North Sikkim Research Articles

GIS-based landslide susceptibility zonation and comparative analysis using analytical hierarchy process and conventional weighting-based multivariate statistical methods in the Lachung River Basin, North Sikkim

GIS-based landslide susceptibility zonation and comparative analysis using analytical hierarchy process and conventional weighting-based multivariate statistical methods in the Lachung River Basin, North Sikkim

Assessment of spatial distribution of rain-induced and earthquake-triggered landslides using geospatial techniques along North Sikkim Road Corridor in Sikkim Himalayas, India

Assessment of spatial distribution of rain-induced and earthquake-triggered landslides using geospatial techniques along North Sikkim Road Corridor in Sikkim Himalayas, India

Assessment of population distribution, conservation status and in vitro propagation of Cymbidium whiteae King & Pantl. in the Sikkim Himalaya, India

Cymbidium whiteae King & Pantl is an endemic and endangered orchid species found in Sikkim, India. We evaluated the current population distribution and conservation needs of this species during 2017–2019 in North Sikkim, Sikkim, India. The distribution of the species ranged from 1020 to 1479 m a.s.l. but was confined to a small restricted area of the lower Dzongu region of North Sikkim district. The numbers of clumps at survey sites varied from 2 to 5 with a total population of 43 clumps at 17 sites. The flower number and capsules per clump varied from 4 to 12 and 3 to 12, respectively. Some flowering‐sized individuals neither flowered nor set any seed pods. Preliminary studies on asymbiotic seed germination indicated that seeds germinate on MS media supplemented with 0.2 mg BAP and develop into plantlets on the same media. We analysed the distribution pattern, prepared a distribution map, assessed the conservation status based on the IUCN criteria, and suggest suitable in situ and ex situ conservation measures and sustainable utilization. Based on the IUCN criteria, Cymbidium whiteae was assessed as critically endangered (CR).

Application of Cloudburst Prediction System: A Review

Abrupt and powerful downpours known as "cloudbursts" can cause disastrous flash floods, landslides, and damage to infrastructure. Twenty-three army troops were washed away and five people killed as a result of the recent flood in Sikkim triggered by a cloudburst over Lhonak Lake in north Sikkim, which overflowed and raised the water levels in the Teesta River. Researchers have created a system based on Convolutional Neural Networks (CNN), weather forecasting, and data mining approaches for weather prediction by modeling meteorological data in order to address the urgent challenge of anticipating and managing cloudburst incidents. The suggested approach in this research describes a real-time cloudburst prediction system that makes use of sophisticated anomaly detection techniques and is based on a machine learning model.

Evaluating the distinct identity and the orogen-scale nature of the Munsiari thrust in the Himalaya

The Munsiari thrust (MT) was first recognized in northwest India within the Paleoproterozoic Lesser Himalayan rocks, but debate persists over its distinct identity and orogen-scale nature. Some researchers have included the MT within a ∼3–10 km-wide Main Central thrust (MCT) zone, whereas others proposed that, it is the northern and deeper extension of the Ramgarh thrust (RT). This study integrates field mapping, quantitative microstructural analysis, grain-size measurement, and piezometry to evaluate the distinct identity of the MT from North Sikkim, in eastern Himalaya. Our study reveals the presence of a ∼1700 m-thick prominent shear zone showing thrust-sense motion. The mylonites in the ∼300 m-thick core of the shear zone deformed by DRX (dynamic recrystallization)-assisted dislocation creep, and by climb-assisted dislocation creep in the ∼400–1000 m-thick flanking zones. We infer the mapped shear zone represents Sikkim-equivalent of the MT, because it transported Paleoproterozoic Lesser Himalayan crystalline rocks over Paleoproterozoic Lesser Himalayan quartzites and phyllites. The MCT and the RT lie ∼6 km structurally above-and-below the MT respectively. By comparing our findings with published results, we infer that, the MT is an orogen-scale structure, traceable from northwest Himalaya to far-eastern Himalaya, and it facilitated rapid exhumation of the Lesser Himalayan crystalline rocks between mid-Miocene and Pliocene. Therefore, we propose to reserve the appellation of the “Munsiari thrust” for a shear zone that transported Paleoproterozoic Lesser Himalayan crystalline rocks over Lesser Himalayan quartzites and phyllites of similar age, and suggest not to confuse it with the MCT or the RT.

