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Context: In Burkina Faso, Sudanian savannas are important ecosystems for conservation of plant diversity. Due to desertification and insecurity, population migration from the North has increased human density and anthropogenic pressure on southern savannas. This study aims to investigate knowledge of local populations on ecosystem services (ES) and perception of their conservation. Method: Individual semi-structured interviews about knowledge on ES and ecosystem conservation issues were conducted. Informants were selected according to sociocultural groups and sex in three areas of different land use intensity: the communal area of Dano (CAD), the Total Wildlife Reserve of Bontioli (TWRB) and the Game Ranch of Nazinga (GRN). The use value and vulnerability index of each plant species were determined. A cluster analysis and a principal component analysis were carried out to identify the particular knowledge of different ethnic groups. Results: Overall, 163 plant species were cited for fifteen ES. Provisioning services were most frequently cited (100%), regulating services second most frequently (92.47%). Entire plants were exclusively used for ES with non-material benefits (protection against wind, for shading, soil fertility, erosion prevention, tourism and religion). The ten species contributing most to ES provision were Vitellaria paradoxa, Parkia biglobosa, Diospyros mespiliformis, Adansonia digitata, Lannea microcarpa, Faidherbia albida, Khaya senegalensis, Afzelia africana, Ficus sycomorus, Pterocarpus erinaceus. Seven of them were identified as highly vulnerable. Around GRN, migrants and natives shared the same knowledge, while migrants in TWRB used the ES only to a small extent due to restricted contact with the native population. Migrants and natives of GRN had more knowledge on tourism and crafts services while the natives of CAD and TWRB made use of the services that sustain the quality of the agricultural land and meet their primary needs. To reduce further degradation, different communities suggested unanimously raising awareness of the importance of biodiversity and ecosystem conservation. The most quoted motivations to preserve ecosystems were vegetation sustainability and village development. Conclusion: This study documented important local knowledge-based information to guide cultivation of local multipurpose species and initiation of communities to practice best management strategies for sustainable conservation of biodiversity. [ABSTRACT FROM AUTHOR]

Climatic aridity and human pressure are factors responsible for the dynamics of species populations in West Africa savannas ecosystems, causing significant effects on their productivity. This study aimed to determine the factors that affect Balanites aegyptiaca fruit production in order to contribute to the control of the species management. Data were collected across two climatic zones and two contrasting land-use systems on trees with different stem diameter classes. A non-destructive method was applied to assess fruit biomass per tree. The results showed that climatic conditions had a significant effect on fruit production of Balanites aegyptiaca (p <.001). In contrast, land use did not affect the production of the species (p >.05). The average fruit biomass was estimated at 2.99 ± 2.03 kg and 6.32 ± 5.0 kg.tree−1, respectively, in the Sahelian and the Sudano-Sahelian zones. Fruit production was correlated to tree stem diameter, crown cover and tree height. B. aegyptica trees start fruiting in both climatic zones, when stem diameter is around 10 cm. This study contributes to highlight the important factors that drive B. aegyptiaca fruit production under different environmental conditions. The results of this study can guide for other similar studies on fruit bearing trees in tropical areas. [ABSTRACT FROM AUTHOR]

Climate variability added to anthropogenic pressures leads to habitat fragmentation, degradation and loss of forest ecosystem resources in Burkina Faso. Studying vegetation structure and woody species composition is important in monitoring vegetation dynamics for efficient forest management. This study was carried out to characterize woody vegetation along a climatic gradient. Stratified sampling according to four vegetation types was conducted in 120 plots in two protected areas. The plot size was 30 m × 30 m in savannas and 50 m × 10 m in gallery forests. In each plot, all woody species with a diameter at breast height (DBH) ≥ 5 cm were systematically identified and measured. Diversity indices, structural parameters and species importance values were calculated and compared among the sites and vegetation types. Linear discriminant analysis (LDA) was used to characterize each vegetation type in each climatic zone. The species diversity, tree density and basal area of woody species increased significantly along the climatic gradient from north to south. Discriminant analysis identified two vegetation types: open vegetation (shrub savannas and tree savannas) with moderate species richness and structural characteristics and closed vegetation (woodland savannas and gallery forests) with higher species richness and structural characteristics. The size class distribution showed that irrespective of the climatic zone, each vegetation type has a stable structure. Compensation among species in different diameter classes does not allow the effect of the climatic gradient between the two sites on the diameter class size distribution to be observed. This study revealed that climate is the main driver influencing the diversity of woody species rather than the site-specific conditions at the two sites. In addition to climate, site ecological conditions affect the structural parameters. The results provide a rational basis for planning and management decisions to ensure the sustainable use of resources in the two protected areas. [ABSTRACT FROM AUTHOR]

