Use and valuation of native and introduced medicinal plant species in Campo Hermoso and Zetaquira, Boyacá, Colombia.

BACKGROUND: Medicinal plant species contribute significantly to folk medicine in Colombia. However, few local studies have investigated whether species used are introduced or native and whether there is a difference in importance of native and introduced medicinal plant species. The aim of the present study was to describe the use of medicinal plants within two municipalities, Campo Hermoso and Zetaquira, both in the department of Boyacá, Colombia and to assess the importance of native and introduced plants to healers, amateur healers and local people. As local healers including amateur healers have no history of introduced species our working hypotheses (H(1-2)) were that H(1): native and introduced medicinal plant species are of equal importance and H(2): healers and amateur healers do not differentiate in their preferences between native and introduced medicinal plant species. METHODS: Ten villages were included in the study. A combination of quantitative and qualitative methods was used including questionnaires, semi-structured interviews, in- depth interviews, and open talks. Voucher specimens were collected in home gardens and during field walks. For data analysis, we calculated use value indices and Jaccard index and tested for the above hypothesis using Spearman rank-correlation coefficients and Wilcoxon-Mann-Whitney tests. RESULTS: Eighty medicinal plant species were described by locals as the most frequently used. Of these, 78 species were taxonomically identified, distributed within 41 families and 74 genera, which included 35 native species and 43 introduced. The highest valued families were: Asteraceae, Lamiaceae, Apiaceae, Rutaceae and Verbenaceae. The species ranked highest according to their Use Values, in both municipalities, were Mentha suaveolens Ehrh., Ambrosia cumanensis Kunth, and Verbena littoralis Kunth. Introduced species were more important than native ones in Zetaquira, while there was no difference in importance in Campo Hermoso. While healers relied most on the uses of native species, amateur healers were inclined to rely on introduced species. Medicinal plant administration in both municipalities follow the usual pattern: Leaves are used most commonly prepared by decoction or infusion and administrated orally. CONCLUSIONS: The high proportion of introduced plant species used in the local traditional medicines is similar to the results of a number of other ethnobotanical studies and emphasise the need for efforts to record and maintain traditional knowledge on native species.