Eastern Bhutan Research Articles

Productive and reproductive traits of yak types in Bhutan: characteristics and comparisons

ABSTRACTThe study characterized and compared productive and reproductive traits of genetically different types of yaks of eastern, central and western Bhutan. The mean daily milk yield, lactation length and lactation yield per cow were 1 kg, 234 days and 153 kg, respectively. The only reproductive traits that differed significantly amongst yak types were age at puberty and postpartum oestrus period. The yak of eastern Bhutan attained puberty earlier in less than 3 years compared with the yaks of central and western Bhutan but the postpartum oestrus period of yaks of eastern Bhutan was longer. Yaks of central and western Bhutan showed a postpartum oestrus period of about 150 days whereas it was close to 170 days for yaks of eastern Bhutan. Mean age at first calving for all yak types was 4–5 years with mean calving interval of approximately 1.3 years. Mean gestation period was about 256 days for all yak types. Mean heat interval was about 21 days and the number of services per conception was a little over 1.50. There is a need to introduce forage and nutrition development programmes to exploit fully the genetic potential of yaks, besides putting in place an appropriate breeding programme and adequate veterinary services.

Propitiating the Tsen, Sealing the Mountain: Community Mountain-closure Ritual and Practice in Eastern Bhutan

Propitiating the Tsen, Sealing the Mountain: Community Mountain-closure Ritual and Practice in Eastern Bhutan

Species composition of the vegetation along the Sherichhu River, lower montane area of Eastern Bhutan

Species composition of the vegetation along the Sherichhu River, lower montane area of Eastern Bhutan

Seismotectonics of Bhutan: Evidence for segmentation of the Eastern Himalayas and link to foreland deformation

The instrumental record of Bhutan is characterized by a lower seismicity compared to other parts of the Himalayan arc. To understand this low activity and its impact on the seismic hazard, a seismic network was installed in Bhutan for 22 months between 2013 and 2014. Recorded seismicity, earthquake moment tensors and local earthquake tomography reveal along-strike variations in structure and crustal deformation regime. A thickened crust imaged in western Bhutan suggests lateral differences in stresses on the Main Himalayan Thrust (MHT), potentially affecting the interseismic coupling and deformation regime. Sikkim, western Bhutan and its foreland are characterized by strike-slip faulting in the Indian basement. Strain is particularly localized along a NW–SE striking mid-crustal fault zone reaching from Chungthang in northeast Sikkim to Dhubri at the northwestern edge of the Shillong Plateau in the foreland. The dextral Dhubri–Chungthang fault zone (DCF) causes segmentation of the Indian basement and the MHT between eastern Nepal and western Bhutan and connects the deformation front of the Himalaya with the Shillong Plateau by forming the western boundary of the Shillong block. The Kopili fault, the proposed eastern boundary of this block, appears to be a diffuse zone of mid-crustal seismicity in the foreland. In eastern Bhutan we image a seismogenic, flat portion of the MHT, which might be either related to a partially creeping segment or to increased background seismicity originating from the 2009 MW6.1 earthquake. In western-central Bhutan clusters of micro-earthquakes at the front of the High-Himalayas indicate the presence of a mid-crustal ramp and stress buildup on a fully coupled MHT. The area bounded by the DCF in the west and the seismogenic MHT in the east has the potential for M7–8 earthquakes in Bhutan. Similarly, the DCF has the potential to host M7 earthquakes as documented by the 2011 Sikkim and the 1930 Dhubri earthquakes, which were potentially associated with this structure.

