despite their ability to interbreed and produce fertile offspring,there is continued disagreement about the genetic relationshipof the domestic horse (Equus caballus) to its endangered wildrelative, Przewalski's horse (Equus przewalskii). Analyses havediffered as to whether or not Przewalski's horse is placed phylogeneticallyas a separate sister group to domestic horses. Because Przewalski'shorse and domestic horse are so closely related, genetic datacan also be used to infer domestication-specific differencesbetween the two. To investigate the genetic relationship ofPrzewalski's horse to the domestic horse and to address whetherevolution of the domestic horse is driven by males or females,five homologous introns (a total of 3 kb) were sequenced onthe X and Y chromosomes in two Przewalski's horses and threebreeds of domestic horses: Arabian horse, Mongolian domestichorse, and Dartmoor pony. Five autosomal introns (a total of6 kb) were sequenced for these horses as well. The sequencesof sex chromosomal and autosomal introns were used to determinenucleotide diversity and the forces driving evolution in thesespecies. As a result, X chromosomal and autosomal data do notplace Przewalski's horses in a separate clade within phylogenetictrees for horses, suggesting a close relationship between domesticand Przewalski's horses. It was also found that there was alack of nucleotide diversity on the Y chromosome and highernucleotide diversity than expected on the X chromosome in domestichorses as compared with the Y chromosome and autosomes. Thissupports the hypothesis that very few male horses along withnumerous female horses founded the various domestic horse breeds.Patterns of nucleotide diversity among different types of chromosomeswere distinct for Przewalski's in contrast to domestic horses,supporting unique evolutionary histories of the two species.     

Wolf Predation Among Reintroduced Przewalski Horses in Hustai National Park,Mongolia

ABSTRACT Depredation by wolves (Canis lupus) could threaten survival of reintroduced wild Przewalski horses (Equus ferus przewalskii) in Hustai National Park (HNP), Mongolia. We conducted scat analysis, spatial analyses of kills, and interviews to study prey species selection and temporal and spatial factors that characterize prey choices of wolves. Diet of wolves in HNP was comprised of >50% of livestock. Diet composition varied during the year, with more livestock taken in winter. Wildlife species were selected over livestock species. From available livestock species domestic horses were predated most, whereas red deer (Cervus elaphus) and marmot (Marmota sibirica) were the preferred wildlife species. Our spatial analyses showed an unexpected significant positive relation between number of domestic horses killed and distance to the park, as well as a significant negative relation with number of gers (tents) in the area. Compared to randomly selected comparison sites (n = 36), we found Przewalski foal kills (n = 36) at sites that were closer to the forest, at higher altitudes, with lower shrub cover, higher forest cover, and higher red deer density. If the negative trend of deer numbers continues and if herdsmen protect their livestock more vigorously, depredation of wild Przewalski horses by wolves will rise. Therefore, a large red deer population could be pivotal in improving the conservation status of Przewalski horses.     

记大连晚更新世马属一新种

本文记述在大连复县古龙山洞穴堆积中发现的马属 (Epuus) 的—新种 (E. dalianensis sp. nov). 它是晚更新世的一种大型马类,曾广泛地分布于中国北方.     

Fragmentation of the Habitat of Wild Ungulates by Anthropogenic Barriers in Mongolia

Habitat loss and habitat fragmentation caused by anthropogenic activities are the main factors that constrain long-distance movement of ungulates. Mongolian gazelles (Procapra gutturosa) and Asiatic wild asses (Equus hemionus) in Mongolia are facing habitat fragmentation and loss. To better understand how their movements respond to potential anthropogenic and natural barriers, we tracked 24 Mongolian gazelles and 12 wild asses near the Ulaanbaatar–Beijing Railroad and the fenced international border between Mongolia and China between 2002 and 2012. None of the tracked gazelles crossed the railroad, even though gazelles were captured on both sides of the tracks at the start of the study. Similarly, we did not observe cross-border movements between Mongolia and China for either species, even though some animals used areas adjacent to the border. The both species used close areas to the anthropogenic barriers more frequently during winter than summer. These results suggest strong impacts by the artificial barriers. The construction of new railroads and roads to permit mining and other resource development therefore creates the threat of further habitat fragmentation, because the planned routes will divide the remaining non-fragmented habitats of the ungulates into smaller pieces. To conserve long-distance movement of the ungulates in this area, it will be necessary to remove or mitigate the barrier effects of the existing and planned roads and railroads and to adopt a landscape-level approach to allow access by ungulates to wide ranges throughout their distribution.     

