Fidèle Bognounou

Woody species composition, diversity and structure of riparian forests of four watercourses types in Burkina Faso

Riparian forests are classified as endangered ecosystems in general, particularly in sahelian countries like Burkina Faso because of human-induced alterations and civil engineering works. The modification of this important habitat is continuing, with little attention being paid to the ecological or human consequences of these changes. The objective of this study is to describe the variation of woody species diversity and dynamic in riparian forests on different type of watercourse banks along phytogeographical gradient in Burkina Faso. All woody species were systematically measured in 90 sample plots with sides of 50 m × 20 m. Density, dominance, frequency and species and family importance values were computed to characterize the species composition. Different diversity indices were calculated to examine the heterogeneity of riparian forests. A total of 196 species representing 139 genera and 51 families were recorded in the overall riparian forests. The species richness of individuals with dbh ≥ 5cm increased significantly from the North to the South along the phytogeographical gradient and varied significantly between the different types of riparian forests. Similarity in tree species composition between riparian forests was low, which indicates high beta diversity and reflects differences in habitat conditions and topography. The structural characteristics varied significantly along the phytogeographical gradient and between the different types of riparian forests. The diameter class distribution of trees in all riparian forests showed a reverse “J” shaped curve except riparian forest of stream indicating vegetation dominated by juvenile individuals. Considering the ecological importance of riparian forest, there is a need to delineate and classify them along watercourses throughout the country.

Regeneration of five Combretaceae species along a latitudinal gradient in Sahelo-Sudanian zone of Burkina Faso

Abstract• Seedling density and the regeneration mechanisms of five tree species, Anogeissus leiocarpa, Combretum aculeatum, Combretum micranthum, Combretum nigricans, and Pteleopsis suberosa were investigated in relation to latitudinal gradient across the Sahelo-Sudanian zone of West Africa.• Data were collected on 461 quadrats (2 m × 5 m) laid out every 30 m on transect lines through Combretaceae communities at four latitudinal positions. Regeneration mechanisms were determined by excavating the below ground root system and assessing basal and aerial sprouts.• The results showed a significant species × latitudinal position effect on the total density of seedling populations, and the density of single- and multi-stemmed individuals (p < 0.001). C. aculeatum and C. micranthum were abundant in the North-Sahelian sector, C. nigricans and P. suberosa in the Sudanian sector and A. leiocarpa across a wide range from the South-Sahelian to South-Sudanian sectors. In general, 58% of the seedlings were regenerated asexually (as coppice, water sprout, layer, and root sucker) while 42% were sexual recruits (as true seedling and seedling sprouts). The proportion of vegetatively propagated seedlings increased with increasing latitude for all species except C. micranthum, for which a clear decreasing trend was observed. The relative importance of the different regeneration mechanisms varied among species: seedling sprouts were important for A. leiocarpa, C. aculeatum and C. nigricans, coppice for C. micranthum and sucker for P. suberosa• The significant interaction observed between species and latitudinal position highlights the importance of accurate species-site matching to ensure successful restoration of degraded areas in the Sahelo-Sudanian zone. Inter-species differences in regeneration mechanism could be related to their biology and ecological adaptation to the site-specific biotic and abiotic factors.Résumé• La densité de semis et les mécanismes de régénération de cinq espèces d’arbres, Anogeissus leiocarpa, Combretum aculeatum, Combretum micranthum, Combretum nigricans, et Pteleopsis suberosa ont été étudiés par rapport au gradient latitudinal dans la zone sahélo-soudanienne de l’Afrique occidentale.• Les données ont été recueillies sur 461 quadrats (2 m × 5 m) disposés tous les 30 m sur des lignes de transects à travers les communautés de Combretaceae dans quatre positions latitudinales. Les mécanismes de régénération ont été déterminés par l’excavation du sol en dessous du système racinaire et par l’évaluation des pousses basales et aériennes.• Les résultats ont montré l’importance de l’effet position latitudinale × espèces sur la densité totale des populations de semis, et la densité des individus à fût simple ou multiples (p < 0,001). C. aculeatum et C. micranthum étaient abondants dans le secteur nord-sahélien, C. nigricans et P. suberosa dans le secteur Soudanien et A. leiocarpa dans une large aire du secteur Sud-sahélien au secteur sud-soudanien. En général, 58 % des plants ont été régénérés par voie végétative (taillis, gourmands, marcottes et drageons), alors que 42 % étaient des recrues sexuées (vrais semis et baliveaux). La proportion de jeunes plants issus de la multiplication végétative s’est accrue avec l’augmentation de la latitude, pour toutes les espèces, sauf C. micranthum, pour laquelle une tendance claire à la baisse a été observée. L’importance relative des différents mécanismes de régénération a varié selon les espèces: les baliveaux sont importants pour A. leiocarpa, C. aculeatum et C. nigricans, les taillis pour C. micranthum et les drageons pour P. suberosa.• L’interaction significative observée entre les espèces et la position en latitude met en évidence l’importance de veiller à une bonne correspondance des espèces et des sites pour assurer le succès de la restauration des terres dégradées dans la zone sahélo-soudanienne. Des différences interspécifiques dans les mécanismes de régénération pourraient être liées à leur biologie et à leur adaptation écologique aux spécificités stationnelles des facteurs biotiques et abiotiques.