Community-based survey during rabies outbreaks in Rangjung town, Trashigang, eastern Bhutan, 2016

BackgroundRabies is a highly fatal disease transmitted through the bite of a rabid animal. Human deaths can be prevented by prompt administering of rabies vaccine and rabies immunoglobulin following the exposure. An assessment of community knowledge, awareness and practices on rabies is important during outbreak to understand their preparedness and target educational messages and response activities by the rapid response team.MethodsA rabies outbreak has occurred in Rangjung town, eastern Bhutan on 4 October 2016. A rapid response team was activated to investigate outbreak and to establish a control program. A community-based questionnaire survey was conducted from 20 to 21 October 2016 to assess the community knowledge of rabies to guide outbreak preparedness and also target educational messages and response activities by the RRT.ResultsA total of 67 respondents were interviewed, of which 61% were female and 39% male. All the respondents have heard of rabies (100%), have knowledge on source of rabies (dog) and its mode of transmission in animals and humans. Most (61%) respondents were aware and also indicated that they would wash the animal bite wound with soap and water and seek medical care on the same day of exposure (100%). Majority (94%) of the respondents have indicated that they would report to the government agencies if they see any suspected rabid dogs in the community and suggested various control measures for dog population management and rabies in Rangjung including neutering procedure and mass dog vaccination. Although only few (10%) of the respondents households owned dogs and cats, but 50% of them have indicated that their dogs were allowed to roam outside the home premises posing risk of contracting rabies through rabid dog bites.ConclusionsAlthough this study indicates a high level of knowledge and awareness on rabies among the community, there exists some knowledge gaps about rabies and therefore, an awareness education should be focused on the source of rabies and rabies virus transmission route to reduce public concern on nonexposure events thereby reducing the cost on unnecessary postexposure treatment.

Along‐strike variations in the Himalayan orogenic wedge structure in Bhutan from ambient seismic noise tomography

AbstractThe geological units and tectonic structure exposed in the Bhutan Himalaya document significant regional variations, expressed primarily as tectonic windows and klippen. The along‐strike variations of these structures and their metamorphic grade are usually associated with the formation of local duplexes in the underlying tectonic units. To investigate these variations and their extent in depth, we image the isotropic shear‐wave velocity structure of the orogenic wedge by ambient noise tomography. Group velocities are extracted from cross correlations of ambient seismic noise, recorded by the temporary GANSSER network in Bhutan. The upper crustal structure beneath Bhutan is mapped down to 18 km depth by directly inverting Rayleigh‐wave group velocity measurements in the period range between 2 and 20 s with a ray tracing based inversion approach. Our results reveal several distinct high shear‐wave velocity anomalies ( km/s) and reflect the along‐strike variations in the upper crustal structure in relation to the alternating tectonic windows and klippen at the surface. In correlation with the surface geology in the northern part of Bhutan, we interpret shallow high shear‐wave velocity anomalies as quarzite‐dominated rocks or felsic migmatites with large intrusions of leucogranites. High‐velocity anomalies in the orogenic wedge in eastern and western Bhutan correlate with the local geometry of the Main Himalayan Thrust and provide evidence for the formation and depth extent of localized duplexes of quartzite dominated lithology in association with the formation of tectonic windows in the Bhutan Himalaya.

<b>A new critical habitat for conservation of the White-bellied Heron <I>Ardea insignis</I> Hume, 1878 (Aves: Ardeidae) from Bhutan</b>

The White-bellied Heron Ardea insignis is listed as Critically Endangered on the IUCN Red List of Threatened Species due to its extremely small and rapidly dwindling population. Bhutan is home to the highest number of White-bellied Heron and the species is distributed patchily across 11 different sites in central and south-west Bhutan. In this note, we present the first evidence of the species in eastern Bhutan, on the Drangmechhu River in Trashi Yangtse district. The finding extends the distribution of the species in Bhutan and recognizes one more potentially critical habitat for immediate conservation attention. As elsewhere, the new site is found to be primarily threatened by hydropower development. The need for conservation initiatives for the species is immediate and highly recommended.

