New categories for traditional medicine in the Economic Botany Data Collection Standard

The Economic Botany Data Collection Standard (EBDCS) has been successfully followed by ethnobotanists investigating plant uses in many parts of the world. However, we have encountered some cases in our study of traditional medicine where the standard seems incomplete and inaccurate when it is applied to plant uses of rural or indigenous societies in developing countries. We propose two categories to be added to the EBDCS: Cultural Diseases and Disorders, and Ritual/Magical Uses. Adding these categories, we believe will give a more accurate insight into traditional medicine and will contribute to developing an integrative ethnomedicinal data collection protocol, which will make ethnomedicinal studies more comparable.

Ritual uses of palms in traditional medicine in sub-Saharan Africa: a review

Palms (Arecaceae) are prominent elements in African traditional medicines. It is, however, a challenge to find detailed information on the ritual use of palms, which are an inextricable part of African medicinal and spiritual systems. This work reviews ritual uses of palms within African ethnomedicine. We studied over 200 publications on uses of African palms and found information about ritual uses in 26 of them. At least 12 palm species in sub-Saharan Africa are involved in various ritual practices: Borassus aethiopum, Cocos nucifera, Dypsis canaliculata, D. fibrosa, D. pinnatifrons, Elaeis guineensis, Hyphaene coriacea, H. petersiana, Phoenix reclinata, Raphia farinifera, R. hookeri, and R. vinifera. In some rituals, palms play a central role as sacred objects, for example the seeds accompany oracles and palm leaves are used in offerings. In other cases, palms are added as a support to other powerful ingredients, for example palm oil used as a medium to blend and make coherent the healing mixture. A better understanding of the cultural context of medicinal use of palms is needed in order to obtain a more accurate and complete insight into palm-based traditional medicines.

Multimillion-year climatic effects on palm species diversity in Africa

Past climatic changes have caused extinction, speciation, and range dynamics, but assessing the influence of past multimillion-year climatic imprints on present-day biodiversity patterns remains challenging. We analyzed a new continental-scale data set to examine the importance of paleoclimatic effects on current gradients in African palm richness patterns. Using climate reconstructions from the late Miocene (-10 mya), the Pliocene (-3 mya), and the Last Glacial Maximum (0.021 mya), we found that African palm diversity patterns exhibit pronounced historical legacies related to long-term climate change. Notably, pre-Pleistocene paleoprecipitation variables differentially affected current diversity patterns of palms grouped by contrasting habitat requirements. Accounting for present-day environment, rain forest palms exhibit greater species richness in localities where Pliocene precipitation was relatively high, whereas open-habitat palms show higher species richness in areas of relatively low precipitation during the Miocene Epoch. Our results demonstrate that diversity-climate relationships among African palm species include multimillion-year lagged dynamics, i.e., with historical legacies persisting across much longer time periods than commonly recognized.

Ethnobotanical knowledge is vastly under-documented in northwestern South America

A main objective of ethnobotany is to document traditional knowledge about plants before it disappears. However, little is known about the coverage of past ethnobotanical studies and thus about how well the existing literature covers the overall traditional knowledge of different human groups. To bridge this gap, we investigated ethnobotanical data-collecting efforts across four countries (Colombia, Ecuador, Peru, Bolivia), three ecoregions (Amazon, Andes, Chocó), and several human groups (including Amerindians, mestizos, and Afro-Americans). We used palms (Arecaceae) as our model group because of their usefulness and pervasiveness in the ethnobotanical literature. We carried out a large number of field interviews (n = 2201) to determine the coverage and quality of palm ethnobotanical data in the existing ethnobotanical literature (n = 255) published over the past 60 years. In our fieldwork in 68 communities, we collected 87,886 use reports and documented 2262 different palm uses and 140 useful palm species. We demonstrate that traditional knowledge on palm uses is vastly under-documented across ecoregions, countries, and human groups. We suggest that the use of standardized data-collecting protocols in wide-ranging ethnobotanical fieldwork is a promising approach for filling critical information gaps. Our work contributes to the Aichi Biodiversity Targets and emphasizes the need for signatory nations to the Convention on Biological Diversity to respond to these information gaps. Given our findings, we hope to stimulate the formulation of clear plans to systematically document ethnobotanical knowledge in northwestern South America and elsewhere before it vanishes.

