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

The influence of exotic and native plants on illnesses with physical and spiritual causes in the semiarid region of Piauí, Northeast of Brazil

BACKGROUND

Local medical systems (LMS) include native and exotic plants used for the treatment of diseases of physical and spiritual nature. The incorporation of exotic plants into these systems has been the subject of many studies. In this context, an analysis was conducted on the influence of the origin of plants on diseases of physical and spiritual nature in order to evaluate the therapeutic versatility of native and exotic species in these therapeutic targets, to investigate whether exotic plants mainly fill gaps not met by native plants (diversification hypothesis), and identify which species are prioritized in the redundant targets in these two therapeutic groups in the rural community of Morrinhos, Monsenhor Hipólito, Piauí.

METHODS

Data collection took place in 2 stages. First, free lists and semi-structured interviews with local residents (n = 134) were conducted to survey plants used for therapeutic purposes and the associated illnesses. Then, another phase of interviews was carried out to evaluate the prioritization between native and exotic plants in redundant therapeutic targets. To test the diversification hypothesis (DH) in each group of illnesses, data were analyzed using generalized linear models (Poisson and Binomial GLMs); versatility was measured by the number of therapeutic indications and compared between resources using the Mann-Whitney test, and prioritization in each group was verified by comparing the proportions of native and exotic plants with the χ2 test.

RESULTS

One hundred and thirty-two species of plants were surveyed, being 71 exotic and 61 native, with indications for physical and spiritual illnesses. The results revealed that the diversification hypothesis did not explain the inclusion of exotic plants in the local medical system to treat physical or spiritual illnesses and that the therapeutic versatility of exotic and native resources in the two groups was also similar (p > 0.05). However, exotic plants were prioritized in illnesses with physical causes and native plants in illnesses with spiritual causes.

CONCLUSIONS

The local medical system presents similar and distinct patterns in the therapeutic targets, depending on the perspective evaluated. Therefore, it is necessary to investigate the patterns of use of medicinal plants in different sociocultural contexts in order to broaden the debate about the role of plant origin in the selection of treatments for illnesses with different causes.

The introduction of an invasive weed was not followed by the introduction of ethnobotanical knowledge: a review on the ethnobotany of Centaurea solstitialis L. (Asteraceae)

Invasive plants are known for their impacts to ecosystems and societies, but their potential cultural use tend to be unexplored. One important mechanism of plant invasion is the use of "allelochemicals" or "novel weapons": chemical defenses which are new to their invaded habitats and that confer them competitive advantages. However, these chemicals are precisely what confers them ethnobotanical and medicinal properties. We reviewed the literature assessing the biogeography of the cultural uses of the model invasive plant yellow-starthistle (Centaurea solstitialis L.; Asteraceae), and assessed the extent to which the introduction of a weed native to Eurasia into several non-native world regions was paralleled by the spread of cultural uses from its native range. We found that the species was rich in pharmaceutically active compounds and that the species had been traditionally used for medicinal purposes, as raw material, and as food. However, ethnobotanical uses were reported almost exclusively in its native range, with no uses described for the non-native range, apart from honey production in California, Argentina, and Australia. Our study exemplifies how, when plant introductions are not paralleled synchronously by significant human migrations, cultural adoption can be extremely slow, even within the native range of the species. Invasive species can provide real-time insights into the cultural processes by which humans learn to use plants. This case study highlights how biological invasions and cultural expansions can be subjected to different constraints.

Very High Food Plant Diversity among Ethnic Groups in Northern Thailand

The combination of the high biodiversity and many ethnicities in Thailand results in extensive ethnobotanical studies, especially in the northern part of the country. Here we have assembled 7620 records from 60 references regarding how plants are used for food among 14 ethnicities in northern Thailand. The uses are based on 1182 different plant species. Vegetables are the most common food category, which contributed more than 60% of all use-reports and involved nearly 900 species. This was followed by the dessert fruit category, which included about 350 species and over 1800 use-reports. The similarity among the different ethnicities was low and the number of uses and species recorded among different ethnicities were significantly related to the number of studies that had been conducted for each group. This implies that additional ethnobotanical studies are still needed in order to conserve and compile the valuable traditional knowledge related to food plants. Many exotic species are now an important part of traditional knowledge, whereas rare endemic species are uncommon among wild food plants. This situation leads to a loss of traditional knowledge about food plants and reduced awareness of their importance. As a key to using this great reservoir of food for local people, traditional knowledge related to local wild food plants can contribute to the zero-hunger goal of the Sustainable Development Goal (SDG). More studies on the nutrient content and health properties of these plants could lead to the development of new crops to meet present consumer demands.

