Anne Mette Lykke

Assessment of species composition change in savanna vegetation by means of woody plants' size class distributions and local information

A new method is presented for assessment of compositional changes in disturbed savanna systems and for identification of species susceptible to local extinction. Such information is urgently needed as a basis for management plans that aim at ensuring conservation and sustainable use of savanna vegetation. Size class distributions (SCDs) of trees and shrubs from a fire-disturbed savanna in Senegal are analysed and compared to observations provided by local people on declining species. Many species, particularly large trees, have few young individuals and therefore flat SCDs that deviate from the reverse-J shape SCD characterizing species with abundant and constant rejuvenation. Based on comparisons of SCDs with local information and historical records, it is concluded that most of the flat distributions analysed are effects of declining population sizes caused by human impact, particularly fire. Results from the analyses certify that a change in species composition from a vegetation characterized by large trees to one dominated by shrubs takes place. Whereas most of the declining species are locally appreciated, this is not the case for the few species with good rejuvenation. Therefore, if the observed trend continues, it will have severe implications for the local communities.

Valuation of local use and dynamics of 56 woody species in the Sahel

A quantitative ethnobotanical method based on structured interviews was used to evaluate local use-preferences and dynamics of practically all woody species in the Sahel of Burkina Faso. One hundred Fulani informants estimated the value of 56 woody species for food, firewood, construction, medicine, field trees, shade and fodder, as well as conservation priority, abundance and dynamics of each species. There was a large consistency in answers, but significant between-village differences existed. Gender and age of informants did not influence answers significantly. The present valuation method identified a large number of species important for local use and demonstrated a more varied plant use than seen from free-listing interviews. Furthermore, the Fulani informants described a decline of practically all woody species. The present valuation provided management-relevant information about plant use and vegetation change. The woody vegetation in the Sahel is currently without sufficient management to uphold a rational use of the vegetation, following the gradual disappearance of the traditional nomadic trekking routes that previously helped to ensure a rational use of the vegetation.

Informant-based valuation of use and conservation preferences of savanna trees in Burkina Faso

Use and conservation preferences for woody savanna species among the Gourounsi people in south-central Burkina Faso were investigated using a new informant-based valuation system. Two hundred informants from 10 villages evaluated the importance of 20 preselected woody species for nine different uses: edible fruits, vegetable sauce, construction, firewood, medicine, commerce, field trees, and conservation. The study identified eight key species: Parkia biglobosa, Vitellaria paradoxa, Tamarindus indica, Adansonia digitata, Vitex doniana, Detarium microcarpum, Bom-bax costatum, and Strychnos spinosa. They all had high commercial and nutritional value. The local knowledge about the selected woody species was similar between men and women, and between young and old, but it differed between villages. The results indicate that knowledge erosion does not take place among the Gourounsi, but considerable local differences exist. Conservation management should focus on the key species, and for these, assisted regeneration, tree planting, and further ecological research is recommended.ResumenLes préférences d’utilisation et de conservation des ligneux de savane chez les Gourounsi au Centre Sud du Burkina Faso ont été examinées á partir d’une nouvelle approche d’appréciation fondée sur I’informateur. Deux cents informateurs répartis dans 10 villages ont apprécié I’importance de 20 espéces ligneuses, préalablement choisies, pour neuf différents types d’utilisation: fruits comestibles, légume pour la sauce, bois de construction, bois de chauffe, pharmacopée, commerce, arbres de champ et conservation. Huit espéces clés ont été identifiées par la présente étude. Ce sont: Parkia biglobosa, Vitellaria paradoxa, Tamarindus indica, Adansonia digitata, Vitex doniana, Detarium microcarpum, Bom-bax costatum et Strychnos spinosa. Elles ont toutes haute valeur commerciale et nutritionnelle. La connaissances locales des ligneux choisis a été similaire entre femmes et hommes d’une part, et entre jeunes et personnes âgées d’autre part. En revanche, une différence a été notée entre les villages. Les résultats ont révélé en que les Gourounsi n’ont rien perdu de leur connaissance ancienne, mais quelques différences notables existent á l’échelle locale, he aménagement de la conservation devrait se focaliser sur les espéces clís identifiées pour lesquelles une régéneration assistée, une plantation d’arbres et d’autres recherches écologiques sont recommandées.