A better knowledge of the impact of environmental conditions on shea tree's fruit production is critical to improve the species management. Fruit production of 237 shea trees was monitored over five successive years (2014–2018) to understand how climatic variables, shea tree population and land use could affect fruit production patterns of the species in Burkina Faso. Data were collected in 12 shea tree populations distributed in three climatic zones with two contrast land use systems. The results showed that fruit production was negatively correlated with mean annual temperature, temperature seasonality, rainfall seasonality and solar radiation, while it was positive with annual rainfall. Therefore, fruiting modelling is needed to predict the impact of future climate change on reproductive ability of the species. In each climatic zone, fruit production was significantly different among shea tree populations (p < 0.05). Within populations, fruit production greatly varies among years with specific patterns of variation. Land use had significant effect on fruit production of shea tree (p < 0.05). Annually, shea trees produced about 12 times more in agroforestry parklands than in protected areas. Interannual variation in fruit production at individual tree level was higher in protected areas. The cultivation of shea tree is recommended to improve its fruit productivity. [ABSTRACT FROM AUTHOR]

Background: Traditional knowledge (TK) on the different uses of under-valued fruit tree species including Gardenia erubescens Stapf & Hutch.—a plant species of least concern (LC) based on International Union for Conservation of Nature (IUCN) classification yet considered threatened due to overharvesting by a National Assessment in addition to 59 other species in Burkina Faso. This study aimed to collect and synthesize information on traditional knowledge and cultural importance of G. erubescens. This information will contribute to document traditional knowledge systems that are fast eroding due to the lack of transmission of the knowledge and will also highlight G. erubescens as a priority species for conservation given that this species is widely used among householders in rural areas in Burkina Faso. Methods: This study assesses TK on the uses and cultural importance (CI) of G. erubescens, among 514 randomly selected respondents across 15 villages bordering three community forest areas located in Eastern and Centre-Western Regions of Burkina Faso through face-to-face semi-structured interviews. Additionally, the uses and CI of G. erubescens were evaluated in relation to informant's gender, ethnicity, generation, and location. Ethnobotanical indices (relative frequency of citation, relative use value, and CI) were computed using generalized linear models, Kruskal-Wallis, and Mann-Whitney tests. Results: Results indicated 30 specific uses of G. erubescens of which food values recorded the highest uses as reported by 58.97% respondents followed by medicine (17.22%) with a very low 0.23% for magical uses. Food and medicinal uses were the most important for women while men valued more the species for constructions, cultural, and magical uses. The fruit is the most preferred and marketable part of the plant while the leaves, fruits, roots, leafy twigs, and bark are mainly harvested for pharmacopeia and psycho-magical problems. Conclusions: Traditional knowledge on the uses of G. erubescens varied significantly in relation to gender, ethnicity, generations, and case study locations. Despite the importance of G. erubescens for food and other livelihood values, this specie is of LC to the IUCN; yet, a National Assessment considers it as threatened. The multiple uses of this specie based on TK systems for uses such as food, income, medicine, etc. is an indication that G. erubescens if sustainable managed could form an important safety net especially for rural households in Burkina Faso that are highly dependent on trees and forest resources. [ABSTRACT FROM AUTHOR]

Questions: West African savanna ecosystems are affected by increasing land use intensity (e.g., agriculture and livestock herds) due to a growing human population. To understand the impact of land use intensification on savanna vegetation, we aim to answer the following questions: How do savanna species composition, diversity and structure change with increasing land use pressure? Are the impacts of land use change different in the woody and the herbaceous layers? Do the effects of land use change differ between vegetation types? Location: Southeastern Burkina Faso, West Africa. Methods: Vegetation plots from the early 1990s representing vegetation types occurring in fallows of different age and in uncultivated pasturing zones were resurveyed. We distinguished between woody (tree and shrub layer) and herbaceous vegetation types. Species composition changes were analyzed using ordination techniques (detrended correspondence analysis, DCA) and indicator species analysis (IndVal). Species turnover and plant diversity as represented by species richness and evenness were compared between the baseline survey and the resurvey. Results: In most woody vegetation types, we found no change in species composition and richness over the past two decades. However, some highly valued woody species decreased in abundance. In contrast, in most herbaceous vegetation types, species composition changed considerably and species richness increased. The proportion of wide‐ranging, ruderal herbaceous species increased, indicating a homogenization of herbaceous vegetation types, while preferred fodder herbaceous species decreased. We assume that the increased grazing intensity over the past two decades is the driver of these changes in the herbaceous layer. Conclusions: Our results show different reactions of vegetation types and layers to land use intensification and reinforce the need for studies on the basis of vegetation type that incorporate both the herbaceous and the woody layers. [ABSTRACT FROM AUTHOR]

