Methodological advances for hypothesis-driven ethnobiology

Core-periphery structure of a medicinal botanical system in Uruguay

BACKGROUND

Human evolution has granted upon an individual's cognitive mechanisms necessary for remembering experiences, vital for both survival and reproduction. These experiences manifest into cultural traits, influencing human culture, particularly in healthcare and maintenance. Studies regarding medicinal plants and treatments are integral to the study of the medical botanical system. Pharmacopeias highlight the prevalence of specific species widely used, aligning with the "consensus within diversity theory" in evolutionary ethnobiology. Within the framework of this theory, we reflect on the results we've achieved in a priority area recognized by UNESCO for its biocultural significance, both locally and regionally.

METHODS

This study integrated network analysis and qualitative methods to examine the botanical medical system of "Parque Regional Quebradas del Norte" in Rivera, Uruguay.

RESULTS

Study results demonstrate a core-periphery structure, with a strongly interconnected core resistant to fragmentation, ensuring structural stability. Additionally, the presence of peripheral nodes throughout the system was identified, enhancing the resilience of the botanical medicinal system against potential disturbances.

CONCLUSION

The core species renowned for their versatility and multiple medicinal uses, treating less severe ailments effectively. Additionally, core plants serve as prototypes for innovations. Their extinction poses a threat to the system's resilience. Conversely, peripheral plants, though vulnerable, offer possibilities for therapeutic innovations. In the face of environmental change, conservation efforts should prioritize species that are vulnerable to extinction, particularly within the core. Simultaneously, preserving knowledge associated with peripheral plants presents a bicultural conservation strategy, ensuring the botanical system's robustness among evolving ecological conditions.

Mother-reliant or self-reliant: the germination strategy of seeds in a species-rich alpine meadow is associated with the existence of pericarps

BACKGROUND AND AIMS

Some plants germinate their seeds enclosed by a pericarp, whereas others lack the outer packaging. As a maternal tissue, the pericarp might impart seeds with different germination strategies. Plants in a community with different flowering times might separately disperse and germinate their seeds; therefore, flowering time can be considered as one manifestation of maternal effects on the offspring. The mass of the seed is another important factor influencing germination and represents the intrinsic resource of the seed that supports germination. Using seeds from a species-rich alpine meadow located in the Hengduan Mountains of China, a global biodiversity hotspot, we aimed to illustrate whether and how the type of seed (with or without a pericarp) modulates the interaction of flowering time and seed mass with germination.

METHODS

Seeds were germinated in generally favourable conditions, and the speed of germination [estimated by mean germination time (MGT)] was calculated. We quantified the maternal conditions by separation of flowering time for 67 species in the meadow, of which 31 produced seeds with pericarps and 36 yielded seeds without pericarps. We also weighed 100 seeds of each species to assess their mass.

KEY RESULTS

The MGT varied between the two types of seeds. For seeds with pericarps, MGT was associated with flowering time but not with seed mass. Plants with earlier flowering times in the meadow exhibited more rapid seed germination. For seeds without a pericarp, the MGT depended on seed mass, with smaller seeds germinating more rapidly than larger seeds.

CONCLUSIONS

The distinct responses of germination to flowering time and seed mass observed in seeds with and without a pericarp suggest that germination strategies might be mother-reliant for seeds protected by pericarps but self-reliant for those without such protection. This new finding improves our understanding of seed germination by integrating ecologically mediated maternal conditions and inherent genetic properties.

