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The Eurasian Otter Lutra lutra is an elusive, solitary animal that has one of the widest distributions of all palearctic mammals. Once widely distributed in Asia, the Eurasian Otter population is now vulnerable to urbanization, pollution, poaching, and dam construction. Eurasian Otter distribution in the Indian Himalayan rivers is little explored, and information from this high-altitude riverine ecosystem is sparse. This publication reports a rare photographic record of the Eurasian Otter which confirms its presence in the high-altitude temperate forest of the Upper Bhagirathi Basin, western Himalayan region. The otter was recorded during investigations of terrestrial and aquatic fauna in the Bhagirathi Basin (7,586 km², 500–5,000 m) of Uttarakhand State, India from October 2015 to May 2019. Among aquatic fauna, Brown Trout were found to be abundant in high altitude river stretches, with a catch per unit effort of 1.02 kg h–1. Additionally, 26 families of freshwater macroinvertebrates underscored a rich diet available for the Brown Trout, which in turn is a potential food source for the otters. The riverine ecosystem is undergoing dramatic changes because of the increasing demand for hydropower plants in the Bhagirathi Basin. Although mitigation measures are currently in place for fish, the presence of otters further necessitates the need for targeted management for high-altitude Himalayan rivers. There is an imperative need for intensive otter surveys using methods such as camera traps in riparian habitats along the Bhagirathi River and its tributaries. [ABSTRACT FROM AUTHOR]

In the present study, detailed morphometric, morphotectonic, statistical and hazard analyses have been carried out in the Upper Alaknanda river basin (UAB) located in Central Himalayas, Garhwal, India. The study area is bounded by the South Tibetan Detachment System in the north and by the Main Central Thrust in the south. The major river flowing in the area is Alaknanda which is a major tributary of river Ganga. The purpose of this study is to examine the influence of active tectonics, flood hazard, and soil erosion on the basis of morphotectonic and morphometric parameters using the Cartosat-1 Digital Elevation Model and ArcGIS software. The study area is divided into 10 sub-basins, where 50 morphometric and 6 morphotectonic parameters were calculated. Bifurcation ratio and stream frequency show that streams up to third order is having steep gradient and rolling through highly dichotomized terrain, due to which high overland flow and less groundwater recharge takes places, whereas drainage density clearly indicates the high flood possibility in the region. Morphotectonic parameters indicate relatively young to an early mature geological stage of sub-basins and tectonically active region. The statistical analysis of morphometric parameters is carried out by using correlation analysis, hierarchal cluster analysis, and principal component analysis. Based on their susceptibility to soil erosion, morphometry and landcover classification is carried out to prioritize the sub-basins of UAB. The combined morphometric, morphotectonic and statistical analysis indicates that the area is tectonically active and highly prone to flood, flood induced landslide and soil erosion. The case study of the 2013 flash flood event at three locations Benakuli, JP HEP and Pulna also confirms that the study area is hydro-geologically active to flood and flood induced hazards. The results obtained in this study are directly related to watershed management and hence soil erosion, tectonic activities and flash flood possibilities should be taken into consideration during future development in the area. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • First glacial and de-glacial chronology from the Sikkim higher Himalaya. • Glaciation dates back to the MIS 2 and started at ∼28 ± 2.8 ka. • We ascribe the glaciation to lower temperature and increase moisture. Abstract The present study investigates the relics of the most extensive glacier advances and their retreat in the transitional climatic zone of the Chopta valley, northern Sikkim Himalaya with an aim to understand the forcing factors. The optically stimulated luminescence (OSL) dating of the stratigraphically oldest glacier advance and its retreat in the Chopta valley revealed that the glacier advanced at ∼28 ± 2.8 ka and sustained through the global Last Glacial Maximum (gLGM; 26.5 ka and 19 ka; Mix et al., 2001). The deglaciation is manifested by recessional moraine (ridge) dated at ∼18 ± 2.2 ka. Comparing the results of the present study with the existing glacial chronologies from the Himalayan region, it has been observed that irrespective of the geographical locations; the intensified mid latitude-westerlies during the gLGM and the associated decrease in winter temperature was the major driver of glacier advance during the MIS-2. [ABSTRACT FROM AUTHOR]

Geomorphic and morphotectonic evaluations of the Kashmir Basin have been carried by implicating different geomorphic indices such as stream-gradient index (SL), hypsometric integral (HI), drainage basin asymmetry (AF), valley floor height and width ratio (Vf), transverse topographic symmetry factor (T), mountain front sinuosity (Smf), drainage basin shape (BS) and sinuosity index (SI) for the categorization of relative index of active tectonics (RIAT) through the use of geographic information systems (GIS) so as to decipher the role of neotectonics in geomorphologic evolution of the basin. The verified RIAT classes through field investigation and validation reveal the traverse of twenty-one active faults in the basin with demarcation of three RIAT classes viz., class-1 (inactive 20.07% of the area), class-2 (moderately active; 36.52% of the area) and class-3 (very active; 43.4% of the area). The observed values of RIAT distribution pattern are well corroborated with field observations. Ultimately, the overall geomorphic outputs and clustering of recent seismicity support the active tectonic control over the Kashmir basin, India. [ABSTRACT FROM AUTHOR]