Highlights • Soil seed banks (SSBs) play a key role in the post-disturbance recruitment of many plant species. • Restoration of different land use systems in savanna-woodland is weakly supported by the SSB. • Fragmentation and change in land use affects the size and composition of the SSB. • Landscape-scale patterns of SSBs should be evaluated to guide active restoration measures. Abstract Soil seed banks (SSBs) play a key role in the post-disturbance recruitment of many plant species. Seed bank diversity can be influenced by spatial and environmental variability and disturbance heterogeneity across the landscape. Understanding the recovery potential of native vegetation from SSBs is important for restoration and biodiversity conservation. Yet, in savanna-woodland, little is known about how SSBs vary in their germination, composition and density under different land uses, and how SSBs relate to aboveground vegetation (AGV). Using a sampling design based on the Land Degradation Surveillance Framework, we assessed the SSB and AGV in twelve 0.25 ha plots among sixteen in four contrasting land use systems of savanna-woodland in Burkina Faso: bushland, cultivated farmland, fallow and wetland. A total of 720 soil samples were taken from four stratified depths of 0–5 cm, >5–10 cm, >10–15 cm, and >15–20 cm. The SSB composition and richness was determined by the seedling emergence technique. Results showed that the SSB in all land uses was largely dominated by annual grasses with few perennial herbaceous and woody species. Seed density was highest in the fallow soil and highest in the upper soil layers for all land uses. A non-metric multidimensional scaling ordination of the SSB and AGV indicated that the SSBs were a poor reflection of the AGV. Based on these findings, spatial variations in landscape characteristics not only influence seed distribution and viability but also have the potential to influence population persistence. These results imply that successful restoration of fragmented ecosystems requires the addition of seeds and seedlings of target species. [ABSTRACT FROM AUTHOR]

Grazing removes a plant’s aboveground vegetative and reproductive tissues and can modify the soil seed bank, potentially impacting the restoration of preferred species. Knowledge about aboveground vegetation and species composition of soil seed bank and the processes that contribute to vegetation recovery on and surrounding watering points subjected to grazing is lacking. Successful restoration strategies hinge on addressing these knowledge gaps. We assessed the effects of livestock grazing on aboveground vegetation and soil seed bank characteristics along a river bank and surrounding areas subject to different grazing intensities and draw implications for restoration. Plots (50 × 50 m) were established along five transects representing differing levels of grazing intensity. Soil samples were taken from three layers within each plot to determine soil properties and species composition of soil seed bank using the seedling emergence method. Heavy grazing resulted in the disappearance of perennial grasses, a reduction in species diversity and a decrease in soil nutrients with increased soil depth. Overall, the similarity between the extant aboveground vegetation and flora within the soil seed bank was low. The soil seed bank was dominated by herbaceous species and two woody species, suggesting that many woody species are not accumulating in the soil. With increasing soil depth, the seed density and richness declined. Canonical correspondence analyses (CCAs) showed that emerged seedlings from the soil seed bank were significantly influenced by soil carbon, organic matter, total nitrogen, total potassium and soil cation exchange capacity. This finding suggests that current grazing practices have a negative impact on the vegetation surrounding watering points; hence there is a need for improved grazing management strategies and vegetation restoration in these areas. The soil seed bank alone cannot restore degraded river banks; active transfer of propagules from adjacent undisturbed forest areas is essential. [ABSTRACT FROM AUTHOR]

Accurate estimates of aboveground biomass (AGB) strongly depend on the suitability and precision of allometric models. Although additive allometric equations are expected to reduce uncertainties due to additivity property between biomass of tree components, methods for developing biomass equations do not comply with the additivity property. This study aimed to evaluate biomass allocation patterns within tree components, and to develop additive allometric equations for Combretum glutinosum and Terminalia laxiflora in West Africa. Sixty trees were destructively sampled and measured for stem, branch and leaf biomass in Sudanian savannas of Burkina Faso. Biomass allocation to stem, branch and leaf was assessed by calculating the biomass fractions for each component. Bivariate relationships between biomass fraction and diameter at beast height (dbh) were further examined. For each biomass component we tested three non-linear allometric equations based on dbh alone, and dbh in combination with height and/or crown diameter as independent variables. Seemingly Unrelated Regressions were used to fit a system of additive biomass allometric equations. Branch biomass accounted for between 60 and 70% of the AGB. Branch mass fraction increased with increasing stem diameter while a reverse trend was observed for leaf and stem mass fractions. The decline in the mass fraction was more pronounced for the leaf than the stem. Additive biomass models developed for the two species exhibited good model fit and performance, with explained variance of 68–89%. The models developed in this study provide a robust estimation of tree biomass components and can be used in Sudanian savannas of West Africa. [ABSTRACT FROM AUTHOR]

