Social-Ecological Theory of Maximization: Basic Concepts and Two Initial Models

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.

Preliminary exploration of herbal tea products based on traditional knowledge and hypotheses concerning herbal tea selection: a case study in Southwest Guizhou, China

BACKGROUND

Herbal tea usually refers to "beverage plants that do not belong to the genus Camellia", and it holds a significant historical legacy as a traditional beverage among specific regions and ethnic groups. In light of this, our research aims to investigate and analyze the traditional knowledge pertaining to herbal tea plants used by local people in the Qianxinan Buyi and Miao Autonomous Prefecture, Guizhou Province. We also initiated preliminary efforts to create tea products from herbal tea leaves using various processing techniques. Additionally, we attempted to test hypotheses to elucidate how local people select herbal tea plants.

METHODS

Data related to the use of herbal tea plants in this study were collected through semi-structured interviews and participatory observations in four villages in Qianxinan. Quantitative indicators, including the relative frequency of citation (RFC) and the relative importance (RI) value, were calculated, and the availability of plants was also evaluated. General linear model was performed to examine the relationship between the frequency of citation and resource availability, as well as the correlation between the relative frequency of citation and the relative importance, to test both the resource availability hypothesis and the versatility hypothesis. Centella asiatica tea was processed using techniques from green tea, black tea and white tea, with a preliminary sensory evaluation conducted.

RESULTS

A total of 114 plant species were documented as being used for herbal teas by local residents, representing 60 families and 104 genera. Of these, 61% of herbal tea plants were found growing in the wild, and 11 species were exotic plants. The family with the highest number of species was Asteraceae (20 species). The study identified 33 major medicinal functions of herbal tea, with clearing heat-toxin and diuresis being the most common functions. General linear model revealed a strong correlation (correlation coefficient of 0.72, p < 0.001) between the frequency of citation and plant availability, as well as a significant correlation (correlation coefficient of 0.63, p < 0.001) between RFC and RI. Under different processing conditions, the characteristics of Centella asiatica tea exhibited variations and were found to be suitable for consumption.

CONCLUSION

The consumption of herbal tea serves as a preventive measure against common ailments for local residents. The resource availability hypothesis, diversification hypothesis and the versatility hypothesis were shown to provide some insight into "how and why local communities select plants for use." Exotic herbal tea plants in the study area also possess valuable therapeutic properties. The processing and production of Centella asiatica herbal tea products hold promising prospects.

Interactions between local medical systems and the biomedical system: a conceptual and methodological review in light of hybridization subprocesses

Local medical systems (LMSs) are complex and dynamic, encompassing local perceptions of diseases, prevention and treatment strategies, and evaluations of therapeutic responses. These systems are not isolated and interact with other medical systems, such as the biomedical system. The interaction between these systems creates a "contact zone", which some authors refer to as intermedicality, involving both competitive and complementary interactions. However, there is limited discussion in the literature regarding the complexity of these interactions. Some studies seek to understand this interaction through the lens of hybridization, a concept introduced to ethnobiology by Ana Ladio and Ulysses Albuquerque. The authors conceptualize hybridization as "discrete structures and practices coming together to form a new practice not necessarily implying homogenization." They discuss hybridization in the context of medicinal plants used in urban settings and propose seven hybridization subprocesses to gain a deeper understanding of this phenomenon. In this study, we update these hybridization subprocesses, expanding the concepts to comprehend the specific interaction of resources from LMS and biomedical systems known and used by different human groups. In this context, we propose a new subprocess and have made adjustments to the existing subprocesses to encompass the diversity of possible interactions between medicinal plants and pharmaceuticals, providing evidence from the literature demonstrating interactions that can be classified within the proposed subprocesses. Furthermore, we discuss, from a theoretical standpoint, how these subprocesses may have implications for the resilience of medical systems. Moreover, we propose a flowchart that can be utilized to identify these hybridization subprocesses in intermedicality contexts in future studies. These classifications are crucial because they enable us to comprehend the complexity of interactions between medicinal plants and pharmaceuticals, as well as the impacts that these different interactions can have on the resilience of LMSs.

Patterns of use of wild food plants by Brazilian local communities: systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis sought to investigate the patterns of use of native wild food plants of Brazil (native and non-cultivated).

