Different patterns in medicinal plant use along an elevational gradient in northern Peruvian Andes

Through the study of mestizo people that share a common culture in a large geographic region and where traditional knowledge (TK) is still poorly documented, we compared medicinal plant use in the northern Andes of Peru.

(1) To compare patterns of the distribution of TK for a human group living between two ecoregions: high tropical montane forests vs. low tropical montane forests; (2) to understand the TK at the gender level; and (3) to analyse TK transmission over five generations.

The study was conducted in two ecoregions, four areas and 12 localities. We gathered information with 600 participants through semi-structured interviews. We worked with 3-7 expert informants per locality using the "walk in the woods" methodology for gathering ethnomedicinal information in the field. We annotated local vernacular names, medicinal indications, and collected the plants in their habitats. Then we interviewed the rest of the participants in their homes. To evaluate significant differences between highlands and lowlands, we use general mixed linear models test and its corresponding post hoc LSD Fisher test of multiple comparisons (p < 0.05) at ecoregion, gender and generation level.

A total of 416 species belonging to 107 plant families and 13,898 use-reports were found in both ecoregions. Overall, significant differences indicated that people in the highlands had higher TK than people in the lowlands for most of the medicinal categories. Women showed higher knowledge on medicinal plants in all medicinal categories and areas in both ecoregions. However, transmission of TK showed different patterns between ecoregions. In the highlands, the TK increased from the youngest to the senior group (51-60 years), with a slight decreasing for those over 60 years, whereas in the lowlands the findings were less clear and generations with highest TK were divergent across localities.

TK on medicinal plants is still widely applied in the tropical montane forests of northern Peru. The localities with less prosperous socioeconomic development (highlands) were the areas with higher TK on medicinal plants. Women are mainly the depositories of the traditional medicine. The older generations maintain most of the TK in the highlands, whereas in the lowlands the TK is more widespread across generations. Future conservation programs on medicinal plants should understand who are the generations depositaries of the TK before dedicate any effort.