The underthrusting Indian crust and its role in collision dynamics of the Eastern Himalaya in Bhutan: Insights from receiver function imaging

AbstractMost of the convergence rate between the Indian and Eurasian plate is assumed to be absorbed along a major basal thrust beneath the Himalaya, the Main Himalayan Thrust (MHT). Deformation along this basal thrust in combination with frontal accretion results in the formation of the upper crustal fold‐thrust belt. The role of the underthrusting Indian crust and its impact on the long‐term growth of the Himalaya are only poorly understood, partly due to the lack of high‐resolution seismic images of the crust. To improve the imaging of lithospheric structures, we developed a 3‐D migration scheme for receiver functions using seismic data from the temporary GANSSER network in Bhutan. Extending the 2‐D high‐frequency ray approximation and common conversion point stacking to 3‐D including linear phase weighting and a quality assessment, we reveal significant along‐strike differences in the lithospheric structure beneath Bhutan. In western Bhutan, the Moho geometry shows an increased dip south of the Higher Himalaya reaching almost 70 km depth thereafter, whereas in eastern Bhutan the Moho is almost subhorizontal at 50 km depth across our network. The appearance of distinct listric structures beneath the MHT indicates intracrustal deformation up to crustal imbrication down to the lower crust. We propose that these variations, in the crustal thickness and in intracrustal structures, influence the upper crustal kinematics of the Bhutan Himalayan orogeny and are primarily driven by an Indian mantle‐slab northwest of Bhutan, and its absence northeast of Bhutan.

Dancing Butterflies of the East Himalayas

The region from eastern Bhutan to Arunachal Pradesh of India and the adjacent south-eastern Tibet and northern Myanmar seems to be one of the last frontiers not only for Meconopsis hunting but also for other botanical exploration. Although there remain political difficulties for foreigners to approach the unsettled border between India and China, including the famous Tsari valley with its prominently rich flora, which was visited by Frank Ludlow, George Sherriff, Frank Kingdon-Ward and a few other plant hunters before 1950, some botanical and horticultural treasures in this region have gradually been revealed to recent travellers. As a result of examining the photographs taken by these travellers and our own botanical field research in eastern Bhutan in 2014, accompaniedby subsequent herbarium studies, two species new to science are described. The first, from eastern Bhutan and adjacent Arunachal Pradesh and Tibet, has long been cultivated under the names M. grandis or M. grandis GS600, and has recently been described as M. grandis subsp. orientalis (Grey-Wilson, 2010). It is the national flower of Bhutan. However, the type of M. grandis from Sikkim belongs to a species quite distinct from the eastern populations and the latter is now described as a new species, Meconopsis gakyidiana. The second novelty, Meconopsis merakensis,is newly described from eastern Bhutan and adjacent Arunachal Pradesh. In the past this species was confused with the closely allied M. prainiana. The two species are isolated geographically, M.prainiana being found only much further to the north-east, in south-eastern Tibet, including theTsari valley. The title of this article is based on a comparison made by Frank Kingdon-Ward of Meconopsis flowers with butterflies in Tibet (see below).

Evidence of interseismic coupling variations along the Bhutan Himalayan arc from new GPS data

AbstractAlthough the first‐order pattern of present‐day deformation is relatively well resolved across the Himalayas, irregular data coverage limits detailed analyses of spatial variations of interseismic coupling. We provide the first GPS velocity field for the Bhutan Himalaya. Combined with published data, these observations show strong east‐west variations in coupling between central and eastern Bhutan. In contrast with previous estimations of first‐order uniform interseismic coupling along the Himalayan arc, we identify significant lateral variations: In western and central Bhutan, the fully coupled segment is 135–155 km wide with an abrupt downdip transition, whereas in eastern Bhutan the fully coupled segment is 100–120 km wide and is limited updip and downdip by partially creeping segments. This is the first observation of decoupling on the upper ramp along the Himalayan arc, with important implications for large earthquake surface rupture and seismic hazard.

