Wild food plants of Brazil: a theoretical approach to non-random selection.

Ethnobiological investigations have focused on identifying factors that interfere with the criteria adopted for selection of plants, especially medicinal plants, by different populations, confirming the theory that plant selection is not random. However, regarding wild food plants, little effort has been made to confirm the theory in this context, especially in Brazil. Therefore, this systematic review aimed to contribute to the establishment of theoretical bases of the non-random selection of wild food plants by local populations in Brazil. For this, searches were made in 4 databases, namely, Web of Science, Scielo, Scopus and PubMed, using 8 sets of keywords in English and Portuguese in order to identify wild food plants occurring in Brazil. The steps were: application of inclusion and exclusion criteria, screening of articles, selection of studies based on risk of bias, data treatment and, finally, data analysis. Eighty articles met the inclusion criteria of this review. However, 45 of them were considered to present high risk of bias and thus 35 articles were kept for the identification of overused and underused families. The results were inferred through two different approaches (IDM and Bayesian). Annonaceae, Arecaceae, Basellaceae, Cactaceae, Capparaceae, Caryocaraceae, Myrtaceae, Passifloraceae, Rhamnaceae, Rosaceae, Sapotaceae, Talinaceae, and Typhaceae were considered overused. Eriocaulaceae, Orchidaceae, and Poaceae were considered underused. Therefore, considering that some families are more (or less) used than others, we confirm that the wild food plants occurring in Brazil, known and used by different populations, are not chosen at random.

Taste and chemical composition as drives for utilitarian redundancy and equivalence: a case study in local medical systems in Northeastern Brazil.

BACKGROUND: We aimed to verify whether the taste and chemical composition influence the selection of plants in each medicinal category, whether within a socio-ecological system or between different socio-ecological systems. To this end, we use the theoretical bases of the Utilitarian Redundancy Model and the Utilitarian Equivalence Model. We studied the local medical systems of four rural communities in northeastern Brazil, used as models to test our assumptions. METHODS: The data on medicinal plants and local therapeutic function were obtained from semi-structured interviews associated with the free-listing method, allowing to generate indexes of similarity of therapeutic use between the plants cited in each region. During the interviews, each informer was also asked to report the tastes of the plants cited. Subsequently, we classified each plant in each region according to the most cited taste. The data about the chemical composition of each plant were obtained from a systematic review, using Web of Knowledge and Scopus databases. RESULTS: Pairs of plants with similar tastes are 1.46 times more likely to have the same therapeutic function within a local medical system (redundancy), but not between medical systems (equivalence). We also find that chemical compounds are not primarily responsible for utilitarian redundancy and equivalence. However, there was a tendency for alkaloids to be doubly present with greater expressiveness in pairs of equivalent plants. CONCLUSIONS: The results indicate that each social group can create its means of using the organoleptic characteristics as clues to select new species as medicinal. Furthermore, this study corroborates the main prediction of the Utilitarian Equivalence Model, that people in different environments choose plants with traits in common for the same functions.

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.

Local knowledge as a tool for prospecting wild food plants: experiences in northeastern Brazil.

This study aims to provide a simple framework to identify wild food plants with potential for popularization based on local knowledge and perception. To this end, we also characterized the distribution of this knowledge in the socio-ecological system. We developed the study in the rural settlement Dom Hélder Câmara in northeastern Brazil. The species with the greatest potential for popularization considering the attributes accessed from local knowledge and perception were Psidium guineense Sw., Genipa americana L., Xanthosoma sagittifolium (L.) Schott and Dioscorea trifida L.f. However, the high variation in local knowledge on wild food plants suggests that species that are not frequently cited can also be promising. The absence of age or gender-related knowledge patterns indicates that studies for prospecting wild food plants in similar socioecological contexts need to reach the population as a whole, rather than focusing on a specific group.

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.

The role of women in Brazilian ethnobiology: challenges and perspectives.

