The aoudad (Ammotragus lervia Pallas 1777) is an ungulate species, native to the mountain ranges of North Africa. In the second half of the twentieth century, it was successfully introduced in some ...European countries, mainly for hunting purposes, i.e. in Croatia, the Czech Republic, Italy, and Spain. We used neutral genetic markers, the mitochondrial DNA control region sequence and microsatellite loci, to characterize and compare genetic diversity and spatial pattern of genetic structure on different timeframes among all European aoudad populations. Four distinct control region haplotypes found in European aoudad populations indicate that the aoudad has been introduced in Europe from multiple genetic sources, with the population in the Sierra Espuña as the only population in which more than one haplotype was detected. The number of detected microsatellite alleles within all populations (< 3.61) and mean proportion of shared alleles within all analysed populations (< 0.55) indicates relatively low genetic variability, as expected for new populations funded by a small number of individuals. In STRUCTURE results with K = 2-4, Croatian and Czech populations cluster in the same genetic cluster, indicating joined origin. Among three populations from Spain, Almeria population shows as genetically distinct from others in results, while other Spanish populations diverge at K = 4. Maintenance of genetic diversity should be included in the management of populations to sustain their viability, specially for small Czech population with high proportion of shared alleles (0.85) and Croatian population that had the smallest estimated effective population size (Ne = 5.4).
Abstract
Habitat fragmentation and loss have contributed significantly to the demographic decline of European wildcat populations and hybridization with domestic cats poses a threat to the loss of ...genetic purity of the species. In this study we used microsatellite markers to analyse genetic variation and structure of the wildcat populations from the area between the Dinaric Alps and the Scardo-Pindic mountains in Slovenia, Croatia, Serbia and North Macedonia. We also investigated hybridisation between populations of wildcats and domestic cats in the area. One hundred and thirteen samples from free-leaving European wildcats and thirty-two samples from domestic cats were analysed. Allelic richness across populations ranged from 3.61 to 3.98. The observed Ho values ranged between 0.57 and 0.71. The global F
ST
value for the four populations was 0.080 (95% CI 0.056–0.109) and differed significantly from zero (
P
< 0.001). The highest F
ST
value was observed between the populations North Macedonia and Slovenia and the lowest between Slovenia and Croatia. We also found a signal for the existence of isolation by distance between populations. Our results showed that wildcats are divided in two genetic clusters largely consistent with a geographic division into a genetically diverse northern group (Slovenia, Croatia) and genetically eroded south-eastern group (Serbia, N. Macedonia). Hybridisation rate between wildcats and domestic cats varied between 13% and 52% across the regions.
Hybridisation and gene introgression are important sources of diversification, the relevance of which in the evolutionary processes is well recognised. Their fitness consequences in animal ...populations, however, are not sufficiently well understood, despite hybridisation rates becoming increasingly important worldwide following human‐related activities such as domestication, game management and habitat alteration.
In Europe, the density and distribution of native ungulates have largely been influenced by humans since pre‐historic times. This, alongside the introduction of non‐native and domesticated species, may bear major consequences at the genetic and population levels. We provide an updated overview of recent hybridisation events in wild European ungulates; we describe their ecological drivers, extent, current distribution, potential consequences and proposed management strategies.
We reviewed the scientific literature published between 2000 and 2018 and found that confirmed hybridisation was described in 75 of the 89 references we included, involving nearly all the species that we investigated. Most researchers relied on genetic information for hybrid identification, which often involved a domestic counterpart. However, introductions and translocations also led to crossbreeding between wild ungulate (sub)species. Only 43 papers provided management recommendations, mostly focused on preventing hybridisation and removing hybrids.
Hybridisation proved to be relatively common in several ungulate taxa in Europe. Despite reported changes in phenotype and fitness‐related traits in some species, the consequences of hybridisation for adaptation, life history, and evolutionary potential remain largely unknown. The current conservation paradigm aims to prevent the spread of domestic or non‐native genes in native populations; accordingly, conservation plans should: 1) determine the genetic origin of possible source populations; 2) protect native populations from the risk of crossbreeding with non‐native ones, and 3) establish permanent monitoring.
