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.
Human disturbance on vegetation is an important concern in biodiversity conservation. In this study we assessed how anthropogenic disturbance affected plant communities pattern, diversity, life form and chorotype composition along a land use gradient. Vegetation relevés were performed along a land use gradient (park-buffer zone-communal land) at W Biosphere Reserve in Benin. Non-metric multidimensional scaling (NMS) was used to assess plant communities patterns. Indicator species were determined for each plant community and land use. Plant community diversity, life forms and chorotypes composition were assessed and compared among land uses using one-way analysis of variance. NMS ordination showed a good separation between relevés of the park and those from the communal land while relevés of buffer zone were mixed within the park and communal land relevés. There was no significant difference between species richness among land uses types (F = 0.68; p = 0.529, ANOVA test at a level of significance of 5%). The Pielou evenness for the plant communities was higher in the park (E= 0.69±0.04) and buffer zone (E = 0.61±0.13) than in the communal lands (E = 0.44±0.02) while Shannon index showed no clear pattern along land use gradient. Therophytes abundance was significantly higher in the communal land while hemicryptophytes abundance was significantly higher in the park. Wide-distributed species abundance was significantly higher in the communal land whilst Sudanian species showed significantly higher abundance in the park. We concluded that monitoring of the indicator species of the plant communities and their traits are relevant tools for managers to follow-up changes in plant communities.
Résumé Cette étude constitue un travail préliminaire à la mise en place de techniques d'amé-nagement, de conservation des eaux et des sols, de défense et de restauration des sols en zone soudanienne (pluviométrie moyenne annuelle de 1 000 mm). Les res-sources ligneuses du bassin-versant du Kou subissent une dégradation accélérée. Pour la contrer, une caractérisation pédologique fine du sol, la description des états de surfaces par la méthode dite line-intercept et un inventaire exhaustif de la végétation ont été réalisés. Les résultats révèlent l'existence de quatre types de sols. L'étude des surfaces élémentaires a montré que seulement 40,7 % des superficies du site pourraient être favorables à l'infiltration. La végétation ligneuse se compose pour l'essentiel de Caesalpiniaceae, de Combretaceae, de Rubiaceae, d'Annona-ceae et de Mimosaceae. La tendance évolutive de la végétation ligneuse s'est révé-lée positive dans toutes les parcelles, ce qui laisse présager des possibilités de restauration assez rapides.
An EU-funded project, SUN, gathered local and international expertise to create a framework for vegetation management in west Africa. Improved interaction between scientists and stakeholders promises to prevent further deterioration of valuable ecosystems. Permalink: http://cordis.europa.eu/result/rcn/89812_en.html
Question: How can quantitative data from vegetation surveys best be assembled in a large regional vegetation database? What effects have intellectual property rights concerns of individual and institutional data holders on data contribution and how can incentives to contribute data be generated? Location: West Africa, with discussion of a possible approach to dealing with property rights concerns being of wider interest. Methods: The management of data property rights in the West African Vegetation Database was developed based on consultations with institutions and scientists in five West African countries over 2 years. It was agreed in two successive Memoranda of Understanding. Results: The West African Vegetation Database addresses property rights concerns by leaving the control over data access with the data owners, and provides incentives to build a distributed research community by fostering data sharing. Conclusion: We present a potential solution to the problem of intellectual property rights issues being an impediment to data sharing and the compilation of large regional vegetation databases. The data property rights management approach implemented in the West African Vegetation Database provided incentives for the contribution of recently acquired and unpublished data. Numerous phytosociological and dendrometric vegetation surveys have been made available by institutions and individual researchers for regional-scale analyses. The structures developed may serve as a model for regional-scale vegetation databases in collaborative settings involving multiple data owners. Schmidt, M.
Land degradation is a major issue in the West African Sahel for human livelihoods. A better understanding of soil and water conservation practices‟ effects on soil nutrients is necessary for their further development. A study was conducted on encrusted sealed bare Luvisols in Central and Northern Burkina Faso to assess the effects of half-moon (HM), sub-soil tillage (ST) and zaï system (Zaï) on soil physical, chemical and biological proprieties. Soil texture was significantly affected by techniques resulting in fines particles particularly in HM system and in ST in a lesser extend. HM technique followed by ST and Zaï, contribute significantly to enhance total organic carbon, total nitrogen, calcium, magnesium, phosphorus and soil pH as well as soil microbial biomass and basal respiration. Soil microbial biomass and basal respiration were significantly (p<0.05) correlated with clay fraction, Soil Organic Carbon (SOC), total N, pH and calcium. These results suggest that the techniques alter soil nutrient and that SOC, pH and phosphorus are mitigating factors that affect the microbial activities. Among the studied techniques, HM system proved to be better in terms of enhancing soil proprieties. Therefore, it may serve as a useful and inexpensive approach to rapidly reclaim degraded soils.