The slopes of western Lesser Himalaya (at Sangaldhan Block of Udhampur near Ramban, Jammu and Kashmir India) are being severely affected by tectonic and erosional activities. These activities result in deposit of a thick cover of rock fragments and overburden just above the hard rock. The thickness of overburden cover has directly affected the stability of slope in the study area, though the traditional stability estimation techniques, rock mass rating and slope mass rating, rate this area as moderately stable which does not represent the real stability condition. In this research work, the geotechnical and geophysical surveys have been carried out to reckon the slope stability conditions more accurately as compared to traditional slope stability estimation techniques. A new rating, new slope mass rating, is developed, which gives a better picture of the stability of slopes. It incorporates a new parameter of overburden thickness profile, along with slope angle and other associated factors on the slopes of the mountainous terrains. The vertical electrical sounding surveys were conducted for the demarcation of rock-overburden interface and for determining the overburden cover. This new classification depicts an increase of 12.84 % in unstable slope areas giving a better assessment and factual picture of slope stability in our study area. This study also enumerates the importance of geophysical applications in slope stability studies. The research work is applicable in mountainous terrains such as Himalaya, and the major component of the application is the orientation of overburden or the profile of thickness in relation with slope of surface. [ABSTRACT FROM AUTHOR]

Abstract: The present study demonstrates how the Paleo-Proterozoic Wangtu Gneissic Complex (WGC) of the Lesser Himalayan Crystalline sequence experienced superposed folding and doming prior to its exhumation, with the help of integrated field, microstructural, magnetic fabric anisotropy and geochronological studies. The WGC forms the basement of the Lesser Himalaya and is bounded by Vaikrita Thrust (VT) to the northeast and Munsiari Thrust (MT) to the southwest. The regional structure consists of upright large scale early folds (D1) trending NW–SE. The mesoscopic fabric is related to axial plane foliation of the D1 folds and, to a lesser extent, late D2 folds. The axis of maximum compression for D1 and D2 folds are mutually orthogonal. The D1 folds have formed simultaneously with the major Himalayan thrusts whereas the D2 folds have developed during a later deformation event. The magnetic lineation at the hangingwall of the VT is sub-horizontal indicating stretching along the strike of the thrust. In the interior parts of the WGC, the magnetic fabric is of two types: (i) magnetic lineation demarks the intersection of mesoscopic and magnetic foliation indicating superposed deformation and (ii) scattered distribution of magnetic lineations due to D2 folding on initially curved and non-cylindrical D1 surface. 40Ar–39Ar dating of biotite from one site from the core of WGC gives an age of 9.3±0.3 (2σ)Ma. It is inferred that the doming of the WGC took place at ∼9Ma and, instead of large scale thrusting, it is characterized by superposed folding and strike-parallel stretching along the VT zone. It is suggested that the effect of superposed folding and ductile deformation of the Himalayan basement rocks has to be taken into account before cross-section balancing or any estimation of crustal shortening is attempted. [Copyright &y& Elsevier]

Hemithecium isidiatum from the Eastern Himalayas is described as new to science. It is the first isidiate species in the genus Hemithecium and is otherwise characterized by hyaline muriform ascospores and the presence of salazinic acid. [ABSTRACT FROM AUTHOR]

Abstract: In order to assess the spatial and temporal extent of sediment transport from the Gangdese batholith of Tibet to the eastern Himalayan Neogene foreland basin, we performed U–Pb and Lu–Hf analyses on eleven sandstone samples from three locations within the Arunachal and Sikkim Himalaya. We also analyzed detrital zircons from eight modern river sand samples of the Yalu–Brahmaputra River system and its major tributaries in the eastern Himalaya. Results from the river sands are used to contrast the provenance characteristics of the Gangdese arc in southern Tibet with nominally equivalent arc rocks east of the Himalaya in the northernmost Indo-Burma Ranges. Our results indicate that the deposition of Gangdese batholith-derived sediment within the eastern Himalayan foreland: (1) occurred throughout Late Miocene and Pliocene time (~10–3 Ma), (2) was limited to the Arunachal Himalaya, and (3) was sourced north of the Himalaya. This detritus may have been deposited by a transverse Himalayan river, such as the Subansiri River, as suggested by high percentages of the Gangdese-derived zircons within the Neogene samples (15–31%) and S- to SW-oriented paleocurrent directions from two of the Neogene sample localities. At this time, our preferred model to explain the data invokes capture of an originally westward-flowing Yalu River by the Subansiri River at ~10 Ma, followed by capture of the Yalu River by the Siang River at ~3–4 Ma. [Copyright &y& Elsevier]