Karen and Lawa medicinal plant use: uniformity or ethnic divergence?

ETHNOPHARMACOLOGICAL RELEVANCE

We here tease apart the ethnopharmacological knowledge of plants in two Thai villages to determine to which degree the uses are particular to individual ethnic groups and to which degree they are part of a generalized and uniform set of widespread medicinal plants used over a large geographic range. We compared Karen and Lawa knowledge of medicinal plants in the Mae Cheam watershed of northern Thailand, where both ethnic groups have settled and share ecological conditions for resource extraction. We were interested in documenting the degree to which these two ethnic groups use the same or different medicinal plant species. The use of the same plant species by the two groups was considered a sign of uniform and cross-cultural local knowledge, whereas the use of different medicinal plants by each group was considered a sign of culturally specific local knowledge that developed within each ethnic group.

MATERIALS AND METHODS

We inventoried the plant species in different habitats around one Karen village and one Lawa village using stratified vegetation plots and using semi-structured questionnaires we interviewed 67 key informants regarding their use of plants for medicine. We then calculated the Fidelity level FL (FL values near 100% for a species indicate that almost all use reports refer to the same way of using the species, whereas low FL values indicate that a species is used for many different purposes) and cultural importance index CI (the sum of the proportion of informants that mention each of the use categories for a given species) to estimate the variation in medicinal plant use. We used Jaccard's Index JI (This index relates the number of shared species to the total number of species) to analyze the similarity of medicinal plant use between the two villages.

RESULTS

A total of 103 species of medicinal plant species in 87 genera and 41 families were identified and they were used to cure 35 ailments. The FL of the medicinal plant species varied from 10% to 100%, was different for each ailment, and differed between the two ethnic groups. The most important medicinal plant species, those with the highest CI value, were not the same in the two villages. Costus speciosus, which is used to treat urinary infections and wounds in animals, had the highest CI value in the Karen village, whereas Sambucus javanica, which is used to treat wounds, fractures, bloat, and edema in humans, had the highest CI value in the Lawa village. Only 17 medicinal species (16.5%) were shared between the two villages. Methods of preparation and application were significantly different between the two villages, whereas the plant parts used, habit, and route of administration were similar.

CONCLUSION

Our study demonstrates that ethnic groups that live in the same geographic area can have significantly different traditional knowledge systems for medicinal plants, at least when it comes to the species used and their preparation and medicinal application. We assume that differences in cultural history and background in the two villages led to differences in medicinal plant use, preparation, and application.

Hyperdominance in the Amazonian tree flora

The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees. Most of these are habitat specialists and only dominant in one or two regions of the basin. We discuss some implications of the finding that a small group of species--less diverse than the North American tree flora--accounts for half of the world's most diverse tree community.

Floral structure and organogenesis of the wax palm Ceroxylon ceriferum (Arecaceae; Ceroxyloideae)

PREMISE OF THE STUDY

Most palm systematists were surprised when molecular evidence pointed to a sister group relationship between the tribe Ceroxyleae and the phytelephantoid palms. The latter comprises three genera of morphological aberrant palms that have previously been considered a subfamily of their own. Here we present the results of a detailed study of the floral structure and development of the wax palm, Ceroxylon ceriferum, which aims at revealing derived traits shared by the sister tribes Ceroxyleae and Phytelepheae.

METHODS

A series of floral stages were sampled from Ceroxylon ceriferum growing in the central coastal range of Venezuela. The samples were prepared for scanning electronic microscopy and serial anatomical sectioning.

KEY RESULTS

The development of male and female flowers of Ceroxylon ceriferum was similar. The receptacle elongated early in the ontogeny. The perianth was differentiated into distinct sepals and petals and was characterized by a lack of postgenital fusion. The stamens were incepted centripetally in 2(-3) whorls. The outer whorl of three stamens was antesepalous. The inner whorl consisted of six stamens arranged in three antepetalous pairs.

CONCLUSIONS

The flowers of Ceroxylon ceriferum share a lack of postgenital fusion in the perianth with members of the tribe Phytelepheae. The elongation of the receptacle is reminiscent of the receptacle expansion in Phytelepheae. However, the multistaminate condition in C. ceriferum is less extreme than in the Phytelepheae, and the stamen initiation is centripetal as opposed to centrifugal in the latter.

