Search

The present paper is the outcome of an extensive floristic survey conducted in two phases by the authors in Kyongnosla Alpine Sanctuary, East Sikkim, India. During the study 411 taxa (400 species, 04 subspecies and 07 varieties) belonging to 173 genera and 54 families were recorded. The most dominating family was Asteraceae with 44 species followed by Ericaceae 28 species, Ranunculaceae 26 species, Polygonaceae 24 species and Rosaceae 20 species. These five families represent 34.13% of the total taxa recorded from the sanctuary. About 12 families were represented by only one species each. The most dominating genus was Rhododendron (18 species) followed by Primula (16 species), Pedicularis (15 species), Gentiana (11 species), and Impatiens (10 species). Among the different growth forms, herbs contributed the maximum (86.61 %) followed by shrubs (7.79%), trees (4.87%), climbers 0.49%, and epiphyte (0.24%). [ABSTRACT FROM AUTHOR]

The present study identified 20 liverwort species from Tirap district, Arunachal Pradesh, India, marking the first ever documentation of bryophytes from the region. The specimens were collected from various locations within the study area and subsequently brought to the laboratory. Micromorphological and anatomical characteristics of the specimens were analysed and identified by consulting relevant literatures. Three species, viz. Plagiochila himalayana Schiffn., P. khasiana Mitt., and Solenostoma lanigerum (Mitt.) Váňa & D.G.Long, are newly reported for the first time from the state of Arunachal Pradesh. The species were found to be an integral part of ecosystem growing in association with various plant species, providing soil stability, and shelter for other organisms. The study is important for understanding bryophyte diversity and ecosystem health of the region. In addition, it will also help in planning conservation strategy and sustainable management of bryophytes, their habitat or host species and the overall biodiversity in the region. [ABSTRACT FROM AUTHOR]

The paper in an attempt to develop an inventory of faunal diversity of Dibru-Saikhwa Biosphere Reserve (DSBR) of Assam which is one of the important Biosphere Reserves of the Eastern Indian Himalaya and to highlight the threats that the BR is facing over the years so as to decisively support the need for conservation efforts. After compilation and analysis from various data sources the BR depicts the presence of 503 species of birds, 37 species of mammals, 42 species of reptiles, 17 species of amphibian, 104 species of fishes, 105 species of butterfly and 91 globally threatened faunal species, while the Soil microbial diversity in the BR is contributed by 26 soil micro-fungal forms. The rich biodiversity of the BR is under stress due to natural and human pressures. As per the recent studies, the BR has lost an area of 77.14km² due to revirine stress and 3.71km² has been encroached as per the State Forest Report. [ABSTRACT FROM AUTHOR]

Profiles of aerosols and cloud layers have been investigated over a high-altitude urban atmosphere in the eastern Himalayas in India, for the first time, using a Raman LIDAR. The study was conducted post-monsoon season over Darjeeling (latitude 27°01 ′ N longitude 88°36 ′ E, 2200 masl), a tourist destination in north-eastern India. In addition to the aerosols and cloud characterization and atmospheric boundary layer detection, the profile of the water vapor mixing ratio has also been analyzed. Effects of atmospheric dynamics have been studied using the vertical profiles of the normalized standard deviation of RCS along with the water vapor mixing ratio. The aerosol optical characteristics below and above the Atmospheric Boundary Layer (ABL) region were studied separately, along with the interrelation of their optical and microphysical properties with synoptic meteorological parameters. The backscatter coefficient and the extinction coefficient were found in the range from 7.15 × 10 − 10 m − 1 sr − 1 to 3.01 × 10 − 5 m − 1 sr − 1 and from 1.02 × 10 − 5 m − 1 to 2.28 × 10 − 3 m − 1 , respectively. The LIDAR ratio varies between 3.9 to 78.39 sr over all altitudes. The variation of the linear depolarization ratio from 0.19 to 0.32 indicates the dominance, of non-spherical particles. The periodicity observed in different parameters may be indicative of atmospheric wave phenomena. Cloud parameters, such as scattering coefficients, top and bottom height, and optical depth for different cloud phases, have been evaluated. A co-located Micro Rain Radar has been used with LIDAR for cloud life cycle study. [ABSTRACT FROM AUTHOR]

