Ethnobotanical surveys

Transcription

1 Session 3c Ethnobotanical surveys Roeland Kindt Outline This session describes the study objects of ethnobotanical surveys lists two classification systems of ethnobotanical surveys (biological/anthropological) and (rapid/in-depth) describes various activities that can be conducted in an ethnobotanical survey, and provides detailed information on the collection of herbarium specimens, collection of information on local classification systems, and bioprospection lists elements of the domestication strategy where ethnobotany can be used, and provides some general reflections on the link between indigenous knowledge and domestication What is ethnobotany? Ethnoecology studies the interactions of local people with the natural environment, and ethnobotany is the part that studies the interactions of local people with plants (Martin 1995 p xx). Ethnobotany tries to get a holistic understanding of local knowledge on plants. As pointed out by Ellen (1996), a distinction can be made between what might be called biological ethnobotany and anthropological ethnobotany. The former is the narrowest as the research is conducted from a bio-economic perspective, and usually results in lists

2 of species identifications against vernacular names and uses. The approach is virtually synonymous to economic botany in that the recent focus has been the discovery of new applied botanical or phytochemical possibilities and the economic valuation of the rainforest. The surveys are extractive in that selected bits of information relevant for a specific purpose (discovery of new drugs, new species, new foods, new materials) are collected without gaining an understanding in the local knowledge system. Anthropological ethnobotany operates within a cultural-linguistic paradigm and stands for the direct investigation of the relations between plants and human, placing plants in their cultural context. This type of ethnobotany recognises that local knowledge is highly variable between individuals, situational, and dynamic. This type of ethnobotany could be called the real ethnobotany. (Maybe a reference to the work of Fergus Sinclair here) Ethnobotanical knowledge goes beyond the knowledge of individual organisms; within the context of tree domestication, this lecture note will however largely focus on species-focussed information. Rapid and in-depth ethnobotanical surveys In addition to the distinction between biological and anthropological ethnobotanical surveys, surveys can also be classified as rapid or in-depth. Rapid surveys are usually based on the methodology of PRA (session 2a). The information gathered will be qualitative rather than quantitative, and will provide a sketch of the interactions of people with plants. A rapid survey should be the starting point for any in-depth study. When the necessary resources are available, in-depth surveys are preferred. These surveys are necessary to provide a sufficient holistic understanding of a local ethnobotany, and to provide data that are statistically more rigorous. In-depth surveys supplement qualitative information from rapid surveys with quantitative data. The tools or exercises developed for PRA may of course be used during in-depth surveys. Obviously, interviewers attitude and behaviour, which were described as very important for the success of PRA surveys, are as important for in-depth surveys. Possible activities of in-depth ethnobotanical surveys In-depth ethnobotanical surveys might involve the following activities (Martin 1995 pp. 7-8): Collection and identification of herbarium specimens of all plant species of a study site, including all documentation necessary for labeling the herbarium voucher. Collection of local knowledge on use (including plant part used, detailed description of preparation of plant parts and user groups), distribution and management of all plant species of interest. Gathering of insight on the local classification systems of plants and of the environment (vegetation, soils, climates, ).