BACKGROUND: The article aims to analyze the representativeness of women in ethnobiological publications within the Brazilian context, as well as to relate the difficulties faced by women in their scientific careers in terms of gender bias. Biases found in publications are relevant themes to different areas of knowledge, considering the historical persistence of male privilege in these activities. We analyzed the role of women in ethnobiological scientific publications and sought to reflect on gender issues in academic practices and fieldwork. METHODS: We conducted a 28-year survey of academic publications in Brazil, through the Scopus and Web of Science databases, in order to infer the female representation in ethnobiological literature. We also sent 77 questionnaires to ethnobiologists associated with the Brazilian society of ethnobiology and ethnoecology or indicted by associates through snowball sampling. RESULTS: We observed that there are more articles where the senior author is male (p < 0.05). However, there are no differences in the number of publications led by men and women (p > 0.05), which shows a positive trend in terms of representation. Within subareas, ethnozoology had more male authors than other subareas of ethnobiology. Articles whose senior authors are men tend to be published in journals with a higher impact (p < 0.05). The interviews with Brazilian ethnobiologists showed that 53.2% of the interviewees reported feeling discriminated against in the academic environment because they were women. Moreover, 61.0% said they had disadvantages in collecting data because they were women. Additionally, most of the researchers reported having witnessed cases of sexism in the studied communities. CONCLUSION: In the current scenarios of female participation, it is possible to reflect and identify advances and challenges associated with gender bias in ethnobiological studies conducted by Brazilian, both in the emic and etic spheres of research and in our scientific practice. As researchers in the area, we deal directly with social problems in the studied communities, such as violence against women, sexism, and prejudice, as well as the many problems faced in the academic universe itself.

Gender and Its Role in the Resilience of Local Medical Systems of the Fulni-ô People in NE Brazil: Effects on Structure and Functionality.

Ethnobotanical studies focused on understanding how local medical systems are functionally maintained suggest that utilitarian redundancy and knowledge transmission are factors that influence the resilience of the system. However, to date, there have not been any studies that analyze these factors in relation to the variables that influence the variation of knowledge. Given the above, this study aims to analyze the influence of gender in the resilience of the system, using utilitarian redundancy and knowledge transmission as factors. Information from 198 married couples (396 people) was collected from the indigenous community of Fulni-ô (NE Brazil). Knowledge between men and women was analyzed based on the total number of known plants, therapeutic targets, information units, utilitarian redundancy, models of transmission, and sharing for each gender. Fulni-ô men know a greater number of plants, therapeutic targets treated with plants, and information units than women. They also had greater utilitarian redundancy. However, regarding knowledge transmission, sharing among women was greater, transmission is related to gender, and there is no difference between the numbers of models of knowledge information. In the system of local medical knowledge, gender exerts an important role in the resilience of the system. This study shows that men have a greater contribution to the structure and function of the system; however, both genders contribute to the flow of information in the system, which makes both genders important in the feedback of information.

Effect of Gender on the Knowledge of Medicinal Plants: Systematic Review and Meta-Analysis.

Knowledge of medicinal plants is not only one of the main components in the structure of knowledge in local medical systems but also one of the most studied resources. This study uses a systematic review and meta-analysis of a compilation of ethnobiological studies with a medicinal plant component and the variable of gender to evaluate whether there is a gender-based pattern in medicinal plant knowledge on different scales (national, continental, and global). In this study, three types of meta-analysis are conducted on different scales. We detect no significant differences on the global level; women and men have the same rich knowledge. On the national and continental levels, significant differences are observed in both directions (significant for men and for women), and a lack of significant differences in the knowledge of the genders is also observed. This finding demonstrates that there is no gender-based pattern for knowledge on different scales.

Medicinal plant knowledge in a context of cultural pluralism: A case study in Northeastern Brazil.