Ecological apparency, ethnobotanical importance and perceptions of population status of wild-growing medicinal plants in a reserve of south-central Mexico

BACKGROUND

The apparency hypothesis in ethnobotany (common plants are used more than less frequent ones) has been studied mostly by comparing usefulness with woody plant density, or large plants (trees) with herbs, with uneven results. Here, we explore the hypothesis for wild-growing medicinal plants, separately for different life forms. Two methodological subjects relevant for testing the hypothesis are also treated: We compare various importance indicators, including recent use, and evaluate active healers' knowledge of plant population size. The study area was the Tenancingo-Malinalco-Zumpahuacán Protected Natural Area in central Mexico in the upper part of the Balsas River Basin, a biogeographic region with a long tradition of using wild medicinal species.

METHODS

Previous work on the vegetation of the protected area contributed information from 100 survey plots and a species list, which included preliminary data on the medicinal plants. Then, in 2019-2020, we held in-depth and repeated interviews with 13 traditional healers in three rural communities. They were interviewed on uses and population size of a selection of 52 medicinal species of different life forms and abundance (number of individuals in survey plots). The data were analyzed with descriptive statistics, use values and linear regression models.

RESULTS

For all species, use value correlated significantly with abundance. When separated by life forms, only herbs and shrubs/lianas showed this association, though with statistical limitations. Trees did not, perhaps because some of the most useful trees have been overcollected. We found a good correlation of recent use with frequency of mention and most other importance indicators; the correlation was weakest for number of uses. Also, active healers had a good estimation of population of their collected species.

CONCLUSIONS

The apparency hypothesis should be studied separating life forms to reduce the influence of this variable. To measure importance for the study of this hypothesis, the data show that frequency of mention is a good indicator and correlated with actual use. Also, local plant users' appreciations of population size are quite accurate in the aggregate and may be more efficient than costly vegetation surveys.

The resource availability hypothesis (RAH) and cross-cultural patterns: which one explains West African Cochlospermum species' uses in Benin?

BACKGROUND

Cochlospermum tinctorium and C. planchonii are two wide edible plants of sub-Saharan countries, e.g., Benin, widely used as food, medicine, dye, handicraft, etc. Unfortunately, the uncontrolled harvest of their rootstocks exposes them to local extension risk. To enhance knowledge on the determinants of their uses in Benin, this study aimed to (i) assess the use forms, use values, abundance and perceived spatiotemporal dynamics, (ii) determine how does local abundance or cultural patterns affect the use of Cochlospermum species, and (iii) assess local harvesting modes and conservation management practices.

METHODS

In total, 756 Dialog Partners through 27 ethnic groups were questioned countrywide using semi-structured interviews. Questions refer to local taxonomy, specific uses, organs sought, harvesting modes and local conservation strategies; afterward, local abundance of each species was assessed. Ethnobotanical indicators were analyzed through citation frequencies to obtain quantitative data. Comparison tests and statistical analyses were performed using R program.

RESULTS

C. tinctorium and C. planchonii are locally well known and involved into 83 specific uses, grouped into ten categories of which medicinal use was the main. The use values of C. planchonii (0.10 ± 0.19) and C. tinctorium (0.23 ± 0.20) varied significantly between the ethnic groups, and only C. tinctorium showed index of commercially value above 75% for some ethnic groups. The current abundance, about 84 and 97 tufts.ha^-1, respectively, for C. planchonii and C. tinctorium was perceived with a decline of 81.09% (C. tinctorium) and 73.7% (C. planchonii) of informants. Moreover, the Spearman's correlation and Kruskal-Wallis tests performed revealed that the use values of C. tinctorium and C. planchonii were significantly correlated on the one hand with their local abundance and on the other hand with the investigated ethnic groups. About 42.3% of women produced the powder as principal activity, while more than 57% produced it mainly at the end of farm work. However, the conservation management was practiced by very few informants and consisted of partial harvesting of rootstocks (41.8%, only in southern Benin), and fallowing of harvesting areas (3.97%, only in northern Benin).

