Naturally fermented milk products of the Eastern Himalayas

India is one of the 17 mega biodiversity countries in the world having two hotspots- the Western Ghats and the Eastern Himalayas, based on species rarity and endemism. Arunachal Pradesh state of India in the Eastern Himalaya is among 200 globally important eco-regions. The state is home to 26 major tribes and about 110 ethnic groups. The majority of the mountainous population of Arunachal Pradesh depends upon agricultural and forest resources for their livelihood, which these communities sustain with their rich and varied traditional ecological knowledge. The issue of recognising and acknowledging the importance of traditional knowledge, creativity and innovativeness of the grassroot level people in biodiversity conservation has been debated for a long time. Some unique ways of utilising traditional knowledge in biodiversity conservation by the local tribes have been discussed in the article.

The present study generates a glacial lake inventory of Arunachal Pradesh, Eastern Himalaya, India using Landsat 8 Operational Land Imager (OLI) images (2016-2018). The study reveals that there are in total 1532 (> 0.001 km2) glacial lakes, covering an area of 93.7 km2. Glacier erosion lakes are the most dominant type with 1268 glacial lakes (82.8%) and an area of 76.8 km2 (∼82%). About 50% of the lakes are located in the four districts of eastern Arunachal Pradesh, while ∼16% in the three districts of central and ∼33% in the four districts of western Arunachal Pradesh. The western Arunachal Pradesh has mixed patterns of glacial lakes types, whereas the erosion lakes dominate the eastern and central Arunachal Pradesh. The current inventory can serve as a baseline database for understanding glacial lake-related flood hazard studies in Arunachal Pradesh.

Arunachal Pradesh is known for its rich biodiversity, including avifauna. However, some areas in Arunachal Pradesh still need to be surveyed to document its biodiversity and avian diversity. In order to document the avian diversity in high altitude areas, especially in the north-western region bordering Myanmar and southern China, I carried out surveys in Tawang district, an important eco-region selected for the proposed Biosphere Reserve, which has similarity in bird assemblages with those of neighbouring Bhutan and southern China. Studies were carried out in four phases from November 2007 to March 2012, with more than three surveys of 14 days durations covering 24 localities of Tawang district. The main aim of the surveys was to document the seasonal bird diversity of Zimmithang-Nelya, an Important Bird Area (IBA) in the Eastern Himalaya. The surveys recorded 113 species of birds, including 25 migrant species. Significant records include the Snow Partridge Lerwa lerwa, Eurasian Woodcock Scolopax rusticola, and Broad-billed Warbler Tickellia hodgsoni.

Glacial lakes (GLs) are integral components of the cryospheric environment. Due to the persistent melting of glaciers and steady rise in the annual mean temperatures, GLs are expanding across the Himalayan mountains. Since the 1980s, the eastern Himalaya have observed a steady increase (0.031°C/year) in annual mean temperature, causing rapid glacial melting, formation of new GLs and expansion of existing ones. Therefore, to assess the role of the increasing annual mean temperature on the expansion of GLs in the eastern Himalaya, we generated GL inventories for 1987, 2005 and 2018 for Dibang Valley district, Arunachal Pradesh, in the eastern Himalaya. We used Landsat multi-temporal satellite images along with the ASTER Digital Elevation Model V2 (DEM). Using the Segment Mean Shift (SMS) method, the GL inventories were generated. Our results show that there were 509 GLs in 2018, whereas only 484 in 2005 and 469 in 1987. GLs observed a growth rate of 8.52% in number and 11.13% in area between 1987 and 2018. Most of the GLs in the study area were of Moraine-dammed lakes (MDL) (~56%), whereas Ice-dammed lakes (IDL) showed the highest expansion rate between 1987 to 2018. GL hotspots show a concentration of GLs in the eastern and southern sections of Dibang Valley but new GLs are forming in the north-western and eastern sections of the study area. An increase in annual mean temperature enhanced the glacial melt water, leading to the growth of GLs connected with the glaciers.

Naturally fermented milk (NFM) products are popular ethnic fermented foods in Arunachal Pradesh and Sikkim states of India. The present study is the first to have documented the bacterial community in 54 samples of NFM products viz. chhurpi, churkam, dahi and gheu/mar by high-throughput Illumina amplicon sequencing. Metagenomic investigation showed that Firmicutes (Streptococcaceae, Lactobacillaceae) and Proteobacteria (Acetobacteraceae) were the two predominant members of the bacterial communities in these products. Lactococcus lactis and Lactobacillus helveticus were the predominant lactic acid bacteria while Acetobacter spp. and Gluconobacter spp. were the predominant acetic acid bacteria present in these products.

