Gustavo Taboada Soldati

A New Application for the Optimal Foraging Theory: The Extraction of Medicinal Plants

The Optimal Foraging Theory was used to identify possible patterns in bark extraction and the selective cutting of Anadenanthera colubrina (Angico), a medicinal plant. The hypotheses were built on two approaches: selection of collection place and bark exploitation occurrence in only one of these resource areas. The results suggest that the distance that must be traveled to reach each gathering site determines the extent of the extraction process, showing that people minimize the time and energy spent in A. colubrina collection. The availability of each site appears not to influence the operation. The resource amount was the optimized variable for bark extraction, which was analyzed in only one collection zone. In contrast to the phenomenon of collection place selection, the distance between angico individuals, the management period, and the tannin content did not affect bark extraction. This study also discusses how certain cultural aspects influence the extraction of angico.

Does Environmental Instability Favor the Production and Horizontal Transmission of Knowledge regarding Medicinal Plants? A Study in Southeast Brazil

Greater socio-environmental instability favors the individual production of knowledge because innovations are adapted to new circumstances. Furthermore, instability stimulates the horizontal transmission of knowledge because this mechanism disseminates adapted information. This study investigates the following hypothesis: Greater socio-environmental instability favors the production of knowledge (innovation) to adapt to new situations, and socio-environmental instability stimulates the horizontal transmission of knowledge, which is a mechanism that diffuses adapted information. In addition, the present study describes “how”, “when”, “from whom” and the “stimulus/context”, in which knowledge regarding medicinal plants is gained or transferred. Data were collected through semi-structured interviews from three groups that represented different levels of socio-environmental instability. Socio-environmental instability did not favor individual knowledge production or any cultural transmission modes, including vertical to horizontal, despite increasing the frequency of horizontal pathways. Vertical transmission was the most important knowledge transmission strategy in all of the groups in which mothers were the most common models (knowledge sources). Significantly, childhood was the most important learning stage, although learning also occurred throughout life. Direct teaching using language was notable as a knowledge transmission strategy. Illness was the main stimulus that triggered local learning. Learning modes about medicinal plants were influenced by the knowledge itself, particularly the dynamic uses of therapeutic resources.

Ethnobotany in Intermedical Spaces: The Case of the Fulni-ô Indians (Northeastern Brazil)

We analyzed the Fulni-ô medical system and introduced its intermedical character based on secondary data published in the literature. Then we focused on the medicinal plants known to the ethnic group, describing the most important species, their therapeutic uses and the body systems attributed to them. We based this analysis on the field experience of the authors in the project Studies for the Environmental and Cultural Sustainability of the Fulni-ô Medical System: Office of Medicinal Plant Care. This traditional botanical knowledge was used to corroborate the hybrid nature of local practices for access to health. We show that intermedicality is a result not only of the meeting of the Fulni-ô medical system with Biomedicine but also of its meeting with other traditional systems. Finally, we discuss how traditional botanical knowledge may be directly related to the ethnogenesis process led by the Fulni-ô Indians in northeastern Brazil.

Impact assessment of the harvest of a medicinal plant (Anadenanthera colubrina (Vell.) Brenan) by a rural semi-arid community (Pernambuco), northeastern Brazil

Rural communities depend on plant resources, and research is necessary to evaluate the impact of their exploitative practices. This study evaluated the use of Anadenanthera colubrina (Vell.) Brenan, angico, a tree species widely employed by the rural community of Carão (Pernambuco, Brazil) and the impacts of this harvesting practice. Angico has been cited as having 28 uses in five categories, and the bark is the most used. The medicinal uses are dominant in the community and the species is collected in four collection zones: home gardens, mountain, pasture and mountain base. In order to evaluate the sustainability of this practice, the extraction events in an A. colubrina population were recorded in 2008, and the population structure was analysed. The 101 interviews resulted in identification of 28 uses of which the medicinal category was most prevalent. The most exploited parts of A. colubrina were the bark and stem; the main collection zones were home gardens and mountains. Of the 1040 A. colubrina individuals that we recorded in an area of 2.7 ha, 70 showed signs of extraction. Although diameter classes do not show any individual preference, the population structure tends towards an inverted J model, which suggests that it is stable and its viability is not affected by the extraction being carried out. The data collected in this study suggest that maintaining the current methods and rates of exploitation of the A. colubrina population is sustainable and allows for the permanence of this local resource stock used by the Carão community. However, projections from our results on A. colubrina population structure should be considered carefully because only one population was analysed, over one-time period.

