Investigating the 7th February, 2021 Landslide Triggered Flash Flood in the Himalayan Region Using Geospatial Techniques

On 7th February 2021 just before noon, news reports came in regarding a flash flood in Rishi Ganga/Dhauli Ganga River in Chamoli district of Uttarakhand state, India. This brief report puts forth the probable causes for this flash flood that has originated in the Nanda Devi Biosphere Reserve using geospatial datasets and techniques. Datasets obtained from MODIS, Sentinel-2B, SRTM, ICESat-2 and ERA5 have been effectively utilized to infer the details about this event. Slow drizzle to severe snowfall has been witnessed during 3rd to 6th February 2021 in various parts of the Himalayan region; even the Rishi Ganga witnessed a heavy snowfall during this time. Data acquired on 10th February shows a scar developed due to a landslide on the shoulder of Ronti Mountain that was situated on the western rim of the Nanda Devi sanctuary. There was a gradual rise in temperature on 7th February 2021 at the surroundings of Ronti Mountain that consequently led to a landslide. The landslide perpetuated a movement under the influence of gravity from ~5900 m to ~3900 m with a mass envelope of ~0.290 km² and a velocity of 198 m/s that may have taken ~20 seconds to hit the Ronti bank. Due to the virtue of heat energy generated during this process resulted in contributing huge moraine filled flood water, that has accelerated towards the downstream of Rishi Ganga River and there after Dhauli Ganga River. Elevation profiles from the ICESat-2 and satellite imageries confirm the pre-existing conditions of landslide that is inclusive of weathering and erosion that led to the unstable condition at transportation back-slope of the Ronti Mountain. The triggering factors that influenced this landslide event and related causes were investigated in this study and reported herewith.

New distribution and range extension records of geometrid moths (Lepidoptera: Geometridae) from two western Himalayan protected areas

This article presents new distribution and range extension records (including new records from the state of Uttarakhand) of 12 species of the Geometridae family along with their taxonomic records. The records are based on field collections, where sampling was done along elevation and vegetation gradients in the buffer zones of Nanda Devi Biosphere Reserve and Kedarnath Wildlife Sanctuary, two prominent protected areas in the western Himalayan Indian state of Uttarakhand. DNA barcoding was performed for some of the species for confirmation of identification in addition to the morphological identifications. Voucher specimens are deposited in a public repository for future reference.

Threat Assessment and Prioritization of High-Value Medicinal Plants in Pindari Valley, Nanda Devi Biosphere Reserve, India

The communication assesses the high-value medicinal plants reported in Pindari Valley, Nanda Devi Biosphere Reserve, Uttarakhand, using a score-based method for prioritization and conservation. A total of 42 high-value medicinal plants were assessed, prioritized and scored on the basis of rapid threat assessment. Maximum threat was recorded for Aconitum heterophyllum followed by Picrorhiza kurrooa and Nardostachys jatamansi given their limited number of individuals observed in the study area as well as high utilization patterns. Minimum threat status was recorded for Epilobium angustifolium, where the species was found in higher density in its natural habitat. Among the recorded species, 64% were observed growing in grassland/alpine pastures and open/alpine slopes. 55% of species were native/endemic to Himalaya and 48% were extracted by the inhabitants. Underground portions (roots/rhizomes/tubers) of 40% of the species were utilized leading to destruction in natural habitat. Out of 42 medicinal plants, 16 species have been prioritized for conservation and recognized in different threat categories and most of these species are collected from natural habitat without scientific knowledge. Conclusion of the study might helpful for identifying threatened plants in the region so as to initiate sustainable use and conservation practices of high-value medicinal plant resources.

Forest Structure, Diversity and Regeneration Pattern Along Altitudinal Gradient in Temperate Zone of Nanda Devi Biosphere Reserve (a World Heritage Site), Western Himalaya, India

BackgroundThe present study exhibited forest structure, plant species composition and regeneration pattern in temperate zone of Nanda Devi Biosphere Reserve (NDBR), western Himalaya along the different altitudinal gradient (2600 to 3600 m asl). The diverse ecosystems of the NDBR contain a tremendous array of floral and faunal diversity, many of which are rare and endangered species. ResultsA total of 223 species of vascular plants (Angiosperm, Gymnosperm and Pteridophytes) were identified within the study area. Rosacaeae (17.69 %) family was exhibited dominant followed by Asteraceae (14.97 %) and Ranunculaceae (12.93 %). Among all the plant species, Betula utilis had highest tree density (724 & 324 individuals ha-1 in each site) and contributed maximum dominance of species cover (44 % and 36 % ) at Tolma and Ghangaria sites followed by Pinus wallichiana (24 %) and Cedrus deodara (15 %), respectively. In Ghangaria site, 56 % tree species showed fair regeneration, 22 % good, 11% exhibited poor and remaining (11 %) indicated no regeneration while at Tolma site, 40 % species showed fair regeneration, 40 % good and remaining 20 % no regeneration. ConclusionOur results suggest to monitor the change in vegetation structure, species composition and regeneration pattern, we should establish permanent study plots in different forest types located along the elevational gradients for an effective and comprehensive monitoring programme to tracks the response of changing climate at both community and species level. Therefore, it is necessary to development of appropriate weather and meteorological station in this sensitive and ecologically important area for regional projection of micro climatic condition and generation of scientific data on changing vegetation composition and advancement of the native species.