Impact of disturbance from roadworks on Pteleopsis suberosa regeneration in roadside environments in Burkina Faso, West Africa

The seedling population structure of Pteleopsis suberosa and their regeneration mechanisms were investigated in four roadside environments (graded, adjacent, intermediate and ungraded areas) along paved and unpaved roads in West Africa. A total of 203 quadrats of 2 m × 5 m in size were surveyed and placed along transects parallel to the roads. Within each quadrat, the total number of seedlings and the number of living shoots per seedling base were recorded. Regeneration mechanisms were determined by assessing basal and aerial sprouts and excavating the root systems below ground level. The results show that the total seedling density and the densities of single- and multi-stemmed individuals varied significantly (p < 0.05) among the four roadside environments. However, all seedlings were produced asexually; root suckers were predominant (98%) compared to water sprout (1%) and coppices (less than 1%). This study demonstrates that an intermediate level of soil disturbance from grading along paved and unpaved roads may stimulate P. suberosa regeneration by root suckering. Road type (paved and unpaved) did not affect seedling density, but was a highly significant variable in relation to the coppicing ability of P. suberosa populations in roadside sites. In conclusion, P. suberosa is a disturbance-tolerant species which can proliferate mainly by root suckering after roadwork disturbance.

A comparison of Guibourtia copallifera Benn. stands in South West Burkina Faso-community structure and regeneration

Shifting agriculture, fire, and over exploitation of wood and copal resin are the major causes of Guibourtia copallifera Benn. vulnerability in the south-west of Burkina Faso. Conservation of endangered species requires a thorough understanding of the dynamics of small populations. In the present study, we investigated the diversity and the dynamics of G. copallifera communities in two different types of land use history, a protected area (stated forest of Comoé-Leraba) and an unprotected area (the woodlands of Tourni and Timba). A total of 17 rectangular plots (50 m × 20 m) were sampled in both protected and unprotected areas. All woody species were systematically identified, measured and classified into diameter and height classes. In the two different types of land use, the dynamics of G. copallifera’s communities were good, and the diversities were similar and low with high β diversity.

Informants based ethnobotany and utility evaluation of five Combretaceae species: differentiation by ethnicity and geographical location.

ABSTRACT In Africa, local communities depend on forests and plants for their daily needs including goods and services. This paper describes ethnobotanical knowledge of five Combretaceae species in western Burkina Faso. Information was obtained from semi-structured interviews, direct observation and personal conversation with local experts and specialists in plant uses. Data were collected in four villages among four ethnic groups. A total of 150 specialist male and female respondents were involved and 400 users were interviewed. The data were analyzed with generalized linear models with binomial errors. The results show that there is a higher share of ethnobotanical knowledge within an ethnic/village group than between ethnic/village groups. The ethnobotanical information was classified in six main categories: food, fodder, construction materials, fuelwood, handicraft and pharmacopoeia, with the six categories except food representing important uses for all the study species. No significant difference was found for gender and age regarding the knowledge of plant species uses, which may be due to the daily life importance, and to the ecological abundance of the selected Combretaceae species.

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.

Erratum to: DOI duplications

Eight articles in Journal of Forestry Research were published online but then became inaccessible when a technical error led to eight other articles being published with the same DOIs. They were then republished under new DOIs, as listed below: Article: Anthropogenic disturbances and status of forest and wildlife in the dry deciduous forests of Chhattisgarh state in India Original Article: Characterization of 14 anonymous nuclear loci in Pinus thunbergii and their cross-species transferability Original The publisher sincerely apologizes to all concerned and regrets the inconvenience caused.