Beekeeping in the Darjeeling Hills of West Bengal, India, presents a nexus of ecological, socio-economic, and cultural complexities. This study delves into the indigenous knowledge systems and practices of beekeepers in this region, juxtaposing them with modern scientific understanding to identify synergies and challenges. Through qualitative analysis, insights into beekeepers’ perspectives on beekeeping-related practices, challenges, and solutions were gleaned. Three main themes and 10 categories emerged from the thematic analysis of responses to semi-structured interviews of 22 indigenous beekeepers, highlighting traditional knowledge, issues faced in beekeeping, and solutions adapted by the beekeepers. The findings underscore beekeepers’ rich insights, which facilitate sustainable organic beekeeping practices with the indigenous Apis cerana and contribute to local livelihoods and ecosystem health. However, challenges such as bee losses, limited infrastructure, and inadequate government support persist, necessitating concerted efforts for policy reform and capacity building. Leveraging Darjeeling's global recognition, strategic marketing interventions could amplify beekeeping's economic potential. Collaboration among the beekeepers, government, non-government organizations, and researchers is essential for addressing these challenges and promoting sustainable outcomes. Despite the qualitative nature and limited sample size of this study, it highlights the importance of integrating indigenous knowledge into beekeeping management strategies. Future research should explore these dynamics quantitatively and prioritize the documentation and preservation of indigenous knowledge for long-term sustainable beekeeping in the Eastern Himalayas and beyond.

The Himalayas are well known for high diversity and ethnobotanical uses of the region’s medicinal plants. However, not all areas of the Himalayan regions are well studied. Studies on ethnobotanical uses of plants from the Eastern Himalayas are still lacking for many tribes. Past studies have primarily focused on listing plants’ vernacular names and their traditional medicinal uses. However, studies on traditional ethnopharmacological practices on medicine preparation by mixing multiple plant products of different species has not yet been reported in published literature from the state of Arunachal Pradesh, India, Eastern Himalayas. In this study, we are reporting for the first time the ethnopharmacological uses of 24 medicines and their procedures of preparation, as well as listing 53 plant species used for these medicines by the Monpa tribe. Such documentations are done first time in Arunachal Pradesh region of India as per our knowledge. Our research emphasizes the urgent need to document traditional medicine preparation procedures from local healers before traditional knowledge of tribal people living in remote locations are forgotten in a rapidly transforming country like India.

The genus Calypogeia Raddi is represented in India by six species (Singh, 2001). All the six species are found in Eastern Himalaya with three species, C. aeruginosa Mitt., C. fissa (L.) Raddi and C. marginella Mitt., restricted to this region alone in Indian bryoflora. Of the remaining three, C. arguta Nees & Mont. is common to Eastern Himalaya, Central India, South India and the Andaman and Nicobar Islands; C. azurea Stotler & Crotz occurs in both Eastern and Western Himalaya and South India and C. lunata Mitt. is common to Eastern as well as Western Himalaya (Mitten, 1861; Chopra, 1943; Sharma & Srivastava, 1993; Singh & al., 2008). During the course of study on the liverworts and hornworts of Mehao Wildlife Sanctuary in Arunachal Pradesh, Eastern Himalaya, the authors came across an interesting species of the genus Calypogeia Raddi. Detailed morphotaxonomic study of the species and study of relevant literature (Bischler, 1962a, 1962b; Srivastava & Sharma, 1986; Sharma & Srivastava, 1993; Paton, 1999) revealed it to be a hitherto undescribed species of the genus. The same has been described and illustrated as C. udarii in the present communication.

