The applicability of similarity indices in an ethnobotanical study of medicinal plants from three localities of the Yunga district, Moquegua region, Peru

Abstract

Background: From ethnobotanical research carried out in the southern region of Peru, the need for further investigation is evident, especially in Moquegua; given this, an ethnobotanical exploration is presented that includes a validation of medicinal plants through the reports of three focus groups and the analysis of similarity or concordance of medicinal species from three nearby localities in the district of Yunga, Moquegua, using two coefficients already known and one new in ethnobotany. Methods: Medicinal plants were collected with the help of experts, which were shown to three separate focus groups (Exchaje, La Pampilla and Yunga), whose composition was representative and decided by local authorities, who established the medicinal quality of the collected plants. For agreement analysis, two similarity coefficients were used, Jaccard (Cj) and Sørensen (Cs), and the use of the Cohen kappa Index (CKI) and Fleiss (FKI) is incorporated and proposed, for which purpose the validation of medicinal species was written in binary; statistical analysis was done using Stata 15 software. Results: Of 61 species of plant collected from experts, 36 were validated as medicinal by the focus groups, naming a total of 127 use reports. The Asteraceae are the most abundant with 18 species, followed by Lamiaceae with three, among others. The medicinal bush yareta (Azorella compacta, Apiaceae) had 11 reports of use. The predominant habit of validated medicinal species was shrub (47.2%). The so-called warm plants were the most abundant (58%) compared to the cold and temperate ones. Digestive system disorders are the category with the most reports (27). La Pampilla and Yunga presented the highest values of similarity (Cj=0.61; Cs=0.76; CKI =0.6) and the FKI showed a concordance value of 53% for the three localities. Conclusions: Traditional knowledge about medicinal plants still exists in Yunga, Moquegua. This is evidenced through the use of medicinal species identified by experts. Interesting ancestral concepts are observed around the quality of plants, about their thermal properties, such as hot, cold and temperate plants; with Digestive System Disorders being those most frequently reported. The Kappa Index is a suitable tool to show the level of agreement between localities, whose values, compared through a scale, allow greater objectivity in the analysis, in comparison with the Jaccard and Sorensen coefficients. The concordances between the evaluated localities becomes almost perfect (values closer to one) when they are influenced by factors such as their proximity, and social and cultural interrelation.