The global relevance of locally grounded ethnobiology

While ethnobiology is a discipline that focuses on the local, it has an outstanding, but not yet fully realized potential to address global issues. Part of this unrealized potential is that universalistic approaches often do not fully recognize culturally grounded perspectives and there are multiple challenges with scaling up place-based research. However, scalability is paramount to ensure that the intimate and context-specific diversity of human-environmental relationships and understandings are recognized in global-scale planning and policy development. Here, we identify four pathways to enable the scalability of place-based ethnobiological research from the ground up: local-to-global dialogues, aggregation of published data, multi-sited studies, and geospatial analyses. We also discuss some major challenges and consideration to encourage continuous reflexivity in these endeavours and to ensure that scalability does not contribute to unnecessarily decontextualizing, co-opting, or overwriting the epistemologies of Indigenous Peoples and local communities. As ethnobiology navigates multiple scales of time and space and seeks to increase its breadth, this study shows that the use of deliberately global approaches, when carefully nested within rich field-based and ecological and ethnographically grounded data, can contribute to: (1) upscaling case-specific insights to unveil global patterns and dynamics in the biocultural contexts of Indigenous Peoples and local communities; (2) bringing ethnobiological knowledge into resolutions that can influence global environmental research and policy agendas; and (3) enriching ethnobiology's field-based ethos with a deliberate global analytical focus.

Wild and cultivated comestible plant species in the Gulf of Mexico: phylogenetic patterns and convergence of type of use

Cross-cultural research on edible plants might include ecological and evolutionary perspectives to understand processes behind species selection and management. With a database of approximately 500 comestible plants of the Province of the Gulf of Mexico in Mesoamerica, phylogenetic analyses are conducted to identify convergence and phylogenetic signal of type of use and significant clustering in the resulting phylogenetic trees. Analyses considered type of management (wild/managed vs. cultivated), type of use (edible, condiment, for wrapping food) and organ utilized. Elevated phylogenetic diversity and signal are expected for wild comestible taxa, indicating that people are using lineages across the angiosperm tree for food, resulting in broadness in diet and use of their regional resources. Main results are: (i) condiment species were identified in groups with an elevated phylogenetic signal; (ii) hot nodes for lineages utilized for wrapping food were found in many monocot groups as well as in epiphytes of cloud forests with leathery leaves; (iii) edible taxa were identified with the highest significant clustering restricted to certain branches in the phylogeny; (iv) wild and cultivated edible plants belong to identical lineages with replacement of species, implying that same plant groups known for their comestible benefits are substituted by species distributed in the Province and (v) wild versus cultivated lineages for condiment are different. Most food species in the Province belong to four families, namely Fabaceae, Cactaceae, Solanaceae and Asparagaceae. Analyses discovered underutilized wild species in identical clades to managed/cultivated taxa that can be studied further to identify cultivation practices. Results suggest that people are utilizing different lineages in the angiosperm tree available locally, for particular uses, like condiment or for wrapping food. Evidence can be used to study further undervalued edible species closely related to the most common food taxa as well as for bioprospection of their nutritional content.

Beyond artificial academic debates: for a diverse, inclusive, and impactful ethnobiology and ethnomedicine

In answer to the question "Should ethnobiology and ethnomedicine more decisively foster hypothesis-driven forefront research able to turn findings into policy and abandon more classical folkloric studies?", in this essay I argue that a major strength of ethnobiology and ethnomedicine is their ability to bridge theories and methods from the natural sciences, the social sciences, and the humanities. Hypothesis-driven research is a powerful way to structure thinking that can lead to forefront research findings. But hypothesis-driven research is not the only way to structure thinking and is not a necessary condition to impact policymaking. To increase policy impact, ethnobiology and ethnomedicine should continue nurturing a mixture of complementary methods and inclusive approaches as fragmentation through opposing different approaches might weaken the discipline. Moreover, with the aim to play a fundamental role in building bridges between different knowledge systems and co-producing solutions towards sustainability, the discipline could benefit from enlarging its epistemological grounds through more collaborative research. Ethnobiologists' research findings, hypothesis-driven, descriptive, or co-constructed can become leverage points to transform knowledge into actionable outcomes in different levels of decision-making.

Does mangrove vegetation structure reflect human utilization of ecosystem goods and services?