A new species of Zographetus Watson, 1893 (Lepidoptera: Hesperiidae) from Sikkim, eastern Himalaya, India

A new species, Zographetus dzonguensis sp. nov., is described based on three male specimens from Upper Dzongu, North Sikkim District, Sikkim, India. The new species is closely similar to Z. pangi from Guangdong and Z. hainanensis from Hainan, China, from which it is distinguished based on the following combination of external characters: (a) forewing with the white spot at the base of space M3 being sharply pointed at the inner edge and conspicuously more elongated, and (b) on underside of hindwing, all chocolate-brown spots being smaller, in Z. dzonguensis sp. nov. compared with both Z. pangi and Z. hainanensis. In Z. dzonguensis sp. nov., the male genitalia may be distinguished as follows: (c) tegumen and uncus are almost equal in length, (d) the dorsal outline of tegumen is relatively flat, and (e) saccus is distinctly bent upward as angle between vinculum and saccus is more acute than in Z. pangi and Z. hainanensis.

Application of earth observation dataset and multi-criteria decision-making technique for forest fire risk assessment in Sikkim, India

Forest fire is one of the primary and recurring problems in Sikkim, India impacting the ecological heritage of the region. The article presents a fire risk model based on the identification of the major factors that contribute to forest fire, namely, vegetation type, vegetation density, land surface temperature, elevation, slope, aspect, and distance from settlements, rivers and roads, and then integrating them using a multi-criteria decision-making technique in a GIS framework. We document that more than 50% of the area of all the districts except North Sikkim falls into high to moderate risk zones. The model shows that 61% of fire information for resource management system data for the last 16 years coincide with the mapped high-risk zone of the state. Areas with low slope and with moderate vegetation density fall into very high risk, whereas areas with high slope and with high vegetation density correspond to moderate risk zones. Further, aspect and density of human intervention differentiate the very high and high-risk zones of the region. This model has provided a robust geographical representation of fire ignition probability and identification of high-risk areas at different regions for the entire state of Sikkim

Observed and simulated winter temperature over Gurudongmar area, North Sikkim, India

The global warming and its impact on the cryosphere is a matter of serious concern. The Sikkim and the Eastern Himalaya are a canvas of vivid landscapes and of different climate zones. The study of cryosphere needs more attention on long term climatic trends of surface air temperature. The Gurudongmar area is very much important because this area is surrounded by glaciers and as well as cold desert and TsoLhamo Lake nearby. The Gurudongmar lake (located at an altitude of 17,800 ft) has been studied by several researchers in the context of Glacial Lake Outburst Floods (GLOFs) and reported a high risk lake which is being largely affected by global warming and climate change. The present study is aimed to investigate the trend of temperature in recent past and in future time periods over the study area of Sikkim. The observed and model’s simulated gridded temperature data is considered to inkling of rising trend in winter months of December-January-February (DJF) over the study area. An increase in temperature is found for the future time period. This can be linked to the increasing hazard risk and change in local cryosphere environment.

Prevalence of gastrointestinal parasites in Tibetan sheep in alpine zone of North Sikkim, India

Prevalence of gastrointestinal (GI) parasites in native Tibetan sheep (Ovis aries), a critically endangered small ruminant of North district of Sikkim, India was studied during July 2014 to June 2015. Of the 213 animals examined, 71 (33.33%) were found positive for different GI parasites. The overall prevalence of different parasites recorded was strongyles (67, 31.46%), coccidia (52, 24.41%), Strongyloides spp. (41, 19.24%), Moniezia spp. (37, 17.37%), Nematodirus spp. (25, 11.73%), amphistomes (12, 5.63%), Dicrocoelium spp. (9, 4.22%) and Trichuris spp. (8, 3.76%). The faecal egg counts (eggs per gram of faeces, epg) of nematodes ranged from 100 to 2700 with higher load during rainy and post rainy seasons. A higher infection rate was recorded in animals above 2 years of age (39.29%) followed by 1 to 2 year (24.14%) while those below 1 year of age showed only 13.33% prevalence and the parasites mostly recorded were Haemonchus spp., Eimeria spp. and Moniezia spp. The seasonal distribution of parasitism indicated a higher percentage of infestation in autumn (44.26%) and summer (37.74%) as compared to spring (31.92%) and winter (17.31%).