CONCLUSION

Facing the declining abundance and increasing market demand for rootstock powder of Cochlospermum species, existing local conservation strategies should be promoted and the domestication process should be initiated for sustainable management of these important wild edible plants before these important resources disappear completely in the wild.

Poorly Investigated Ecuadorian Medicinal Plants

Ecuador has, in proportion of its size, one of the richest floras of Latin America and the world; the country also has an immense cultural heritage due to the presence of different ethnic groups that have implemented the use of many wild and cultivated plants, mainly as medicinal remedies. In a recent publication, we have summarized the results of research activities recently carried out on about 120 plants native to Ecuador, which includes the structures of non-volatile isolated compounds, as well as the chemical composition of essential oils (EOs) and the in vitro tested biological activity data. For the sake of completeness, we have collected in this paper the main information obtained from recent ethnobotanical investigations on other important Ecuadorian medicinal plants for which phytochemical, pharmacological, and toxicological studies are, however, still largely lacking. Thus, one of the objectives of this paper is to preserve the traditional knowledge of Ecuadorian Indigenous communities which, being transmitted orally, is in danger of becoming lost. Moreover, it is our intention to stimulate more extensive studies on the rich medicinal flora of the country, which can provide economic and social benefits, especially to the people who traditionally cultivate or collect the plants.

Medicinal plants cultivated in urban home gardens in Heredia, Costa Rica

BACKGROUND

Urban ethnobotanical research in Costa Rica is rather rare and home gardens are poorly studied so far. Investigating their biodiversity is crucial in gathering knowledge on the uses of this particular flora, especially related to the owners' health. This study therefore explores the diversity and knowledge of medicinal plants of private garden owners from three different urban neighborhoods in Heredia, Costa Rica, an thus far understudied area.

METHODS

Semi-structured interviews (n = 61) were conducted with garden owners in three socioeconomically different urban neighborhoods (Central Heredia, Maria Auxiliadora and Bernardo Benavides). Information was collected about medicinal plants cultivated in the garden, treatments, plant part used and mode of administration. All species were identified and their geographical origin was determined. This information was then compared with the available regional and local (ethno)pharmacopoeias to detect possible newly documented uses.

RESULTS

The majority or 90% of garden owners who also held knowledge on medicinal plants species were women (n = 30) of all ages (between 26 and 85 years old). A list of 27 species of medicinal plants was obtained from the participants of three urban neighborhoods. In Central Heredia, 74% (n = 20) of the total species were present, in Maria Auxiliadora 33% (n = 9) and in Bernardo Benavides 56% (n = 15). Most plant species were used by the participants to treat respiratory problems (11 spp.), hair and skin problems (9 spp.) and digestive disorders (8 spp.). Some plants were used to treat multiple ailments (10 spp.). About a third of all species (n = 8) were used by the participants to treat disorders that were not indicated in the regional and local pharmacopoeias. More specifically, Aloe saponaria, Blechum pyramidatum, Costus scaber, Impatiens walleriana, Lippia alba, Tradescantia zebrina, Psidium friedrichsthalianum and Solenostemon scutellarioides used for medicinal purposes by the participants were not found in the above-mentioned resources.

CONCLUSIONS

The present study provides new information about the use of medicinal plants in a thus far understudied urban area in Costa Rica. We documented new medicinal uses for several plants listed in the regional and local pharmacopoeias as well as for plants not previously reported in an urban environment. In general, there is little information about the types of plants used for medicinal purposes in urban ecosystems in Costa Rica. Although the country has a high endemic diversity of plants, many exotic medicinal plant species were introduced by the Spaniards during the colonization and by Afro-Costa Rican descendants. The present results thus show how the diversity of the medicinal plants used by these garden owners' confirms a socioeconomic gradient and reflects both Costa Rica's colonial history as well as the current epidemiological profile of the country. These findings underline the need for more ethnobotanical research in urban areas in Costa Rica.

