Diversity of medicinal plant species along subalpine-nival gradient in Nyeshang Valley, Manang, Nepal

Abstract

This study examines the ethnomedicinally important plants extracted from the vulnerable sub nival zone in the Nyeshang Valley, Manang, Central Himalaya, Nepal. A list of medicinal plant species in Nyeshang valley was prepared through empirical ethnobotanical study and literature review. An ecological sampling was done along the subalpine- nival gradient by following the standard methodology of Global Research Initiative in Alpine Environments (GLORIA). Four mountain summits (SMA,SMB, SMC and SMD) were investigated along an elevation gradient of 4150-5005m asl (above sea level). Two measures of species diversity i.e. α and γ for both the overall plants and medicinal plants at all scales of measurement decreased along the elevation gradient with major influence of elevation, aspect and substrate type. However, the proportion of medicinal plant species remains almost similar among four elevation levels (summits). This implies that high altitude habitats provide unique sets of environment for the growth of diverse medicinal plant species. Therefore, landscape-level heterogeneity should be maintained for the preservation of medicinal plant species in the Himalaya. The local inhabitants are highly knowledgeable but not as compared to their ancestors and dependent upon plant resources for their livelihood. A total of 97 plant species were found to have medicinal value on the basis of empirical ethnobotanical study and literature review. Out of this only 58 species were recorded as medicinal by local inhabitants and Amchi and the rest 39 species were found to have their use elsewhere in the country. Present study added 17 medicinally important species to the list of the Nyeshang valley and Jomsom valley as well as to the country. Intensity of utilization of local plant resources differed at different habitats, with more pressure towards the lower alpine region. Life form analysis revealed that the study area was characterized by harsh environmental climate with majority of taxa belonging to forbs. Himalayan mountain summits possess potential species with high local medicinal value. Therefore, management should be considered on landscape approach integrating different mountain summits, associated species and indigenous knowledge.