The Dinaric Mountains in Slovenia, Croatia, and Bosnia and Herzegovina provide a unique system to address the effects of past hunting on the genetic structure of northern chamois (Rupicapra ...rupicapra) and possible hybridization in the contact zone in the Velebit Mountains. The northern Dinaric Mountains should be occupied by alpine chamois (Rupicapra rupicapra rupicapra), whereas the central and southern areas are inhabited by the Balkan chamois (R. rupicapra balcanica). This is the first study to characterize the genetic variation in chamois populations in the area. We used microsatellite and mitochondrial markers to analyze the genetic variation and structure of chamois populations from different geographical areas with different histories. Specifically, we explored the influence of recent human translocations and geographical isolation on the genetic architecture of chamois populations in the assumed contact zone. We successfully genotyped 74 individual samples and the number of alleles/locus ranged from 6 to 20 with a mean of 9.20. Allelic richness across populations ranged from 2.94 in the Prenj Mountains, Bosnia and Herzegovina to 3.56 in the Biokovo Mountains, Croatia. A similar pattern was also observed for heterozygosity, ranging between 0.729 and 0.572, and expected heterozygosity, ranging between 0.762 and 0.644 in the Prenj and Biokovo mountains, respectively. The global genetic distance (FST) for 7 population samples was 0.103 ±0.047 (range = 0.0156–0.185). The STRUCTURE tree clusters separated samples from the northern Dinaric Mountains from those of the southern Dinaric Mountains into 2 clusters according to geographic location. The results obtained using a Bayesian clustering methodology was similar. By using mtDNA variation in chamois from Slovenia, Croatia, and Bosnia and Herzegovina, the existence of alpine chamois haplotypes in northern areas and Balkan chamois haplotypes in southern areas was confirmed. These results confirm the impact of recent human management (i.e., translocation) into the Velebit Mountains, which established a new contact (hybridization) zone between the subspecies. Therefore, future translocations must be planned carefully to avoid compromising genetic integrity and posing a serious risk to native species, as in this case.
Abstract
Hybridization between wild animals and feral individuals from closely related domestic species can occur when they share the same habitat. Such events are generally regarded as a threat to ...the genetic integrity and survival of established wild populations. The aim of this study is to confirm a hybridization between European mouflon and feral sheep on the Adriatic island Dugi Otok, where a group of individuals phenotypically indicative of a possible introgression was photographed. Using an ovine medium-density SNP array genotypes, we provided genetic evidence of recent gene admixture between the two species. The ADMIXTURE analysis suggests that two hybrid individuals had 82.2% and 94.1% of their ancestry attributable to feral sheep, respectively, with the rest of the mouflon in origin. NEWHYBRIDS analysis estimated the combined probabilities for the putative hybrid individuals belonging to one of the hybrid classes at 87.0% and 90.1%, respectively. The main phenotypic differences in the hybrids were observed in the shape of the horns, a stronger horn circumference than in the mouflon and weaker than for the sheep, pronounced horn rings, a shorter tail, and intermediate color. We therefore recommend constant monitoring of the purity of the mouflon population to maintain its genetic integrity. In addition, all feral sheep should be removed from the wild, and released sheep raised in semi-wild conditions should be better controlled.
After a strong demographic decline before World War II, wild boar populations are expanding and the species is now the second-most abundant ungulate in Europe. This increase raises concerns due to ...wild boar impact on crops and natural ecosystems and as potential vector of diseases. Additionally, wild boar can hybridize with domestic pigs, which could increase health risks and alter wild boar adaptive potential. We analysed 47,148 Single Nucleotide Polymorphisms in wild boar from Europe (292) and the Near East (16), and commercial (44) and local (255) pig breeds, to discern patterns of hybridization across Europe. We identified 33 wild boars with more than 10% domestic ancestry in their genome, mostly concentrated in Austria, Bosnia and Herzegovina, Bulgaria and Serbia. This difference is probably due to contrasting practices, with free-ranging vs. industrial farming but more samples would be needed to investigate larger geographic patterns. Our results suggest hybridization has occurred over a long period and is still ongoing, as we observed recent hybrids. Although wild and domestic populations have maintained their genetic distinctiveness, potential health threats raise concerns and require implementation of management actions and farming practices aimed at reducing contact between wild and domestic pigs.