METHODS

We searched ethnobiological works with food plants in Web of Science, Scielo, Scopus and PubMed using different sets of keywords. Initially, the studies were evaluated based on inclusion criteria (systematic data collection instruments, such as interviews; specification of methods for data collection; and the presence of a species list). The methodological quality of each study was evaluated to define the risk of bias. A total of 20 articles met all criteria and were included in the review.

RESULTS

The results showed that there was a predominance of consumption of fruits, followed by leaves and seeds, which together represented 85.8% of the total parts. As for the meta-analysis, there was a predominance of use of plant parts classified as reproductive, non-persistent, non-destructive and parts of woody plants. There was no interference from the type of ecosystem (seasonally dry x moist). The results did not support the seasonality hypothesis.

CONCLUSIONS

The concentration of studies in the Northeast, Southeast and South regions of Brazil and in the Atlantic Forest and Caatinga biomes points to the need for a greater effort in terms of quantitative ethnobotanical research in other regions and biomes. The predominance of fruits and plant parts classified as reproductive, non-persistent and non-destructive points to the high potential for implementation of sustainable management strategies aimed at these plants in the country.

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.

Vegetation cover and seasonality as indicators for selection of forage resources by local agro-pastoralists in the Brazilian semiarid region

Local knowledge and uses of forage resources are highly dynamic, and can be mediated by multiple factors, such as seasonality, floristic diversity and the morphophysiological characteristics of plants. We investigate how seasonality and vegetation cover mediate the use of forage resources. The study was carried out with agro-pastoralists from two areas of Brazilian semiarid region. To select the areas, we used the normalized difference vegetation index. We selected one area with low vegetation cover (Area I) and another with high vegetation cover (Area II). Respondents were selected using the snowball technique. Using semi-structured interviews, we collect the information about forage use in the dry and rainy seasons, preferences of ruminants and specific characteristics of plant species. A total of 57 informants were interviewed in the two areas. We used the Chi-square test to assess differences in the richness of species cited between areas, seasons (dry/rainy), origins (exotic/native) and strate (herbaceous/woody). Our results revealed that agro-pastoralists living in the area with the highest vegetation cover (Area II) cited a greater number of species. We found that the use and selection of species is guided by a series of functional characters, related to palatability and nutritional value, which change between seasons. These results highlight the vast knowledge of ecological characteristics of species and diet of ruminants acquired by agro-pastoralists during field experience, with seasonality defining the use of species. Different from what we expected, the richness of exotic species mentioned did not differ between areas. This diversity of information contributes to a better understanding of the use of forage resources and indicates the importance of including local experiences as strategies to ensure proper use and provide insights for the conservation of local resources.

Short-term temporal analysis and children's knowledge of the composition of important medicinal plants: the structural core hypothesis

BACKGROUND

Measures of the importance of medicinal plants have long been used in ethnobotany and ethnobiology to understand the influence of social-ecological system factors in the formation of individuals' differential knowledge and use. However, there is still a gap in empirical studies that seek to understand the temporal aspects of this process.

METHODS

To overcome this issue, we used the concept of the structural core of medicinal plants, a theoretical-evolutionary model, which argues that the importance of medicinal plant resources is related to the increase in individual and population fitness. It represents the set of the most effective and available resources that would treat the most common diseases in an environment. This composition of knowledge would be conservative over space and time. To test these questions, we hypothesized that the composition of the structural core remains constant during temporal changes in a social-ecological context, and that the composition of the infantile structural core (new generation) is similar to that of the adults (older generation). For 2 years, we tracked the structure of important medicinal plants among the same 49 residents of a community located in Vale do Catimbau in Pernambuco, Brazil. We also compared the importance of the medicinal plants among two different generations, children/adolescents and adults, in the same space/time context.

RESULTS AND CONCLUSION

Our results refuted both hypotheses. Regarding the composition of important medicinal plants through temporal variations and for children's learning, our results were not predicted by the model. This suggests that the structural core should not be regarded as a conservative phenomenon, but rather a congenital, dynamic, and plastic occurrence that has adapted to configure itself as a short-term population response to the treatment of local diseases.