Medicinal plants from swidden fallows and sacred forest of the Karen and the Lawa in Thailand

BACKGROUND

Many ecosystem services provided by forests are important for the livelihoods of indigenous people. Sacred forests are used for traditional practices by the ethnic minorities in northern Thailand and they protect these forests that are important for their culture and daily life. Swidden fallow fields are a dominant feature of the agricultural farming landscapes in the region. In this study we evaluate and compare the importance of swidden fallow fields and sacred forests as providers of medicinal plants among the Karen and Lawa ethnic minorities in northern Thailand.

METHODS

We made plant inventories in swidden fallow fields of three different ages (1-2, 3-4, 5-6 years old) and in sacred forests around two villages using a replicated stratified design of vegetation plots. Subsequently we interviewed the villagers, using semi-structured questionnaires, to assess the medicinal use of the species encountered in the vegetation survey.

RESULTS

We registered a total of 365 species in 244 genera and 82 families. Of these 72(19%) species in 60(24%) genera and 32(39%) families had medicinal uses. Although the sacred forest overall housed more species than the swidden fallow fields, about equal numbers of medicinal plants were derived from the forest and the fallows. This in turn means that a higher proportion (48% and 34%) of the species in the relatively species poor fallows were used for medicinal purposes than the proportion of medicinal plants from the sacred forest which accounted for 17-22%. Of the 32 medicinal plant families Euphorbiaceae and Lauraceae had most used species in the Karen and Lawa villages respectively.

CONCLUSION

Sacred forest are important for providing medicinal plant species to the Karen and Lawa communities in northern Thailand, but the swidden fallows around the villages are equally important in terms of absolute numbers of medicinal plant species, and more important if counted as proportion of the total number of species in a habitat. This points to the importance of secondary vegetation as provider of medicinal plants around rural villages as seen elsewhere in the tropics.

Dispersal and niche evolution jointly shape the geographic turnover of phylogenetic clades across continents

The turnover of phylogenetic clades across space is a fundamental biodiversity pattern that may depend on long-term evolutionary processes, and that has downstream effects on other aspects of diversity including species richness and community structure. Limited niche evolution and limited dispersal are two major processes causing spatial restriction, and thus turnover, of clades. We studied the determinants of clade turnover within the World's richest floristic kingdom, the Neotropics, using the palm family (Arecaceae) as a model. We show that continental-scale clade turnover is driven by a combination of limited niche evolution - with respect to temperature and soil tolerances - and limited dispersal. These findings are consistent with strong dispersal barriers within the Neotropics, and the observation that some palm lineages are most diverse in certain biomes or climates. The importance of such deep-time effects suggest that palms might be slow to adapt or disperse in response to anthropogenic climate change.

Medicinal plants used in Hmong women's healthcare in northern Thailand

ETHNOPHARMACOLOGICAL RELEVANCE

We studied traditional knowledge of medicinal plants used for women's healthcare in three Hmong villages in northern Thailand and determined how prevalent such knowledge is. We documented traditional medical practices and determined which of the species used are culturally important among the Hmong.

MATERIALS AND METHODS

We interviewed six key informants and 147 non-specialist informants about their traditional knowledge of medicinal plants used in Hmong women's healthcare. We selected nine species that were known in all three villages as the domain for questionnaire interviews with 181 additional and randomly selected non-specialist informants. We calculated the Cultural Importance index (CI) for each species and use category. We tested normality of the data, age correlations, and gender correlations with Kolmogorov-Smirnov tests, Spearman's rank correlation coefficient, Kruskal-Wallis test, and Mann-Whitney tests.

RESULTS

We documented traditional knowledge of 79 medicinal plants used in women's healthcare. Of these, three species were culturally important to the Hmong. Our questionnaire interviews revealed significant difference in traditional medicinal plant knowledge between genders and age groups.

CONCLUSIONS

The Hmong people in northern Thailand possess large amounts of traditional knowledge related to women's healthcare and plants used for this purpose. However, this knowledge, even for the culturally important species, is not possessed by all Hmong and there were signs of knowledge erosion. Preservation of the Hmong intellectual heritage related to medicinal plants used in women's healthcare requires intensive traditional knowledge dissemination to the young Hmong generation.