Exploitation of optical and SAR amplitude imagery for landslide identification: a case study from Sikkim, Northeast India

Detection and mapping of landslides is one of the most important techniques used for reducing the impact of natural disasters especially in the Himalaya, owing to its high amount of tectonic deformation, seismicity, and unfavorable climatic conditions. Moreover, the northeastern part of the Himalaya, severely affected by landslides every monsoon, is poorly studied. The information on the inventories is inhomogeneous and lacking. In this context, satellite-based earth observation data, which has significantly advanced in the last decade and often serves as a potential source for data collection, monitoring, and damage assessment for disasters in a short time span, has been implemented. Keeping in mind the above framework, this study aims to exploit the potentials of Sentinel-1 synthetic aperture radar (SAR) and Sentinel-2 optical imagery for identifying new landslides in vegetated and hilly areas of the northeastern part of India. In order to assess the potentials of our data and methodology, a landslide event which occurred on 13 August 2016 13:30 h (IST) in North Sikkim, India, triggered due to rainfall has been explored in detail. The landslide also resulted in the formation of a lake, 2.2 km in length and 290 m in width. Difficulty in procurement of cloud-free datasets immediately after the event led us to the use of Sentinel-1 SAR backscatter data, to assess its potential for this purpose. It is observed that the potential of SAR amplitude imagery is limited to different aspects as per the sensor look direction during the mode of acquisition. Furthermore, the present study also incorporates a change detection algorithm to evaluate the performance of the Sudden Landslide Identification Product (SLIP) model to identify new landslides using Sentinel-2 multispectral imagery. Overall, the results exhibit that integrated usage of both optical and SAR amplitude imagery may provide a plethora of information for identification and mapping of new landslides for damage assessment and early warning. All the above results combined together suggest this method for rapid identification of landslides in the Himalayan terrain with special emphasis on the northeastern part of the Himalaya. The automation of this method for future operational usage is also suggested.

Snow Cover Area Changes in the Changme Khangpu Basin during 2002-2019, North Sikkim Himalaya, India

The Himalayan region is characterised by snow-covered mountains and glacierised basins which directly or indirectly regulates many large to small rivers downstream. To simulate and forecast stream-flow in these glacierised basins, an accurate snow cover area (SCA) estimation is of utmost importance. The present study assesses the snow cover dynamics (monthly, annual and seasonal) in the Changme Khangpu Basin (CKB) for almost two decades, from 2002 to 2019. The spatial and temporal variations in the SCA have been estimated using Moderate Resolution Imaging Spectro-radiometer (MODIS) 8-day maximum composite snow cover products from Terra (MOD10A2). Further, the SCA change has been compared with a remotely sensed meteorological parameter like temperature. The result shows a decreasing trend in annual mean SCA of the basin in the last two decades and an increase in seasonal mean SCA in the ablation period (May, June, July, August and September), whereas a decrease in seasonal mean SCA in accumulation period has been observed. The seasonal change in SCA will help in estimating the availability of water in the region for the people residing downward in the valley.

Local Perceptions and Trends of Climate Change in the Sikkim Himalaya, North-East India

The Himalayan high mountain areas are more vulnerable to climate change and the awareness of its impacts among the natives is very crucial as well as beneficial to stakeholders and policymakers. The impacts of climate change via food security, water availability, natural hazards, agriculture, and livelihoods have a direct relation or threat to the lives of high mountain communities, as these areas are experiencing the immediate and greatest impacts of climate change. Although the tourism industry has become the backbone of the economy in these areas, a significant increase in tourist footfall has also impacted the environment, livelihoods, culture and food habits. To understand the local perceptions of climate change, a binary question-based survey (interview) was conducted in six main subdivisions of North Sikkim, which is a biodiversity and tourism hotspot. The data revealed that irrespective of the locality (urban/rural) people are aware of climate change. Significant coherence in the responses among gender and age groups, and between remote and developed areas exist. The transhumant herder populations are also well aware of climate change (80%). Peoples’ perception about temperature change and the meteorological data are also consistent, however, a misperception is observed with the precipitation data. Decreasing snowfall patterns and increasing landslides in the higher altitudes are major concerns among the natives. The majority of people have denied any positive outcome of climate change and around 85% of the respondents are willing to participate at the community level in mitigation efforts to help curb climate change.

The draft genome sequence of Parageobacillus sp. strain SY1 gives insights into its physiological properties and protease production

Parageobacillus sp. strain SY1 was isolated from the Yumthang hot spring of the North Sikkim, Himalayan region of India. A detailed study was carried out on this strain as these strains are thermophilic and are very important due to the thermostable nature of their enzymes. In the present study we are reporting the draft genome sequence of Parageobacillus sp. strain SY1. The genome possesses the size of 3,216,693 bps, with an average G + C content of 42.5%. The genome assembly has 1407 contigs (with Protein Encoding Genes PEGs). The genome contains 4360 coding sequences with 19 tRNA and 22 rRNA predicted genes. Based on COG classification, the predicted proteins were divided into 27 functional categories. Parageobacillus sp. strain SY1 genome have genes for sulfur, nitrogen, and phosphorous metabolism. The strain possesses various nitrate and nitrite ammonification genes. Carbohydrate metabolism constitutes lactate fermentation and mixed acid fermentation. Analysis of the genome also suggested the presence of ATP-dependent proteases which help in the bacterial degradation of peptides during the damage caused at the time of its invasion. Moreover, the genome also harbors genes for various other proteases which might also be responsible for extracellular proteolysis. The genome information of Parageobacillus sp. strain SY1 might help in better understanding of its functional properties and can be used as thermostable protease producer.