Genetic studies of blood markers in Przewalski's horses

Ninety-six Przewalski's horses (Equus przewalskii) were blood typed using systems of inherited blood variants known to be highly effective for parentage testing of domestic horses (E. caballus). Sixteen red cell antigenic factors detected using sera prepared by alloimmunization of domestic horses were shown to be inherited in six systems (A, C, D, P, Q, and U) and in the same patterns as domestic horses. Family data confirmed autosomal, codominant inheritance at five loci of serum protein variants (Al, Tf, Xk, Pi, and Es) and three loci of red cell proteins (PGM, PHI, and Hb). One serum protein locus (Gc) and two red cell protein loci (PGD and CA) appeared to be monomorphic. Despite the narrow genetic base and high inbreeding coefficients of captive Przewalski's horses, average heterozygosity calculated over 18 loci was estimated to be 0.320 +/- 0.05, which was similar to that found in five breeds of domestic horses.     

Genetic characterization of free-ranging Asiatic wild ass in Central Asia as a basis for future conservation strategies

Loss of genetic diversity due to drift and inbreeding reduces a population’s ability to respond to environmental change and may result in inbreeding depression. The Asiatic wild ass (Equus hemionus), regionally also known as Gobi khulan, Turkmen kulan, or Persian onager, has become confined to less than 3% of its historic distribution range. Remaining populations in Central Asia outside of the Mongolian Gobi are small and fragmented. Questions concerning subpopulation status remain disputed and concerns over the viability of these populations have been raised because of small size, past bottlenecks, or recent founder events. We used non-invasive faecal samples to assess the genetic diversity and divergence among Turkmen kulan and Persian onager from five free-ranging and one captive population from Turkmenistan, Kazakhstan and Iran and compared their genetic constitution to the large autochthonous population in the Mongolian Gobi. We observed loss of genetic diversity (drift and inbreeding) in the captive and reintroduced populations as well as in one rapidly declining autochthonous population. Population differentiation and structure using microsatellites and mtDNA based phylogenetic analysis do not support the current separation of the autochthonous populations of Turkmen kulan and Persian onager into different subspecies, but rather suggest a cline with the Iranian population in Bahram-e-Goor at the southern end and the Turkmen population in Badhyz at the northern end falling into two distinct clusters, and the northern Iranian population in Touran being intermediate. We compare our findings to other population genetics studies of equids and discuss the implications of our findings for the future conservation of the Asiatic wild ass in the region.     

Genetic variation in Przewalski's horses, with special focus on the last wild caught mare, 231 Orlitza III

In our continuing efforts to document genetic diversity in Przewalski's horses and relatedness with domestic horses, we report genetic variation at 22 loci of blood group and protein polymorphisms and 29 loci of DNA (microsatellite) polymorphisms. The loci have been assigned by linkage or synteny mapping to 20 autosomes and the X chromosome of the domestic horse (plus four loci unassigned to a chromosome). With cumulative data from tests of 568 Przewalski's horses using blood, hair or tooth samples, no species-defining markers were identified, however a few markers were present in the wild species but not in domestic horses. Inheritance patterns and linkage relationships reported in domestic horses appeared to be conserved in Przewalski's horses. A derived type for the last wild caught mare 231 Orlitza III provided evidence for markers apparently not found in (or not currently available by descent from) the other species founders that were captured at the end of the nineteenth century. This information has been critical to the development of parentage analyses in the studbook population of Przewalski's horses at Askania Nova, at one time the largest herd of captive animals and the source of stock for reintroduction efforts. Some horses in the study showed genetic incompatibilities with their sire or dam, contradicting published studbook information. In many cases alternative parentage could be assigned from living animals. To assist in identification of correct parentage, DNA marker types for deceased horses were established from archived materials (teeth) or derived from offspring. Genetic markers were present in pedigreed animals whose origin could not be accounted for from founders. Genetic distance analysis of erythrocyte protein, electrophoretic and microsatellite markers in Przewlaski's horses and ten breeds of domestic horse place the Przewalski's horse as an outgroup to domestic horses, introgression events from domestic horses not withstanding.     

