Research
We seek to understand how plant populations respond to regular human-caused disturbance and changing biotic and abiotic environmental conditions. Since the earth’s ecosystems are essential to the survival of human societies that depend on them for food, medicines, non-timber resources, livelihood strategies and overall well-being, studying these human-environmental relationships is essential to enhancing our ability to project the effects of future social-ecological interactions and our understanding of their biological consequences. A greater understanding of these human-environmental interactions is a central goal of contemporary ecology and conservation biology. Our work aims to address important challenges in conservation biology of tropical ecosystems including deforestation and habitat fragmentation, frequent harvest, fire and flooding events in study sites in the Amazon basin. We investigate the ecological consequences of wild plant harvest while focusing on the roles of unpredictability and variation in environmental conditions and harvesting activities on plant population responses over the short- and long-term. In the Ucayali River region of the Peruvian Amazon basin, we are investigating the ecological responses of ayahuasca (Banisteriopsis caapi (Spruce ex Griseb.) C.V. Morton) to frequent harvest and varying environmental conditions including periodic drought and flooding events. We are also investigating the sustainable harvest limits of these ayahuasca plant populations in restored ecosystems to help inform novel strategies for the production of locally grown and sustainably sourced plant medicine.
Does harvest cause a decline in genetic diversity of ayahuasca lianas by increasing clonal reproduction in response to short- and long-term disturbance?
Ayahuasca (Banisteriopsis caapi (Spruce ex Griseb.) C.V. Morton) is a jungle liana that can reproduce both sexually (production of flowers and samaras) and asexually (clonal production). Since ayahuasca lianas often experience bark harvest for medicinal use, reproductive strategy trade-offs in favor of clonal reproduction are expected given that sexual reproduction generally requires greater energetic demands and increased investments in clonality are often a direct result of liana disturbance. Therefore, stressful conditions caused by regular harvest may reduce genetic diversity leading to reduced liana population fitness and stability (e.g. inbreeding depression) over time making the population dynamics and biological consequences of reduced genetic diversity driven by harvest unclear. We are investigating if clonal reproduction adequately mediates the effect of short and long-term harvest along with the consequences of reproductive strategy trade-offs on ayahuasca liana genetic diversity.
What are the short- and long-term effects of harvest on ayahuasca variety populations in restored habitats?
Banisteriopsis caapi (Spruce ex Griseb.) C.V. Morton, is a jungle liana most commonly known as ayahuasca among human societies living throughout the Amazon basin. While botanists have identified and classified only one species of liana (B. caapi) widely used traditionally to produce the medicinal tea also known as ayahuasca, several liana varieties with a distinct local vernacular taxonomy along with morphological and anatomical variations have also been reported to be used throughout the Amazon basin making the systematics and botanical identity of these liana varieties unclear. Beyond B. caapi, these local varieties are also harvested for their bark and used in combination with other plants to produce ayahuasca tea used for plant medicine, yet little is known about their population dynamics and how they respond to harvest over the short- and long-term making our understanding of their responses to harvest and sustainable harvest limits unclear. In the Ucayali region of the Amazon basin, we are investigating the systematics and population dynamics of four ayahuasca varieties in restored ecosystems that periodically experience flooding events.
What factors most influence medicinal plant use and selection among human societies worldwide that use plants a primary source of healthcare?
A common misconception is that human societies historically have selected plants and their specific organs for medicinal use at random and subsequently developed plant medicines via trial-and-error. Theories in ethnobiology suggest that local people have extensive ecological knowledge of their environment and they use this knowledge to non-randomly identify useful plants for medicine. It has been shown that plant families closely related evolutionarily are more likely to have similar medicinal uses than those that are distantly related because these species often share plant defense characteristics inherited from common ancestors that influence their effectiveness as medicines. Therefore, certain plant families are expected to have a greater proportion of species that produce chemical compounds that are more useful or effective as medicines compared to other plant families. It is also expected that human societies primarily select plant organs that are rich in chemical compounds because they are more useful for medicinal use. Therefore, plant organs such as young leaves are more likely to be selected for medicinal use because they have greater chemical defenses such as alkaloids rather than old leaves that are often become rich in physical defenses over time. Using meta-analyses, we aim to directly test these theories by using hypothesis-driven research to understand global patterns on how human societies select certain plant species and plant organs for medicinal use. In doing so, we apply tools from ethnobiology, ecology, and mathematical modeling to test hypotheses on the factors influencing medicinal plant selection, plant organ uses for medicine, and dynamics of local ecological knowledge.
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We must not let this precious opportunity to learn how to respectfully manage ayahuasca production slip through our fingertips for there is much at stake beyond the revenue streams of commercialization and subsistence of local livelihoods. We must honor the wisdom of the ages and learn from the symbiotic relationships of the natural world to ensure that the diversity of ways of being and ways of knowing inspired by the interconnection between the human experience and ayahuasca teacher plants remain and continue their dialog in reverence. Therefore, it is critical that we develop a deeper understanding of the ecology and demography of these plants and how they respond to increasing harvest pressures and environmental variability over time.
- Michael Coe