In the face of the current changes in land use and climate as well as habitat destruction, it is important to study herbaceous vegetation as an indicator of changes occurring in savanna ecosystems. We investigated the effects of climate, land use and habitat, both alone and in combination, on the diversity and occurrence of West African savanna herbaceous plant communities. Floristic data and environmental variables were sampled in Burkina Faso and subjected to ordination and indicator species analysis to explore the variation in nine vegetation types. Regression analyses showed that climate, land use, humidity gradient, soil fraction and vegetation structure discriminate herbaceous plant communities. Climate, habitat and their interaction had the greatest effect on the occurrence of these communities. Changes in species richness of the studied communities were mainly due to climate, land use and their interaction, which were more important for increasing rather than decreasing diversity. In all cases, climate conditions remained the most important environmental factor driving vegetation variation in West African savannas. Beside this, the effects of habitat degradation in interaction with land use and climatic conditions indicate land use to be a threat for the diversity of the herbaceous vegetation. [ABSTRACT FROM AUTHOR]

Herbaceous plants account for more than three-fourths of the total biomass in savanna ecosystems. However, which environmental factors mainly drive the biodiversity of herbaceous species is still under debate. In this study, we investigated the influence of climate, habitat and land use on species richness and cover in the West African savanna ecosystems of Burkina Faso. For a broader understanding, we analysed responses of the most important taxonomical groups of the herbaceous layer (Poaceae, Cyperaceae, Fabaceae s.l. and juvenile woody species) to the above mentioned environmental factors. We found light limitation by trees or shrubs and nutrient availability to be the variables that were mainly able to explain the differences in species richness, whereas precipitation and soil water-holding capacity, in general, drive species cover. However, specifically which environmental parameters influenced species richness and cover differed between taxonomical groups. Species richness of Cyperaceae species depended on water availability, while high Cyperaceae cover was found in soils with high water-holding capacity. Cyperaceae species are able to tolerate stagnant water. By contrast, Poaceae species cover was higher in dry habitats, and species richness declined with higher mean annual precipitation. Fabaceae species richness and cover were both higher in communal areas and sandy soils. This study revealed that both species richness and species cover, important aspects to describe the community composition, should be examined, as they are driven by sometimes different environmental conditions. Differentiating between the most important taxonomical groups of the savanna ecosystem increases the understanding in the important ecological processes that effect the herbaceous vegetation composition. [ABSTRACT FROM AUTHOR]

Useful woody species contribute enormously to maintain livelihoods in rural areas of West Africa and are strongly influenced by environmental conditions and human activities. To assess species-specific responses to these factors, we studied potential distributions and richness patterns of useful woody species in relation to several environmental factors in a communal and protected area in eastern Burkina Faso. We applied species distribution models, separately for adults and juveniles. While potential distributions of adults can be interpreted as the current state of the species, modeled distributions of juveniles give hints about the species' future development. Our results reveal that elevation and precipitation were the most influencing environmental factors on potential distributions of both juvenile and adult richness. Furthermore, we demonstrated that overall modeled adult richness (the same in communal and protected area) and juvenile richness (more successful in protected area) of woody species reacted differently to human disturbances. However, the fact that the responses to human activities differed widely between species and often even between adults and juveniles of the same species emphasizes the difficulty of giving simplified statements about the human impact on useful woody species. We discuss whether woody species might persist under increasing human pressure in the future. [ABSTRACT FROM AUTHOR]