Importance and seasonality of vegetable consumption and marketing in Burkina Faso

The use of vegetables in two rural communities in Burkina Faso is quantified through the use of food diaries kept by 13 households during one year. Interviews on preferences, field registration, and a market survey supplement the diaries. The use of wild species is concentrated onParkia biglobosa, Corchorus spp.,Adansonia digitata, andBombax costatum. At least five other wild species are mentioned as important but very rarely occur in the diet, indicating the usefulness of diaries compared to interviews.Capsicum frutescens, Abelmoschus esculentus, Allium cepa, andSolanum lycopersicon are the most commonly used cultivated species. Wild vegetables constitute 35% and 59% of the total vegetable consumption in the two communities. Most products are highly seasonal in supply and prices vary accordingly. Households compensate for the seasonality by drying products, but stocks are often insufficient and vegetable purchases needed. Many of the vegetable species studied should be integrated in agricultural research and extension programs.

Local knowledge, pattern and diversity of use of Sclerocarya birrea

BackgroundGrowing interest is on food tree species in general, and particularly indigenous fruit tree species in developing countries since they are inherent to most tropical landscapes and serve the dual function of local livelihood support and biodiversity conservation. It is therefore relevant to assess the level of integration of these species in local cultures and the factors affecting them. This study aims at assessing knowledge and uses of Sclerocarya birrea subsp. birrea and factors affecting the use values within and between communities.MethodsThis study combines quantitative and qualitative ethnobotanical approaches to investigate uses and factors affecting the use value of S. birrea subsp. birrea. Nine group discussions as well as 161 individual interviews were held in the dry and typical Sudanian zones. Seven different ethnic groups were involved and the survey focused on local uses and perception of factors affecting the dynamics of S. birrea.ResultsThe species has a multitude of uses; all organs are used for more than 20 different purposes. The study highlights how gender, local availability, ethnicity and community location interact to influence the utilization value of the species. People living in drier areas with high occurrence of the S. birrea use it more than those living in wetter areas with low occurrence. While domestic and subsistence uses do not appear to threaten the species, carving, clearing and drought stand out as the major causes of its decline.ConclusionsMany factors and their interactions influence the use pattern of the species within and between communities. When compared to the level of exploitation of S. birrea subsp. caffra in southern Africa, the subspecies birrea is at this point relatively underutilized. A high commercial potential exists due to its simple propagation ability and makes it an interesting agroforestry resource.

Declining Wild Mushroom Recognition and Usage in Burkina Faso

Declining Wild Mushroom Recognition and Usage in Burkina Faso. Ethnomycological investigation was carried out in Burkina Faso, West Africa, using standardized interviews focused on 40 representative mushroom species assembled in a traveling herbarium (photographs plus preserved specimens). A total of 540 informants from 18 localities representing three main ethnic groups—Mòosé, Bobo, and Gouin—were interviewed, though the bulk of those interviewed were Mòosé (or Mossi) from the more populous central region of the country. Among the study species, as many as 24 were considered edible by the different ethnic groups; a few medicinal uses also were noted. The edibility of a common Chlorophyllum species is confirmed for the three ethnic groups. Mushroom nomenclature is not well developed in any of the three groups as evidenced by the fact that many mushrooms, including some common edible species, do not appear to have specific local names, but are instead simply referred to by a general term for “mushroom.” Preliminary observations about inter–ethnic variation in recognition, naming, and appreciation of mushrooms are noted. Older people recognized many more mushroom species than did younger people, and women appeared to be slightly more knowledgeable about mushrooms than men. The most important finding is that the gathering and consumption of wild edible mushrooms seems to be dying out in Burkina Faso, especially in the central part of the country, apparently because of declining mushroom populations resulting from disappearing forest habitats.

Spatial optimization of carbon-stocking projects across Africa integrating stocking potential with co-benefits and feasibility

Carbon offset projects through forestation are employed within the emissions trading framework to store carbon. Yet, information about the potential of landscapes to stock carbon, essential to the design of offset projects, is often lacking. Here, based on data on vegetation carbon, climate and soil, we quantify the potential for carbon storage in woody vegetation across tropical Africa. The ability of offset projects to produce co-benefits for ecosystems and people is then quantified. When co-benefits such as biodiversity conservation are considered, the top-ranked sites are sometimes different to sites selected purely for their carbon-stocking potential, although they still possess up to 92% of the latter carbon-stocking potential. This work provides the first continental-scale assessment of which areas may provide the greatest direct and indirect benefits from carbon storage reforestation projects at the smallest costs and risks, providing crucial information for prioritization of investments in carbon storage projects.