3 Describing the environment (location, elevation, climate, geology, vegetation types, species diversity, ), the people (ethnic group, language, population size and distribution, migration, social groups, education, ) and the interactions between them (land-use systems, tenure systems, human disturbance, ). Correct phonetic transcription of all local names of plant species, alternatively in the accepted local writing system. Standardized sampling and chemical analysis of plant species (bioprospection). Economic validation of biological resources (e.g. market survey). Basic rules for surveys, as mentioned in Session 1b, should be adhered to. For example, attempts should be made to validate findings through experimentation where possible, as in bioprospection. The following chapters focus on some of the possible activities: herbarium specimen collection (the first activity listed); selection of informants for collection of local knowledge on plants (second activity); gathering an insight in local classification systems (third activity); and bioprospecting (sixth activity). Herbarium specimen collection Plant collections are basic to ethnobotanical surveys. They allow for determination of the botanical identity of plants studied, so that information collected can be referenced to botanical names. They also allow for later checking, for instance by Herbarium staff. They allow for checking years after the plants were collected, which would be especially useful if taxonomic changes would affect the species studied. They can also allow collecting use information from local informants if living plants are not available at the interview site. Herbarium specimen collection involves collecting and preserving plant parts that enable their scientific determination, mounting them on herbarium sheets and providing an accompanying label. The basic tools for collections are a fieldpress and a field notebook. The fieldpress is typically made of two hardwood frames, where each frame is made from four wood strips (2 cm 12 mm 45 cm) crossed at regular intervals on six wood strips (2 cm 12 mm 3 dm). Plants are placed in newspaper, which is placed inside blotting paper and is changed daily. In between blotting papers, corrugated cardboard or corrugated aluminium ventilators are placed to allow ventilation to facilitate drying. Appropriate press straps (with minimum length of 15 dm) tie the press firmly together, which is necessary for effective drying. For successful drying, newspaper and blotting paper should also be changed after one day, and the plant press placed in a warm and dry place with circulating air. In humid environments, aluminium ventilators are recommended as well as placing the plant press on top of a plant dryer, as these will allow for fast drying. A plant dryer is a wooden box placed over a heating element, where the plant press can be placed on a horizontal frame. Faster drying prevents fungal infections and preserves colour.

4 The field notebook should contain all information that will be presented on the label. The label should contain the collection number (typically the initials of the collector and a sequential number), the collector s name, the collection date, names of other collectors, location (name, geographical co-ordinates possibly collected through a Global Positioning System Receiver, altitude), the local name (with the language), the institute and the project by which the collection is done. In the field notebook (and possibly the label), all information that cannot be seen from the herbarium sheet that could assist in identification should also be noted. Such information could for instance be plant characteristics such as the plant size, colours, branching habit, odour, root system or a description of the bark, or characteristics of the environment, which could be physical and/or biological characteristics. Basically, a herbarium specimen is collected because the plant can not be identified in the field the herbarium specimen and the information in the field notebook should include all information that could have been used when the plant would have been identified in the field. If ethnobotanical information is collected at the same time as plant samples are taken, these should be noted in the notebook at the same time. Information on the abundance of the plant could also be noted. It is always better to note information directly, rather than awaiting recall at the end of the collection. Preferably, a carbon copy of the information entered is made directly. Pre-printed notebooks can be used to ensure that all relevant information is collected. Some further guidelines for collection and mounting are: A good voucher should have all the parts needed for accurate identification. As this information is not known before determination, branches, leaves, flowers and/or fruits should be collected (flowers and/or fruits are recommended, as sterile specimens may not allow determination to the species level and should be avoided). Include both sexes for dioecious plants. For some genera, both mature and juvenile leaves should be collected; for other bark is necessary. Collection of he whole plant (including roots) is recommended for herbaceous species since root features may be necessary for correct determination. Put all information in the field notebook with the collection number and label all plant parts in the press with a jeweller s tag. Select vigorous and typical specimens, avoiding insect-damaged plants. Specimens should include the variation present. Collect plants from their typical habitat as some features may change in other (disturbed) environments. Duplicates should be collected with each containing all relevant parts. Collect and press fresh material, laying it out in the way intended for mounting after cleaning it. Note the collector s number on the newspaper too. Sort material according to number (so that material can be identified again if tags and numbers get lost). When material cannot be pressed immediately, keep them in labelled plastic bags, wrapped in damp paper, stored at a cool place if possible. The plant press should be kept level to allow even distribution of pressure. For bulky parts, foam could be used. When changing newspaper, keep the same plant parts up.

