Ethnobotanical study of wild edible plants in Pa Tio District, Yasothon Province, Thailand

Wild edible plants (WEPs) are integral to food security, nutrition, healthcare, and cultural identity in rural northeastern Thailand. However, systematic ethnobotanical documentation of WEP diversity, cultural importance, and economic roles in Pa Tio District, Yasothon Province, has been limited. This study provides the first comprehensive assessment of WEPs in the district, highlighting their multifunctional roles within local food systems, traditional medicine, and livelihoods. Ethnobotanical data were collected through semi-structured interviews, group discussions, and guided field walks with 50 Lao-Isan informants selected using purposive and snowball sampling. Recorded species were categorized by use, and quantitative indices—Cultural Food Significance Index (CFSI), Fidelity Level (FL), and Informant Consensus Factor (ICF)—were applied to evaluate cultural prominence and medicinal consensus. One-year market surveys were conducted to estimate the economic value (EV) of traded WEPs, while cross-regional similarity was assessed using the Jaccard Similarity Index. A total of 100 WEP species from 48 families were recorded, with vegetables and fruits dominating local diets. CFSI values showed strong differentiation among taxa; Ipomoea aquatica Forssk. had the highest value (140,625.00), reflecting its role as a daily staple. FL values ranged from 8.70% to 80.00%, and consistently high ICF values (0.857–0.955) indicated strong agreement among informants and a well-structured traditional knowledge system. Fifty-one species were traded in local markets, with Limnophila geoffrayi Bonati generating the highest annual economic return. Species similarity with neighboring regions was low (8.6–14.8%), underscoring pronounced local specificity. WEPs in Pa Tio District form a resilient biocultural system linking food security, health, cultural continuity, and livelihoods. Supporting community-based management and sustainable use is essential for strengthening rural food systems and biodiversity conservation.