André Luiz Borba do Nascimento

The Cultural Value of Invasive Species: A Case Study from Semi–Arid Northeastern Brazil

The Cultural Value of Invasive Species: A Case Study from Semi–Arid Northeastern Brazil. Invasive species are often considered the pariahs of the plant kingdom. In this study, we investigate the utility of native and exotic invasive plants to local residents in a semi–arid area of northeastern Brazil. We address the following questions: Are invasive species considered useful? How are they useful? Are they more or less useful than non–invasive species? Is there a relationship between use categories and taxonomic groups (families, genera, and species)? What plant parts are preferentially used and how are they distributed by categories of usage? And are there differences in the perceived usefulness of native vs. exotic invasive plants? We employed plot sampling of vegetation in anthropogenic habitats. Semi–structured, checklist interviews were carried out with 106 individuals. A total of 56 invasive species were recorded, of which 55 were considered useful. There was no statistical difference in the perceived utility of native vs. exotic invasive species; however, invasive species overall were considered useful more often than non–invasive species. The predominant use was as animal fodder, followed by medicine, food, and technology. Nearly half (44%) of the animal fodder species also served as medicine for people. Herbaceous plants were the most common. Uses varied significantly within taxonomic ranks (species, genus, and family). The most recognized plants were those that are most used locally. This study underscores the value of invasive species in semi–arid Brazil, as well as the need to include local people in regional and national strategies to address invasive species management.O Valor Cultural das Espécies Invasoras: Um Estudo de Caso no Semiárido do Nordeste do Brasil. As espécies invasoras são muitas vezes consideradas as párias do reino vegetal. Neste estudo, investigamos a utilidade de plantas invasoras nativas e exóticas para moradores locais no semiárido nordestino do Brasil. Nós procuramos responder as seguintes questões: São as espécies invasoras consideradas úteis? Como? São elas mais úteis que as espécies não invasoras? Existem relações entre categorias de uso e os grupos taxonômicos (famílias, gêneros e espécies)? Quais partes das plantas são preferencialmente usadas e como elas estão distribuídas por categorias de uso? E existem diferenças na utilidade percebida entre plantas nativas e exóticas invasoras? Nós empregamos o método de parcelas para a amostragem de vegetação em ambientes antropogênicos. Entrevistas semi–estruturadas foram realizadas com 106 pessoas. Um total de 56 espécies invasoras foram registradas, das quais 55 foram consideradas úteis. Não houve diferença estatística na percepção de utilidade das espécies invasoras nativas versus exóticas, no entanto, as espécies invasoras no geral (nativas e exóticas) foram frequentemente consideradas mais úteis do que as plantas citadas como não invasoras. O uso predominante foi o forrageiro, seguido do medicinal, alimentício e tecnológico. Quase metade (44%) das espécies forrageiras são reportadas como medicamento. Houve diferenças significativas entre os usos e categorias taxonômicas (espécies, gêneros e famílias). As plantas mais reconhecidas foram também as mais usadas localmente. Este estudo ressalta o valor de espécies invasoras no semiárido do Brasil, bem como a necessidade de incluir a população local em estratégias regionais e nacionais para lidar com a gestão de espécies invasoras.

Gender and Age

Traditional biological/ecological knowledge (TBK) of natural resource use is dynamic, thanks to the innovation and experimentation that different human groups have performed throughout their evolutionary history. However, this knowledge may suffer from variations that reflect intrinsic characteristics of the human species. In this chapter, how gender and age influence the knowledge of different resources used by human populations and the possible contexts in which these variations can be analyzed will be discussed.

An ethnopharmacological assessment of the use of plants against parasitic diseases in humans and animals.

ETHNOPHARMACOLOGICAL RELEVANCE Ethnobotanical surveys are detecting an increasing frequency of exotic plant species in pharmacopeias, which has led researchers to investigate the role of such species in traditional medical systems. According to the diversification hypothesis, exotic species are included to complete pharmacopeias, i.e., to treat diseases for which no native species are known, thus broadening the scope of the plant repertoire. MATERIALS AND METHODS The present study was conducted at two rural communities in northeastern Brazil aiming at a survey of the plants known or used by the population to treat endo- and ectoparasitic diseases in humans and animals. In addition, plant extracts exhibiting acaricide activity were assessed using the engorged female immersion and larval packet tests (LPT). RESULTS The results of the present study showed a tendency for native species to be used against ectoparasites and exhibit a broader scope of use compared to exotic species. In turn, exotic species were predominantly indicated to treat diseases caused by endoparasites, although there was an overlap of native and exotic species relative to some therapeutic purpose, e.g., ticks. Only two of the plant species tested exhibited acaricide activity (Nicotiana glauca Graham and Croton blanchetianus Baill.), and in both cases, the activity was weak. CONCLUSION The ethnobotanical data do not fully support the suggested hypothesis. Overall, the wide versatility of exotic species was not exclusively used to treat parasitic diseases in humans and animals. In addition, the selection of acaricide plants based on the ethnopharmacological study generated uninteresting results.