Questions Which environmental variables influence grass diversity in West Africa? What are the effects of climate and grass functional traits on the spatial patterns (richness and abundance) of the grass clades Andropogoneae, Paniceae and Chloridoideae? Location West Africa, demarcated by the Atlantic Ocean in the west and south (20° W and 4° N), the Sahara desert in the north (25° N) and the border between Niger and Chad in the east (20° E). Methods Based on 38 912 georeferenced occurrence records, we modelled the distribution of 302 grass species (51% of West African grass diversity). We integrated species richness, abundance and functional traits (life cycle, photosynthetic type and height) to determine the contribution of the most speciose grass clades (Andropogoneae, Paniceae and Chloridoideae) to overall grass diversity in West Africa. Results Precipitation is the variable most often influencing the species distribution models of grasses in West Africa. Richness and relative abundance of the tribe Andropogoneae show a centre of diversity in Sudanian savanna regions. The height of Andropogoneae species, generally >150 cm, is driving this ecological dominance. Species richness of the tribe Paniceae is more dispersed and shows two main centres of abundance: The southern regions with higher mean annual precipitation and tree density are dominated by C3 Paniceae species. The Sahelian regions in the north are dominated by short Paniceae species with the C4 NAD- ME photosynthetic subtype, as well as Chloridoideae possessing the same functional attributes. Conclusions Our study provides insight into the environmental correlates of grass species richness in West Africa and contributes to the much-needed research on tropical rangelands. Moreover, the integration of evolutionary history significantly improves our understanding of large-scale biodiversity patterns. [ABSTRACT FROM AUTHOR]

To determine the resilience of soil organic C and N pools during land degradation processes in a semi-arid landscape of West Africa, we compared the magnitude of soil organic C and N differences in bulk soil and aggregate fractions between contrasting types of land cover (degraded land and native land cover) and soil (Luvisols and Cambisols). We analyzed the following soil key indicators: CEC, soil respiration, C and N contents, and δ 13 C and δ 15 N signatures of soil organic C. The average CO 2 respired from native land cover was at least 82% higher than its value from degraded land cover and was significantly higher in Luvisols than in Cambisols. Likewise, the soil organic C and N contents in bulk soil were significantly affected by land cover and soil contrasts. The average C loss in bulk soil from degraded land cover was equivalent to 49% in Cambisols and 54% in Luvisols. In both soil types, all aggregate fractions were sensitive to land degradation processes and the C loss decreased from macroaggregates to the clay + silt fraction. Compared to the native land cover, organic C loss from the macroaggregates in degraded land cover was 92% and 84%, respectively, in Cambisols and Luvisols. The soil type affected significantly the C content only in the clay + silt fraction. The C/N ratio of finer fractions (microaggregates and clay + silt) was significantly higher in degraded land cover than in native land cover, indicating greater losses of N than C during land degradation processes. The differences of δ 13 C signatures throughout C pools between the two types of land cover suggest a relative dominance of C 3 derived C in macroaggregates and C 4 derived C in the clay + silt fraction in the degraded lands. The reduction of soil respiration and the rapid N loss in degraded land cover slowed down the humification processes of C 3 plant derived materials which were effectively dominant in macroaggregates. [ABSTRACT FROM AUTHOR]

Abstract: In West Africa, plant diversity is threatened by future climate and land use change, however, synergistic forecasts for this area are lacking to date. We investigated the impact and the interplay of future (2050) climate and land use change on plant diversity in Burkina Faso, which covers the major bioclimatic gradient in West Africa. Thus, regions with different levels of species richness can be investigated. The LandSHIFT model was adapted for this study to derive novel future (2050) land use simulations. One-class support vector machines (SVMs) were performed with these land use simulations together with current and future (2050) climate projections at a 0.1° resolution. Our modeling results show that the flora of Burkina Faso will be primarily negatively impacted by future climate and land use changes. However, we found contrasting latitudinal patterns. The more humid regions in Southern Burkina Faso would be more affected in terms of species loss than the Sahel. Climate change is more important than land use change under the assumption of technological stagnation in the agricultural sector. Our results suggest that, in general, the plant diversity in dry and humid regions of the tropics might respond differently to climate and land use change. [Copyright &y& Elsevier]

Vitellaria paradoxa , the shea tree, an economically important fruit-tree species native to savanna regions is threatened in Burkina Faso due to overexploitation and changing land-use. Furthermore, it remains unclear how climate change will influence its frequency and distribution. We investigated the impact of climate change on the projected spatial distribution of favorable habitats for V. paradoxa. Species distribution modeling techniques implemented in MaxEnt combined with GIS were used to forecast the current and future distribution of V. paradoxa. We selected two climatic scenarios (RCP4.5 and RCP8.5) and two global climate models (MPI-ESM-MR and HadGEM2-ES) to encompass the full range of variation in the models. Presence records of the species were collected and linked to bioclimatic and edaphic variables. The most characteristic and least correlated variables were selected for modeling after a collinearity test. Under current climatic conditions, ~51% of the national area was found to be favorable for cultivation and conservation of the species. Under future climate projections, our models predict that favorable habitats of this species will decline by 12% (RCP4.5) and 13% (RCP8.5) by 2070. The predictive modeling approach presented here may be applied to other economically important tree species. • Vitellaria paradoxa is a multipurpose, and agroforestry tree species in West Africa. • Species occurrence records were combined with climatic and soil data in MaxEnt. • We used the IPCC's RCP4.5 & RCP8.5 emission scenario for 2050 & 2070 for our modeling. • Suitable habitats for Vitellaria paradoxa likely to decrease by up to 13.25%. • Results could be used as basis in formulating appropriate adaptation policies. [ABSTRACT FROM AUTHOR]