Alien woody plants are more versatile than native, but both share similar therapeutic redundancy in South Africa

Understanding why alien plant species are incorporated into the medicinal flora in several local communities is central to invasion biology and ethnobiology. Theories suggest that alien plants are incorporated in local pharmacopoeias because they are more versatile or contribute unique secondary chemistry which make them less therapeutically redundant, or simply because they are locally more abundant than native species. However, a lack of a comprehensive test of these hypotheses limits our understanding of the dynamics of plants knowledge, use and potential implications for invasion. Here, we tested the predictions of several of these hypotheses using a unique dataset on the woody medicinal flora of southern Africa. We found that the size of a plant family predicts the number of medicinal plants in that family, a support for the non-random hypothesis of medicinal plant selection. However, we found no support for the diversification hypothesis: i) both alien and native plants were used in the treatment of similar diseases; ii) significantly more native species than alien contribute to disease treatments particularly of parasitic infections and obstetric-gynecological diseases, and iii) alien and native species share similar therapeutic redundancy. However, we found support for the versatility hypothesis, i.e., alien plants were more versatile than natives. These findings imply that, although alien plant species are not therapeutically unique, they do provide more uses than native plants (versatility), thus suggesting that they may not have been introduced primarily for therapeutic reasons. We call for similar studies to be carried out on alien herbaceous plants for a broader understanding of the integration of alien plants into the pharmacopoeias of the receiving communities.

Productos Forestales No Maderables de la comunidad El Tundo: un remanente boscoso de biodiversidad y conocimiento ancestral del sur del Ecuador

Los Productos Forestales No Maderables (PFNM) constituyen una fuente importante de subsistencia para las comunidades rurales del Ecuador. El presente estudio buscó identificar los PFNM más relevantes, así como su uso tradicional y actual en la comunidad El Tundo del cantón Sozoranga, Provincia de Loja. La información etnobotánica y etnozoológica se obtuvo a través 30 entrevistas orales y observaciones de campo. Se determinó el consenso entre los informantes en cada categoría de uso mediante (FIC), así como otros índices cuantitativos que permitieron calcular la importancia o valor cultural (IVU), validación científica (UST) y uso común (IF) de las especies. Se registraron 123 PFNM, de los cuales 116 fueron vegetales y 7 animales distribuidos en 12 categorías de uso, de las cuales destacaron la medicina humana y materiales. Las especies más versátiles localmente son Juglans neotropica Diels, Myroxylon peruiferum L. f, y Verbena litoralis Kunth. De las especies registradas, 33 constituyen recursos potenciales por su elevada aceptación socio-cultural, mientras que 17 de ellas presentaron los más altos niveles de fidelidad en toda la comunidad. Este trabajo contribuye a valorizar el conocimiento local para generar alternativas de aprovechamiento y uso sostenible de la biodiversidad.

Uso tradicional de especies de plantas en trece provincias de Ecuador

Se valida la hipótesis que el uso tradicional de plantas introducidas y nativas es análogo en Ecuador. Ciento veinticuatro entrevistas se desarrollan en 13 provincias de Ecuador, a 99 mujeres y 25 hombres, 107 del total son mestizos y 17 son indígenas, mayoritariamente comerciantes con estudios primarios y constan de 1 a 60 años de experiencia, que adquirieron el conocimiento del uso tradicional de las plantas de sus padres o madres principalmente. Se registra el uso de 274 especies, 138 (50,36%) del total son introducidas y 136 (49,63%) son nativas, 3 de las cuales son endémicas (1,09%); pertenecientes a 224 géneros incluidos en 88 familias botánicas, originarias de América (61,85%), Asia (15,68%), Europa (10,45%), África (9,58%) y Oceanía (2,44%). Se presentan 28 usos generales, particularmente como medicinal (71 usos terapéuticos), destacando el uso como antiinflamatorio, analgésico, antibiótico, antiespasmódico, diurético, sedante y antigripal. El conocimiento tradicional de las plantas no varía significativamente entre etnias y género; lo opuesto ocurre a nivel de edad y entre especies nativas e introducidas. Existe gran concordancia entre los informantes sobre los usos etnomedicinales de las plantas con un valor del Factor de Consenso de los Informantes (FIC) de 0,98.