Discourse on Rural Settlement of Sikkim with special reference to Hee-Gyathang, North Sikkim

Discourse on Rural Settlement of Sikkim with special reference to Hee-Gyathang, North Sikkim

Impact of Religion on Traditional Health Care Practices Among the Lepchas of Upper and Lower Lingthem of Upper Dzongu, Sikkim, India

In all cultures and regions, the concept of health varies, based on the type of environment and prevalent sociocultural traditions. The present study is conducted among the Lepchas of the village of Lingthem divided into two sectors—Upper and Lower Lingthem, Upper Dzongu, North Sikkim. This population comprising Buddhist Lepchas residing away from the mainstream through poor infrastructural facilities still maintain ethnomedical health care practices without influence of major Indian healing systems. Living in the area of Dzongu exclusively inhabited by Lepchas revival of ancient cultural practices is evident among Lepchas of Lingthem. The structure of religious beliefs prevalent among the Lepchas, including traditional animistic as well as Buddhist practices, greatly influence forms of treatment sought for specific ailments. Even today, the use and maintenance of traditional health care with syncretized Buddhist religious belief among residents of Lingthem act as a vital source for understanding the influence of religion on traditional health care practices. Despite the presence of a few modern health care agencies, the traditional treatment of Bongthing (Lepcha shaman) and Buddhist monks remain widely popular as primary means of health care.

Diversity and composition of the North Sikkim hot spring mycobiome using a culture-independent method.

Fungi are considered to be the most resilient and economically important microbial community that can easily survive and optimally grow under a wide range of growth conditions. Thermophilic fungi from the geothermal sources have been less pondered upon and lie unexplored. Here, a microbiome approach was conducted to understand the concealed world of the environmental mycobiota from the two hot springs of North Sikkim district located in North-east India. The solfataric muds from the hot springs were analyzed. In both the samples, on the basis of genus level classification, genus Fusarium had the highest abundance followed by Colletotrichum, Pochonia, Pyricularia, Neurospora, etc. Analyzing the predicted genes, the functional proteins of New Yume Samdung mycobiome were found to be dominated by the genera Fusarium (22%), Trichoderma (12%), and Aspergillus (11%), whereas in the case of Old Yume Samdung, it was dominated by the genera Aspergillus (11%), Saccharomyces (6%), and Fusarium (5%). Interestingly, in the studied mycobiome, environmental yeasts were also detected. From the functional metagenomics, sulfate adenylatetransferase (SAT) proteins for sulfur assimilation were found in some of the fungal reads. Toxin protein reads such as AM-toxin biosynthesis proteins, AF-toxin biosynthesis proteins, Gliotoxin biosynthesis proteins, and aflatoxin biosynthesis proteins were detected in the mycobiomes.

Inventory and GLOF hazard assessment of glacial lakes in the Sikkim Himalayas, India

Glacial Lake Outburst Floods (GLOFs) are a recurring hazard in the Himalayas, posing significant threat to downstream communities. The North Sikkim district of India, comprising the upper reaches of the Teesta River in the Eastern Himalayas, has experienced past GLOF events. The identification of lakes susceptible to this phenomenon is therefore paramount. Using multi-temporal satellite images, this study tracks lake growth in the region, revealing that 203 new lakes had developed herein during the observation period (2000–2018). Of these, 82 lakes had formed during 2011–2018 alone; indicating marked glacial retreat and consequent lake area growth, alongside a rising temperature trend. Using various weighted geometric and geomorphic parameters, the 36 most hazardous lakes were identified, from which the 10 lakes posing the greatest GLOF threat were discerned. These lakes are mostly situated along the main snowline and Great Himalayan water-divide in the north-eastern part of Sikkim and should be monitored continuously.