5 When mounting, use the space provided on the mounting paper (typically 45 cm 30 cm) at maximum, leaving space for the label. All material should be inside the press. Bend plant parts if necessary (in V or N, not U shapes) and cover as little plant features as possible showing both features (for instance fold the leaf tips to the front rather than letting them be covered by the rest of the leaf). When removing leaves, clip them off above the petiole to show where the leaf was attached, and do the same for other plant parts that are removed. For very small plants, mount several individuals. Present top and bottom surface of leaves, and possibly inner parts of flowers (either by pressing them opened, or split). Use wood glue or strings to attach the material to the mounting paper. The latter system is preferred by some herbaria as material can be investigated more easily again. The voucher will contain a label presenting the information collected in the field notebook, the scientific name of the plant (genus, species, authority, and potential infraspecific information) and the name of the person who identified the plant. Avoid damaging plants, especially if plants are rare (in this case the 1 in 20 rule may be applied). Also, obtain the permissions necessary for collection, and contact government and herbarium personnel. A final, but very important tip to shorten the long and laborious process of pressings plants is the following one: avoid reading all the advertisements and news items in the old newspapers when changing them. Selection of informants As knowledge on plants will vary in communities, information has to be obtained from discussions with several people. Two methods to select informants are commonly used: random selection, and targeted selection. Both methods have been outlined in session 2a as well. Random selection is appropriate to obtain information on the distribution of knowledge in communities; targeted selection is better at obtaining specialist information, as exactly local specialists will be targeted. Random selection of informants can be done by random sampling or by stratified random sampling. The latter technique can be used to include more informants from some smaller groups or from less-populated sections of the survey area. Using systematic sampling techniques will reduce bias in the sampling, such as spatial bias (urban, tarmac, roadside), project bias (success stories), person bias (progressive farmers, leaders, men, adopters) or seasonal bias (dry season, post harvest). Stratified sampling can be especially useful to obtain information from marginal groups, for example women or children. Key informants, local experts, or gatekeepers have to be identified based on their expertise. Other local people can select them (by the procedure described under PRA). If local specialist user groups will be targeted, then another method of selecting these is by their profession, such as traditional medical practitioners, blacksmiths, traditional birth attendants, beekeepers, craftsworkers, or cattle owners. Elderly people can be targeted for historical information by in-depth collection of life histories.

6 The context in which the information is collected may be as important as the selection of informants. Ideally, interviews are conducted with growing specimens of various stages in their lifecycles in the environment in which they are used and in the context in which the plants are used. Some ethnobotanical inventories of forests have for example opted to visit the same forest plots with various informants separately. Visiting the same plot with various informants also allows better to investigate differences in knowledge among individuals and among specialist groups, which could be statistically tested. Estimating the completeness of a survey Martin (1995, pp ) gives some easily calculated parameters, which can help to evaluate the completeness of a survey, be it intended to collect herbarium specimens, or to collect information on plant usage. These parameters are: Breath : C( s) ; C( t) with : Depth : S( s) S( t) and C( t) Replication : N( s) C( t) C(s) = number of categories surveyed C(t) = total number of categories S(s) = number of sub-categories surveyed S(t) = total number of sub-categories N(s) = number of samples per category (Example to be worked out: ) Breadth, depth and replication of botanical families and species for the hypothetical ethnobotanical survey documented in Table 1 are for example: 2/3, (4/8 + 2/5 + 0/2)/3 and 17/15. Table 1. Species and families sampled during an ethnobotanical survey. Family (category) Species (subcategory) Samples A 1 2 A 2 3 A 3 1 A 4 5 A 5 0 A 6 0 A 7 0 A 8 0 B 9 4

7 B 10 2 B 11 0 B 12 0 B 13 0 C 14 0 C 15 0 Calculations can be made for floristic categories (families, genera, species), thus comparing the botanical diversity in the survey with the total (estimated) diversity of the environment. Calculations can also be made for ethnofloristic categories (plant functional use groups, groups of a folk taxonomy, local plant names; local classification systems are described below). These formulas can also be used to calculate the breadth and depth of knowledge on species used versus the total number of species present. Studies on rainforests have for example documented the large breath of knowledge of plant species, where at least two-thirds of all tree species are used (Ellen 1996). (The large breath of plant usage actually suggests that rainforests have been domesticated, while similarly patchiness and biodiversity has been increased through human disturbance.) The changes in the figures of breadth, depth, and replication as the survey continues should be studied. Decisions could be made to focus on underrepresented categories. A rule of thumb is to finalise the survey when the breath and depth of the survey no longer significantly change, while at the same time an acceptable level of replication has been achieved. As the calculations depend on totals of categories and sub-categories, species accumulation curves (Session 6a) may be used if these totals are not known for the area studied. Some formulas and software developed to estimate the total species richness of an area could also be used (Colwell 1997). Total species richness is often not known for the majority of richer ecosystems being studied, such as tropical rain forests or agroforests. Ethnobotanical rather than botanical inventories are recommended for these habitats because local collectors are usually more efficient in detecting rare individuals than alien explorers. Understanding local classification systems By studying the correspondence between floristic and ethnofloristic categories, an understanding will be gained on local plant classification systems and how these compare with botanical classifications. Understanding local taxonomies requires an insight in local plant names. Linguists distinguish several types of names (Martin 1995 pp ): primary name: name which is semantically unitary (e.g. wattle)