The soil seed bank (SSB) is an important source of resilience for plant communities subjected to disturbances. This study aimed to identify characteristics of the SSB, its relationship with aboveground vegetation (AGV), and its significance for restoration of vegetation in West African savanna-woodlands. Data were collected from two long-term factorial experiments established in 1992 in Burkina Faso to examine the long-term ecological effects of grazing, early fire, selective tree cutting on savanna-woodland ecosystem. A total of 1920 soil samples were taken from three soil layers (i.e. 0-3 cm, 3–6 cm and 6–9 cm) and the SSB was assessed using the seedling emergence technique. The emerged seedlings were dominated by non-woody taxa. Only two woody species that were Flueggea virosa and Mitragyna inermis emerged, showing that woody species feature little in the SSB. The SSB density and richness decreased significantly with soil depth. Non-metric multidimensional scaling (NMDS) ordination indicated a lack of correspondence between the AGV and SSB. The results suggest site-specific responses to disturbance also following long-term disturbance, the SSB will be ineffective in regenerating the remnant vegetation of West African savanna-woodlands. Hence, ensuring the resilience of West African savanna woodland ecosystems will require targeted introductions (i.e. planting and seeding) of indigenous species and a reduction in on-going disturbances. • Soil seed bank (SSB) is an important source of resilience for plant communities subjected to frequent disturbances. • Resilience of savanna-woodland ecosystems will require targeted introduction of indigenous species and a reduction in on-going disturbances. • Evaluation of size and composition of SSB in savanna-woodlands that are annually disturbed could guide active restoration measures. • Long-term prescribed fire, grazing and selective tree cutting induced the relative abundance of annual herbaceous species in the SSB community. [ABSTRACT FROM AUTHOR]

Reliable estimates of carbon stocks for drylands are constrained by a limited number of biomass models for predicting accurately the biomass of dominant tree and shrub species. In this study, 119 trees with a diameter at breast height (dbh) between 3.82 and 45.48 cm were destructively sampled to evaluate aboveground biomass (AGB) allocation and prediction for four dryland species (Senegalia dudgeonii , Senegalia gourmaensis , Vachellia nilotica and Vachellia tortilis) commonly found in the Sudanian and Sahelian zones of Burkina Faso. Biomass allocation to leaf, branch and stem was examined using a classmometric analysis. Allometric equations relating biomass to dbh alone, and to dbh in combination with height and/or crown area were developed with and without consideration of the additivity property. Branches stored the largest (up to 90%) proportion of AGB. For three of the species, the branch mass fraction increased with increasing tree size at the expense of stem and leaf mass fractions. The statistical evaluations of the selected additive and non-additive models were satisfactory with no severe deficiencies. Diagnostics of model performance revealed that non-additive models performed better than additive models. The biomass models developed can be used for improved quantification of carbon stock and dynamics in dry savanna ecosystems. • Additive and non-additive biomass models were developed for four dryland woody species • Biomass allocation influenced the predictive ability of allometric equations • Branches were the tree component with the largest share (up to 90%) of aboveground biomass • Consideration of tree architectural variables improved models' predictions • Mixed-species equations provided reliable species-specific biomass estimations [ABSTRACT FROM AUTHOR]