Geographical ecology of the palms (Arecaceae): determinants of diversity and distributions across spatial scales

BACKGROUND

The palm family occurs in all tropical and sub-tropical regions of the world. Palms are of high ecological and economical importance, and display complex spatial patterns of species distributions and diversity.

SCOPE

This review summarizes empirical evidence for factors that determine palm species distributions, community composition and species richness such as the abiotic environment (climate, soil chemistry, hydrology and topography), the biotic environment (vegetation structure and species interactions) and dispersal. The importance of contemporary vs. historical impacts of these factors and the scale at which they function is discussed. Finally a hierarchical scale framework is developed to guide predictor selection for future studies.

CONCLUSIONS

Determinants of palm distributions, composition and richness vary with spatial scale. For species distributions, climate appears to be important at landscape and broader scales, soil, topography and vegetation at landscape and local scales, hydrology at local scales, and dispersal at all scales. For community composition, soil appears important at regional and finer scales, hydrology, topography and vegetation at landscape and local scales, and dispersal again at all scales. For species richness, climate and dispersal appear to be important at continental to global scales, soil at landscape and broader scales, and topography at landscape and finer scales. Some scale-predictor combinations have not been studied or deserve further attention, e.g. climate on regional to finer scales, and hydrology and topography on landscape and broader scales. The importance of biotic interactions - apart from general vegetation structure effects - for the geographic ecology of palms is generally underexplored. Future studies should target scale-predictor combinations and geographic domains not studied yet. To avoid biased inference, one should ideally include at least all predictors previously found important at the spatial scale of investigation.

Testing the water-energy theory on American palms (Arecaceae) using geographically weighted regression

Water and energy have emerged as the best contemporary environmental correlates of broad-scale species richness patterns. A corollary hypothesis of water-energy dynamics theory is that the influence of water decreases and the influence of energy increases with absolute latitude. We report the first use of geographically weighted regression for testing this hypothesis on a continuous species richness gradient that is entirely located within the tropics and subtropics. The dataset was divided into northern and southern hemispheric portions to test whether predictor shifts are more pronounced in the less oceanic northern hemisphere. American palms (Arecaceae, n = 547 spp.), whose species richness and distributions are known to respond strongly to water and energy, were used as a model group. The ability of water and energy to explain palm species richness was quantified locally at different spatial scales and regressed on latitude. Clear latitudinal trends in agreement with water-energy dynamics theory were found, but the results did not differ qualitatively between hemispheres. Strong inherent spatial autocorrelation in local modeling results and collinearity of water and energy variables were identified as important methodological challenges. We overcame these problems by using simultaneous autoregressive models and variation partitioning. Our results show that the ability of water and energy to explain species richness changes not only across large climatic gradients spanning tropical to temperate or arctic zones but also within megathermal climates, at least for strictly tropical taxa such as palms. This finding suggests that the predictor shifts are related to gradual latitudinal changes in ambient energy (related to solar flux input) rather than to abrupt transitions at specific latitudes, such as the occurrence of frost.

American palm ethnomedicine: a meta-analysis

BACKGROUND

Many recent papers have documented the phytochemical and pharmacological bases for the use of palms (Arecaceae) in ethnomedicine. Early publications were based almost entirely on interviews that solicited local knowledge. More recently, ethnobotanically guided searches for new medicinal plants have proven more successful than random sampling for identifying plants that contain biodynamic ingredients. However, limited laboratory time and the high cost of clinical trials make it difficult to test all potential medicinal plants in the search for new drug candidates. The purpose of this study was to summarize and analyze previous studies on the medicinal uses of American palms in order to narrow down the search for new palm-derived medicines.

METHODS

Relevant literature was surveyed and data was extracted and organized into medicinal use categories. We focused on more recent literature than that considered in a review published 25 years ago. We included phytochemical and pharmacological research that explored the importance of American palms in ethnomedicine.

RESULTS

Of 730 species of American palms, we found evidence that 106 species had known medicinal uses, ranging from treatments for diabetes and leishmaniasis to prostatic hyperplasia. Thus, the number of American palm species with known uses had increased from 48 to 106 over the last quarter of a century. Furthermore, the pharmacological bases for many of the effects are now understood.