8 secondary name: name which is semantically binary (higher category with a modifier of a lower category, e.g. black wattle, golden wattle, silver wattle) Studying local names can be difficult because a primary name can be composed of two words (complex name), with one word referring to a higher category (called productive complex primary names, e.g. peppertree, elephantgrass). Confusion can also arise when objects are being described (black wood), opposed to descriptions which became names (blackwood). It is therefore advisable to have a linguist in the team, or to record the names on tape to have them translated afterwards. Having somebody in the team with good understanding of the language will also avoid that plant names are recorded that actually mean I don t know, I don t like that tree, or When can we go home in the local language. Researchers should be aware that not only visual, but also other senses (smell, surface) might be used to differentiate plants. It will be more difficult to describe non-visual diagnostic criteria. Often primary names refer to genera, while secondary names refer to species or varieties. Local plant names may therefore show a one-to-one relationship with botanical species. Botanical species could be overdifferentiated (more local names for the same species) or underdifferentiated (local name given for several species). Overdifferentiation is normally an expression of the importance of the species to local people (Martin 1995 pp ). However, it has been observed for forest use that agriculturists would have larger linguistically-encoded knowledge that is however less substantive than that of non-agricultural people (Ellen n.d.). The reason would be that much knowledge by food collectors would be gained through personal experience and not be shared by the community which would require naming. Local classification systems usually group plants into higher categories, such as lifeforms (trees, herbs, vines...) and intermediates (groups of several plants of the same lifeform). Gaining an understanding in classification systems can be achieved with PRA sorting exercises (see lecture note on PRA). Several classification systems and associated names could be used in the same community. Some plants might be grouped differently than the general-purpose classification if some specific characteristics are referred to. For example, some trees could be grouped together with some herbs and some grasses when looking specifically at medicinal properties. As these groupings cut across the general-purpose classification, they are referred to as crosscutting categories. In case crosscutting categories are complex and extensive, they could provide a parallel classification system. General-purpose classification Tree Herb Vine Grass Medicinal classification Type a Type b

9 Type c Bioprospecting Bioprospection has attracted large attention recently. With 118 of the top 150 prescription drugs used in the United States of America being based on natural sources, and 74 percent of these being derived from plants, the commercial value of pharmaceuticals is enormous. Bioprospecting involves intensive exploration of organisms for naturally occurring substances that could improve human life. Studies have shown that ethnobotanical surveys involving local specialists are more successful in identifying plants with biological activity. In trials involving a traditional healer versus random collections conducted in Belize, ethnobotanical surveys had a 25 percent success rate versus 6 percent of random surveys in selecting plants with activity against HIV (Ethnobotany in the Forests of Belize). The intermediate strategy used was targeting families high in biologically active compounds. A much larger study was conducted in Suriname (Can the economic promise of drug discovery continue to preserve the Suriname forest?), resulting in the finding that 3.8 percent of plants used by shamans had biological activity versus 2.8 percent of randomly collected plants. Success rates may have been higher if tests would have been available to directly test against the intended application. Researchers should be aware of the intellectual property rights of the communities from which knowledge has been obtained and ensure that they benefit in a fair manner from any economic returns obtained through the research findings, if not legally required then from an ethical perspective. Some guidelines for biodiversity research protocols relevant for bioprospection have been developed by the Biodiversity and Ethics Working Group of Pew Conservation Fellows and can be consulted on the Internet at Another approach to make local people directly benefit is not to link with pharmaceutical companies, but to validate local knowledge in laboratories and provide local communities with these confirmations. This approach has been used in the Venezuelan rain forest where Indian communities have been assisted in cultivating medicinal plants for their own use and for exports (Medical discoveries from the forest will help both Indians and rain forest conservation, Cornell researcher predicts). By ethnobotanical surveys, ten plants with biological activity against malaria were identified. Ethnobotanical surveys and agroforestry tree domestication Because the goal of domestication is to enhance the role of particular agroforestry tree species in the systems in which they are used, it is obvious that it is necessary to gain an understanding on: Local uses of trees and their management What is the tree used for?