Functional aspects of the use of plants and animals in local medical systems and their implications for resilience

ETHNOPHARMACOLOGICAL RELEVANCE This study sought to understand the role of plants and animals in traditional medical systems and evaluate the capacity of these systems to absorb impacts and maintain their identity by determining the existence of functional substitutes. MATERIAL AND METHODS Ethnobiological data were collected through semi-structured interviews and free lists at a rural community in the semiarid region of northeastern Brazil. The data were subjected to the utilitarian redundancy model and analyzed by tests of proportion and variance. RESULTS We found that most of the therapeutic targets treated with animal-based remedies were also treatable by plant-based remedies; these targets were perceived as very usual, although they were not considered dangerous. Furthermore, people considered the plants and animals to be equally effective at curing overlapping therapeutic targets, but the plant remedies were used more frequently. The findings show that local knowledge about medicinal plants and animals follows similar patterns regarding the utilitarian redundancy, with high functional overlap among these features. However, the ease of access to the medicinal resource influences the choice of treatment, leading to an increased preference for plants over animals. In addition, we suggest that during the cultural evolution process, people concentrated their efforts on experimenting with different resources for the treatment of diseases that were very frequent locally, even if not very severe, which contributed to the resilience of the local medical system. CONCLUSION Furthermore, we infer that plants may effectively perform the function of healing, whereas animals act as reserves of resilience for the system, maintaining system function in the face of disturbances that may affect the availability of plant species.

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.

Assessment of the hunting of mammals using local ecological knowledge: an example from the Brazilian semiarid region

The hunting of wild animals remains a common activity in various parts of the world, especially in rural communities with poor socioeconomic conditions. To investigate patterns of mammal hunting, this study adopted a rural community located in semiarid Brazil as a model to test whether variables such as perceived abundance, activity period (day or night) and animal biomass could influence the consumption potential of mammal taxa. For this study, a checklist/interview technique using 32 photographs of mammals recorded in the region and two photographs of species that did not occur in the region, which acted as “control” species, was used, in addition to other visual stimuli and free lists. All species presented in the photographs, with the exception of the “control” species, were recognized as occurring in the region. Fourteen species were cited as being those most hunted locally. The species cited as most hunted had an average perceived abundance higher than the group of the least-hunted species. However, there was no significant relationship between hunting of a species and its locally perceived abundance. No significant difference in hunting pressure between diurnal and nocturnal species was found, nor was a relationship between animal biomass and hunting pressure observed. Our findings suggest that perceived abundance is an important factor for choosing a resource fauna, but other factors such as intended use, meat flavor and vulnerability to hunting, among others, may influence the potential use of a species.

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.

Religiosity/Spirituality Matters on Plant-Based Local Medical System

Religiosity/spirituality can affect health and quality of life in myriad ways. Religion has been present since the first moments of our evolutionary history, whether it is understood as a byproduct or as an adaptation of our cognitive evolution. We investigated how religion influences medicinal plant-based local medical systems (LMSs) and focuses on how individual variation in the degree of religiosity/spirituality affects the structure of LMSs. The knowledge of people about their medical systems was obtained through the free-listing technique, and level of religiosity/spirituality was calculated using the Brazilian version of the Brief Multidimensional Measure of Religiousness/Spirituality. We employed a Generalized Linear Model to obtain the best model. Religiosity/spirituality is predictive of structural and functional aspects of medicinal plant-based LMSs. Our model encourages a discussion of the role of religion in the health of an individual as well as in the structure of an individual’s support system. Religiosity/spirituality (and the dimensions of Commitment and Religious and Spiritual History, in particular) act to protect structural and functional elements of LMSs. By providing protection, the LMS benefits from greater resilience, at both the individual and population levels. We suggest that the socialization process resulting from the religious phenomenon has contributed to the complexity and maintenance of LMSs by means of the interaction of individuals as they engage in their religious observances, thus facilitating cultural transmission.

Evolutionary ethnobiology and cultural evolution: opportunities for research and dialog

The interest in theoretical frameworks that improve our understanding of social-ecological systems is growing within the field of ethnobiology. Several evolutionary questions may underlie the relationships between people and the natural resources that are investigated in this field. A new branch of research, known as evolutionary ethnobiology (EE), focuses on these questions and has recently been formally conceptualized. The field of cultural evolution (CE) has significantly contributed to the development of this new field, and it has introduced the Darwinian concepts of variation, competition, and heredity to studies that focus on the dynamics of local knowledge. In this article, we introduce CE as an important theoretical framework for evolutionary ethnobiological research. We present the basic concepts and assumptions of CE, along with the adjustments that are necessary for its application in EE. We discuss different ethnobiological studies in the context of this new framework and the new opportunities for research that exist in this area. We also propose a dialog that includes our findings in the context of cultural evolution.