Utilitarian redundancy in local medical systems - theoretical and methodological contributions

Abstract

The utilitarian redundancy model (URM) is one of the recent contributions to ethnobiology. We argue that URM can be applied to access use-pressure on plant species, the resilience of socioecological systems (e.g., local medical systems), cultural keystone species, and the role of exotic species in social-ecological systems. Based on previous URM studies, we also emphasize the need to differ practical (considering plants and uses that are currently employed) and theoretical (considering both currently employed and potentially employed plants and uses) redundancy. Based on the main applications of the URM, we propose a new index to access redundancy of a therapeutic indication: the Uredit, so that Uredit = NSp + CR, were Uredit is the Utilitarian Redundancy Index for the therapeutic indication; NSp is the total number of species mentioned for the indication, and CR is the species’ contribution to redundancy (in terms of knowledge sharing). The maximum value that the Uredit could reach is twice the number of species employed for the therapeutic indication. We believe that this theoretical and methodological improvement in the model can improve comparisons of redundancy in different social-ecological systems. We also highlight some limitations of the URM (and our Uredit), and we believe that conscious reasons behind people’s decisions should be incorporated into future studies on the subject.

Local ecological knowledge dynamics of farmers in areas which have been chronically disturbed by human actions in the Brazilian Caatinga

“…In this study, the utilitarian redundancy values obtained for local uses in each study area were lower in the area of high chronic anthropic impact. This phenomenon can be explained through the following hypothesis: first, that the species cited for may have different weights (in terms of information sharing between people) due to the prioritization of certain species (Medeiros et al 2020), favoring few species in a given use. Our results also highlight the importance of uses for firewood and wire fencing, a pattern also observed in forests in Madagascar (Brown et al 2011), Caatinga (Oliveira et al 2019) andChaco (Jiménez-Escobar et al 2021), especially for firewood.…”

“…We chose to calculate the utilitarian redundancy index (uredit "utilitarian redundancy for therapeutic indication") (Medeiros et al 2020) at the system level in terms of usage categories for each use and for the community. We used the index for the categories and their local subcategories: fuel (firewood and coal), construction (hedge fence, wire fence, stick fence and roof) and technology (tool handles and household items).…”

“…The index considers information sharing about used plants. Therefore, by increasing the redundancy value, there is a greater number of species used for a particular use, and greater information sharing by people in a rural community (Medeiros et al 2020). Thus, we calculated the Uredit for the uses in each study area.…”

“…Thus, we calculated the Uredit for the uses in each study area. In a hypothetical scenario, Medeiros et al (2020)…”

Local Knowledge and Use of Medicinal Plants in a Rural Community in the Agreste of Paraíba, Northeast Brazil

“…Different hypotheses have been proposed and tested in ethnobotanical studies with medicinal plants such as utilitarian redundancy, which seeks to explain the resilience of local medical systems [ 39 , 40 ]; the hypothesis of diversification, which proposes explaining the incorporation of exotic species to local pharmacopeias through a possible increase in bioactive compounds that these plants can bring [ 41 ]; or the hypothesis of appearance, which seeks to explain how medicinal plants are selected considering their chemical composition or ecological characteristics, classifying them as apparent and not apparent, based on the thought that, from a chemical perspective, herbaceous (or nonwoody) species are considered to be apparent, assuming that they contain a higher concentration of metabolites, whereas shrubs and trees (or woody) are considered as nonapparent [ 27 , 42 ]. Equally, from an ecological perspective, species easily visible due to their size (such as trees and shrubs) or life-cycle characteristics are more apparent, while small herbaceous species are considered not apparent in the initial stages of succession [ 42 – 45 ].…”