10 What are the user groups? What are the regional and ethnic differences? How do products differ between species? Local naming and classification Are several varieties distinguished, or is the species grouped together with other species under the same name? What are the higher groups of plants in which the plant is grouped into? How do local people discriminate between different species and varieties? Further to these inventories, marketing studies could be undertaken, especially for products with higher values, which produce income for the household. The information that is gathered through these surveys will help to decide on the most promising species to work with (cf. lecture on species priority setting) and on the objectives of domestication of the species. Surveys could gather the opinions of local people on how the trees could be improved, e.g. by undertaking ranking and rating exercises. Important information is also, on how germplasm has been distributed in the area and how local people access and manage the current sources of germplasm. Is material selected locally? How is the genetic diversity managed in the community? Guarino (1995) gives an overview on how IK could be useful for collections. IK could be used in deciding which material to collect (e.g. material with higher potential, landraces), where to collect (e.g. locations with high diversity) and how much to collect (assessing the completeness of the collection). The collections could be documented with local knowledge on properties and adaptations of landraces; folk taxonomies; origin and distribution of the material; origin, distribution and management of diversity and the assessment of the extent and dangers of genetic erosion. Participation in on-farm domestication trials may be bigger when local communities have been involved from the initial stages when information is gathered on the different uses of trees, or with the gathering of information on species selection (inter and intraspecific selection). In summary, IK and therefore ethnobotanical surveys, will be useful at every step of the domestication process, from the initial stages of decision-making on the domestication strategy, over the identification (inter- and intra-specific) of quality material, until the distribution of domesticated material. An important issue to incorporate in the domestication strategy is that indigenous knowledge is not static, and that the collective knowledge of a group of agroforesters if often much larger than the individual knowledge. For example, during survey work in western Kenya, various farmers mentioned that neighbours would collect parts of trees occurring in their farm for medicinal purposes, but that the neighbours were not willing to share information on preparation, treatment or ailment. Increasing participation in domestication activities could focus on differences in ethnobotanical knowledge and seek to increase the collective and individual knowledge. A process parallel to the FAO Farmers Field Schools could be promoted (Session 6c?).

11 Bibliography Guarino, L. (1995). Secondary sources on cultures and indigenous knowledge systems. In: Guarino, L.; Ramanatha Rao, V. & Reid, R. Collecting plant genetic diversity: technical guidelines. CAB International, Wallingford; pp Martin, G. (1995). Ethnobotany: a methods manual. Chapman & Hall, London; pp. xx, 7-9, 61-65, Plant Collection Procedures and Specimen Preservation. Centre for Plant Biodiversity Research. URL Preparation of Plant Specimens for Deposit as Herbarium Vouchers. URL Pressing plants. URL Plant Collections. URL Ellen, R (1996). Putting plants in their place. Anthropological approaches to understanding the ethnobotanical knowledge of rainforest populations. In: 'Tropical rainforest research: current issues', eds. D. S. Edwards, W.E. Booth and S.C. Choy. Kluwer: Dordrecht 1996, pp URL Ethnobotany in the Forests of Belize. URL Medical discoveries from the forest will help both Indians and rain forest conservation, Cornell researcher predicts. Grow anti-malaria plants where malaria is the greatest threat, in the tropics, biologist Eloy Rodriguez tells AAAS audience. URL Colwell, RK (1997). EstimateS: Statistical estimation of species richness and shared species from samples. Version 5. User s Guide and application published at: Can the economic promise of drug discovery continue to preserve the Suriname forest? Virginia Tech. URL Ellen, R (nd). Indigenous knowledge of the rainforest: perception, extraction and conservation. URL Bowles, JM. (nd). Guide to Plant Collection and Identification. Plant Evolutionary Ecology. URL