Land degradation is a major issue in the West African Sahel for human livelihoods. A better understanding of soil and water conservation practices‟ effects on soil nutrients is necessary for their further development. A study was conducted on encrusted sealed bare Luvisols in Central and Northern Burkina Faso to assess the effects of half-moon (HM), sub-soil tillage (ST) and zaï system (Zaï) on soil physical, chemical and biological proprieties. Soil texture was significantly affected by techniques resulting in fines particles particularly in HM system and in ST in a lesser extend. HM technique followed by ST and Zaï, contribute significantly to enhance total organic carbon, total nitrogen, calcium, magnesium, phosphorus and soil pH as well as soil microbial biomass and basal respiration. Soil microbial biomass and basal respiration were significantly (p<0.05) correlated with clay fraction, Soil Organic Carbon (SOC), total N, pH and calcium. These results suggest that the techniques alter soil nutrient and that SOC, pH and phosphorus are mitigating factors that affect the microbial activities. Among the studied techniques, HM system proved to be better in terms of enhancing soil proprieties. Therefore, it may serve as a useful and inexpensive approach to rapidly reclaim degraded soils. Keywords: Land reclamation; Soil properties; Microbial activity; Soil erosion; Vegetation cover.
This study aims to assess population structure and ecological indicators of woodland vegetation dominated by Pterocarpus erinaceus and Anogeissus leiocarpa as a basis for sustainable management and conservation strategies. We sampled 34 plots each measuring 30 m × 30 m in W National Park in Niger and analyzed structural parameters (tree density, basal area, Lorey's mean height and size class distribution) and ecological indicators (species richness, Shannon diversity index, Pielou evenness index and Importance Value Index) of woodland in general and for the two key species. Mean tree density was 752.6 stems/ha and basal area was 24.5 m²/ha in woodlands including 145.4 stems/ha and 14.1 m²/ha for A. leiocarpa and 3.3 stems/ha and 0.7 m²/ha for P. erinaceus. The woodland was composed of 59 tree species belonging to 34 genera and 17 families. A. leiocarpa had the highest IVI value (0.93), whereas P. erinaceus was among the species with the lowest IVI value (0.03). The mean diameter of both species was higher (24 cm and 47 cm for A. leiocarpa and P. erinaceus respectively) than the mean diameter in woodlands (16 cm). A “reverse J” shape distribution was found for woodland in general and for A. leiocarpa, but P. erinaceus showed a left dissymmetric distribution. Findings of this study showed that urgent actions are needed for sustainable management and conservation of some key species especially P. erinaceus.
Burkina Faso is a landlocked country in the sahelo-sudanian savanna belt of West Africa. Comprehensive data from herbarium collections, field surveys and literature have been assembled and digitised in our studies on plant diversity in West Africa conducted in the course of the BIOTA project. An important product is the “Checklist of the vascular plants of Burkina Faso”. The checklist is nearly completed, comprises 1630 species and allows us to analyse the composition of the Flora with respect to taxonomic and functional groups, distribution types and frequency. Angiosperms outnumber other groups by far. Gymnosperms are completely absent from Burkina Faso, the few pteridophytes are mostly aquatic, such as the genera Marsilea, Azolla and Isoetes or prefer humid habitats like Selaginella. The most species rich families are Poaceae, Fabaceae and Cyperaceae. Probably their adaptations to high light intensity, dryness and N-deficiency, such as C4-metabolism and root nodules constitute an advantage to other groups under the environmental conditions of the West African savanna belt. The most important life forms are therophytes and phanerophytes, each contributing about a third of all species. While therophytes are most important in the Sahel, phanerophytes take over towards the Guinean Zone. Sudano-zambesian species are the most common chorological type, nevertheless guineo-congolian elements reach Burkina Faso e.g. in gallery forests. About 15% of vascular plants in Burkina Faso make use of C4 photosynthesis. Most of the known C4 plants are grasses. The flora of Burkina Faso is determined by a strong seasonality with a long dry season. This is reflected in the composition of taxa and life forms as well as chorological types.