The safeguarding and sustainable management of natural resources, particularly plant resources, requires the implementation of conservation strategies. The study of plant communities is an essential tool for monitoring the development of plant formations. The aim of this study was to identify the plant communities on inselbergs of Burkina Faso in West Africa, to provide a database to supporting the sustainable management of the plant resources withing these fragile ecosystems. Stratified and random sampling was carried out on selected inselbergs in different parts of Burkina Faso along a climatic gradient. In the different phytogeographical sectors, inselbergs consist of granite or sandstone. Plant surveys were conducted using 900 m 2 plots for the woody stratum and 100 m 2 plots for the herbaceous stratum. An exhaustive list of plant species was compiled and an abundance-dominance coefficient for each species was determined. A DCA, through PCord.6, was used to obtain preliminary groups. Indicator species were determined by a Monte Carlo test with p < 0.05 and calculation of the fidelity index (Phi). Diversity indices through the Shannon index and equitability of Pielou were calculated using Pcord.6 to compare plant communities. A total of 12 plant communities were identified for the inselbergs of Burkina Faso, including 9 communities for savannah and 3 communities for monocotyledonous-mats and ephemeral flush vegetation. The main ecological factors governing the distribution of these inselberg plant communities were found to be were found to be climate, soil depth, soil moisture and altitude. In savannah plant communities, the Terminalia laxiflora and Tephrosia nana communities (unit 6) had the highest number (13) of diagnostic species and the highest fidelity (Phi = 0.97) was for Cleome viscosa species in the Acacia tortilis and Aristida kerstingii communities (unit 1). Diagnostic species numbers vary from 6 to 4 in monocotyledonous-mats and ephemeral flush vegetation and the Dopatrium longidens (Phi = 0.76) and Cyperus podocarpus (Phi = 0.75) have the highest fidelity to unit 3. The Shannon diversity index of deep soil plant communities was highest and significantly different from that of the other savannah communities. Concerning the Piélou equitability index, high values were found in all plant groups, reflecting the absence of species dominance and a balance of the different plant groups. Floristically, Afrotrilepis pilosa infestation of inselbergs is common in West Africa. In Burkina Faso, in addition to Afrotrilepis pilosa , 10 other plant species are found specifically on inselbergs. Given the fragility of the ecosystems in which they live, these inselberg species should be protected., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Urban and peri-urban forests greatly contribute to the well-being of urban dwellers in West Africa. However, increasing urban densification and spatial expansion negatively affect the functioning of urban ecosystems. Therefore, highlighting the negative impacts of land use change on the ecological attributes of urban landscapes is fundamental for sustainable urban planning. This study aimed to assess the impacts of land use on woody species diversity, structure and carbon storage in peri-urban areas in Burkina Faso. Forest inventories were conducted in 167 plots across two peri-urban forests and their adjacent agroforestry systems. We found a total diversity of 91 woody species representing 69 genera and 26 families. Diversity indices were significantly higher (p-value < 0.0001) in the peri-urban forests than in the agroforestry systems, highlighting a negative impacts of land use on tree diversity. Besides, peri-urban forests had significantly lower tree diameter (15.749 ± 9.194 cm), but higher basal area (5.030 ± 4.407 m 2 . ha -1 ) and denser stands (317.308 ± 307.845 ind. ha -1 ) compared to the agroforestry systems. Tree aboveground biomass was significantly higher (p-value < 0.0001) in the peri-urban forests (18.198 ± 23.870 Mg. ha -1 ) than in the agroforestry systems (7.821 ± 6.544 Mg. ha -1 ). Multivariate analyses revealed that denser stands hold higher diversity in peri-urban areas, and that stand basal area mostly drives carbon storage than tree density and diversity. These findings highlight the potential of peri-urban forests to conserve plant biodiversity and mitigate climate change. The study advocates for a sustainable urban land use and planning., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

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., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

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., Competing Interests: The authors declare no conflict of interest., (© 2021 The Author(s).)

Balanites aegyptiaca (L.) Delile is native to semi-arid regions in Africa where it is a well-known and conspicuous component of savannas. The species is highly preferred by local people because of its high socio-economic, cultural and ecological values. However, the species faces multiple environmental challenges such as desertification and human pressure. This study aimed to develop allometric models to predict aboveground biomass (AGB) of B. aegyptiaca in two climatic zones in Burkina Faso. Overall, thirty trees were sampled using destructive method in six study stands along two climatic zones. We assessed the biomass allocation to the different components of trees by computing its fraction. Furthermore, allometric models based on diameter at breast height (dbh) and basal diameter at 20 cm height (D 20 ) were fitted separately as well as combined with crown diameter (CD) and/or tree total height (Ht). For each biomass component, non-linear allometric models were fitted. Branch biomass accounted for 64% of the AGB in the two climatic zones and increased with dbh. No significant difference in carbon content was found. However, biomass allotment (except leaves) varied across climatic zones. Although both dbh and D 20 are typically used as independent variables for predicting AGB, the inclusion of the height in the equations did not significantly improve the statistical fits for B. aegyptica. However, adding CD to dbh improved significantly the equations only in the Sudano-Sahelian zone. The established allometric models can provide reliable and accurate estimation of individual tree biomass of the species in areas of similar conditions and may contribute to relevant ecological and economical biomass inventories., (© 2020 The Author(s).)

