PARENT SESSION
Oral Session - Management and Planning Chair(s): White, Mary¹, ¹ US Environmental Protection Agency Region V, Chicago, IL
Wednesday, March 31, 2004 3:00 PM - 5:20 PM Apollo Room 3

Ecology of Landslides in Eastern Himalayas: Landscaping in a Pristine Ecosystem. ^*DEY, DIPAYAN , ¹ South Asian Forum for Environment, Bhagalpur, Bihar, INDIA

ABSTRACT- Sudden physiographic catastrophes like landslides and rock slips, quite frequently alters the landscape in the fragile mountain ecology of eastern Himalayas. These events not only paralyze the phenomenal processes of vegetation dynamics and soil formation but also cause huge loss of natural resources, biodiversity, life and property. The present study attempts to acquire a quantitative assessment of landslide occurrence and hazards in the eastern districts of Bhutan that are worst affected. In all 57 locations are mapped by overlapping the base maps from Soil Topography Sheet and enlarging them to study landslide distribution, frequency and density, exposure, surface loss and susceptibility etc. The events can be correlated with climatic thresholds and terrain textures including slope gradient, surface stability, shear strain etc. The present study further identifies the cause and consequences of landslides in some parts of Eastern Himalayas in Bhutan from a different angle, in relation to soil physico-chemistry and vegetation profile. Findings reveal that high content of organic matter, nitrates and carbonates and physical features of the soil like porosity and water holding capacity also has bearing with it. Stages in vegetation dynamics, forest patterns and dominant plant species are also important factors that are linked to landslides. The results also reveal that human interferences and activities trigger such physiographic processes and may lead to further destabilization of surface.

KEY WORDS: Ecology, Landslide, Himalayan, Landscape, Assessment