West Africa is a floristically understudied region that is facing severe environmental changes in the 21st century. Basic distribution data and information on the conservation status for most plant species of the region are scarce, and good information only exists for small areas of interest or for key species. This lack of knowledge seriously hampers urgently needed regional conservation efforts. Here we present comprehensive distribution information and preliminary, automated species conservation assessments for the flora of Burkina Faso, a country in tropical West Africa with a flora and vegetation typical for the savanna belt of the region. We documented and analysed the distribution of 1,568 species or 80% of the flora of Burkina Faso based on an expert curated dataset comprising ca. 150,000 occurrence records from herbarium specimens and vegetation surveys. We used this dataset and environmental niche models to calculate three indicator variables for a preliminary, automated conservation assessment. We classified 350 species (18% of the flora, excluding introduced species) as potentially "Critically Endangered", "Endangered", "Vulnerable" or "Near-Threatened" on the national level. The analyses confirmed species-rich areas in the south-west and south-east of the country, and showed a particular concentration of potentially Endangered species in the south. Furthermore, the proportion of potentially Endangered species differed between plant families, growth forms and habitats. Our results set the base for further plant geographical and ecological studies and are a data-driven baseline for further conservation assessments and large scale conservation strategies of the West African flora.
Introduction Poaceae is by far the most important plant family in the African Savanna regions which cover 65% of the continent. The family has been shown to be a good predictor of total plant diversity for the Sahelo-Sudanian region (Schmidt & al. 2007). In the course of studies on coevolution of savanna grasses and large herbivores, the distribution of grasses in West Africa (fig. 2) is analysed in a cooperation of CIRAD, Montpellier, University of Ougadougou and Senckenberg Research Institute. The results presented here are based on observation data (“FloTrop” contributed by CIRAD, Montpellier, and “VegDa”, a vegetation database with data from University Ouagadougou and Senckenberg Research Institute). Altogether, 93,787 observations of grass distribution have been included. Based on these data, distribution areas for 471 grass species have been modelled and combined to analyse overall grass diversity and the distribution of plant functional, physiological and morphological types. Material • 471 grass species (Poaceae) • 10,678 relevé sites (25°N to 0°, 20°W to 20°E; see Fig. 1) • 80,328 occurrence data Methods • Nomenclature was checked against the African flowering plants database (www.ville-ge.ch/musinfo/bd/cjb/africa/) • Morphological data was extracted from GrassBase (/www.kew.org/data/grasses-db/ident.htm) • Worldclim layers 2.5’ (annual precipitation; precipitation of June and September; maximum temperature of June and September; minimum temperature of February) (www.worldclim.org/) • MaxEnt 3.3.1, regularization maximiser set to 3 • Predicted distribution for individual species have been summarized into ASCII files using a VBA script Results and Discussion As could be expected, our model predicts (Fig. 3) the highest grass diversity in the Sudanian zone of West Africa, with sharply decreasing diversity towards the more arid Sahelian zone in the North and the (originally) forested areas in the Southwest and Southeast. The “Dahomey gap” and adjacent areas to the West are identified as highly diverse in grass species. The area of Guinean rain forests stands out as poor in grass species, nevertheless, this may be an artefact due to scarce data from this area. Because data on morphology, functional and photosynthetic types were not available for every species, the distribution maps are based on a smaller sampling. Fig. 4 compares predicted diversity of annual (4A) and perennial grasses (4B). Areas of highest diversity for annuals are located further north, extending far into the Sahelian region. Fig. 5 compares predicted diversity for C3 and C4 grasses. C4 grasses are less abundant in forested areas and at higher altitudes. Perspectives • Include specimen data to overcome biases of observation data (Schmidt & al., in press) Model potential distributions under different scenarios • of climate change • Focus on two important savanna grasses genera, Andropogon and Hyparrhenia
The Fifth International Workshop on the Analysis of Multi-temporal Remote Sensing Images,
The West African Vegetation Database is an online database that has been designed to securely store, edit and manage phytosociological and dendrometrical relevés from West Africa to provide data for research projects dealing with, but not limited to, plant communities, biogeography, population structure, and vegetation dynamics.
