Altitudinal variation in medicinal plant distribution and ethnomedicinal knowledge among Chepang and Tharu communities in Central Nepal

Abstract

Background: Medicinal and aromatic plants (MAPs) are important to traditional healthcare and rural livelihoods in Nepal, and their diversity is influenced by altitudinal and climatic variation. This study investigated medicinal plant distribution and ethnomedicinal knowledge among Chepang and Tharu communities in central Nepal.

Methods: A stratified random sampling design was used to assess MAP distribution across four elevation classes (330–535, 536–740, 741–945, and 946–1150 m). Ethnobotanical information was collected from 130 respondents through semi-structured questionnaires and key informant interviews. Descriptive statistics, Informant Consensus Factor (FIC), Relative Frequency of Citation (RFC), correlation, ANOVA, and chi-square tests were used to evaluate plant diversity, cultural importance, and ethnomedicinal knowledge.

Results: The survey documented 142 medicinal plant species belonging to 91 families, while the forest inventory recorded 97 species, including 16 trees, 30 shrubs, and 51 herbs. Herbs were the dominant life form, leaves were the most frequently used plant part, and oral administration was the principal mode of application. Phyllanthus emblica and Terminalia chebula had the highest RFC among Chepang respondents, whereas Dioscorea bulbifera and Justicia adhatoda were most frequently cited among Tharu respondents. Medicinal trees were most abundant at 330–535 m, whereas shrubs and herbs reached their highest densities at 741–945 m. Ethnomedicinal knowledge increased significantly with age (r = .35, p < .001).

Conclusions: The findings demonstrate substantial medicinal plant diversity and ethnomedicinal knowledge, while highlighting the importance of mid-elevation habitats, sustainable management, conservation, and intergenerational knowledge transmission. These patterns underscore the relationship between ecological variation, plant availability, and community-based traditional healthcare practices.

Keywords: Medicinal and aromatic plants, communities, indigenous, healthcare, elevation