Prevalence of methanogens in the uncultured Sikkim hot spring solfataric mud archaeal microbiome

Solfataric mud sediment samples were analyzed from two hot springs of North Sikkim district of the Sikkim Himalayas, located at the north-eastern region of Indian Himalayan Geothermal Belt. Old Yume Samdung hot spring (OYS) and New Yume Samdung hot spring (NYS) are located 4500m above the mean sea level and are one of the highest located hot springs of Sikkim. OYS hot spring had more abundance of archaea than the NYS hot spring. The solfataric mud sediments of NYS had 0.03% and OYS had 1.06% archaeal reads of the whole microbiome. Both the samples were dominated by Euryarchaeota (NYS~85%; OYS~95%) followed by few representatives from Crenarchaeota (NYS~12%; OYS~3%) and Thaumanarchaeota (NYS~2%; OYS~1%). Based on abundance, Methanocaldococcus, Pyrococcus, Archaeoglobus, Methanobacter, and Thermococcus were the predominant genera in both the hot springs. Functional protein reads for Crenarchaeota were found among the orders of Desulfurococcales, Sulfolobales and Thermoproteales; whereas reads for the order Nanoarchaeales belonging to Nanoarchaeota phylum and orders Cenarchaeales; Nitrosopumilales from phylum Thaumarchaeota were present in the samples. Functional metagenomics revealed the methanogens of the hot springs. There were no functional genes detected for methanogenesis in NYS, whereas in the case of OYS it was abundantly present in various orders of Euryarchaeota - Methanobacteriales, Methanococcales, Methanopyrales, and Methanosarcinales. Three types of methanogenesis were found – aceticlastic, methylotrophic and hydrogenotrophic in the OYS metaarchaeome. Methanopyrus kandleri, Methanosarcina acetivorans, Methanothermobacter marburgensis, Methanothermobacter thermautotrophicus, and Methanocaldococcus jannaschii were the dominant methanogens found in the metaarchaeome, based on their functional proteins for methanogenesis.

Geochemical signatures of recent bar deposits in the Tista river, Bangladesh: Implications to provenance, paleoweathering and tectonics

Petrography and geochemical composition of sediments is a sensitive indicator which archives the signature of a previous record of a source rock and depositional environments in a basin. This study deals with the elemental geochemistry of recent bar deposits of the Tista river in the north western part of Bangladesh to evaluate their provenance, paleoweathering and tectonic setting. Petrographically, the sediments are rich in quartz (70%), whereas feldspar and lithic fragments are found about 8% and 3%, respectively. The geochemical composition of the samples exhibits dominantly quartzose litharenites with low grade sedimentary and metasedimentary lithics, low feldspar indicates tectonic provenance field of recycled orogeny. Discrimination functions revels that the sediments of the Tista river are the derivation of active continental margin. The analyses also reflect that the sediments are dominantly a mixture of felsic (e.g., granitic/Gneiss, quartzite, amphibolite, granulite facies rock types) and some of mafic source (e.g., alkali-basalt/greenschist facies). It may occur, since 60% of the sedimentary flux carried out by the river from low-grade metamorphic rock and the rest from high-grade rock (in the west and north Sikkim Himalaya respectively). The weathering indices highlight that the source rocks have not undergone significant chemical weathering. The immature sorting status and petrographic evidences indicate that the sediments deposited in the Tista river basin are simply the product of mechanically weathered rocks.

Distribution of antibiotic and metal resistance genes in two glaciers of North Sikkim, India

Glacier studies as of late have ruffled many eyeballs, exploring this frigid ecology to understand the impact of climate change. Mapquesting the glaciers led to the discovery of concealed world of “psychrophiles” harboring in it. In the present study, the antibiotic resistance genes (ARGs) and heavy metal resistance genes (MRGs) were evaluated through both the culture-dependent and culture-independent methods. Samples were collected from two different glaciers, i.e., debris-covered glacier (Changme Khangpu) and debris-free glacier (Changme Khang). Functional metagenomics of both the glacier samples, provided evidence of presence of resistant genes against various antibiotic groups. Bacitracin resistant gene (bacA) was the predominant ARG in both the glaciers. MRGs in both the glacier samples were diversified as the genes detected were resistant against various heavy metals such as arsenic, tungsten, mercury, zinc, chromium, copper, cobalt, and iron. Unique MRGs identified from Changme Khangpu glacier were resistant to copper (cutA, cutE, cutC, cutF, cueR, copC, and copB) and chromium (yelf, ruvB, nfsA, chrR, and chrA) whereas, from Changme Khang glacier they showed resistance against cobalt (mgtA, dmef, corD, corC, corB, and cnrA), and iron (yefD, yefC, yefB, and yefA) heavy metals. ARGs aligned maximum identity with Gram-negative psychrotolerant bacteria. The cultured bacterial isolates showed tolerance to high concentrations of tested heavy metal solutions. Interestingly, some of the antibiotic resistant bacterial isolates also showed tolerance towards the higher concentrations of heavy metals. Thus, an introspection of the hypothesis of co-occurrence and/co-selection of ARGs and MRGs in such environments has been highlighted here.