Current paper aims to review the climate change scenario of Arunachal Pradesh and its impact on the agricultural productivity and the farming system of the state. Arunachal Pradesh is witnessing climate change with rise in average temperature, particularly the minimum temperature. Though the amount of rainfall remains more or less constant, but the intensity increases with lowering of number of rainy days by 11 per cent in the recent decades. Also, there are profound variations in the spatial and temporal distribution in rainfall patterns with persistent mid season dry spell during July and August. Climate change is threatening food production system and therefore the livelihood and food security of people across the State, particularly that of the hill regions. Fragile and poorly accessible landscapes with sparsely scattered settlements, primitive agricultural practices and poor infrastructure make agriculture of Arunachal Pradesh extremely vulnerable to climate change. The observed and likely future effects are diverse and geographically differentiated, creating uncertainty, which makes the task of preparing for climate change impacts very difficult. To increase the resilience of sector in the state needs pro-environment and pro-development research and policies tailored to the local needs and conditions. [ABSTRACT FROM AUTHOR]

The along‐strike heterogeneity in the tectonics of Himalaya is well recognized; however, the eastern segment of Himalaya is less studied compared to the other segments. This study combines the comprehensive field data, as well as the U–Pb geochronology of sandstone samples from the Indo‐Burma Range (east India). The study shows that the Lower Disang Formation was deposited in an open marine environment with a steep gradient during the Late Cretaceous to Mid‐Eocene, accommodating the detritus solely from an Indian source. Furthermore, during the Early to Late Eocene interval, the sedimentary basin changed to a shallow marine shelf when the sediments from Himalayan as well as trans‐Himalaya were deposited. The Upper Disang Formation must have been deposited just before or during the collision process between the Indian and Asian plates. After the India‐Asian collision, there was a remnant ocean, in which the sediments of the Barail and Surma groups were deposited in the shallow marine to deltaic environments. The Tethys Ocean completely dried out in the Late Miocene resulting in a change from marine to fluvial environments, which facilitated the deposition of the sandstones of the Tipam Formation. Based on the U–Pb ages, the Palaeogene basin history in the Indo‐Burma Range was unlike the central Himalaya, that is, the detritus were mainly sourced from the Burmese Plate and adjoining magmatic rocks. [ABSTRACT FROM AUTHOR]

The Matiali fan is a coarse-grained, small alluvial fan in the eastern Himalayan foothills. It co-exists side by side with the large Tista megafan and other Quaternary fluvial deposits, and has been affected by a number of young thrust faults. It is generally believed that tectonics is the main control in the deposition of these proximal fan–terrace systems. In this paper, geomorphologic and sedimentologic study of the Matiali fan and associated river terraces are combined with five OSL dates from these deposits to understand the succession of events and the forcing mechanism that shaped the geomorphology in the study area during late Quaternary time. Two aggradational terraces (T1 and T2; T2 > T1) occur within the river valleys incised on the Matiali fan. Three E–W scarps cross the fan surface, and they represent the steeper limb of the asymmetric fault-propagation folds formed over blind thrusts. These folds have deformed the fan (T3) and T2 terrace sediments, but the youngest T1 terrace deposits have remained undeformed. Sedimentological studies indicate continuous gradation from the coarsening-upwards mass-flow megagravel in the proximal part to the traction transported finer sheetflood gravels in the distal part, implying a continuous sedimentation history across the fan, uninterrupted by any evidence of syn-depositional tectonic movement. Poorly consolidated sandy gravels of the terraces indicate deposition through braided fluvial processes during a later period of sediment aggradation that filled up the incised river valleys. Previously published 14 C dates indicate that deposition of the Matiali fan started around 34 ka coinciding with a period of the intensified Indian summer monsoon of MIS-3. It is suggested that the fan was abandoned and river valleys incised during the LGM between 24 and 18 ka when the discharge decreased substantially. Increased rainfall and sediment supply, with their inherent fluctuations, during wetter periods of MIS-2 and MIS-1 since 12 ka probably resulted in the aggradation of T2 and T1 as shown by our OSL dates. OSL dates from the top of deformed T2 and base of undeformed T1 indicate that the Chalsa fold formed between ~ 11 and ~ 6 ka. Succession of geomorphic and deformational events reconstructed from this study and available age data indicate that the Matiali fan and terrace aggradation coincides with periods of increased monsoonal precipitation, whereas tectonic movements along blind thrusts of Chalsa and Matiali took place later, deforming the fan and older terrace deposits. The evidence unequivocally indicates, contrary to the prevalent notion of tectonic control of geomorphic features in the proximal mountain-front setting, that the deposition of the fan–terrace system was primarily controlled by the fluctuation of the Asian summer monsoon rather than Himalayan tectonics. [ABSTRACT FROM AUTHOR]

