Przewalski's Horse (Equus ferus przewalskii) Re-introduction in the Great Gobi B Strictly Protected Area: from Species to Ecosystem Conservation

The genome of Przewalski's horse (Equus ferus przewalskii)

The Przewalski's horse (Equus ferus przewalskii) is an endangered equid native to the steppes of central Asia. After becoming extinct in the wild, multiple conservation efforts convened to preserve the species including captive breeding programs, reintroduction and monitoring systems, protected lands, and cloning. Availability of a highly contiguous reference genome is essential to support these continued efforts. We used Oxford Nanopore sequencing to produce a scaffold-level 2.5 Gb nuclear assembly and 16,002 bp mitogenome from a captive Przewalski's mare. All assembly drafts were generated from 111 Gb of sequence from a single PromethION R10.4.1 flow cell. The mitogenome contained 37 genes in the standard mammalian configuration and was 99.63% identical to the domestic horse (Equus caballus). The nuclear assembly, EquPr2, contained 2,146 scaffolds with an N50 of 85.1 Mb, 43X mean depth, and BUSCO quality score of 98.92%. EquPr2 successfully improves upon the existing Przewalski's horse reference genome (Burgud), with 25-fold fewer scaffolds, a 166-fold larger N50, and phased pseudohaplotypes. Modified basecalls revealed 79.5% DNA methylation and 2.1% hydroxymethylation globally. Allele-specific methylation analysis between pseudohaplotypes revealed 226 differentially methylated regions (DMRs) in known imprinted genes and loci not previously reported as imprinted. The heterozygosity rate of 0.165% matches previous estimates for the species and compares favorably to other endangered animals. This improved Przewalski's horse assembly will serve as a valuable resource for conservation efforts and comparative genomics investigations.

Habitat use by semi-feral Konik horses on wetlands-three-year GPS study

Free-ranging grazers are increasingly being introduced to areas of high natural value, such as wetlands. There is also growing attention that has been paid to the historical role of herbivores in shaping ecosystems and landscapes. Even though studies on the grazing of free-range horses were carried out in different regions and climates, still little is known about their habitat selection on heterogeneous marshy areas in the temperate region of Europe. The aim of this study was to investigate the habitat use by contemporary Konik horses during the growing season on the basis of three-year GPS data for a semi-feral herd kept on wetlands. Almost 68% of the occurrence of Konik horses were in open habitats. The assessment of habitat selection by the horses confirmed their strong preferences for grasslands on mid-forest dunes and forest avoidance. Konik horses somewhat preferred mowed fen meadows, but the animals displayed differences in the selection of habitat, probably depending on its humidity and weather conditions in a given year which may limit the role of grazing in protecting these communities. Horses need different habitats in wetlands such as fen meadows, forest, and grasslands on the mineral hills. This should be taken into consideration for landscape management in areas where the introduction of wild or semi-wild horse populations is planned.

An Update on Status and Conservation of the Przewalski's Horse (Equus ferus przewalskii): Captive Breeding and Reintroduction Projects

This review summarizes studies on Przewalski's horse since its extinction in the wild in the 1960s, with a focus on the reintroduction projects in Mongolia and China, with current population status. Historical and present distribution, population trends, ecology and habitats, genetics, behaviors, conservation measures, actual and potential threats are also reviewed. Captive breeding and reintroduction projects have already been implemented, but many others are still under considerations. The review may help to understand the complexity of problem and show the directions for effective practice in the future.

Effects of Gasterophilus pecorum infestation on the intestinal microbiota of the rewilded Przewalski's horses in China

Horse botflies have been a threat to the Przewalski’s horses in the Kalamaili Nature Reserve in Xinjiang of China since their reintroduction to the original range. As larvae of these parasites could infest the intestine of a horse for months, they could interact with and alter the structure and composition of its intestinal microbiota, affecting adversely its health. Nonetheless, there are no such studies on the rewilded Przewalski’s horses yet. For the first time, this study characterizes the composition of the intestinal microbiota of 7 rewilded Przewalski’s horses infected severely by Gasterophilus pecorum following and prior to their anthelmintic treatment. Bioinformatics analyses of the sequence data obtained by amplicon high throughput sequencing of bacterial 16S rRNA genes showed that G. pecorum infestation significantly increased the richness of the intestinal microbial community but not its diversity. Firmicutes and Bacteroidetes were found the dominant phyla as in other animals, and the parasitic infestation decreased the F/B ratio largely by over 50%. Large reduction in relative abundances of the two genera Streptococcus and Lactobacillus observed with G. pecorum infestation suggested possible changes in colic and digestion related conditions of the infected horses. Variations on the relative abundance of the genus groups known to be pathogenic or symbiotic showed that adverse impact of the G. pecorum infestation could be associated with reduction of the symbiotic genera Lactobacillus and Bifidobacterium that are probiotics and able to promote immunity against parasitic infection.

Oviposition site selection by Gasterophilus pecorum (Diptera: Gasterophilidae) in its habitat in Kalamaili Nature Reserve, Xinjiang, China

Oviposition site selection is an important aspect of the behavioural ecology of insects. A comparison of the habitats used by a species enhances our understanding of their adaptation to altered environments. We collected data on the oviposition behaviours of Gasterophilus pecorum (Diptera: Gasterophilidae) in its habitat in Kalamaili Nature Reserve (KNR), Xinjiang, China between March and October 2014. We found 91 quadrats were used by G. pecorum for oviposition. Examining 13 ecological factors using the t-test, chi-square test, and principal component analysis showed that G. pecorum's oviposition habitat was preferentially on slopes with inclinations of 10-30° that were semi-sunny, semi-cloudy slopes, in positions high or low on the slopes, with preferences for total plants lower than 10% and Stipa capillata coverage lower than 10% on the low slopes, but Ceratoides latens coverage on the high and intermediate slopes, when the numbers of plant species and families were lower than five. G. pecorum often selected sites at a distance < 2000 m from a water source and average altitude 900-1000 m. The oviposition site selection by G. pecorum may be correlated with the behaviour of Przewalski's horses (Equus ferus przewalskii), and water and food resources may strongly influence oviposition site selection, as Przewalski's horses rest and forage in these areas.