ETHNOPHARMACOLOGICAL RELEVANCE: The study of plant use in contexts of migrations can give important insights to cultural evolution, since people face rapid changes in their environments and often start interacting with native dwellers, both constituting forces that can lead to change. Therefore, this study focused on medicinal plant knowledge and transmission in order to understand what happens to such knowledge when people from several regions converge to a single place already inhabited by native people. METHODS: The study was carried out in the rural community of Caeté-Açu (known as Capão Valley), placed in the state of Bahia (NE Brazil). Native and migrant people's knowledge on medicinal plans was accessed with a free listing. People were also asked about whom in the community once taught them about medicinal plants. Four groups (native, regional migrants, national migrants and international migrants) were compared in terms of number of cited plants, plant repertoires and knowledge transmission. For each group we also ran simple regressions between age and number of cited plants and residence time and number of cited plants. RESULTS AND DISCUSSION: We found no differences among groups in terms of number of known species. However, plant repertoires differ in some extent among groups. While migrants claim to have learnt with both native people and other migrants, most native claim to have learned mainly with other natives. Age influences plant knowledge only for the natives, what strengthens evidence that this group's knowledge is based on experience while migrants'' knowledge is based on an active search. Residence time in the community did not influence migrants' knowledge. CONCLUSION: Native and migrant people have differences in their ways of acquiring medicinal plant knowledge and less popular species are also different between groups. However, we can observe a tendency of fusion and indissolubility of migrant and native knowledge since the new generations are in contact with both sources.

Can organoleptic properties explain the differential use of medicinal plants? Evidence from Northeastern Brazil.

ETHNOPHARMACOLOGICAL RELEVANCE: This study examined how people classify plants in terms of their taste and smell, and how those organoleptic properties influence the differential use of medicinal plants for treating different diseases. METHODS: We conducted an ethnobotanical survey of household heads in the community of Sucruiu, located in Barreiras, Bahia, Brazil. The head of each family was questioned concerning their knowledge and use of medicinal plants, as well as the therapeutic indications (TIs), taste, and smell of each plant. We then tested for associations between the therapeutic indications and taste attributes of various plants using the Chi-squared test on a contingency table with Monte Carlo simulations. The same analysis was performed for associations between TIs and smell. RESULTS: The study participants provided more details when classifying tastes than when classifying smells. We considered only the most cited TIs and attributes, and found significant associations between both taste and therapeutic indications (p<0.001) and smell and therapeutic indications (p<0.0001). CONCLUSIONS: Our results showed that the taste and smell of a plant can influence its differential medicinal use, since plants with certain tastes and smells prevailed in the treatment of distinct diseases. However, our results are valid only for the most popular TIs and organoleptic attributes.

Patterns of medicinal plant use by inhabitants of Brazilian urban and rural areas: a macroscale investigation based on available literature.

ETHNOPHARMACOLOGICAL RELEVANCE: Although the relationship between local people and plants may be idiosyncratic, some human behaviors are common to different communities and can be influenced by cultural and environmental factors. Thus, this study drew upon a systematic review and meta-analysis to evaluate if there are patterns of medicinal plant use in different Brazilian ethnobotanical studies and if these patterns are influenced by the urbanization or ecosystems where the studies were conducted. MATERIALS AND METHODS: The factors evaluated concerned the origin of the species used (native vs. exotic), plant habit (woody vs. non-woody) and plant parts (permanent and non-permanent). Two kinds of analysis were performed: the integrative and the meta-analytical. RESULTS: The factors varied depending on the ecosystems in which the studies were conducted. In the Amazon, Cerrado and Caatinga, native and woody medicinal species dominated; conversely, this pattern was not the case for the Atlantic Forest and Pampas ecosystems. Permanent plant parts were predominant in the Cerrado, and considering only native plants, permanent parts dominated in the Amazon, Cerrado and Caatinga. Urbanization did not significantly affect these patterns. Additionally, the species relative importance (RI) did not change as a function of the ecosystem or the degree of urbanization. CONCLUSIONS: The phenomena observed in this study can be explained in light of the chemical ecology and historical and cultural aspects of the species, and the findings have important implications for bioprospecting and conservation.

The ecological apparency hypothesis and the importance of useful plants in rural communities from northeastern Brazil: an assessment based on use value.