First assessment of the population structure of the Asiatic wild ass in Mongolia

The Mongolian Gobi is the most important stronghold of the Asiatic wild ass (Equus hemionus), housing >?75% of the remaining global population. However, even in this remote refuge, poaching and changes in land use are challenging the species’ conservation. Whereas progress has been made in monitoring population size, little data are available on population structure and dynamics. To fill this gap, we determined the age and sex of 440 skulls collected in two regions of the Mongolian Gobi. Foals and yearlings were underrepresented in our skull sample with 3 and 7.3% only, but the rest of the age pyramid was well balanced. The mean age was 7.7 years, the maximum age 29 years, and the sex ratio was not different from even. Mortality risk analysis revealed low annual mortality rates of about 15% in the most productive age classes of 5–10 years, followed by a slow increase with age until about 17 years and a likely faster increase thereafter. As the large majority of carcasses suggested a poaching-related mortality which appears random, our dataset provides the first insight into the structure of the largest remaining Asiatic wild ass population and can be used as a benchmark for future monitoring and population viability modeling.     

马科在中国的分布与现状

蒙古野驴(Asinus h．hemionus)分布于内蒙和甘肃西北角、新疆东北部至准噶尔盆地西部。1982年航调,卡拉麦里山保护区内有356头,O.02头／平方公里;1986年调查为O.03头／平方公里。估计目前我国境内不超过2000头。西藏野驴(Asinus k.kiang)分布于西藏西部、新疆南缘山地;A.k.holdereri分布于除湟水河谷外青海全境、四川西北角、甘肃祁连山。1984年调查,阿尔金山保护区内有41,262头,0.917头／平方公里。估计我国境内种群约在20万头上。多年考察未发现野马(Equus przewalskii),目前可能在北塔山以东尚有少数残存。     

The case of an arctic wild ass highlights the utility of ancient DNA for validating problematic identifications in museum collections

Museum collections are essential for reconstructing and understanding past biodiversity. Many museum specimens are, however, challenging to identify. Museum samples may be incomplete, have an unusual morphology, or represent juvenile individuals, all of which complicate accurate identification. In some cases, inaccurate identification can lead to false biogeographic reconstructions with cascading impacts on paleontological and paleoecological research. Here, we analyzed an unusual Equid mandible found in the Far North of the Taymyr peninsula that was identified morphologically as Equus hemionus, an ancestor of present‐day Asiatic wild asses. If correct, this identification represents the only finding of a putative Late Pleistocene hemione in the Arctic region, and is therefore critical to understanding wild ass evolution and paleoecology. To confirm the accuracy of this specimen's taxonomic assignment, we used ancient DNA and mitochondrial hybridization capture to identify and place this specimen in the larger equid phylogeny. We find that the specimen is actually a member of E. caballus, the ancestor of domestic horses. Our study demonstrates the utility of ancient DNA to validate morphological identification, in particular of incomplete, otherwise problematic, or taxonomically unusual museum specimens.     

Molecular phylogeny of extant equids and effects of ancestral polymorphism in resolving species-level phylogenies

Short divergence times and processes such as incomplete lineage sorting and species hybridization are known to hinder the inference of species-level phylogenies due to the lack of sufficient informative genetic variation or the presence of shared but incongruent polymorphism among taxa. Extant equids (horses, zebras, and asses) are an example of a recently evolved group of mammals with an unresolved phylogeny, despite a large number of molecular studies. Previous surveys have proposed trees with rather poorly supported nodes, and the bias caused by genetic introgression or ancestral polymorphism has not been assessed. Here we studied the phylogenetic relationships of all extant species of Equidae by analyzing 22 partial mitochondrial and nuclear genes using maximum likelihood and Bayesian inferences that account for heterogeneous gene histories. We also examined genetic signatures of lineage sorting and/or genetic introgression in zebras by evaluating patterns of intraspecific genetic variation. Our study improved the resolution and support of the Equus phylogeny and in particular the controversial positions of the African wild ass (E. asinus) and mountain zebra (E. zebra): the African wild ass is placed as a sister species of the Asiatic asses and the mountain zebra as the sister taxon of Grevy's and Burchell's zebras. A shared polymorphism (indel) detected among zebra species in the Estrogen receptor 1 gene was likely due to incomplete lineage sorting and not genetic introgression as also indicated by other mitochondrial (Cytochrome b) and nuclear (Y chromosome and microsatellites) markers. Ancestral polymorphism in equids might have contributed to the long-standing lack of clarity in the phylogeny of this highly threatened group of mammals.     