How do people select plants for use? Matching the Ecological Apparency Hypothesis with Optimal Foraging Theory

The present study aimed to understand human plant resource usage strategies in the context of the Ecological Apparency Hypothesis and Optimal Foraging Theory. The relationship between plant resource knowledge and availability was tested in a rural community (Palmital) in a dry Atlantic Forest fragment in the state of Minas Gerais, Southeastern Brazil, using data from phytosociological studies and interviews. We considered both total use and separate use categories. Use Value (UV) was significantly associated with all of the analyzed ecological variables, but there was an association with relative dominance and a weak relationship with relative density. When the UVs were separately analyzed for each category, we found that some, i.e., fuel and construction, corroborate the Ecological Apparency Hypothesis, while others do not, particularly the medicinal and food categories. In addition, we found large differences with respect to the ecological variables that best correlated with UV. The data suggest that the cost/benefit relationship predicted by Optimal Foraging Theory can explain the Ecological Apparency Hypothesis when the following factors are considered: (a) resource acquisition optimization and security; (b) a higher probability of acquiring more abundant species during random collection events; and (c) differential utilization patterns (distinct requirements for a specific use) for each use category. Some implications for conservation are also discussed.

The Influence of the Environment on Natural Resource Use: Evidence of Apparency

This chapter evaluates the mechanisms by which certain characteristics of a specific natural resource (particularly a plant), such as its environmental availability or chemical composition, can affect its local use. An evaluation of the factors that influence people’s decision to select and try a natural resource and, possibly, incorporate it in their social-ecological systems is the main guiding issue for this chapter. To address this issue, we explore the assumptions of the ecological apparency hypothesis (EAH), the optimal foraging theory (OFT) and the resource availability hypothesis (RAH). EAH, OFT and RAH were first introduced in classic ecological research but were subsequently adapted to the fields of human ecology and ethnobiology. We also discuss how these ideas can complement one another to explain people’s choices for plant resource use and management. Finally, we bring some evidence from the available literature in favor or against these assumptions, especially to what concerns the EAH.

Utilitarian Redundancy: Conceptualization and Potential Applications in Ethnobiological Research

The utilitarian redundancy model (URM) enables a simple and objective evaluation of the functionality of knowledge systems based on species known to perform similar functions. It emerges from the redundancy model in ecology that analyzes, from a functional perspective, the use of natural resources by human populations. The model includes three basic assumptions. The first is that several species exist with the same function (redundancy), which leads to a shared use pressure among these similar species. Second, locally preferred species experience higher use pressure even if their function is redundant, and third, functional redundancy provides flexibility to cope with disturbances caused by local species loss and positively contributes to the resilience of social-ecological systems. The applicability of this model is explained in this chapter, primarily through examples of local medical systems, and its applicability to studies focusing on the resilience of traditional ecological knowledge systems is detailed.

Information Retrieval during Free Listing Is Biased by Memory: Evidence from Medicinal Plants

Free listing is a methodological tool that is widely used in various scientific disciplines. A typical assumption of this approach is that individual lists reflect a subset of total knowledge and that the first items listed are the most culturally important. However, little is known about how cognitive processes influence free lists. In this study, we assess how recent memory of use, autonoetic and anoetic memory, and long-term associative memory can affect the composition and order of items in free lists and evaluate whether free lists indicate the most important items. Based on a model of local knowledge about medicinal plants and their therapeutic targets, which was collected via individual semi-structured interviews, we classify each item recorded in free lists according to the last time that the item was used by the informant (recently or long ago), the type of relevant memory (autonoetic or anoetic memory) and the existing associations between therapeutic targets (similar or random). We find that individuals have a tendency to recall information about medicinal plants used during the preceding year and that the recalled plants were also the most important plants during this period. However, we find no trend in the recall of plants from long-term associative memory, although this phenomenon is well established in studies on cognitive psychology. We suggest that such evidence should be considered in studies that use lists of medicinal plants because this temporal cognitive limit on the retrieval of knowledge affects data interpretation.

Resilience and Adaptation in Social-Ecological Systems

Social-ecological systems are open and dynamic systems. A major challenge in ethnobiological research involves understanding how social-ecological systems maintain their functions and processes upon facing disturbances over time. In this chapter, we present the concepts of resilience and adaptation, aiming to provide a scenario for ethnobiological studies that seek to investigate how social-ecological systems respond to disturbances. Moreover, we provide some examples of ethnobiological studies that sought to understand the resilience of social-ecological systems.

Ecological-Evolutionary Approaches to the Human–Environment Relationship: History and Concepts

In this chapter, we examine several schools of thought that have considered the influence of the environment on certain aspects of human behavior. We show the main interpretations and critics to determinism, the arising of possibilism as an alternative discourse, the ideas of a cultural core and multilinear evolution applicable to cultural ecology, the adoption of a systems perspective (and the functioning of feedbacks), neo-Darwinian approaches and processual approaches in anthropology and human ecology. Additionally, considerations regarding the potential of the evolutionary approaches to understand the relationship between nature and society are offered.