Two new species of the subfamily Dorylinae Leach, 1815 namely Parasyscia ganeshaiahi sp. nov. and Syscia indica sp. nov. are described and illustrated based on the worker caste. These species were collected in the Eaglenest Wildlife Sanctuary, Arunachal Pradesh, Northeast India. Keys to Parasyscia of India and Syscia of Asia are provided based on the worker caste. [ABSTRACT FROM AUTHOR]

Moth biodiversity assessments at Tale Wildlife Sanctuary in Arunachal Pradesh, India, which consisted of over 29 days of survey during the months of April, May, August and September in 2011 and 2019, resulted in a checklist of 497 moth species of which 460 species are identified to species level, while 37 are identified to genus level. There are 17 species for which no published records exist from India and are additions to the known moth fauna of India, and more than a hundred species for which no published records exist from Arunachal Pradesh. Over 200 species still remain to be identified. We also include two additional plates with species identified after the submission of the manuscript and some prominent unidentified species. [ABSTRACT FROM AUTHOR]

We present a comprehensive geochemical data set of whole‐rock geochemistry and mineral phases from the mantle peridotites and mafic intrusives of the Tuting–Tidding Suture Zone (TTSZ) ophiolites, eastern Himalaya, north‐east India. Modal mineralogy, low Al2O3 and CaO, high Cr# of Cr‐spinels, and forsterite number (Fo90–92) in primary olivine indicate the highly refractory nature of the TTSZ peridotites. LREE‐enriched patterns, cumulative olivines in dunites, and Cr‐spinel and olivine compositions further suggest that the peridotites were subjected to high‐temperature melt–rock interaction from a percolating boninitic melt in the nascent forearc of an intra‐oceanic subduction zone. The associated mafic intrusives are tholeiitic in nature and their geochemical characteristics [∑REE = 23.34–59.12; nearly flat rare earth elements (REE) pattern (LaN/YbN = 1.49–2.58); negative anomalies of Nb and Ti] show mid‐oceanic ridge basalt affinity. Trace elemental modelling of the mafic intrusives along with their mineralogy and geochemistry suggests that they formed due to different degrees of partial melting with the involvement of a subduction component in the spreading regime of the forearc region. Based on the presence of hydrous minerals like Cr‐chlorite and tremolite in the peridotites and P–T modelling (525–575°C, 1.05–1.09 GPa) of the mafic intrusives, it is considered that TTSZ ophiolites underwent low‐temperature metamorphism by fluid–rock interaction either during the later phase of subduction (in a cool mature subduction zone) or during Himalayan Orogeny. We also infer that the TTSZ ophiolites resemble other Neo‐Tethyan ophiolites of the Indus‐Tsangpo Suture Zone in terms of their geochemical and petrogenetic aspects. [ABSTRACT FROM AUTHOR]

The Soil and Water Assessment Tool (SWAT) model was configured to simulate streamflow under data scarcity scenario for a snow-dominated, forested, mountainous Mago River basin located in the Eastern Himalayan region of India. To account for the role played by snowmelt dynamics on streamflow and its influence on water balance components of the basin, two separate projects were set up: a Reference project in which only hydrological parameters related to streamflow were considered without regard to snow-related parameters, elevation bands, and associated lapse rates and another project referred to as Elevation Band project in which 10 elevation bands were set up for six snow-dominated headwater sub-basins. Sensitivity analysis and calibration was performed using SWAT Calibration Uncertainty Programs/Sequential Uncertainty Fitting 2 for both the projects. The result of the sensitivity analysis showed that curve number (CN 2) was found to be most sensitive. The comparison between the two calibrated projects revealed that inclusion of snow-related parameters, elevation bands, and the associated lapse rates in the snow-dominated headwater catchments improved the hydrological simulation performance and this improvement propagated downstream towards the outlet of the basin. This enhancement highlighted the ability of SWAT to capture the snowmelt dynamics prevailing in the Eastern Himalayan region. Analysis of the water balance components showed that water yield and percolation increased, while evapotranspiration decreased under the effect of snow cover. The contribution of snowmelt runoff to the annual streamflow of the basin was about 8%, and the maximum contribution was made during the pre-monsoon period. This study also highlighted the importance of the presence of snow cover to sustain the ecosystem of the region. [ABSTRACT FROM AUTHOR]

