Assessing the role of Alnus nepalensis D. Don in stabilizing landslide and its potential distribution: a case study from Uttarakhand, Western Himalaya.

The rising frequency and severity of landslides in the vulnerable Himalayan region of India threaten human settlements and critical infrastructure. This growing issue demands urgent action and innovative strategies to mitigate risks and bolster the resilience of affected communities and infrastructure in this fragile area. The research explores the use of Alnus nepalensis for slope stabilization, illustrated by a case study near Ukhimath, Uttarakhand, India, and elucidates the potential ecological niche of Alnus in the temperate region of Uttarakhand using well-dispersed species occurrence records along with environment. The study used Sentinel-2 (2021) data for land use and land cover (LULC) mapping and Landsat 4-5, Sentinel-2, and Google Earth imagery from 1998, 2004, 2015, 2019, and 2020 for landslide slope recovery assessment. The Ukhimath landslide, spanning 54.61 ha in August 1998, demonstrated a remarkable recovery, with 98.20% coverage of Alnus by 2020, showcasing the species efficacy in stabilizing slopes without human intervention. The research forecasts a total potential distribution area of Alnus in the temperate region (1,000-2,500 m·asl [above mean sea level]) of Uttarakhand as ∼7,833 km2, with 782.30  km2 highly suitable, 2,104.33  km2 moderately suitable, and the rest showing low suitability. These distribution insights provide a foundation for in situ planning to leverage Alnus-based bioengineering for early slope stabilization, which is especially relevant in landslide-prone areas like Uttarakhand. The study provides a comprehensive and scientifically rigorous strategy for achieving sustainable outcomes in landslide-prone areas, particularly in the lower temperate region of the Himalaya.