Methods for estimating population densities of unmarked species using camera traps are still under development. One such method is called ‘random encounter model (REM)’ and, to our knowledge, has ...never been used to estimate densities of mountain-dwelling ungulates. In this study, we tested the REM method to estimate the density of Balkan chamois (
Rupicapra r. balcanica
) in a Mediterranean habitat, Mt. Biokovo. To meet the assumptions of REM, we systematically placed 25 camera traps throughout the known range of the population (approximately 65 km
2
) at the intersections of 2-km grid cells. Prior to data collection, population density was estimated by visual counts on sample plots in August 2020. Cameras were operational between July 2020 and September 2020 and active throughout the 24-h period. All parameters for REM (i.e. average movement speed, angle and radius) were estimated using exclusively camera trap data. We obtained 279 independent events of chamois from 2503 camera trap days. The density estimate obtained by REM resulted to be 20.65 ± 5.27 ind. km
−2
, slightly higher than the reference value obtained by visual counts: 17.33 ± 0.98 ind. km
−2
. Other parameters required to calculate density were speed (1.62 km·day
−1
± 0.21), detection radius (5.56 m ± 0.21) and detection angle (1.16 + 0.05 radians). Therefore, REM has shown comparable results to visual counts and may have potential for estimating density of mountain ungulates, especially in rugged and inaccessible mountainous areas with low detectability where other approaches are inadequate or impossible.
Hepatozoon spp. are tick-borne parasites causing subclinical to clinical disease in wild and domestic animals. Aim of this study was to determine Hepatozoon prevalence and species distribution among ...wild mammals and ticks in Europe.
Samples of wild mammals and ticks, originating from Austria, Bosnia and Herzegovina, Croatia, Belgium and the Netherlands, were tested with PCR to amplify a ~ 670-bp fragment of the small subunit ribosomal RNA gene.
Of the 2801 mammal samples that were used for this study, 370 (13.2%) tested positive. Hepatozoon canis was detected in samples of 178 animals (3 Artiodactyla, 173 Carnivora, 1 Eulipotyphia, 1 Lagomorpha), H. martis in 125 (3 Artiodactyla, 122 Carnivora), H. sciuri in 13 (all Rodentia), Hepatozoon sp. in 47 (among which Hepatozoon sp. Vole isolate, all Rodentia) and H. ayorgbor in 4 (all Rodentia). Regarding origin, 2.9% (6/208) tested positive from Austria, 2.8% (1/36) from Bosnia and Herzegovina, 14.6% (173/1186) from Croatia and 13.9% (190/1371) from Belgium/the Netherlands. Of the 754 ticks collected, 0.0% (0/35) Hyalomma sp., 16.0% (4/25) Dermacentor spp., 0.0% (0/23) Haemaphysalis spp., 5.3% (24/50) Ixodes and 1.4% (3/221) Rhipicephalus spp. tested positive for Hepatozoon (4.2%; 32/754), most often H. canis (n = 22).
Hepatozoon canis is most present in mammals (especially in Carnivora such as gray wolves and golden jackals) and ticks, followed by H. martis, which was found merely in stone martens and pine martens. None of the rodent-associated Hepatozoon spp. were detected in the ticks, suggesting the possible implication of other arthropod species or non-vectorial routes in the transmission cycle of the hemoprotozoans in rodents. Our findings of H. canis in ticks other than R. sanguineus add to the observation that other ticks are also involved in the life cycle of Hepatozoon. Now that presence of Hepatozoon has been demonstrated in red foxes, gray wolves, mustelids and rodents from the Netherlands and/or Belgium, veterinary clinicians should be aware of the possibility of spill-over to domestic animals, such as dogs.
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