CONCLUSIONS

Palms are important in American ethnomedicine. Some, like Serenoa repens and Roystonea regia, are the sources of drugs that have been approved for medicinal uses. In contrast, recent ethnopharmacological studies suggested that many of the reported uses of several other palms do not appear to have a strong physiological basis. This study has provided a useful assessment of the ethnobotanical and pharmacological data available on palms.

Medicinal plant knowledge and its erosion among the Mien (Yao) in northern Thailand

ETHNOPHARMACOLOGICAL RELEVANCE

We studied local knowledge and actual uses of medicinal plants among the Mien in northern Thailand, documenting traditional medical practices and its transfer between generations.

AIM OF THE STUDY

With the assumption that discrepancies between knowledge and actual use represent knowledge erosion, we studied whether actual use of medicinal plants corresponded to people's knowledge of such uses.

MATERIALS AND METHODS

We used local knowledge from four specialist informants as the domain for semi-structured interviews with 34 randomly selected non-specialist informants. We calculated informant consensus, use value, and fidelity level for each species and use category and performed statistical analyses with Kolmogorov-Smirnov tests, Pearson correlation coefficient, Spearman's rank correlation coefficient, and paired-sample t-tests.

RESULTS

We found significant discrepancies between knowledge and actual use of medicinal plants. The number of known and actually used plants increased with increasing informant age and decreased with increasing years of formal education.

CONCLUSIONS

Medicinal plant knowledge and use in these Mien communities is undergoing inter-generational erosion because of acculturation and interrupted knowledge transmission. Preservation of Mien medicinal plant intellectual heritage requires continued documentation concerning use, conservation, and sustainable management of this resource, which should be publicized to younger Mien.

To what extent does Tobler's 1st law of geography apply to macroecology? A case study using American palms (Arecaceae)

BACKGROUND

Tobler's first law of geography, 'Everything is related to everything else, but near things are more related than distant things' also applies to biological systems as illustrated by a general and strong occurrence of geographic distance decay in ecological community similarity. Using American palms (Arecaceae) as an example, we assess the extent to which Tobler's first law applies to species richness and species composition, two fundamental aspects of ecological community structure. To shed light on the mechanisms driving distance decays in community structure, we also quantify the relative contribution of geographic distance per se and environmental changes as drivers of spatial turnover in species richness and composition.

RESULTS

Across the Americas, similarity in species composition followed a negative exponential decay curve, while similarity in species richness exhibited a parabolic relationship with geographic distance. Within the four subregions geographic distance decays were observed in both species composition and richness, though the decays were less regular for species richness than for species composition. Similarity in species composition showed a faster, more consistent decay with distance than similarity in species richness, both across the Americas and within the subregions. At both spatial extents, geographic distance decay in species richness depended more on environmental distance than on geographic distance, while the opposite was true for species composition. The environmentally complex or geographically fragmented subregions exhibited stronger distance decays than the more homogenous subregions.

CONCLUSION

Similarity in species composition exhibited a strong geographic distance decay, in agreement with Tobler's first law of geography. In contrast, similarity in species richness did not exhibit a consistent distance decay, especially not at distances >4000 kilometers. Therefore, the degree to which Tobler's first law of geography applies to community structure depends on which aspect hereof is considered - species composition or species richness. Environmentally complex or geographically fragmented regions exhibited the strongest distance decays. We conclude that Tobler's law may be most applicable when dispersal is a strong determinant of spatial turnover and less so when environmental control predominates.

A comparative study on medicinal plants used in Akha's traditional medicine in China and Thailand, cultural coherence or ecological divergence?

AIM OF THE STUDY

The survey aims to study the effect of geographic separation of ethnic groups on local knowledge of medicinal plants used by Akha people in Thailand and China, who were separated 100-120 years ago, to see how different the two geographically distinct but culturally similar groups were in this respect.

MATERIALS AND METHODS

Interviewing 10 villagers in each of five Akha villages, three in Thailand and two in China, about which plants they used and how they used them.

RESULTS

A total of 95 medicinal plants registered in the five villages only 16 were shared between China and Thailand. Otherwise the use patterns were quite similar with respect to which plant families and plant growth forms were used and also in terms of in which habitats the Akha found their medicinal plants.

CONCLUSIONS

The moving to a different site has forced the Akha to find a new set of species, but that when using these new species they have maintained other traditions relating to medicinal plants.