Ethnobotany and conservation of the species Celtis toka (Forssk.) Hepper & J.R.I. wood: A way forward for sustainable use in Burkina Faso.

Celtis toka (C. toka), a critically endangered mystical plant, is a highly valued and overharvested multiuse tree species by local population in Burkina Faso. The ethnobotany of C. toka can lead to its sustainable use, therefore it is a great challenge because little information is available on this aspect concerning the species in Burkina Faso as well as in Africa. Thus, this study aims to assess the sustainable use and management of C. toka in Burkina Faso. The study was conducted along a climate gradient (Sudanian and Sudano-Sahelian climatic zones) in Burkina Faso. Data were collected randomly through selected semi-structured interviews with 405 informants (148 women and 257 men) randomly selected from 34 villages and 25 ethnolinguistic groups. Frequency of citation was computed. Kruskal-Wallis test, Mann-Whitney test and Generalized Linear Models analyses were performed to determine whatever information varied according to site and socio-demographic parameters. Among eight use categories, food (27.89%), livestock (18.97%), shade (16.23%), and pharmacopeia (14.92%) were the most recorded. Leaves (63.83%), roots (19.20%), and bark (17.11%) were the most valued plant parts. All plant parts were used to heal 29 ailments in 37 ways. The most common diseases treated by C. toka were vitamin deficiencies (FL = 8.84%), malaria (FL = 8.44%), cast (FL = 5.84%), madness (FL = 3.25%), eye ache (FL = 2.77%) and yellow fever (FL = 2.60%). Sacred forests (39%) and protected areas (27%) were the key biotopes of C. toka. Value of C. toka was well-treasured in the study sites. The frequency of citation of some use patterns and plant parts varied significantly across some ethnolinguistic groups, sex and generation levels (p < 0.05). Management such as sowing (0%), seedling transplantation (0%) and assisted natural regeneration (0%) were lacking. Sacred (37.99%), taboo (25.04%), mystic (11.62%), magic (10.28%) fetish (8.96%) and medico-magic (6.12%) characters of C. toka determined the traditional conservation strategies of the species in Burkina Faso. Our results recommend that the conservation policies and sustainable use of C. toka should be prioritized. Furthermore, studies should thus emphasize the domestication potential of C. toka for its plant parts.

Impacts of climate change on the geographic distribution of African oak tree (Afzelia africana Sm.) in Burkina Faso, West Africa.

Afzelia africana Sm - a multipurpose leguminous tree species - is threatened in West Africa - a climate change hotspot region. Yet, although the impacts of land use on this species dynamics have been widely reported, there is a little literature on the impacts of climate change on its spatial distribution. This study aimed to predict the impacts of climate change on the geographic distribution of A. africana in Burkina Faso. A total of 4,066 records of A. africana was compiled from personal fieldwork and vegetation database. Current and future bioclimatic variables were obtained from WorldClim website. For future climatic projections, six global climate models (GCMs) were selected under two emission scenarios (RCP 4.5 & RCP 8.5) and two horizons (2050 & 2070). Presence data and bioclimatic variables were processed in ArcGIS software and used in the algorithm MaxEnt (maximum of entropy) to predict the species distribution. Findings showed that maximum temperature of warmest month and mean temperature of coldest quarter mostly affect the habitat suitability of A. africana. About 25.54% of Burkina Faso land surface was currently suitable for A. africana conservation. Under future climatic projections, all the climate models predict climate-driven habitat loss of the species with a southward range shift. Across the two emission scenarios, the spatial extent of suitable habitats was predicted to decline from 9.43 to 23.99% and from 12.29 to 25% by the horizons 2050 and 2070, respectively. Habitat loss and range shifts predicted in this study underline the high vulnerability of A. africana to future climate change. Reforestation actions and the protection of predicted suitable habitats are recommended to sustain the species conservation.

Use patterns, use values and management of Afzelia africana Sm. in Burkina Faso: implications for species domestication and sustainable conservation.

BACKGROUND: The lack of literature on the interactions between indigenous people and the valuable agroforestry trees hinder the promotion of sustainable management of plant resources in West African Sahel. This study aimed at assessing local uses and management of Afzelia africana Sm. in Burkina Faso, as a prerequisite to address issues of domestication and sustainable conservation. METHODS: One thousand forty-four peoples of seven dominant ethnic groups were questioned in 11 villages through 221 semi-structured focus group interviews. The surveys encompassed several rural communities living around six protected areas along the species distribution range. Questions refer mainly to vernacular names of A. africana, locals' motivations to conserve the species, the uses, management practices and local ecological knowledge on the species. Citation frequency was calculated for each response item of each questionnaire section to obtain quantitative data. The quantitative data were then submitted to comparison tests and multivariate statistics in R program. RESULTS: A. africana is a locally well-known tree described as a refuge of invisible spirits. Due to this mystery and its multipurpose uses, A. africana is conserved within the agroforestry systems. The species is widely and mostly used as fodder (87.55%), drugs (75.93%), fetish or sanctuary (70.95%), food (41.49%), and raw material for carpentry (36.19%) and construction (7.05%). While the uses as fodder, food and construction involved one organ, the leaves and wood respectively, the medicinal use was the most diversified. All tree organs were traditionally used in 10 medical prescriptions to cure about 20 diseases. The species use values differed between ethnic groups with lower values within the Dagara and Fulani. The findings reveal a total absence of specific management practices such as assisted natural regeneration, seeding, or transplantation of A. africana sapling. However, trees were permanently pruned and debarked by local people. Harvesting of barks mostly contributed to the decline of the species populations. Local people acknowledged declining populations of A. africana with lower densities within the agroecosystems. They also perceived between individuals, variations in the traits of barks, leaves, fruits and seeds. Significant differences were found between ethnic groups and gender regarding the species uses. Local knowledge on the species distribution differed between ethnic groups. CONCLUSION: This study showed the multipurpose uses of A. africana throughout Burkina Faso. The results provide relevant social and ecological indicators to all stakeholders and constitute a springboard towards the species domestication and the elaboration of efficient sustainable conservation plans.

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.