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.

Abstract:The basic information necessary for biogeographical analysis is the geographical location appended to the data contained in biological databases. Reliability of analyses thus crucially depends on the quality of the spatial information available. In the present study we build on a database of vascular plants of West Africa (Ivory Coast, Burkina Faso, Benin), containing 53,205 georeferenced observations distributed over 2,931 collection localities. We propose a methodology to quantify the quality of the database through a series of spatial analyses of spatial configuration of the collection localities, their spatial and environmental bias and inventory completeness. The spatial configuration of the database followed a highly clustered pattern and was strongly biased with respect to the distance to cities, the coast, rivers, roads and protected areas. The same biased pattern was found in relation to several environmental factors. Inventory completeness was calculated by estimating the total number of species based on two non-parametric estimates (firstorder Jackknife and Bootstrap) and at different grid cell sizes. At the highest resolution (100 km²) only 5.5% of the cells contained a near-complete (> 80% of Jackknife estimates) species inventory. The percentage of near-complete cells increased as the resolution of analysis decreased. Results of all analyses were integrated into a new index (Gap Selection Index) that serves to guiding future field work campaigns and as cautionary criterion for the uncertainties related to biogeographical application based on the current database.

Background: High harvesting of Non-Timber Forest Products (NTFPs) for food and fodder supply leads many tree species to be vulnerable or endangered due to overexploitation. This study aimed to assess harvesting pressure on food and forage species and to understand how the socio-economic profile of people affects their perception on species state as well as on the impact of harvesting methods on species dynamics.Methods: Semi-structured ethnobotanical surveys were conducted near the active stakeholders involved in NTFPs harvesting -children, women, herders, and former actors (old persons >50 years old, both women and herders). Hundred and four (104) people from 4 ethnic groups were interviewed. We have calculated the overharvesting index (OI) based on three pressure parameters: Fidelity level of use (FL), Relative frequency of harvesting (FH) and Relative intensity of pruning (IP). The difference between respondent's perceptions on species state was tested using logistic regression followed by analysis of variance of the model. Results:The overharvesting index (OI) showed that eight (8) species are overharvested of which the first three species are Pterocarpus erinaceus Poir (OI = 122.1%), Saba senegalensis (A. DC.) Pichon (OI = 100%) and Lannea microcarpa Engl. & K. Krause (OI = 97.4%). These overharvested species are generally exploited using destructive methods, especially branch pruning for leaves and/or fruits harvesting. Local people´s perception on species state was significantly influenced by the type of actors and their age (p<0.0001 for both). This suggests that specific awareness message considering socio-economic profiles of people need to be developed for a truth conservation impact on the field. 82.3% of respondents declared that harvesting methods have no significant impact on species state, revealing that most people are still using forest resources in traditional considerations.

Knowledge of spatial patterns of biological diversity is fundamental for ecological and biogeographical analyses and for priority setting in nature conservation, particularly in West Africa where the existing high biodiversity is increasingly threatened by human activities. The maximum entropy approach was used to model the geographic distribution of 3,393 vascular plant species at a spatial resolution of 0.0833°. Species richness decreases along temperature and precipitation gradients with high species numbers in the south and lower numbers towards the north of the transect. All centres of plant species diversity are confined to humid areas in concordance with the high positive correlation between species richness and rainfall which appears to be the most important delimiter for the distribution ranges of many species in the area. The effectiveness of the existing protected areas at regional and national levels is investigated based on the proportion of species covered. Considering the whole study area, 95% of all species are covered by protected areas according to their distribution ranges. However, the proportion of species covered is considerably lower for some countries such as Benin and Togo. Our results could provide guidance for essential land use management interventions to decision‐makers and conservationists in the region.