Trees, Shrubs and Herbs for Slope Stabilization in Landslide Prone Areas of Eastern Himalaya

Abstract

The Himalayan region is prone to natural calamities such as flash flood, glacial lake outburst, landslide and avalanche. The region falls within high risk seismic zone ‘V’ and witnesses unpredictable weather conditions like cloud-bursts and incessant rainfall. Developmental activities undertaken in these areas compounds the risk considerably. Of all, landslides are the most commonly occurring natural disasters in the Eastern Himalayan Region. Technologies for mitigating the landslide hazard focus mostly on building civil engineering structures such as retainer walls and boulder sausages. As part of the long-term solution, and to ensure the provisioning of ecological services, native plant species having slope stabilizing traits must be planted along with the engineering structures. Trees having a deep tap root system keeps boulders from sliding while herbs and shrubs with their fibrous root system prevent soil run-off. We surveyed the landslide prone areas of the Tawang river basin in Arunachal Pradesh and identified species with potential to stabilize the landslide affected/vulnerable slopes. The species were selected based on their relatively broad niche preferences, efficacy and usefulness in soil characteristics improvement, r-selection life history strategy, contribution to the ecosystem services and local economy, and extent of occurrence, in addition to their root architecture. In most circumstances, the growth of such species escalates after the landslide event, and they form the pioneer species in the secondary succession of the destabilized slope.