From hunter-gatherers to rancheros, traditional plant knowledge and use prevail in Baja California Sur, México

Complex histories have linked human groups in Baja California Sur (BCS) to natural resources across landscapes characterized by high aridity, limited freshwater, and extreme climate conditions. The region was initially inhabited by hunter-gatherers for thousands of years but underwent dramatic changes with the arrival of Europeans in the 16th century. The original inhabitants of BCS were almost replaced by foreign colonizers who settled in rancherías. As these new cultures expanded into new territories, they absorbed and shared some knowledge from earlier settlers. The aims of this study are to systematize the records on the knowledge and use of plants from archaeological and historical sources; document current records on the knowledge and use of plants in Baja California Sur rancherías; analyze the temporal dynamics of plant knowledge and use in Baja California Sur, and analyze how knowledge and use of plants vary across different ecoregions. The present study compiles archaeological, historical, and contemporary knowledge and use of plants in rancherías and examines the influence of environmental factors on this knowledge. Historical and modern studies documenting the knowledge and use of plants in the state were reviewed. Through a selection based on geopolitical divisions of BCS and on the state’s population census, from 2022 to 2023, we visited 29 sites, selected with at least 50 residents within each site. We conducted 106 interviews to gather information on past and present plant knowledge and collected specimens. Informants were chosen according to their availability to participate in the interview. A total of 595 taxa from 107 botanical families were documented, mainly medicinal and food plants. The most culturally significant families were Cactaceae, Arecaceae, and Fabaceae, with uses dating back to prehistoric times. Only a few names remain in their original languages (Cochimí and Guaycura), as well as some uses (such as ritual or ceremonial). Our fieldwork yielded 78 taxa with current traditional knowledge and use. We observed a correlation between ecoregions and traditional plant knowledge and use, with more species mentioned in southern BCS, likely reflecting greater plant resource abundance and a wider range of microenvironments. The Central Desert exhibited the highest values for species mentioned in the northernmost part of BCS, potentially due to its location within a transition zone, and serves as a refuge for many species from the most arid zones and northern regions. Based on the total records and compared with other studies, current rancheros preserve a rich tradition of plant knowledge and uses. A dynamic transmission of plant knowledge and uses has been involved since hunter-gatherers, shaped during European contact, and enriched by their daily experiences, included modern knowledge influenced by tourism and federal programs such as protected natural areas. Nevertheless, their traditional knowledge endures, remaining connected to this rugged environment, which is limited by climatic and geographical factors.