A REVIEW OF THE BARSINE FLAMMEALIS SPECIES-COMPLEX WITH DESCRIPTION OF A NEW SPECIES FROM HIMALAYA (LEPIDOPTERA, EREBIDAE, ARCTIINAE)

<p>The paper contains a review of the <em>Barsine flammealis </em>species-complex. The status of <em>Barsine pretiosa </em>Moore, 1879 is revised, diagnoses for <em>B. flammealis </em>Moore, 1878 and <em>B. pretiosa </em>are given. A new species, <em>Barsine pseudomactans </em>Volynkin & Černý, sp. nov. is described from Himalaya (eastern India, Bhutan and Nepal). Adults, male and female genitalia of all species mentioned are illustrated.</p>

Bird Offerings in the Old Tibetan Myths of the Nyen Collection (Gnyan ’bum)

The article introduces a corpus of Tibetan texts containing apparently old Tibetan myths on the Nyen (gnyan); beings representing the natural environment. The myths mostly narrate their conflicts with the original people, which are eventually resolved by ritual means. These texts are known as the Nyen Collections (Gnyan ’bum). Three examples of them are currently known and references from the Tibetan chronicles of the Bon religion speak about the rediscovery of some of its versions in western Tibet prior to 1017. The content, nevertheless, points to eastern Tibet as the place of origin of the core items of these texts. These texts represent a certain mythopoetic lore stemming from oral tradition, which might well be related to the traditions of the Naxi people in the Sichuan province of the PRC, as well as to some surviving traditions in eastern Bhutan and Arunachal Pradesh, as recently described. Extracts from the myths dealing with birds are presented in translation and paraphrase. These myths use their own specific poetic register and manifest an extraordinary veneration of birds. The other aspect of this veneration is the evident tradition of offering birds up to the Nyen. This is in sharp contrast with the orthodox Indo-Buddhist world-view, which does not ascribe any specific value to the animal realm.

Late Miocene-Pleistocene evolution of India-Eurasia convergence partitioning between the Bhutan Himalaya and the Shillong Plateau: New evidences from foreland basin deposits along the Dungsam Chu section, eastern Bhutan

The Shillong Plateau is a unique basement-cored uplift in the foreland of the eastern Himalaya that accommodates part of the India-Eurasia convergence since the late Miocene. It was uplifted in the late Pliocene to 1600 m, potentially inducing regional climatic perturbations by orographically condensing part of the Indian Summer Monsoon (ISM) precipitations along its southern flank. As such, the eastern Himalaya-Shillong Plateau-ISM is suited to investigate effects of tectonics, climate, and erosion in a mountain range-broken foreland system. This study focuses on a 2200 m thick sedimentary section of the Siwalik Group strategically located in the lee of the Shillong Plateau along the Dungsam Chu at the front of the eastern Bhutan Himalaya. We have performed magnetostratigraphy constrained by vitrinite reflectance and detrital apatite fission track dating, combined with sedimentological and palynological analyses. We show that (1) the section was deposited between ~7 and 1 Ma in a marginal marine deltaic transitioning into continental environment after 5 Ma, (2) depositional environments and paleoclimate were humid with no major change during the depositional period indicating that the orographic effect of the Shillong Plateau had an unexpected limited impact on the paleoclimate of the Bhutanese foothills, and (3) the diminution of the flexural subsidence in the basin and/or of the detrital input from the range is attributable to a slowdown of the displacement rates along the Main Boundary Thrust in eastern Bhutan during the latest Miocene-Pleistocene, in response to increasing partitioning of the India-Eurasia convergence into the active faults bounding the Shillong Plateau.

Burning for enhanced non‐timber forest product yield may jeopardize the resource base through interactive effects