Methodological advances for hypothesis-driven ethnobiology

Ethnobiology as a discipline has evolved increasingly to embrace theory-inspired and hypothesis-driven approaches to study why and how local people choose plants and animals they interact with and use for their livelihood. However, testing complex hypotheses or a network of ethnobiological hypotheses is challenging, particularly for data sets with non-independent observations due to species phylogenetic relatedness or socio-relational links between participants. Further, to account fully for the dynamics of local ecological knowledge, it is important to include the spatially explicit distribution of knowledge, changes in knowledge, and knowledge transmission and use. To promote the use of advanced statistical modelling approaches that address these limitations, we synthesize methodological advances for hypothesis-driven research in ethnobiology while highlighting the need for more figures than tables and more tables than text in ethnobiological literature. We present the ethnobiological motivations for conducting generalized linear mixed-effect modelling, structural equation modelling, phylogenetic generalized least squares, social network analysis, species distribution modelling, and predictive modelling. For each element of the proposed ethnobiologists quantitative toolbox, we present practical applications along with scripts for a widespread implementation. Because these statistical modelling approaches are rarely taught in most ethnobiological programs but are essential for careers in academia or industry, it is critical to promote workshops and short courses focused on these advanced methods. By embracing these quantitative modelling techniques without sacrificing qualitative approaches which provide essential context, ethnobiology will progress further towards an expansive interaction with other disciplines.

Utilitarian redundancy in local medical systems - theoretical and methodological contributions

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.

Medicinal plants in homegardens of four ethnic groups in Thailand

ETHNOPHARMACOLOGICAL RELEVANCE

Homegardens are important habitats for medicinal plants and traditional knowledge, especially among indigenous groups in remote areas. In homegardens, medicinal plants and traditional knowledge are well conserved through human management and ease of access.

AIM OF THE STUDY

To understand the drivers of diversity and the composition of homegardens with focus on medicinal plants, including exotic species, and their uses. We compare the homegardens of four ethnic groups in northern Thailand (Thai Yuan, Lahu, Karen, and Lisu).

METHODS

We inventoried all medicinal species in 195 homegardens from four villages belonging to the four ethnic groups. The owners were asked to point out all useful species in their homegardens. For any medicinal species, they were then interviewed about their main and secondary uses, medicinal properties, plant part used, preparation methods, and route of administrations.

RESULTS

We recorded 95 medicinal homegarden plant species ranging from 20-59 species per village and ethnic group. Most of the medicinal plants had a primary use as food plants, which demonstrated the close relationship between local food and medicine in the lives of these ethnic groups. Many of the medicinal plants were also used as food additives, ornamentals, or materials, showing that medicinal plants are not an exclusive category in the homegardens. The number of homegarden plants varied almost four-fold from 58 species in one village to 211 in the most species rich village. The number of medicinal homegarden plants varied accordingly from 20 to 59 in the poorest and the richest villages. Five medicinal species were found in all villages, but 70% of the medicinal plants were found in only one village. Infection & infestation, Nutritional disorders, and Digestive system disorders were the three most important medicinal use categories for plants in the homegardens, and all three categories were found in most of the studied homegardens. Of the 95 species with medicinal uses, 26 (27%) were exotic, which shows that local people amplify the spectrum of alternative ways to treat their illnesses.

CONCLUSION

Homegardens are an important source of ethnomedicinal species and knowledge. These species are beneficial for treating acute and common ailments; they are easy to access and can be prepared by simple methods, which are suitable for treating disorders, such as infections or any digestive system ailments. Medicinal plants in homegardens have been important in improving health, at least, at the family level.