Socioeconomic factors influencing knowledge and consumption of food plants by a human group in a mountainous environment in the semiarid region of Bahia, Northeast Brazil

BACKGROUND

The relationship of people with natural resources is guided by different sociocultural, ecological and evolutionary factors. Regarding food plants, it is not different. Studies around the world have evaluated the effects of socioeconomic factors, such as age, gender, income, profession, education level, time of residence, ethnic diversity, religion, festive rituals, access to urban areas and migrations. In this sense, the objective of the present study was to characterize the diversity of knowledge and use of food plants by people from Serra dos Morgados and evaluate if the socioeconomic factors influence knowledge and consumption of food plants in the community.

METHODOLOGY

This research was conducted in the village of Serra dos Morgados, municipality of Jaguarari, Bahia, with the purpose of evaluating the factors that influence in the knowledge and use of food plants. Socioeconomic data such as age, gender, time of residence, and monthly income were collected. The free list technique was applied during the collection of ethnobotanical data in order to analyze the preference of the plants based on the salience index (SI). To analyze the factors that influence knowledge and use forms, we used GLM Lasso.

RESULTS

A total of 33 people were interviewed, 8 men and 25 women; their age ranged from 30 to 82 years. People cited 98 species of plants, 41 species being identified of spontaneous occurrence. The plant with the highest salience index (SI) was "cheirosa" (Psidium ganevii) (SI = 0.5679), followed by "massaranduba" (Micropholis sp.) (SI = 0.4323); "araça" (Campomanesia guazumifolia) (SI = 0.3320); and "cambuí" (Siphoneugena sp.) (SI = 0.3144).

CONCLUSIONS

The main factors that influence knowledge and use forms in the locality were family income and the collection site, with homegardens cited as the preferred area for collection of food plants. This study provided an overview related to potentially important species for a community located in a region where there are few ethnobiological studies. The results presented here can be used in future studies, providing clues for investigations. Also, there is a contribution to the conservation of biocultural aspects related to the use of food plants in a community living in mountainous regions.

Medicines in the Kitchen: Gender Roles Shape Ethnobotanical Knowledge in Marrakshi Households

Differences in gendered knowledge about plants are contingent on specific cultural domains. Yet the boundaries between these domains, for example food and medicine, are sometimes blurred, and it is unclear if and how gender plays a role in creating a continuum between them. Here, we present an in-depth evaluation of the links between gender, medicinal plant knowledge, and culinary culture in Marrakech, Morocco. We interviewed 30 women and 27 men with different socio-demographic characteristics and evaluated how gender and cooking frequency shape their food and medicinal plant knowledge. We documented 171 ethno-taxa used in Marrakshi households as food, medicine, or both, corresponding to 148 botanical taxa and three mixtures. While no clear differences appear in food plant knowledge by gender, women have a three-fold greater knowledge of medicinal plants, as well as plants with both uses as food and medicine. Women’s medicinal and food plant knowledge increases with their reported frequency of cooking, whereas the opposite trend is observed among men. Men who cook more are often single, have university-level degrees, and may be isolated from the channels of knowledge transmission. This demonstrates that the profound relations between the culinary and health domains are mediated through gender.

Gender differences in traditional knowledge of useful plants in a Brazilian community

Genders differ in traditional ecological knowledge (TEK) about plants, but how gender influences TEK sharing is still poorly understood. Here, we examined how gender is associated with the diversity, transmission, and structure of TEK. We tested whether women and men differ in terms of plant knowledge (species richness, α-diversity), knowledge heterogeneity (β-diversity), and in the structure of social-ecological networks they form. The study was carried out in a suburban community in the city of Ouro Preto, Southeastern, Brazil. Using the snow-ball technique, semi-structured interviews, guided tours, and participant observation, we gathered information from 33 women and 33 men in the community. We collected information about their culture, social-economic profiles, and plant knowledge from which we identified 291 plant species in 10 use categories. Overall, our results indicated that the cognition and sharing of ethnobotanical knowledge are structured by gender. Women rated better in their plant knowledge repertory (greater α-diversity), while plant knowledge among men was more heterogeneous (greater β-diversity), suggesting less information sharing among them. We observed that the network among women is more connected, exhibited greater information sharing, with a greater number of central individuals, who likely provide the cohesion and maintenance of TEK in the community. Our findings indicate how social-ecological networks can provide insights and information to unveil social patterns of knowledge transmission. Understanding how TEK is fostered and shared among community members will favor better planning of ethnobotanical studies, as well as inform decision-makers about strategies for the conservation of plant TEK.