Many coastal communities in developing countries depend on mangrove ecosystem services (ES). A combination of anthropogenic and environmental stresses threatens mangroves globally. This study at the Ankobra catchment communities in Ghana focused on the relation between ES utilization and mangrove forest structure. Through vegetation survey, we observed significant effects of selective logging, branch cutting, density of Acrostichum aureum, and water stress on tree stocking and sapling densities. We observed through interviews in five communities that about 98% and 88% of mangrove wood harvested are used for fuelwood and construction respectively. The vegetation structure of the forest areas receiving high harvesting pressures was less complex, with lower tree and sapling density, as well as lower seed-bearing trees than less-disturbed areas. Existing mangrove harvesting regulations are compromised to accommodate the needs of the surrounding communities. Recognizing these impacts is important to improve management decisions, address community needs, and reduce pressure on mangroves.

Desert Endemic Plants in Algeria: A Review on Traditional Uses, Phytochemistry, Polyphenolic Compounds and Pharmacological Activities

Due to their robust antioxidant capabilities, potential health benefits, wide variety of biological activities, and strong antioxidant qualities, phenolic compounds are substances that have drawn considerable attention in recent years. The main goal of the review is to draw attention to saharian Algerian medicinal plants and the determination of their bioactivity (antioxidant, anti-cancer, and anti-inflammatory importance), and to present their chemical composition as well as in vivo and in vitro studies, clinical studies, and other studies confirming their real impact on human health. Research results have revealed a rich variety of medicinal plants used to treat various disease states in this region. Based on in vivo and in vitro studies, biological activity, and clinical studies, a list of 34 species of desert plants, belonging to 20 botanical families, useful both in preventive actions and in the treatment of neoplastic diseases has been established, and polyphenolic compounds have been identified as key to the health potential of endemic diseases and desert plants. It has been shown that people who follow a diet rich in polyphenols are less prone to the risk of many cancers and chronic diseases, such as obesity and diabetes. In view of the increasing antioxidant potential of these plant species, as well as the increasing trade in herbal products from the Sahara region, phytosanitary and pharmaceutical regulations must change in this respect and should be in line with Trade Related Aspects of Intellectual Property Rights (TRIPS), and the sustainable use and development of plant products must be addressed at the same time.

Ecological apparency, ethnobotanical importance and perceptions of population status of wild-growing medicinal plants in a reserve of south-central Mexico

BACKGROUND

The apparency hypothesis in ethnobotany (common plants are used more than less frequent ones) has been studied mostly by comparing usefulness with woody plant density, or large plants (trees) with herbs, with uneven results. Here, we explore the hypothesis for wild-growing medicinal plants, separately for different life forms. Two methodological subjects relevant for testing the hypothesis are also treated: We compare various importance indicators, including recent use, and evaluate active healers' knowledge of plant population size. The study area was the Tenancingo-Malinalco-Zumpahuacán Protected Natural Area in central Mexico in the upper part of the Balsas River Basin, a biogeographic region with a long tradition of using wild medicinal species.

METHODS

Previous work on the vegetation of the protected area contributed information from 100 survey plots and a species list, which included preliminary data on the medicinal plants. Then, in 2019-2020, we held in-depth and repeated interviews with 13 traditional healers in three rural communities. They were interviewed on uses and population size of a selection of 52 medicinal species of different life forms and abundance (number of individuals in survey plots). The data were analyzed with descriptive statistics, use values and linear regression models.

RESULTS

For all species, use value correlated significantly with abundance. When separated by life forms, only herbs and shrubs/lianas showed this association, though with statistical limitations. Trees did not, perhaps because some of the most useful trees have been overcollected. We found a good correlation of recent use with frequency of mention and most other importance indicators; the correlation was weakest for number of uses. Also, active healers had a good estimation of population of their collected species.

CONCLUSIONS

The apparency hypothesis should be studied separating life forms to reduce the influence of this variable. To measure importance for the study of this hypothesis, the data show that frequency of mention is a good indicator and correlated with actual use. Also, local plant users' appreciations of population size are quite accurate in the aggregate and may be more efficient than costly vegetation surveys.

