Habitat Ecology and Human-Induced Threats to Nardostachys jatamansi in Lingzhi, Western Bhutan

Abstract

Nardostachys jatamansi, a high-altitude medicinal herb (Valerianaceae), remains ecologically understudied in Bhutan. This study assessed its phytosociology, habitat, morphometry, biomass, and threats across 3,500–5,000 m in Lingzhi, western Bhutan. Density and Importance Value Index increased significantly with altitude, soil moisture, nitrogen, and slope, while plant size and biomass declined at higher elevations. Grazing and harvesting were key threats, with the most disturbed plots showing the lowest densities. The species thrives in moist, steep alpine habitats but is vulnerable to overharvesting, warranting site-specific monitoring and adherence to Bhutan's CITES-mandated harvest limits.