Background: The W National Park and its two hunting zones represent a unique ecosystem in Burkina Faso for biodiversity conservation. This study aims at providing a detailed view of the current state of the floristic diversity as a baseline for future projects aiming at protecting and managing its resources. We combined intensive inventories and distribution records from vegetation plots, photo records and herbarium collections., New Information: This is the first comprehensive checklist of vascular plants of the Burkina Faso part of the transborder W National Park. With 721 documented species including 19 species new to Burkina Faso, the Burkina Faso part of the W National Park is, so far, the nature reserve with most plant species in Burkina Faso. To a large extent, this may be assigned to its high habitat diversity and moderate degree of disturbance, but also to a relatively large area within an even larger complex of neighbouring protected areas, as well as comprehensive spatial, ecological and seasonal sampling efforts. However, as a World Heritage Site and regarding the current general context of insecurity, the W National Park and the entire WAP Complex require more international attention in order to ensure its conservation., (Blandine M. I. Nacoulma, Marco Schmidt, Karen Hahn, Adjima Thiombiano.)

Efforts to develop allometric models for accurate estimation of biomass and carbon sequestration in Sub-Saharan African savanna ecosystems remain inconclusive. Most available allometric models are not site-specific, and hence do not account for the effects of regional climate variabilities on tree growth and capacity to sequester carbon. In contrast, site-specific biomass allometric models constitute a robust tool for forest and carbon emission management in the context of the reducing emissions from deforestation and degradation program (REDD+). Although site-specific models have been developed for several tropical tree species, such models do not exist for Pterocarpus erinaceus in Burkina Faso. In this study, we investigated biomass fraction patterns and used a system of additive allometric models for predicting aboveground biomass and carbon stocks of P. erinaceus components. Thirty P. erinaceus trees were destructively sampled to estimate the biomass of their stems, branches and leaves. The biomass fraction of each component was assessed and its relationship with tree diameter at breast height (dbh) examined. The best allometric equations of the tree components, selected from three non-linear models with dbh, height (ht) and crown diameter (C d ) as predictors, were combined to develop an additive allometric model, using the Seemingly Unrelated Regressions (SUR) method. The Ash method was then used to estimate the carbon content of the different components. Leaf and stem biomass fractions decreased when the dbh increased, whereas a reverse trend was observed for branch biomass. Dbh was the most correlated independent variable with all biomass components. AGB = e -3.46 (dbh) 1.62 +e -2.45 (dbh) 2.31 +e -2.68 (dbh) was the most appropriate additive allometric equation for estimating the biomass of P. erinaceus trees. The carbon content of the leaves, branches and stems was 55.73%, 56.68% and 56.23%, respectively. The developed allometric equations can be used to accurately estimate the aboveground biomass of P. erinaceus in the savannas of Burkina Faso and other similar ecosystems in Sub-Saharan Africa., (© 2020 The Author(s).)

Anthropogenic and climatic factors are important determinants of algal distribution in aquatic systems. This study aimed to identify temporary pond-groups of phytoplankton assemblages and to establish the interactions between environmental variables and phytoplankton structure. Phytoplankton samples were collected and preserved with 5% formalin; water samples for chemical analysis were taken in August and September 2007, 2008, and 2009 in 86 ponds randomly selected in the Sahelian sector and the Sudanian sector (protected and unprotected areas) of Burkina Faso. Plankton species were examined using light microscopy and identified using standard methods. A Fuchs-Rosenthal chamber was used for algal cell counting. NMDS ordination, indicator species analysis and canonical analysis were performed using Pc-Ord and CANOCO. Kruskal-Wallis and Mann-Whitney U-tests using the software Statistica were performed to compare parameters between pond-groups. Three pond-groups were identified: the Sahelian pond-group, dominated by Lyngbya martensiana and Pseudanabaena constricta; the protected area pond-group, dominated by Euglena caudata and Trachelomonas raciborskii; and the unprotected area pond-group, dominated by Closterium venus and Euglena proxima. At P < 0.05, species composition and abundance in algal groups were mostly associated with nitrate, pH, dissolved oxygen, and conductivity. The Sahelian and the Sudanian sectors were different in pH, water transparency, and species richness. Univariate and multivariate analyses illustrate that variations in the physicochemical properties of water and algal structure followed climatic and anthropogenic gradients. The classification of ponds into algal associations demonstrated that algal assemblages may be used as reliable indicators of habitat conditions., (© 2019 Phycological Society of America.)

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.