Medicinal plant agrobiodiversity, biocultural management, and conservation in a Mixtec indigenous community in Oaxaca, Mexico

Medicinal plants constitute an important component of agrobiodiversity in Indigenous landscapes, where wild, cultivated, and locally managed resources contribute to household health care, biocultural continuity, and biodiversity conservation. This study characterized medicinal plant agrobiodiversity, therapeutic uses, management practices, and intracultural variation in ethnobotanical knowledge in Santiago Ixtaltepec, a Mixtec Indigenous community in Oaxaca, Mexico. Semi-structured questionnaires were administered to 32 adult household members. After taxonomic standardization and data-quality control, 578 individual use reports representing 82 operational medicinal taxa were documented, of which 78 taxa were assigned to 37 botanical families. Citation-frequency diversity was high (Shannon-Wiener H′ = 3.902; Simpson 1 - D = 0.972), while Hill diversity declined from 82 observed taxa at q = 0 to 49.51 and 35.71 effective taxa at q = 1 and q = 2, respectively. Calea ternifolia had the highest relative frequency of citation (RFC = 0.781), followed by Tournefortia mutabilis (RFC = 0.688), while culturally defined illnesses showed the highest informant consensus (ICF = 0.809). Medicinal plant knowledge richness varied markedly among informants and was negatively associated with age but positively associated with formal education, whereas no significant gender differences were detected. Collection from the surrounding landscape involved 76.8% of medicinal taxa, while 40.2% were associated with backyard cultivation, indicating overlapping acquisition and management strategies. Multivariate analyses detected no significant differentiation in medicinal plant repertoires according to gender, age, education, or agricultural involvement, whereas correspondence analysis revealed distinct therapeutic gradients, particularly for digestive disorders and culturally defined illnesses. Overall, these findings show that medicinal plant diversity is embedded within a broader biocultural management system integrating household practices, landscape use, therapeutic knowledge, and culturally specific health traditions. This study highlights the importance of community-based approaches to the conservation and governance of medicinal agrobiodiversity, while emphasizing the need for complementary population- and habitat-level assessments to evaluate ecological sustainability and harvesting impacts.