The vertically integrated horizontal vapour transport (IVT) accompanied by westerlies and southwesterlies mainly contributes as a distant source of moisture to the seasonal precipitation (PR). The moisture transport and PR patterns across the eastern Himalayas (Sikkim, northern Sub‐Himalayan West Bengal and Arunachal Pradesh) are strongly modulated by the orographic setup, local land‐atmospheric factors and teleconnection with climate indices of the Indian and Pacific oceans. This study elaborates on the changing patterns of PR and IVT, changes in IVT contribution to the seasonal PR under the nonstationary framework and evaluates the nonlinear dependency on local and distant drivers with piecewise regression model. Asymmetries in significant seasonal trends are conspicuous due to multi‐altitude interactions. Strong declining trend over Assam and Arunachal Pradesh is evident for PR with concurrent rising trend over the Meghalaya plateau. The IVT signals show a significant decline in post‐monsoon (October and November) and winter (December to February) across Assam Plain. The increase in mean IVT contributes significantly to seasonal PR. Significant decline in the contribution of heavy IVT to winter PR is observed over Manipur, Mizoram, Tripura and part of Assam. Surface 2 m temperature and net thermal radiation exhibit contrasting influence on seasonal PR. IVT shows mainly positive association with surface 2 m dew point temperature and latent heat flux across the eastern Himalayas. NINO3.4 index exhibits strong negative influence on post‐monsoon PR. The Pacific Decadal Oscillation is strongly associated with summer (March to May) PR. Monsoon (June to September) IVT is negatively influenced by the Pacific Decadal Oscillation over the Sub‐Himalayan West Bengal, Gangetic West Bengal, Bihar and Jharkhand. The Southern Oscillation Index is negatively linked with summer IVT. The combination of local driving forces mainly controls the seasonal PR and IVT across all seasons. Besides, distant drivers are prominent in monsoon and post‐monsoon. This study reveals insights into recent changes of PR and IVT, their contribution to seasonal water resources in the eastern Himalayas and the controlling strength of local land‐atmosphere feedback mechanism and distant land‐ocean coupling drivers under nonstationary climate.

The Eastern Himalayas is known for its fragile mountain ecosystems and is highly sensitive towards climate change. In recent decades, rapid warming and glacial retreat caused significant changes in the number, size and distribution of lakes. These changes increased concerns over a major hazard for downstream regions called Glacial Lake Outburst Floods (GLOFs). The present study focuses on changes in the number and area of different lake classes and GLOF risks in Arunachal Pradesh, Eastern Himalaya during 1988 and 2020. Using multitemporal satellite data, results indicate a significant increase in both number and area of nonglacial lakes (NGLs) by 498 lakes and 3212.56 ha, respectively. Proglacial lakes (PGLs) decreased slightly in number but expanded in area, whereas unconnected glacial lakes (UGLs) increased in number while decreasing in area. The majority of newly formed lakes were located between 4000 and 5000 m above mean sea level (AMSL). A total of 127 lakes was selected for GLOF risk assessment using the Analytic Hierarchy Process (AHP), with lake expansion rate and proximity to glaciers as the most critical parameters. Results indicated that 2 lakes are identified as high risk, 36 as medium risk and 89 as low risk, with a consistency ratio of 0.091. The study highlights the increasing risk potential of expanding glacial and high altitude lakes under climate change. The study further emphasized the need for continuous monitoring, targeted risk mitigation strategies and early warning systems to mitigate the downstream regions in the Eastern Himalaya.

Consumption of naturally fermented milk (NFM) products is the dietary culture in India. The mountainous people of Arunachal Pradesh in India prepare the assorted artisanal home-made NFM products from cow and yak milk. Previously, we isolated and identified 76 strains of lactic acid bacteria (LAB) from NFM products of Arunachal Pradesh, viz. mar, chhurpi and churkam. We hypothesized that some of these LAB strains may possess probiotic potentials; hence, we investigated the probiotic potentials of these strains. On the basis of in vitro and genetic screening for probiotic attributes including haemolytic ability, 20 LAB strains were selected out of 76 strains, for further analysis. Using in silico analysis, viz. multivariate heatmap and PCA (principal component analysis) biplot, Levilactobacillus brevis AcCh91 was selected as the most promising probiotic strain, which was further characterized by the whole-genome analysis. Lev. brevis AcCh91 showed the highest survival rate of 93.38% in low pH and 86.68 ± 2.69% in low bile and the highest hydrophobicity average of 86.34 ± 5.53%. This strain also showed auto-aggregation and co-aggregation with antimicrobial properties against the pathogens, showed ability to produce beta-galactosidase and cholesterol reduction property and, most importantly, produced GABA, an important psychobiotic element. Genomic analysis of Lev. brevis AcCh91 showed the presence of genes corresponding to GABA, vitamins, amino acids, cholesterol reduction, immunomodulation, bioactive peptides and antioxidant activity. The absence of antimicrobial-resistant genes and virulence factors was observed. Hence, genome analysis supports the probiotic potentials of Lev. brevis AcCh91, which may be further investigated to understand its health-promoting properties.