An approach for commercialising a product from Parkia biglobosa in order to improve the economic situation of rural women in southwestern Burkina Faso was explored. Income is generated from sales of a derivative from the fermented seeds called soumbala. About one fifth of the women (18%) were involved in the sale of soumbala, and 34% of those not participating in soumbala sales were interested in getting involved, suggesting that there is a basis for expanding the soumbala trade. Possible factors that could motivate more women to participate in soumbala sales were sustainability, sowing of seeds and amount of seeds harvested per year. In addition, 90% of the informants managed Parkia sustainably, suggesting that enhanced exploitation of Parkia for commercial purposes can be ecologically sustainable if present management techniques are maintained. The results suggest that Parkia have a potential to improve the economic situation of women through increased production and sale of soumbala.
RÈSUMÈ: La présente étude est une contribution à la connaissance des plantes médicinales et des recettes médicamenteuses chez l'ethnie Goin dans la région de Niangoloko, au sud-ouest du Burkina Faso. A partir d'enquêtes semi-structurées, cinq tradithérapeutes ont été interrogés sur les plantes qu'ils utilisent. Cent trente quatre recettes médicamenteuses faites à partir de 106 espèces médicinales ont été recensées. Dix espèces nouvelles pour la flore du Burkina Faso, ont été enregistrées. Ces espèces médicinales sont réparties dans 98 genres et 46 familles dont les plus représentées sont les Fabaceae (12 espèces), les Caesalpiniaceae (6 espèces), les Combretaceae (6 espèces) et les Rubiaceae (6 espèces). Les maladies ou symptômes fré-quemment cités sont l'asthénie, le paludisme, les inflammations, les plaies et les hémorroïdes. SUMMARY: This study is a contribution to the knowledge of the medicinal plants and herbal remedies of Goin ethnic group in Niangoloko region, in the southwest of Burkina Faso. By semi-structured interviews, five healers were questioned about the medicinal plants they use; 134 herbal remedies made from 106 medicinal species were described, 10 of them were listed for the flora of Burkina Faso for the first time. These medicinal species belong to 98 genera and 46 families. The most represented families are Fabaceae (12 species) Caesalpiniaceae, Combretaceae, and Rubiaceae (jeweils 6 species). Diseases or symptoms frequently cited are asthenia, malaria, inflammations, wounds and hemorrhoids.
Research on conservation and sustainable management of natural resources in West Africa depends on the availability of species occurrence data with good spatio-temporal coverage. Observation data is especially important in this context, because it is widely available in African research institutions and can complement rare species bias in collections-based data. Observation data is, however, often unpublished and frequently not archived at an institutional level. A database providing researchers with an overview of existing observation data is highly desirable, because it will help to avoid redundant data collection, promote the closure of data gaps and create research synergies. In order to provide incentives for data contribution, such a database must be perceived by researchers and institutions as a user-friendly tool perfectly integrating with their work flow. It must address data property rights concerns, allow researchers to work offline as well as online and provide added value for data management. The West African Vegetation Database (online) stores relevé data, i.e. lists of species observed on a given surface at a given time including or not cover or dendrometric data. It closely integrates with the MS Access database VegDa 3.0 (offline), includes a data property rights management system and offers the advantages of data security, standardisation as wells as powerful search and sharing functions.
West Africa, like many other regions in the tropics, is lacking detailed plant diversity information. Therefore we have used our collection and observation databases to search for possible indicator groups. Digitization of specimen label data for Burkina Faso from the Herbarium Senckenbergianum (FR) and the Ouagadougou University Herbarium (OUA) led to a database including 18,000 specimens. Field observations from about 3,700 relevés (Braun-Blanquet method, BIOTA standard relevés, simple inventories) were added to the database and together used to model potential species distributions for Burkina Faso on a ten minute grid. Genetic Algorithm for Rule-set Production (GARP) was used with temperature, precipitation, humidity and elevation data. Based on these modeled distributions, overall vascular plant diversity is correlated to the diversities of the ten most common families (Poaceae, Fabaceae, Cyperaceae, Rubiaceae, Combretaceae, Euphorbiaceae, Mimosaceae, Asteraceae, Caesalpiniaceae, Malvaceae). Poaceae and Fabaceae turned out to be the most suitable taxa. The value of these families as indicators for assessing biodiversity is discussed. The results are compared to similar analyses based on relevés only.