Summary Non‐timber forest product (NTFP) harvest is frequently accompanied by resource management practices that interact with the harvesting itself, other disturbances and abiotic conditions. These interactions, in turn, lead to diverse environmental effects. Few studies focus on these practices in the context of harvesting NTFPs, product properties and environmental impacts, including biological invasions. In Pine woodlands in Eastern Bhutan, Cymbopogon flexuosus East Indian Lemon Grass is harvested and distilled to obtain essential oil, an economically important NTFP. Prescribed fires are applied in late winter (before annual harvest in summer) to induce regeneration of new tillers with increased essential oil content. This practice is based on local ecological knowledge and renders the utilization of C. flexuosus economically viable. On two sites with contrasting stand structure, we evaluated the effects of different prescribed burning regimes (no burning vs. burning with two levels of frequency and intensity) on the sustainability of annually harvested C. flexuosus, regarding cover, biomass yield, essential oil yield and quality. At the same time, we evaluated the effects of prescribed burning on the spread of the invasive shrub Chromolaena odorata. Cymbopogon flexuosus biomass declined over time, likely as a result of harvesting. In more closed stands, it was moreover marginally negatively influenced by fire. We confirmed local ecological knowledge regarding significantly higher essential oil yield on burned plots, without differences between fire regimes. In open stands, fire led to rapid expansion of C. odorata, specifically with frequently applied, higher intensity fires. Additionally, the spread of C. odorata showed adverse effects on C. flexuosus cover. Synthesis and applications. Our results highlight the importance of studying the wider impacts of non‐timber forest product (NTFP) harvest. We confirmed local ecological knowledge that fire increases lemon grass essential oil yield, making prescribed burning an attractive land management tool for farmers. Nevertheless, the practice of annual harvesting may lead to resource decline that may be exacerbated by fire in closed stands. Caution needs to be practiced on open sites where invasive C. odorata may spread rapidly after fires. Management needs to focus on preventing concentration of annual harvesting and associated prescribed burning in the same areas. Amending national forestry rules to legalize fire as a land management tool can support local economies and potentially prevent wildfires that regularly devastate human infrastructure across eastern Bhutan.

Pressure–temperature–structural distance relationships within Greater Himalayan rocks in eastern Bhutan: implications for emplacement models

AbstractIn the Himalayan orogen, Greater Himalayan (GH) rocks were buried to mid‐ to lower‐crustal levels and are now exposed across the strike of the orogen. Within the eastern Himalaya, in the Kingdom of Bhutan, the GH is divided into structurally lower (lower‐GH) and upper (upper‐GH) levels by the Kakhtang thrust (KT). Pressure–temperature estimates from lower‐ and upper‐GH rocks collected on two transects across the KT yield similar P–T–structural distance trends across each transect. In the eastern transect, temperatures are similar (from 730 to 650 °C) over a structural thickness of ~11 km, but peak pressures decrease from ~10 to 6 kbar with increasing structural level. In comparison, peak temperatures in the central Bhutan transect are similar (from 730 to 600 °C), but pressures decrease from 10 to 6.5 kbar with increasing structural level over a structural thickness of ~6 km. The structurally highest sample reveals slightly higher pressures of 8.0 kbar in comparison to pressures of ~6.5 kbar for samples collected from within the KT zone, ~4 km below. Within each transect, there are increases in pressure ± temperature within the overall upright P–T gradient that may demarcate intra‐GH shear zone(s). These P–T results combined with evidence that the timing of initial melt crystallization becomes older with increasing structural level suggest that the intra‐GH shear zones emplaced deeper GH rocks via progressive ductile underplating. These shear zones, including the KT, likely aided in the initial emplacement and construction of the GH as a composite tectonic unit during the Late Oligocene to Early Miocene, from c. 27 to 16 Ma.

Pediatric tele-echocardiography in the diagnosis of congenital heart diseases in a regional referral hospital in eastern Bhutan

Introduction: Congenital Heart Diseases are the commonest birth defects and the most common reason for out-country referral of pediatric patients in Bhutan.Without any qualified pediatric cardiologists in the country, early diagnosis and appropriate care of pediatric cardiac patients is often delayed or inappropriate. Collaboration through telemedicine between general pediatrician and pediatric cardiologist can improve the diagnosis of congenital heart diseases in Bhutan.
 Methods: Pediatric patients clinically suspected to have congenital heart diseases underwent Echocardiography at Mongar regional referral hospital. The Echocardiograms, performed by general pediatrician, were e-mailed to Pediatric Cardiologist working in UK, who gave the diagnosis after viewing the Echo-loops. This was compared with the final diagnosis made at tertiary cardiac centre in India.
 Results: 30 echocardiograms performed by general pediatrician at Mongar Hospital in eastern Bhutan were mailed to Pediatric Cardiologist working in UK. Of the thirty cases, 20 required no immediate referral and were put on medications and follow up plans. 10 of the 30 cases requiredearly referral to tertiary care hospital in India. There was excellent concordance between the diagnosis made through tele-echocardiology and the final diagnosis made at tertiary cardiac centre.
 Conclusions: Tele-echocardiography between a general Pediatrician and a Pediatric Cardiologist can greatly enhance the diagnosis of congenital heart diseases in children.