Can grass phytoliths and indices be relied on during vegetation and climate interpretations in the eastern Himalayas? Studies from Darjeeling and Arunachal Pradesh, India

Silkmoths are both ecologically significant and economically valuable insects, with larval host plant associations playing a crucial role in shaping their development, survival, and silk yield. Arunachal Pradesh, a biodiversity hotspot in the Eastern Himalayas, harbours diverse silk moth species. However, comprehensive documentation of their host plants remains limited. Through extensive field surveys conducted in various parts of Arunachal Pradesh, we recorded 14 species of wild silkworms, and documented seven species of new host plant associations for three wild silkmoth species in addition to the previous records. The new records include Gunda ochracea Walker (Bombycidae) on Ficus rumphii Blume (Moraceae), Antheraea frithi Moore on Terminalia chebula Retz, Terminalia myriocarpa Van Heurck and Müll. Arg, Combretum pilosum Roxb. ex G.Don (Combretaceae), Lagerstroemia speciosa (L.) Martyn (Lythraceae), Castanopsis lanceifolia (Oerst.) Hickel and A.Camus (Fagaceae) and Samia canningii (Hutton, 1859) on Litsea monopetala (Roxb.) Pers. (Lauraceae). These results fill a major gap in the ecological knowledge of wild silkmoths in the Eastern Himalayas. Additionally, it supports sericultural applications of the documented larval host plants.

<div> <p>One of the first order questions regarding a cross-section representation through a fold-thrust belt (FTB) is usually “how unique is this geometrical interpretation of the subsurface?”  The proposed geometry influences perceptions of inherited structures, decollement horizons, and both rheological and kinematic behavior.  Balanced cross sections were developed as a tool to produce more accurate and thus more predictive geological cross sections.  While balanced cross sections provide models of subsurface geometry that can reproduce the mapped surface geology, they are non-unique, opening the possibility that different geometries and kinematics may be able to satisfy the same set of observations. The most non-unique aspects of cross sections are: (1) the geometry of structures that is not seen at the surface, and (2) the sequence of thrust faulting.  We posit that integrating sequentially restored cross sections with thermokinematic models that calculate the resulting subsurface thermal field and predicted cooling ages of rocks at the surface provides a valuable means to assess the viability of proposed geometry and kinematics.  Mineral cooling ages in compressional settings are the outcome of surface uplift and the resulting focused erosion.  As such they are most sensitive to the vertical component of the kinematic field imparted by ramps and surface breaking faults in sequential reconstructions of FTB.  Because balanced cross sections require that the lengths and locations of hanging-wall and footwall ramps match, they provide a template of the ways in which the location and magnitude of ramps in the basal décollement have evolved with time.  Arunachal Pradesh in the eastern Himalayas is an ideal place to look at the sensitivity of cooling ages to different cross section geometries and kinematic models. Recent studies from this portion of the Himalayan FTB include both a suite of different cross section geometries and a robust bedrock thermochronology dataset. The multiple published cross-sections differ in the details of geometry, implied amounts of shortening, kinematic history, and thus exhumation pathways. Published cooling ages data show older ages (6-10 Ma AFT, 12-14 Ma ZFT) in the frontal portions of the FTB and significantly younger ages (2-5 Ma AFT, 6-8 Ma ZFT) in the hinterland. These ages are best reproduced with kinematic sequence that involves early forward propagation of the FTB from 14-10 Ma.  The early propagation combined with young hinterland cooling ages require several periods of out-of-sequence faulting. Out-of-sequence faults are concentrated in two windows of time (10-8 Ma and 7-5 Ma) that show systematic northward reactivation of faults.  Quantitative integration of cross section geometry, kinematics and cooling ages require notably more complicated kinematic and exhumation pathways than are typically assumed with a simple in-sequence model of cross section deformation.  While also non-unique, the updated cross section geometry and kinematics highlight components of geometry, deformation and exhumation that must be included in any valid cross section model for this portion of the eastern Himalaya.</p> </div>

Three East and South-east Asian species of the genus Radula Dumort., viz. R. chinensis Steph., R. kojana Steph. and R. sumatrana Steph. are newly reported for the Indian bryoflora, from Arunachal Pradesh in Eastern Himalaya. Asexual reproduction through caducous leaves is described for the first time in R. sumatrana. Descriptions and illustrations of the three species based on Indian material are presented. A key to the Indian species of Radula is provided.