The ecological apparency hypothesis in ethnobotanical studies predicts that the apparent plants (i.e., the most easily found in the vegetation) would be the most commonly collected and used by people. To test this hypothesis, it has been used the concept of use value (VU), which measures the relative importance of useful plants for a group of people. However, the use value has got some limitations, including the fact that it does not distinguish "current use" (plants which are effectively used) from "potential use" (well known plants, however not used). Therefore, this study has tested whether the obtained results through three different use value calculations could be useful in testing the ecological apparency hypothesis. These calculations have included the current use value, the potential use value, and the general use value. It has been carried out a vegetation survey and an interview for residents from the rural communities from Barrocas and Cachoeira (Soledade, Paraíba, Brazil). It has been used Spearman's coefficient to correlate phytosociological and ethnobotanical data. It has been observed that phytosociological parameters in Cachoeira were not correlated with any of the use values calculations, except the relationship between the current use value and the relative dominance (r(s) = 0.57; p < 0.05). In Barrocas, every use value calculation was correlated with the basal area and the relative dominance. When each category of use is analyzed separately, it has been observed that there was no correlation between the use value and the phytosociological parameters, except for the construction category, in which the current use value in Cachoeira was correlated with the relative dominance (r(s) = 0.63; p < 0.05), importance value (r(s) = 0.67; p < 0.01), relative frequency (r(s) = 0.71; p < 0.05), and relative density (r(s) = 0.72; p < 0.01). In Barrocas, the UVc for the construction category was correlated with relative frequency (r(s) = 0.69; p < 0.05) and relative density (r(s) = 0.66; p < 0.01). These results have suggested that, the use value calculation, which takes into consideration just the current use of the species, is the one that best fits in the ecological apparency hypothesis.

The use of medicinal plants by migrant people: adaptation, maintenance, and replacement.

Given the importance of studying the knowledge, beliefs, and practices of migrant communities to understand the dynamics of plant resource use, we reviewed the scientific literature concerning the use of medicinal plants by migrant populations engaged in international or long-distance migrations. We considered the importance of two processes: (1) adaptation to the new flora of the host country (i.e., substitution and incorporation of plants in the pharmacopoeia) and (2) continued use and acquisition of the original flora from migrants' home countries (i.e., importation, cultivation, and/or continued use of plants that grow in both host and home environments). We suggest that, depending on the specific context and conditions of migration, different processes that determine the use and/or selection of plants as herbal medicines may become predominant.

Natural products from ethnodirected studies: revisiting the ethnobiology of the zombie poison.

Wade Davis's study of Haitian "zombification" in the 1980s was a landmark in ethnobiological research. His research was an attempt to trace the origins of reports of "undead" Haitians, focusing on the preparation of the zombification poison. Starting with this influential ethnopharmacological research, this study examines advances in the pharmacology of natural products, focusing especially on those of animal-derived products. Ethnopharmacological, pharmacological, and chemical aspects are considered. We also update information on the animal species that reportedly constitute the zombie poison. Several components of the zombie powder are not unique to Haiti and are used as remedies in traditional medicine worldwide. This paper emphasizes the medicinal potential of products from zootherapy. These biological products are promising sources for the development of new drugs.

Pressure indicators of wood resource use in an Atlantic forest area, northeastern Brazil.

Wood resources are often used to support the needs of the local population. In order to protect biodiversity and resources, conservation strategies need to consider what types of wood use have the strongest impacts on forested areas. This study aimed to identify the use categories that put higher pressure on an Atlantic forest region located in the municipality of Igarassu in Pernambuco, northeastern Brazil. To conduct the study, we measured the volume of all wood products in 62 surveyed residences and registered the average replacement time for such products. The fuelwood category was most important locally and accounted for 92% of annual wood consumption. However, the construction category harvests more destructively and concentrates on the consumption of a few wood species. Therefore we recommend the fuelwood category to be the main focus of conservation effforts. In addition, the most important species for construction purposes (e.g., Eschweilera ovata (Cambess.) Miers, Apuleia leiocarpa (Vogel) J.F. Macbr. and Pogonophora schomburgkiana Miers ex Benth) should also be considered as a priority for conservation.