Trees as brokers in social networks: Cascades of rights and benefits from a Cultural Keystone Species

Indigenous trees play key roles in West African landscapes, such as the néré tree (Parkia biglobosa (Jacq.) R.Br. ex G.Don). We applied social-ecological network analysis to understand the social-ecological interactions around néré. We documented the benefits néré provides and the multiple social interactions it creates amongst a large range of actors. The flows of rights over the trees and benefits from them formed two hierarchical networks, or cascades, with different actors at the top. The two forms of power revealed by the two cascades of rights and benefits suggest possible powers and counter-powers across gender, ethnicity, and age. We documented how the tree catalyses social interactions across diverse groups to sustain vital social connections, and co-constitute places, culture, and relationships. We argue that a paradigm shift is urgently needed to leverage the remarkable untapped potential of indigenous trees and Cultural Keystone Species in current global restoration and climate change agendas.

Interaction networks reveal highly antagonistic endophytic bacteria in native maize seeds from traditional milpa agroecosystems

Milpas are traditional Mesoamerican agroecosystems maintained with ancestral practices. Maize landraces are grown in polyculture, creating highly productive and diverse ecosystems. Recent studies suggest that milpas maintain beneficial plant-microbe interactions that are probably absent in modern agroecosystems; however, direct comparisons of the microbiome of plants between traditional and modern agroecosystems are still needed. Here, we studied seed endophytic bacterial communities from native maize landraces from milpas (NME) and hybrid varieties (HME). First, we quantified the abundance of culturable endophytic microbes; next, we assessed pairwise antagonistic interaction networks between bacterial isolates; finally, we compared bacterial community structure by 16S rRNA amplicon sequencing. We found that seeds from native maize landraces harbor a higher endophytic microbial load, including more bacterial strains with antagonistic activity against soil-borne bacteria, and overall harbor more diverse bacterial communities than the hybrid varieties. Noteworthy, most of the seed-endophytic strains with antagonistic activity corresponded to Burkholderia spp. that were only found in native maize seeds, through both culture-dependent and independent strategies. Altogether, our results support that crop modernization alters the functions and structure of plant-associated microbes; we propose native maize from milpas could serve as a model for understanding plant-microbe interactions and the effect of modernization.

Predicting potential medicinal plants with phylogenetic topology: Inspiration from the research of traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Plants are a dominant source of pharmacological drugs for the treatment and cure of different disorders and diseases. However, selecting the most biologically active plant species for further screening is still challenging. Phylogeny has strong explanatory powers and provides predictive perspectives that are not available in traditional plant classifications. China, which is endowed with a diverse set of therapeutic cures from Mother Nature, represents an ideal environment for the phylogenetic analysis of potential medicinal plants.

MATERIALS AND METHODS

Herein, we prepared a database of 7,451 traditional Chinese medicinal (TCM) plants, including species with therapeutic effects grouped in 14 categories. To limit our exploration of novel therapeutic species, we plotted the medicinal effects on the phylogenetic tree of almost 30,000 species of China to find hot nodes of therapeutic effects. We used the net relatedness index (NRI) and the nearest taxon index (NTI) to identify clustering and overdispersion of the phylogenetic distribution of TCM plants.

RESULTS

The NRI and NTI analyses highlighted 3,392 hot node species with single therapeutic effects within 507 genera and 89 families on the phylogenetic tree and about 70% of the 14 medicinal categories clusters identified. The general pattern of the hot nodes on the phylogenetic tree indicates that basal angiosperms and basal eudicots radiated for therapeutic effects.

CONCLUSIONS

Our study may provide a more targeted way to discover phylogeny-guided drugs in the early screening stage, which may lead to a higher discovery efficiency of new drugs with meaningful biological activities. Phylogenetic studies of plants that are richer in bioactive compounds can set the ground for the identification and discovery of alternative drugs.