In the course of the international BIOTA (Biodiversity Monitoring Transect Analysis) West Africa project we have built up a large specimen-based database (over 20,000 specimens) as well as one for observation data for Burkina Faso (about 100.000 records from 4,596 relevés). These data are analysed to pinpoint advantages and disadvantages of both sets, comparing representation of rare vs. common species and selected families. Our results confirm biases for both data types and give evidence for using a combination of both for modelling approaches.
During the last decades ecological conditions in West Africa have dramatically changed. Very evident is the climate change, which has resulted in a southward shift of the climate zones, e.g. a spread of the desert (Sahara) into the Sahelian zone. After the drought period of the early 1970s and 1980s, livestock density increased resulting in an intensification of grazing pressure. This anthropogenous phenomenon leads to similar landscape changes as those caused by the climate. Only very few investigations exist on vegetation dynamics, climate changes and land use changes for the Sudanian zone. The paper presents data on changes of precipitation, of land use, of the geographical range of species, and of the composition of the flora, which have to be regarded as proofs of the sahelisation of large areas of the Sudanian zone. Area of investigation: Burkina Faso. Precipitation data analysis: precipitation data from 67 stations; time series analysis and geo-statistical spatial interpolation. Analysis of land use change: Landsat satellite MSS and ETM+ data, acquired for two different dates between 1972 and 2001 analyzed by the software ERDAS/IMAGINE version 8.6 and ArcView 3.2 with the Spatial Analyst extension. Intensive ground truthing (160 training areas). Inventory of the flora: based on the data of the Herbarium Senckenbergianum (FR) in Frankfurt, Germany, and of the herbarium of the university of Ouagadougou (OUA), Burkina Faso, as well as on various investigations on the vegetation of Burkina Faso carried out in the years 1990 to 2005 by the team of the senior author. Life form analysis of the flora: based on the inventory of permanent plots. Precipitation: Remarkable latitudinal shift of isohyets towards the South translates to a general reduction of average rainfall in great parts of the country. The last decade (1990-1999) shows some improvement, however, the more humid conditions of the 1950's and 1960's are not yet established again. Landcover change: In the study region the extent of arable fields and young fallows increased during the last 30 years from 580 km(2) in 1972 to 2870 km(2) in 2001. This means an average land cover conversion rate of 0.9% per year for the 6 departments considered. Change of the distribution of Sahelian and Sudanian species: Several species, mentioned in older literature as strictly Sahelian, today also occur in the Sudanian zone. Parallel to the spread of former strictly Sahelian species into the Sudanian zone, some former Sahelo-Sudanian species have withdrawn from the Sahel. Changes of the life form spectra of the flora: Considering their life form spectra, the flora of heavily grazed and of protected areas in the Sudanian zone show great differences. On areas intensively grazed the percentage of therophytes is evidently higher than on protected areas. Just the opposite is true for the phanerophytes. Their percentage is higher on the protected area than on the grazed zones. At the first glance, it is obvious to link the changes in flora and vegetation with the climate changes that have occurred during the last five decades (decrease of annual precipitation). However, not only climatic conditions have changed, but also population has increased, the percentage of land intensively used for agriculture and pasturing has increased and the time for soil regeneration today is much shorter than it was some decades ago. Thus, the landscape of the Sudanian zone has become a more Sahelian character. A comparison of the flora of an intensively used area of the Sudanian zone with that of a protected area shows a remarkable change in the life form spectra. The spectrum of the intensively used area is almost identical with that of the typical Sahelian flora. This comparison shows that the anthropogenic influence plays a greater role in the sahelisation of the Sudanian zone than the climate change. Climate change and anthropogenic influence both, lead to a sahelisation of landscape and flora. Thus in many parts of the Sudanian zone of West Africa sahelisation phenomena will remain and even increase independently from the reestablishment of the more humid climate conditions of the 1950ies. In order to maintain some parts of the characteristic Sudanian landscape with its characteristic flora and vegetation, the number and size of protected areas should be augmented. For all protected areas it has to be ensured, that protection is reality, i.e. respected an understood by local people, not only fiction. As long as the enlargement of intensively used areas continues the sahelisation of flora, vegetation and landscape will continue too.