Use-value and importance of socio-cultural knowledge on Carapa procera trees in the Sudanian zone in Mali

BackgroundCarapa procera is a native oil tree species with multipurpose values traditionally exploited by the local population in Southern Mali. This study focused on the assessment of local knowledge about the use of Carapa procera.MethodsSemi-structured ethnobotanical questionnaires were conducted among the ethnic groups Senufo, Fulani and Bambara in two localities in the Sudanian zone in Mali. Use values among these ethnic groups and gender were evaluated.ResultsThis study showed that Carapa procera is a species with multiple uses and high use values. According to the consensus value for plant parts (CPP), the nuts constituted 57% of exploited plant parts followed by bark and leaves (12%), wood and roots (7%), mistletoes (4%) and gum (1%). The use diversity (UD) values of Carapa procera showed a high proportion of cosmetic (UD = 0.49) and therapeutic (UD = 0.36) uses. The UD for therapeutic uses was higher for ethnic groups in Ziékorodougou than in Niankorobougou. In contrast, the UD for cosmetic uses was higher for ethnic groups in Niankorobougou than in Ziékorodougou. Comparative analysis between ethnic groups revealed that the highest UD for cosmetic uses (0.63) was observed in the Bambara ethnic group, whereas the highest UD for therapeutic uses (0.39) was obtained in the Senufo ethnic group. The UD showed that cosmetic uses were higher for women than for men in both locations. Men in Ziékorodougou had the highest level of knowledge regarding plant parts used, forms of use and the specific reasons for using Carapa procera.ConclusionThis study highlighted the sociocultural importance of Carapa procera. In the light of its multipurpose uses, the promotion and enhancement of Carapa procera can provide significant socio-economic benefits to local people. In this perspective, it is necessary to implement conservation strategies and sustainable management through domestication of the species.

Physicochemical Characteristics and Composition of Three Morphotypes of Cyperus esculentus Tubers and Tuber Oils

Tuber characteristics and nutrient composition of three morphotypes of Cyperus esculentus tubers and tuber oils were determined. The mean value for length and width of the tuber and one thousand dried tuber weights ranged from 0.98 to 1.31 cm, 0.90 to 1.19 cm, and 598 to 1044 g, respectively. Tubers displayed high level of starch (30.54–33.21 g 100 g−1), lipid (24.91–28.94 g 100 g−1), and sucrose (17.98–20.39 g 100 g−1). The yellow tubers had significantly higher content in lipid compared to black ones. Levels of ascorbic acid, tocopherol, and β-carotene of the three morphotypes differed significantly. Yellow ones (morphotypes 1 and 2) were the richest in tocopherol and the poorest in β-carotene. Saturated fatty acid content of morphotype 2 was significantly lower than that of morphotypes 1 and 3. Morphotype 3 had the significantly lowest PUFA content compared to morphotypes 1 and 2. Morphotype 1 was found to be richer in Ca, Cu, and Mn contents. Al, Mg, P, S, and Si were most abundant in morphotype 2. Morphotype 3 had the highest content of Cl, K, and Zn.

Spatially explicit multi-threat assessment of food tree species in Burkina Faso: A fine-scale approach

Over the last decades agroforestry parklands in Burkina Faso have come under increasing demographic as well as climatic pressures, which are threatening indigenous tree species that contribute substantially to income generation and nutrition in rural households. Analyzing the threats as well as the species vulnerability to them is fundamental for priority setting in conservation planning. Guided by literature and local experts we selected 16 important food tree species (Acacia macrostachya, Acacia senegal, Adansonia digitata, Annona senegalensis, Balanites aegyptiaca, Bombax costatum, Boscia senegalensis, Detarium microcarpum, Lannea microcarpa, Parkia biglobosa, Sclerocarya birrea, Strychnos spinosa, Tamarindus indica, Vitellaria paradoxa, Ximenia americana, Ziziphus mauritiana) and six key threats to them (overexploitation, overgrazing, fire, cotton production, mining and climate change). We developed a species-specific and spatially explicit approach combining freely accessible datasets, species distribution models (SDMs), climate models and expert survey results to predict, at fine scale, where these threats are likely to have the greatest impact. We find that all species face serious threats throughout much of their distribution in Burkina Faso and that climate change is predicted to be the most prevalent threat in the long term, whereas overexploitation and cotton production are the most important short-term threats. Tree populations growing in areas designated as ‘highly threatened’ due to climate change should be used as seed sources for ex situ conservation and planting in areas where future climate is predicting suitable habitats. Assisted regeneration is suggested for populations in areas where suitable habitat under future climate conditions coincides with high threat levels due to short-term threats. In the case of Vitellaria paradoxa, we suggest collecting seed along the northern margins of its distribution and considering assisted regeneration in the central part where the current threat level is high due to overexploitation. In the same way, population-specific recommendations can be derived from the individual and combined threat maps of the other 15 food tree species. The approach can be easily transferred to other countries and can be used to analyze general and species specific threats at finer and more local as well as at broader (continental) scales in order to plan more selective and efficient conservation actions in time. The concept can be applied anywhere as long as appropriate spatial data are available as well as knowledgeable experts.