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.

Wild plants and the food-medicine continuum-an ethnobotanical survey in Chapada Diamantina (Northeastern Brazil)

BACKGROUND

Ethnobotanical research has demonstrated that several wild food plants (WFP) are used for medicinal purposes. Therefore, in addition to constituting an important source of nutrients, WFP can be used to help treat and avoid health problems. This study sought to characterize the traditional use of plants considered simultaneously as food and medicine by local specialists in the community of Caeté-Açu, which borders Chapada Diamantina National Park (NE Brazil). We also sought to identify the variables that influence the species' cultural importance.

METHODS

We selected local specialists based on a snowball sample and used a free-listing technique to register the wild plants they knew that are both edible and medicinal. Then, we asked the specialists to rank each plant component cited according to the following attributes: (1) ease of acquisition, (2) taste, (3) smell, (4) nutritional value, and (5) medicinal value. We used multiple regression to determine the variables that influence the cultural salience.

RESULTS

The most culturally salient species was Anredera cordifolia (Ten.) Steenis. The main medicinal effects associated with this species were related to body strengthening, intestinal regulation, and stomach issues. The most salient used species were those that were easiest to acquire and had the highest perceived nutritional values.

CONCLUSION

It is likely that the sociocultural backgrounds of the respondents (elders, former miners, or descendants of miners) and the historical importance of wild food plants to local diets increased the predictive power of the perceived nutritional importance and ease of acquisition of these plants.

Can medicinal use protect plant species from wood uses? Evidence from Northeastern Brazil

Several ethnobotanical studies have attempted to understand the criteria for the differential use of plant resources. However, we need more effort to understand the interaction between local uses: how using a species for a given purpose may affect its use for another purpose. Thus, we hypothesize that high importance species in a more specialized category of use may have their use reduced for other categories with a more generalist nature. We have conducted the study in three rural communities in northeastern Brazil, set in seasonally dry tropical forest areas. We applied the free-list technique to identify woody species used for medicinal and/or wood purposes (fuelwood, construction and technology). Respondents rated the species according to their efficiency for wood purposes and their local availability. We performed a multiple regression to assess the effects of medicinal popularity, perceived availability, and perceived efficiency for wood uses over the species popularity for wood uses. Our results showed that medicinal use has a significant protective effect against wood uses. Perceived availability and efficiency were significant explanatory variables for wood use. Maintaining the medicinal importance of certain species can be a powerful tool in protecting their populations against more harmful uses.

What interferes with conducting free lists? A comparative ethnobotanical experiment

BACKGROUND

The free list, also written "freelist", or "free recall", is an ethnographic method that characterizes the local knowledge of a population about a given cultural domain. However, there is still much to elucidate about the variables that can influence the number of items that participants cite using this technique. This study applied a casual-comparative experimental design to analyze whether 3 months' time, age, and external stimuli influence the similarity of plant free lists applied at different times.

METHODS

Data was collected from 103 farmers from the rural community Alto dos Canutos, in the municipality of Picos, Piauí state, Brazil. Two free lists were conducted at two different times, with an interval of three months between them. Subsequently, the similarity between the first and second free lists of each participant was calculated using the Jaccard Similarity Index. The generalized linear model (GLM) with binomial errors and stepwise approach was used to analyze the effects of age and external stimuli on information collection when comparing free lists applied at different times.

RESULTS

Participants' age influenced the information that the free lists collected, demonstrating that the older the participants, the lower the similarity among the free lists. Among the external stimuli analyzed, only the presence of third parties influenced the content of the free lists at the time of the interview. However, contrary to expectations, third-party presence positively influenced the similarity of the lists.

CONCLUSION

The results show that the studied variables age and third-party presence can influence the capture of knowledge. These findings warrant future research into the influences' causes and their potential mitigation, e.g., by isolation or by breaking the medicinal plant domain into focused sub-domains and conducting simpler, successive free-lists, which can mitigate memory issues.

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.