Theories and Major Hypotheses in Ethnobotany ,1,2,3,4 1 1 1 OROU G. GAOUE* ,MICHAEL A. COE ,MATTHEW BOND ,GEORGIA HART , 1 1,5 BARNABAS C. SEYLER , AND HEATHER MCMILLEN 1Department of Botany, University of Hawai‘iatMānoa, Honolulu, HI 96822, USA 2Faculty of Agronomy, University of Parakou, Parakou, Benin 3Department of Geography, Environmental Management and Energy Studies, University of Johannesburg, APK Campus, Johannesburg, South Africa 4Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996, USA 5U.S. Forest Service, Northern Research Station, New York City Urban Field Station, Bayside, NY, USA *Corresponding author; e-mail: [email protected] Ethnobotany has evolved from a discipline that largely documented the diversity of plant use by local people to one focused on understanding how and why people select plants for a wide range of uses. This progress has been in response to a repeated call for theory-inspired and hypothesis- driven research to improve the rigor of the discipline. Despite improvements, recent ethnobo- tanical research has overemphasized the use of quantitative ethnobotany indices and statistical methods borrowed from ecology, yet underemphasized the development and integration of a strong theoretical foundation. To advance the field of ethnobotany as a hypothesis-driven, theoretically inspired discipline, it is important to first synthesize the existing theoretical lines of research. We review and discuss 17 major theories and hypotheses in ethnobotany that can be used as a starting point for developing research questions that advance our understanding of people–plant interactions. For each theory or major hypothesis, we identify its primary predictions and testable hypotheses and then discuss how these predictions have been tested. Developing research to test these predictions will make significant contributions to the field of ethnobotany and create the critical mass of primary literature necessary to develop meta-analyses and to advance new theories in ethnobotany. Key Words: Hypothesis-driven research, medicinal plant selection, optimal defense theory, utilitarian redundancy model, taboo as luxury, theory in ethnobotany.. Introduction 1996). Exceptions include the theoretically ground- ed, extensive body of research in cognitive ethno- Ethnobotany, the science of survival (Prance botany (e.g., Atran 1998; Alexiades 1996: xii; et al. 2007), has long been concerned with its Brown 1977;Conklin1954;Hunn1975;Medin relationship to theory. In its early stages, ethnobo- and Atran 2004;Turner2000)whichledtogeneral tanical research largely consisted of acontextual lists principles of folk biological classification (Berlin of plants with their associated preparations and uses et al. 1973; Berlin 1973;Brown2000). Of partic- in remote areas (Balick 1996;Etkin1988). This ular interest are the principles of ranked taxonomy work, and by extension the discipline, has been and biological essentialism. Fundamentally, people criticized as Bweak^ or Bpseudoscience^ tend to think/rank/classify plants and animals in (Albuquerque and Hanazaki 2009; Alexiades the same way across culture (folk biology), and this contrasts with the way they think/rank/classify oth- er elements of the world. Furthermore, there is a 1 Received 23 November 2016; accepted 22 August cross-cultural convergence in the way people realize 2017; published online 7 September 2017 that species appearance, behavior, and ecological niche are not randomly established but guided by Economic Botany, 71(3), 2017, pp. 269–287 © 2017, by The New York Botanical Garden Press, Bronx, NY 10458-5126 U.S.A. 270 ECONOMIC BOTANY [VOL 71 lawful underlying internal processes (Medin and addition, Bennett (2005) noted that ethnobotanical Atran 2004). In contrast to cognitive ethnobotany, education also needs a major shift to meet the needs research in ecological ethnobotany has lacked clear of the discipline’s evolution. The challenges faced theoretical frameworks. Notable exceptions include by ethnobotany are similar to those of other sister biocultural research which focuses on an in-depth disciplines. For example, in the 1990s, several analysis of the biochemical basis and pharmacologic prominent ecologists questioned if the discipline of implications of food, psychoactive, and medicinal ecology had general laws or a unifying theory plant uses by local people (Etkin 1988;Johns (Aarssen 1997;Lawton1999; Marquet et al. 1986). As the discipline has continued to evolve, 2014;Weiner1995). As a result of this self-reflec- there has been a repeated call for a paradigm shift tion, ecology progressed as a discipline, moving and more theory-inspired research mainly in eco- from simply documenting patterns to understand- logical ethnobotany. ing the