title: Plant extractivism in light of game theory: a case study in northeastern Brazil.
abstract: BACKGROUND
  Game theory enables the predictive study of the behavior of agents that recognize the mutual interdependence of their decisions and act rationally and strategically to maximize their own gains. In this paper, the extractivism of pequi (Caryocar coriaceum Wittm.) and fava d'anta (Dimorphandra gardneriana Tul.) in an area of common use of the semiarid region of northeastern Brazil is described as a model to illustrate a practical application of game theory in the interpretation of the phenomena analyzed in ethnobiological research.
  
  
  METHODS
  Field research was conducted in the Araripe-Apodi National Forest. Semi-structured interviews were conducted with 55 informants recognized as knowledgeable and experienced in the extractivism of pequi and fava d'anta in the region. In the interviews, information that could contribute to the identification and understanding of the focal points of extractivism in the region was surveyed. Data were analyzed under an analytical/descriptive approach using the "content analysis" technique.
  
  
  RESULTS
  There was a logic of competitive entrepreneurship around the commercial extractivism of pequi and fava d'anta in the region. Among the extractivists of pequi, one of the main collection rules refers to the prohibition of removing immature fruits by using sticks or shaking the branches. In the extractivism of fava d'anta, no specific rules have been established by collectors, but there is a predominant behavior of withdrawing all available fruits (pods) on a tree in a single visit. In an analysis guided by game theory, the collection decisions adopted by extractivists to maximize gain from the activity can be considered justifiable from the standpoint of economic rationality.
  
  
  CONCLUSIONS
  The "game of extractivism" of pequi and fava d'anta operates under conditions similar to the "tragedy of the commons." In this game, the non-cooperative solution is converted to the Nash equilibrium. The approach used in this study contributed to the identification of strategies and solutions to problems arising from the extractivism of pequi and fava d'anta.
authors.affiliation: Centro de Ciências Agrárias, Área de Engenharia Florestal, Universidade Federal de Alagoas, BR-104 Norte, Km 85, Mata do Rolo, CEP: 57100-000, Rio Largo, Alagoas, Brazil. rafaelrvsilva@gmail.com.
authors.forename: Rafael Rv
authors.initials: RR
authors.lastname: Silva
authors.affiliation: Departamento de Ciências Florestais, Universidade Federal de Sergipe, Avenida Marechal Rondon, Jardim Rosa Elze, CEP: 49100-000, São Cristóvão, Sergipe, Brazil. laurabuturi@gmail.com.
authors.forename: Laura Jane
authors.initials: LJ
authors.lastname: Gomes
authors.affiliation: Departamento de Biologia, Laboratório de Etnobiologia Aplicada e Teórica, Universidade Federal Rural de Pernambuco, Avenida Dom Manoel de Medeiros, Dois irmãos, CEP: 52171-900, Recife, Pernambuco, Brazil. upa@db.ufrpe.br.
authors.forename: Ulysses Paulino
authors.initials: UP
authors.lastname: Albuquerque
mesh_terms: D001938:Brazil; D003247:Conservation of Natural Resources / Q000379:methods; D020448:Ericales; D019448:Ethnobotany / Q000191:economics / Q000379:methods*; D007887:Fabaceae; D005638:Fruit; D005716:Game Theory; D006801:Humans; D007407:Interviews as Topic; D010936:Plant Extracts; D010946:Plants, Medicinal; D012959:Socioeconomic Factors
chemical_list: D010936:Plant Extracts