A single male specimen of Leptobrachium bompu was collected from Talle Valley Wildlife Sanctuary, Lower Subansiri District, Arunachal Pradesh in 2015. This is the first report of this species after its original description in 2011 based on a male specimen. The present collection locality is about 200km from the type locality. Additional notes on morphological variations have added to the much-needed study on the intra-specific variation of the species. [ABSTRACT FROM AUTHOR]

In the hilly tropics, although shifting cultivation is a widespread practice, government policies have attempted to replace it with other land uses. However, several factors determine whether farming communities can make the shift. We tried understanding the factors that facilitate or impede the shift to settled cultivation through interviews with the Adi tribe in north-east India. Although settled cultivation was initiated in the 60s, about 90 % of the families still practise shifting cultivation, observing 13 festivals associated with the annual agricultural calendar. Our results indicate that the economic status of a household determined whether a family undertook settled cultivation, while labour availability was important for shifting cultivation. Often, these nuances are ignored in the Government policies. We conclude that future policies should be mindful of cultural and socio-economic factors that affect the community and of the social-ecological resilience of the landscapes and not use a one-size-fits-all strategy. [ABSTRACT FROM AUTHOR]

Symbrenthia silana, the Scarce Jester Butterfly (Nymphalidae: Nymphalinae), is legally protected under Schedule-I of India's Wildlife (Protection) Act, and listed as Vulnerable to extinction following IUCN's Red List Categories and Criteria in the Red Data Book of Indian butterflies. However, the species is so rare that it has not been seen for ca 90 years and nothing is known about its status, habitat and populations. Here I report rediscovery of the species from Sikkim, Namdapha Tiger Reserve and Nokrek National Park in the Eastern Himalaya and Garo Hills of northeastern India. The first pictures of live butterflies are presented along with information on the habits and habitat of the species, and a discussion of its status as a vulnerable species. [ABSTRACT FROM AUTHOR]

Due to their restricted distribution range and dwindling population endemic and threatened species need considerable attention from ecologists. Sikkim is a part of the Eastern Himalayas Endemic Bird Area that represents high concentrations of globally threatened species. This study collected information on endemic and threatened birds of Sikkim using point count method. The number of species and their density at five elevation zones were calculated. Out of 10 species endemic to Sikkim, five were recorded during the present study. These species were restricted to one to three habitats but densities varied among the habitats. Similarly, out of 17 threatened and 10 near-threatened species of birds that occur in Sikkim, we could observe only three species. The results show that these birds are rare or their occurrence is doubtful in recent years. The principal threat to birds in the state appears to be loss of breeding habitat. Species-specific studies focusing on population status, habitat requirements and assessment of threats are necessary for the execution of conservation measures. [ABSTRACT FROM AUTHOR]

Copyright of Conservation Biology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We use broad-band teleseismic data recorded at eight sites along a north–south profile from Karimganj (24.84°N, 92.34°E), south of the eastern Shillong Plateau, to Bomdilla (27.27°N, 92.41°E) in the eastern Lesser Himalaya, to determine the seismic characteristics of the crust in northeastern India. We also analyse data from the Chinese Digital Seismic Network station at Lhasa and INDEPTHII stations located on the southern Tibetan Plateau north of our profile, to extend the seismic images of the crust further northwards. Although the northeastern Indian stations and the Tibetan stations do not lie along a linear profile across the Himalaya, the well-recognized uniformity of the Himalaya along strike make this comparison of the two profiles meaningful. Receiver functions calculated from these data show that the crust is thinnest (∼35–38 km) beneath the Shillong Plateau. Receiver functions at Cherrapunji, on the southern edge of the Shillong Plateau, have a strong azimuthal dependence. Those from northern backazimuth events show that the Moho beneath the southernmost Shillong Plateau is at a depth of∼38 km while receiver functions from southern backazimuth events indicate that the Moho beneath the northernmost Bengal Basin is at a depth of∼44 km. Receiver functions from sites on the Brahmaputra Valley demonstrate that the Moho is deeper by∼5–7 km than below the Shillong Plateau, a result which agrees with the hypothesis that the Shillong Plateau is supported by shearing stress on two steep faults that cut through the crust. Further north of the eastern Himalayan foredeep, the Moho dips gently northwards, reaching a depth of∼48 km beneath Bomdilla in the Lesser Himalaya, and 88 km below Lhasa in Tibet. Using the crustal velocity models obtained from receiver function inversions, we redetermined focal depths of well-recorded earthquakes across this part of the Indo-Tibetan collision zone and find all of these to occur within the crust. Hence we find no evidence for bimodal depth distribution of earthquakes beneath this region of northeastern India. [ABSTRACT FROM AUTHOR]