The forgotten donkey's history. Remarks on African wild asses of the Giardino Zoologico in Rome and their relevance for Equus africanus (von Heuglin & Fitzinger, 1866) taxonomy and conservation

This paper reviews the history of African wild asses in the Giardino Zoologico of Rome, highlighting their relevance to taxonomy of Equus africanus (von Heuglin & Fitzinger, 1866). Specifically, it is demonstrated that the so-called Munich/Catskill stock of African wild ass originated from three animals imported in Rome from Eritrean Danakil in August 1932. Available evidence suggests that contrary to some recent statements, these ‘wild’ asses were not related to the Nubian wild ass and are better considered as the result of some intergradations between Somali wild asses and local Danakil donkeys.     

Can a spider web be too sticky? Tensile mechanics constrains the evolution of capture spiral stickiness in orb-weaving spiders

Owing to habitat loss and fragmentation, large mammal populations all over the world are becoming increasingly small and isolated. It is therefore a conservation priority to understand mechanisms influencing the demography of such populations, which can easily be driven to extinction. The Przewalski's horse Equus ferus przewalskii remains one of the world's most endangered species and reintroduced animals are still vulnerable. Over 9 years, we analysed factors affecting mortality and female fecundity at the individual level in a predator-free, closed population of Przewalski's horses, which grew from 11 to 55 individuals. Similar to other wild equids, the annual growth rate of the population was r =0.169. Typically, adult mortality was much lower than juvenile mortality, the latter being correlated with neither inbreeding coefficient of foals nor population density. We found no link between female fecundity and operational sex ratio of the herd, or inbreeding coefficient, lactation status and body condition of the mares. Although food therefore seemed not to be limiting in this population, density (number of horses ha⁻¹) clearly reduced fecundity, especially in subadult mares. Thus, our results show that space can slow the growth rate of a population before resources become limited, a potential source of concern for increasingly shrinking habitats of endangered large mammals. Possible mechanisms causing this may be found in incest avoidance or other social parameters. Finally, in large herbivores, population density is said to exert influence in a sequential order: juvenile survival first, followed by fecundity of young females, then adult females, and adult survival last. Although we observed no link between density and juvenile survival in the studied population, our results otherwise support this hypothesis.     

Stochastic modelling of shifts in allele frequencies reveals a strongly polygynous mating system in the re‐introduced Asiatic wild ass

Small populations are prone to loss of genetic variation and hence to a reduction in their evolutionary potential. Therefore, studying the mating system of small populations and its potential effects on genetic drift and genetic diversity is of high importance for their viability assessments. The traditional method for studying genetic mating systems is paternity analysis. Yet, as small populations are often rare and elusive, the genetic data required for paternity analysis are frequently unavailable. The endangered Asiatic wild ass (Equus hemionus), like all equids, displays a behaviourally polygynous mating system; however, the level of polygyny has never been measured genetically in wild equids. Combining noninvasive genetic data with stochastic modelling of shifts in allele frequencies, we developed an alternative approach to paternity analysis for studying the genetic mating system of the re‐introduced Asiatic wild ass in the Negev Desert, Israel. We compared the shifts in allele frequencies (as a measure of genetic drift) that have occurred in the wild ass population since re‐introduction onset to simulated scenarios under different proportions of mating males. We revealed a strongly polygynous mating system in which less than 25% of all males participate in the mating process each generation. This strongly polygynous mating system and its potential effect on the re‐introduced population's genetic diversity could have significant consequences for the long‐term persistence of the population in the Negev. The stochastic modelling approach and the use of allele‐frequency shifts can be further applied to systems that are affected by genetic drift and for which genetic data are limited.