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Title: Phylogeny and ecology of the Himalayan wolf
Author: Werhahn, Geraldine
ISNI:       0000 0004 8507 7348
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2020
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This thesis researches the evolutionary history, phylogeny, and ecology of the overlooked Himalayan wolf of the Asian high-altitudes. It explores why this wolf has evolved, what may have been the ultimate causes that led to its speciation, and what proximate mechansism may be responsible for its persistence as a distinct wolf lineage. This work aims to ascertain the appropriate taxonomy of the Himalayan wolf and advance the conservation of this unique high-altitude wolf. Himalayan wolves have been largely overlooked by science and conservation until recently, and their formal taxonomic classification is pending. This thesis presents unprecedented phylogenetic insights into this taxon, its distribution range, and ecology. It draws genetic inferences about its speciation based on samples from across the estimated range, analysed at diverse genetic markers from the mitochondrial to the nuclear DNA including functional genes. The research was conducted in three study areas in Nepal, from Humla in the far north-western Nepalese Himalayas, to Dolpa in the west, to Kanchenjunga Conservation Area in the far north-eastern Himalayas, and two sites on the Tibetan Plateau of China, Namsai and Zhaqing in the Sanjiangyuan National Nature Reserve in Qinghai province. In addition, genetic samples from a wider range of regions of the Tibetan Plateau of China, the Tian Shan Mountains in Kyrgyzstan, and the southern Pamir Mountains in Tajikistan have been included in the phylogenetic analysis, in collaboration with several research groups. Wolf faecal samples were analysed with novel tailor-made genetic protocols developed in collaboration with the WildGenes Laboratory at the Royal Zoological Society of Scotland for the non-invasive study of an elusive carnivore. Subsequently, using genetically verified sample locations and the maximum entropy algorithm, the first distribution range approximation to date was modelled for the species. Himalayan wolves present a phylogenetically distinct Canis lineage. The phylogenetic distinction of the Himalayan wolf from the Holarctic grey wolf is supported by mitochondrial DNA (D-loop and cytochrome b), the ZF protein gene sequences on the Y and Z sex chromosomes, a microsatellite panel of 17 loci, and four Single Nucleotide Polymorphisms (SNPs) covering three hypoxia-pathway related functional nuclear genes. Furthermore, a unique genetic adaptation to life in the extreme high-altitudes, where low available oxygen levels challenge all life forms, was revealed for the Himalayan wolf. This hypoxia adaptation was not found in any of the other wolf lineages tested in the study. It seems to give the Himalayan wolf a fitness benefit and selective advantage in the extreme high-altitude habitats compared to the Holarctic grey wolf which is found in the surrounding lower lying habitats. The adaptation is found in diverse functional genes of the nuclear genome presumably involved in the hypoxia pathway, which is the physiological mechanism to cope with low oxygen levels at high-altitudes. The Himalayan wolf is found in habitats above 4,000m elevation in the Himalayas (Nepal and India) and the Tibetan Plateau of Qinghai and the Tibetan Autonomous Region (TAR, China), whereas the surrounding lower elevation regions are inhabited by grey wolves - the Indian wolf C. l. pallipes to the south and Holarctic grey wolf C. lupus to the west, north, and east. In the distribution boundaries of Himalayan and grey wolves, admixed individuals were found in a geographically stable belt where the elevation is gradually dropping. These admixed individuals showed a consistent pattern of Himalayan wolf mtDNA, and the correlated hypoxia adaptation on most of the SNPs, while their nuclear DNA appeared intermediate between Himalayan and grey wolves. Such admixed individuals at the distribution boundaries of wolf-like Canis lineages would be expected, and they may serve an important evolutionary function. The dietary study of Himalayan wolves presented in-depth insights into their diet by relating what the wolves have eaten to the abundance of respective prey species in the landscape across the study areas. The findings revealed that Himalayan wolves consistently consistently used wild prey species over-proportionally, with a preference for Tibetan gazelle (Procapra picticaudata), a small-sized plain-dwelling ungulate. Depredation of livestock, leading to retaliatory killings as a key threat for the Himalayan wolf, was enhanced during the herding season by the high abundance of livestock compared to that of wild prey. This leads to high encounter rates with livestock compared to wild prey and further exacerbates the problem by livestock competing with and displacing wild prey. The herding season temporally overlaps with the wolf pup rearing season, a time when wolves are spatially bound to the denning area, also intensifying conflict. Extensive killing of wolves as retaliation and for illegal wildlife trade was documented. Conservation actions for the Himalayan wolf are recommended based on the combined results from the phylogenetic research, the dietary habits study and the insights on the local people's perspective of wolves. Conservation must move away from a single species focus to a more holistic conservation approach including the entire carnivore guild. It ought to closely involve local communities and provide them with support from education to financial and material resources. Livestock herding ought to become more sustainable while wild prey populations ought to be restored and safeguarded. Protecting top predators is increasingly recognized in its importance for maintaining ecosystem function and integrity. The Asian high-altitude ecosystems, home to the Himalayan wolves, present some of the last intact wilderness habitats on our planet and host the water resources for billions of people in southeast Asia. As such, the protection of the Himalayan wolf, sympatric wildlife and its ecosystem, is of global interest. In conclusion, this phylogenetic research confirms that the Himalayan wolf is an evolutionarily distinct taxon basal to the Holarctic grey wolf, and thus merits taxonomic recognition. It is deeply diversified, to a similar extent as the African wolf (recently recommended to be reclassified as Canis lupaster), and more ancient and genetically diversified than any of the presently acknowledged Holarctic grey wolf subspecies. The high-altitude adaptation, unique to the Himalayan wolf, is hypothesized to be a key cause for its speciation and an important mechanism for its persistence by preserving its genetic integrity. This hypothesis is supported by a) the Himalayan wolf's unique genetic adaptation, b) the distributional restriction of the Himalayan wolf to habitats above 4,000m elevation, c) its distribution range being discrete and adjacent to that of the grey wolf, and d) elevation being the main predictor for its distribution. This thesis informs the Himalayan wolf's taxonomic classification, a critical step required based on the widespread evidence from phylogeny and ecology to its differentiated vocalisation. An appropriate taxonomy is crucial to advance conservation by paving the way for assigning the Himalayan wolf an IUCN Red List Status. These two steps of formal recognition, taxonomic classification and red listing, will provide much needed leverage to raise awareness in the scientific community, governments, and conservation agencies to include this charismatic high-altitude wolf in their conservation and research focus.
Supervisor: Sillero-Zubiri, Claudio ; MacDonald, David W. ; Senn, Helen Sponsor: Oxford-Lady Margaret Hall NaturalMotion Graduate Scholarship
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available