Can Social Capital Reduce Poverty? A Study of Rural Households in Eastern Bhutan

This study examines the impact of social capital on the poverty of rural households in eastern Bhutan, with a particular focus on households' participation in community groups, which can be a proxy for the structural aspect of social capital. Using a two‐stage probit least squares simultaneous equation model, the present study reveals that social capital positively contributes to poverty reduction in Bhutan. This study also finds that non‐farm income is important for poverty reduction in rural areas. Our results, however, indicate that poor households in remote areas are discouraged from participating in community groups.

New distribution records of Epiophlebia laidlawi Tillyard, 1921 (Insecta: Odonata) in Bhutan

An opportunistic survey for Epiophlebia laidlawi larvae was carried out within five districts in Western and Central Bhutan from 2012 to 2014. The study recorded a total of 21 individuals from five districts and also recorded F0, F3 and F8 instars larvae for the first time in Bhutan. The study adds December and February as possible months to record F0 instars within its range. The record of E. laidlawi from Bumthang District extends its range to the eastern most part of the Himalayas, and it also extends its range from Chhukha District to its southern most range within Bhutan. A record from Punakha District fills the gap between the previous and current record of E. laidlawi from Wangchhu basin in Western Bhutan and Drangmechhu basin spanning central and eastern Bhutan with Punatshangchhu basin in between. The record from Trongsa District emphasises the importance of the study area as E. laidlawi ’s habitat. The extent range of E. laidlawi within Bhutan is now extended to six districts, viz., Haa, Thimphu, Chhukha, Punakha, Trongsa and Bumthang.

Exploring the patterns of alpine vegetation of Eastern Bhutan: a case study from the Merak Himalaya.

A survey was conducted from March to September 2012 along the altitudinal gradient of the Jomokungkhar trail in the Merak Himalaya of Sakteng Wildlife Sanctuary to study the floristic compositions and the patterns of alpine vegetation of Eastern Bhutan. The vegetation of the sampled plots is classified into five types of communities based on the hierarchical cluster analysis at similarity index 63% viz., (1) Riverine Community; (2) Abies–Rhododendron Woodland Community; (3) Juniperus Scrub Community; (4) Rhododendron Krummholz and (5) Alpine Meadow, based on the floristic compositions. In addition, it was noticed that the fragile alpine environment of the Merak Himalaya has high plant diversity and important plants that are susceptible to the anthropogenic pressures.

Timing and conditions of metamorphism and melt crystallization in Greater Himalayan rocks, eastern and central Bhutan: insight from U–Pb zircon and monazite geochronology and trace-element analyses

Within the eastern Himalaya in central and eastern Bhutan, Greater Himalayan (GH) rocks are inter- preted to have been thickened by the Kakhtang thrust (KT). In order to understand the metamorphic and exhumation history of the GH and to evaluate the structural significance of the KT, zircon and monazite from twenty samples were analyzed by laser-ablation split-stream ICPMS. In eastern Bhutan, zircon and monazite from samples collected in the KT hanging wall revealed ca. 36-28 Ma metamorphism. Subsequently, the initiation of melt crystallization shows a trend with structural distance above the KT, with early melt crystallization (ca. 27 Ma) in the structurally highest samples and younger melt crystallization (ca. 16 Ma) for leucosomes within the KT zone. Melt crystallization was protracted and continued until ca. 14-13 Ma in both the KT hanging wall and the footwall. In comparison, in central Bhutan, two leucosomes revealed extended melt crystal- lization from ca. 31 to 19 Ma. The youngest zircon dates from samples exposed structurally above and below the KT are similar, indicating that the KT was not as significant of