Ethnobotanical study of medicinal plants used to treat human and livestock ailments in Addi Arkay district, northwest Ethiopia.

Background: Ethiopia harbors a wealth of plant biodiversity, diverse ecological zones, rich cultural heritage, and long-standing traditional knowledge and medical practices. Despite documentation of this knowledge in few regions, information remains limited for the Addi Arkay district of northwestern Ethiopia. Therefore, this study aimed to document the indigenous and local knowledge on the use of human and livestock medicinal plants.

Methodology: Ethnobotanical data were collected between October and December 2024 through semi-structured interviews, guided field observations, focus group discussions, and ranking exercises conducted with 385 informants. Stratified sampling, random, and purposive sampling techniques were employed. A mixed-methods approach (both qualitative and quantitative) was used for data analysis. Quantitative analyses included preference ranking, Direct Matrix Ranking (DMR), Informant Consensus Factor (ICF), fidelity level (FL), Jaccard Similarity Index (JSI), and Rahman's Similarity Index (RSI). T tests and one-way ANOVA were employed to compare mean levels of indigenous and local knowledge across different socio-demographic and socio-economic factors.

Results: This study documented 112 medicinal plant species (105 genera, 58 families, including four endemic and one nearly endemic) were used for human and livestock remedies in the Addi Arkay district, northwestern Ethiopia. Fabaceae was the dominant family (7.14%). The majority of plant species (75.89%) were used to treat human ailments, while a smaller proportion (5.36%) were used for livestock, and 18.75%) were used for both human and livestock ailments. The most frequently used plant parts were leaves (34.6%) followed by roots (27.9%), and grinding was the most common method of preparation (30.4%). The preference ranking exercise revealed Opuntia ficus-indica as the top choice for treating human hemorrhoids and Phytolacca dodecandra as the preferred treatment for rabies in livestock. DMR revealed Cordia africana, Olea europaea subsp. cuspidata, and Terminalia leiocarpa as the most threatened multipurpose medicinal plants. Informant Consensus Factor values ranged from 0.63 to 0.93. Fidelity level analysis revealed that Phytolacca dodecandra was most effective against rabies, followed by Rubia cordifolia for cough and Plumbago zeylanica for swelling. Agricultural expansion posed the most significant threat, followed by overgrazing and fuel (charcoal and fuel wood). The highest levels of indigenous and local medicinal plant knowledge were predominantly transmitted orally through family lines, with paternal contributions often playing a significant role. Compared to other studies conducted in Ethiopia, the Jaccard Similarity Index (JSI%) for human medicinal plants ranged in value from 6.9% to 68.92% and for veterinary plants from 10.91% to 27.91%, whereas the Rahman's Similarity Index (RSI) ranged from 0.98% to 15.63%. Ten novel medicinal plant uses, not previously documented in Ethiopia or elsewhere, were identified.

Conclusion: This pioneering study in Addi Arkay district, northwestern Ethiopia, documented 112 medicinal plants for the treatment of human and livestock ailments, revealing the significant array of plant resources utilized for local primary healthcare services. However, threats from agricultural expansion, overgrazing, and fuel (charcoal and fuel wood) use necessitate in situ and ex situ conservation actions. Implementing sustainable harvesting practices and community-based conservation initiatives is recommended to protect the rich medicinal plants wealth of the district for continual use across generations besides ensuring preservation of valuable ethnomedicinal knowledge.