underpinning processes that generate eco- Nearly 40 years ago, Ford (1978) questioned wheth- logical patterns across time and spatial scales. Eth- er or not ethnobotany had a unifying theory, while nobotany, drawing inspiration from sister disci- Phillips and Gentry (1993a) criticized the predom- plines (ecology, evolution, anthropology, archeolo- inant use of descriptive studies in ethnobotany as gy, etc.), can do the same (Salick and Alcorn 2003). well as the lack of theoretical frameworks and/or The most promising hypothesis-driven ap- methodological rigor. This self-criticism successfully proaches to date have come from testing whether prompted more recent ethnobotanical studies to patterns of human use of medicinal plants align with follow the lead of Begossi (1996) by incorporating the predictions of the theoretical frameworks from ecological methods in ethnobotany but without a ecology (e.g., Albuquerque 2006; Albuquerque and clear theoretical framework. As a result, an increas- de Oliveira 2007; Alencar et al. 2010; Bennett ing number of studies, in an effort to include quan- 2007; Bennett and Husby 2008;Vandebroekand titative rigor, utilized species-area curves to estimate Balick 2012; Reyes-García et al. 2013b;Quirozand the diversity of species used by cultural groups, and van Andel 2015: Voeks and Leony 2004;Voeks ethnobotanical indices (see Hoffman and Gallaher 2007). However, for such efforts to expand beyond 2007). International and locally meaningful proto- individual research groups and sites, it is important cols and procedures for conducting ethical research for ethnobotanists to recognize the breadth of cur- are now considered essential components of the rent ethnobotanical theories and understand how research process. Recent efforts have focused on these theories can be used to develop testable hy- advancing ethnobotanical education based on inter- potheses. Further, it is critical for emerging ethno- disciplinary training, core concepts, and competen- botanists to be exposed to these theories in a sys- cies that bridge the natural and social sciences tematic way. We postulate that providing a synthesis (McClatchey et al. 2013). Though important, these that clearly identifies theories and major hypotheses approaches have not addressed Phillips and Gentry’s about people–plant interactions will focus future eth- (1993a,b) call for formulating a theoretical frame- nobotanical research toward delineating the theoretical work, emphasizing instead methodological rigor bases for plant selection and use by people. These (Albuquerque 2009) and a generalized use of eth- theoretical frameworks are resources for designing nobotanical indices (Hoffman and Gallaher 2007). research questions and developing testable hypoth- Acknowledging the persistent lack of theory- eses to advance our understanding of the dynamic inspired research in ethnobotany, Martin (2007,pp. relationships between plants and people. 23–25) detailed precisely how this progress could be For simplicity, we have adopted a less-rigid use of achieved using a hypothetico-deductive approach. the terms Btheory^ and Bhypothesis^ in this paper. This approach includes developing testable hypoth- However, readers should be aware of existing discus- eses (from theory or general principles) on the sions on theory and how it differs from a hypothesis, drivers of the patterns in people’s knowledge and a prediction, a model, or a universal law (Krebs use of their environment, collecting data collected 2000; Quinn and Dunham 1983). Hypotheses are using ethnographic methods, and using statistical proposed explanations of observed natural phenom- analyses to test if these data lend support (or not) to ena or patterns, whereas a theory is an Bintegrated these hypotheses. Recently, Bennett (2005) and and hierarchical set of empirical hypotheses that Albuquerque and Hanazaki (2009) repeated the call together explain a significant fraction of a scientific for Bless quantification^ and more theory-inspired observation^ (Krebs 2000). As such, theories are and hypothesis-driven research in ethnobotany. In hypotheses which have been rigorously tested and 2017] GAOUE ET AL.: THEORIES AND MAJOR HYPOTHESES IN ETHNOBOTANY 271 for which we found support for the generalization. disproportionately large number of exotic plants Most of the theories or hypotheses we present are utilized in traditional medicine. They acknowledge adapted from ecology or related disciplines and traditional medicine as dynamic systems and sug- serve as possible explanations of ethnobotanical pat- gest possible drivers of this phenomenon. terns. Some of these theories have not yet been The versatility hypothesis suggests that introduced formally presented as major theoretical