Availability, diversification and versatility explain human selection of introduced plants in Ecuadorian traditional medicine

Abstract

Globally, a majority of people use plants as a primary source of healthcare and introduced plants are increasingly discussed as medicine. Protecting this resource for human health depends upon understanding which plants are used and how use patterns will change over time. The increasing use of introduced plants in local pharmacopoeia has been explained by their greater abundance or accessibility (availability hypothesis), their ability to cure medical conditions that are not treated by native plants (diversification hypothesis), or as a result of the introduced plants’ having many different simultaneous roles (versatility hypothesis). In order to describe the role of introduced plants in Ecuador, and to test these three hypotheses, we asked if introduced plants are over-represented in the Ecuadorian pharmacopoeia, and if their use as medicine is best explained by the introduced plants’ greater availability, different therapeutic applications, or greater number of use categories. Drawing on 44,585 plant-use entries, and the checklist of >17,000 species found in Ecuador, we used multi-model inference to test if more introduced plants are used as medicines in Ecuador than expected by chance, and examine the support for each of the three hypotheses above. We find nuanced support for all hypotheses. More introduced plants are utilized than would be expected by chance, which can be explained by geographic distribution, their strong association with cultivation, diversification (except with regard to introduced diseases), and therapeutic versatility, but not versatility of use categories. Introduced plants make a disproportionately high contribution to plant medicine in Ecuador. The strong association of cultivation with introduced medicinal plant use highlights the importance of the maintenance of human-mediated environments such as homegardens and agroforests for the provisioning of healthcare services.

Molecules from nature: Reconciling biodiversity conservation and global healthcare imperatives for sustainable use of medicinal plants and fungi

“…Conservation risks associated with exploitation of certain medicinal species are well‐documented (Figure 1), so the relatively low mean extinction risk to medicinal plants may seem surprising to the general reader. However, this low mean extinction risk is consistent with observations over two decades that ‘weedy’ and/or introduced species are over‐represented in traditional medicinal floras, and that availability is a key factor in explaining this (Stepp & Moerman, 2001; Hart et al, 2017). Low mean extinction risk for medicinal plants is also consistent with the fact that weeds are over‐represented among plants that are the sources of modern drugs (Stepp, 2004), and a more recent report notes that the likelihood of development of an alkaloid into a medicinal product is considerably influenced by the abundance of the source species (Amirkia & Heinrich, 2014).…”

Utilitarian redundancy in local medical systems - theoretical and methodological contributions

“…The author called it the 'diversification hypothesis'. Subsequent investigations have been favorable to the hypothesis, identifying chemical and utilitarian differences between native and exotic species [31][32][33].…”

Drivers of Management of Spider Plant (Gynandropsis gynandra) Across Different Socio-linguistic Groups in Benin and Togo

“…Perceived availability of the species (AI) Very abundant (5); abundant (4); moderately abundant (3); rare (2); very rare (1) Perceived availability is an important factor explaining the cultural importance of edible plants (Cruz et al 2013;Pieroni 2001) and depends on the demand in the species. Available useful plant species tend to be more widely used than rarer ones Hart et al 2017) and their decreasing availability might trigger the domestication process if the demand cannot be satisfied (Vodouhè and Dansi 2012). In our case, the perceived availability of the species may contribute to explain patterns of knowledge and use.…”